Robotron WRG3P Scanning Receiver User Manual

Robotron Pty Ltd Scanning Receiver Users Manual

Users Manual

iWiNRADiOG3 Series Radio ReceiverUser’s Guide
- ii -Published byWiNRADiO CommunicationsPO Box 6118, St Kilda Road, Melbourne 3004, Australia© 2002 WiNRADiO Communications, MelbourneAll rights reserved. No part of this book may be reproduced or transmitted in any form or byany means without the written permission of the publisher.TrademarksWiNRADiO, G3 and G303 are trademarks or registered trademarks of Rosetta LaboratoriesPty. Ltd.All other brand and product names are trademarks or registered trademarks of their respectiveowners.PatentsWiNRADiO technology is protected by US Pat. No. 6,289,207 and other pending US andinternational patent applications.Printed in Australia
- ii -FCC NoticeThe WiNRADiO G3 SERIES receiver has been tested and found to comply with the limits for aClass B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed toprovide reasonable protection against harmful interference in a residential installation. Thisequipment generates, uses and can radiate radio frequency energy and, if not installed andused in accordance with the instructions, may cause harmful interference to radiocommunications. However, there is no guarantee that interference will not occur in a particularinstallation. If this equipment does cause harmful interference to radio or television reception,which can be determined by turning the equipment off and on, the user is encouraged to try tocorrect the interference by one or more of the following measures:• Reorient or relocate the receiving antenna• Increase the separation between the equipment and the receiver• Connect the computer into a different outlet so that the two devices are on differentbranch circuits• Consult an authorised dealer or an experienced radio/TV technician for helpCautionTo comply with the limits for the Class B digital device, pursuant to Part 15 of of the FCC rules,the WiNRADiO card must be installed in computer equipment certified to comply with the ClassB limits. Only peripherals certified to comply with the Class B limits may be attached to thecomputer containing the WiNRADiO receiver. All cables used to connect the computer andperipherals must be shielded and grounded. Operation with non-certified peripherals mayresult in interference to radio and TV reception.ModificationsAny changes or modifications to the WiNRADiO receiver not expressly approved in this bookcould void the user's authority to operate this equipment.Limitation of Liability and RemediesThe information published in this book has been compiled from several sources. While everyeffort has been made to ensure its accuracy, neither the authors nor the publisher canguarantee that all information is entirely correct or up-to-date. Furthermore, neither the authorsnor the publisher can take any responsibility for the use of this information or anyconsequences arising therefrom.WiNRADiO Communications shall have no liability for any damages due to lost profits, loss ofuse or anticipated benefits, or other incidental, special or punitive damages arising from the useof, or the inability to use, the WiNRADiO receiver, whether arising out of contract, negligence,tort or under any warranty, even if WiNRADiO Communications has been advised of thepossibility of such damages. In no event shall WiNRADiO Communications ' liability fordamages exceed the amount paid for this product. WiNRADiO Communications neitherassumes nor authorises anyone to assume for it any other liabilities.WarningIn certain countries or states it may be illegal to monitor certain frequencies. We cannot acceptany responsibility for the consequences of your non-compliance with government regulations.If you are in doubt about the regulations in your country or state, please contact your nearestradio communications regulatory authority.
Introduction3IntroductionOne could easily conclude that, in the era of the Internet and communicationsatellites, short waves are destined for obsolescence. But the reality is quitedifferent. On the contrary, shortwave communications seem to beexperiencing a new period of revival and vigorous growth.This revival is partially caused by the fact that shortwave is still the onlytechnology able to send signals around the globe with minimum power andwithout the need for expensive, and potentially failure-prone or sabotage-prone infrastructure. In the era of increased security concerns, this is animportant reason for the continuing interest in shortwave.The other reasons include newly found applications, for example HF email,and emerging new types of digital modulations (such as DRM broadcasting),offering more reliable and higher quality communications than before.All this will ensure that shortwave will remain what it always has been; anamazing place of action, a cacophony of sounds; a babel tower of exoticlanguages and music, alive with broadcasters both official and clandestine;a haven of spies; a playground of pirates, terrorists and freedom fightersalike; an exciting mix of the respectable, the serious, the crazy and thedangerous. Long before the Internet, the shortwave world was alwaysborderless. And quite like the Internet, impossible to tame and control.Welcome to shortwave. And welcome to the WiNRADiO G3 SERIESreceiver. Your new receiver is a world-first in more than one respect. Mostimportantly, it is the first commercially available Software Defined Receiver(SDR), where the entire demodulator and the last intermediate frequencystage are performed by software running on a personal computer ratherthan using conventional hardware circuits, or a dedicated Digital SignalProcessor. Your PC probably has more power than even the fastest DSPhad only a few years ago. Your new WiNRADiO G3 SERIES receiver is nowready to take advantage of that power. Enjoy!WiNRADiO provides regular upgrades to our application software. Don’tforget to register as a WiNRADiO user to receive news about new products,accessories and software upgrades for your WiNRADiO G3 SERIESreceiver. Use our on-line registration form on www.winradio.com/registerto take advantage of this free service.
Installation4InstallationThe WiNRADiO package contains the following items:• WiNRADiO G3 SERIES receiver card• WiNRADiO software on a CD ROM• Start-up indoor antenna• Audio cable• This User’s Guide• Warranty informationIn order for the WiNRADiO receiver to function, your IBM PC compatiblecomputer must meet the minimum system requirements specified below.System RequirementsMinimum RecommendedCPU 500 MHz,Pentium III 1GHz or higher,Pentium IV or AthlonRAM 64 MB 256 MB or moreDisplay SVGA SVGA (16 mil. colors)HD free space 20 MB 40 MBSound card SoundBlastercompatible, 16 bit,full duplexCreative Sound Blaster,16 or 32 bitOS Windows98/ME/NT/2000/XP Windows98/ME/NT/2000/XPHardware Installation1. Turn the off computer and disconnect the power cord.2. Remove the computer case. Choose an empty PCI slot, as far aspossible from the power supply and from other cards.
- 5 -3. First touch the computer metalwork with your hand to drain any staticcharge, then carefully insert the card into the vacant slot and push downuntil it is firmly seated. Screw the metal bracket at the end of the card tothe computer case. (This must be done to provide proper grounding forthe card).4. Replace the computer case and reconnect the power cord.5. Connect the supplied audio lead between the receiver output (astandard audio jack) and the sound card Line Input. (If there is no Lineinput on your PC, as is the case with some laptops, you may usealternative inputs, such as the Microphone input.)6. Connect the supplied start-up antenna to the SMA connector at the rearof the card.7. Extend the antenna so that it is as far away from the computer aspossible.Please use only the WiNRADiO-supplied audio lead cable to connect thereceiver to the sound card. This is a stereo cable (as is the case with allstandard PC multimedia cables). Mono jacks are not compatible with stereoones because they short the right channel to ground. A mono cable shouldnot be used under any circumstances and will not work with the G3 SERIESreceiver.Software Installation1. After installing the card, turn the PC on. Windows will find the card andautomatically start the usual New hardware found driver installationroutine. Insert the installation CD ROM into the drive, and follow on-screen instructions. (Note: Windows NT will not automatically detect thecard, as it does not support Plug and Play.)2. After installing the drivers, choose the Run command from the Startmenu in Windows and type D:INSTALL (if the CD ROM is the D: driveon your PC).3. This will run the application installer, which will guide you in theinstallation process.4. After all the files have been installed to your hard disk, run theWiNRADiO G3 SERIES application.
- 6 -Note: If the card is not detected by Windows, you can simply skip the driverinstallation procedure, insert the CD ROM, and run the installation program,which will also install the drivers.After installing the hardware and software, you will now need to set-up thesound card parameters. This is done both in the WiNRADiO application andin the Windows sound card control panel – this provides the actualconnection between the receiver front-end and the PC back-end of yourradio system.Setting up the Sound CardIn computer terminology a sound card is a wave device. A computer mayhave several such wave devices installed (for example a modem with voicecapabilities). That’s why you need to select the sound card as the desiredwave device first. Start the WiNRADiO G3 SERIES application and click onthe Setup button (located below the USB button) in the Demodulator panel:The Demodulator set-up window opens, as shown:
- 7 -The Wave device drop-down list shows all the installed wave devices:Windows default is the Control Panel setting specified under Start | Settings| Control Panel | Multimedia Properties | Audio. If a sound card is specifiedin this Control Panel setting for both playback and recording (this is verylikely, but not always necessarily so), then you can simply select WindowsDefault as the wave device for the demodulator. Otherwise, the specificname of the sound card should be selected. The selected sound card mustsupport duplex operation and the standard 44100 or 48000samples/second sampling rates, 16 bits per sample, stereo. Most modernsound cards do satisfy all these conditions, but some cards may have a highlevel of distortion at 48000 samples per second; for such cases, the 44100samples/second sampling rate is provided.The next parameter to select is the mixer device associated with the alreadyselected sound card, using the Mixer device drop-down list, and the Mixerline (the sound card input line). If the signal is arriving at the sound card viaan external cable, the cable should be physically connected to the LineInput of the sound card. If the receiver is connected internally, mostprobably the input would be called Aux or CD Line.With some laptops, only the Microphone input may be available; in suchcase you will need to connect the receiver to this input, and also select thisinput in the software.In the drop-down list of sound card inputs, each line is available either asnormal, or Reversed. If the reversed line is selected, this means that theRight and Left channels (of the sound card stereo input) are to be reversed.Normally, you should not need to select any of these reverse inputs.However, there is a very small number of sound cards where the Left andRight inputs are swapped. Normally, the G3 SERIES Demodulator expectsthe receiver output to be connected to the Right sound card input. If it is to
- 8 -be connected to the Left input instead, the reverse input line needs to beselected from the drop-down list.These are all the settings required on the WiNRADiO G3 SERIESapplication side. Now you need to set up your Windows sound card controlpanel, and the marriage between the radio and the PC will be complete.Click on the speaker icon in the task bar in the bottom, to bring up the soundcard Volume Control panel (consult Appendix B – Sound Card Controls ifyou have difficulties locating and the sound card settings).Sound Card Volume Control PanelMute the input line the receiver is actually connected to. (This is the sameline as selected in the WiNRADiO G3 SERIES Demodulator Setup. Usually,this will be the Line-In input.)Why are we muting the input line? This is because the signal coming fromthe receiver is not an audio signal, but rather the intermediate frequencysignal. It needs to be processed (demodulated) by the PC first, before it isoutput back to the sound card. (That’s why the sound card needs to be fullduplex, to allow for such simultaneous input/output processing.)Failure to mute this line will cause a high-pitched intermediate frequencysound to be combined with the demodulated signal.
- 9 -If you are using the Microphone input instead of Line input, please check ifthere is an Advanced button under the Microphone volume control in thesound card control panel. If so, then click on it and uncheck the +20dB gaincheck box if it exists. (The extra large gain would result in overloading thesound card and cause distortion.)The same line must be now selected in the Recording Control of the soundcard control panel. To get to the Recording Control, you need to selectOptions | Properties | Recording in the top bar menu of the Volume Controlpanel.Sound Card Recording ControlThe position of Volume control slider should be set to approximately half, toget started. The same control is duplicated in the Demodulator Setup panel(where it is labeled Input level). You can adjust this level either in the sound card recording window, or,preferably, return to the Demodulator Setup panel to take advantage of theClipping indicator. The input level must be adjusted below the point of theinput signal clipping, i.e. just before the Clipping indicator turns red.While adjusting the input level, you will also see the floor of the signalspectrum shown in the main demodulator window rising proportionally.Please pay attention to the sound card set-up, as most initial problemsassociated with using this type of receiver can be attributed to an incorrectsound card setting. Typical problems include:
- 10 -• Not selecting the Recording input line correctly (which will manifest itselfby the absence of any signal appearing in the spectrum scope);• Failing to mute the Volume control line (which will result in listening tothe high-pitched 12 kHz intermediate frequency sound superimposed onthe demodulated signal);• Failing to adjust the signal input level properly, which may result either inlow (or no) audio output, or, on the other hand, distortion if the signallevel is too high.Getting StartedThere is often a degree of understandable impatience when exciting newequipment such as a new WiNRADiO receiver is acquired. The followingfast-forward introduction makes it possible for you to start using your newacquisition as quickly as possible. Detailed operation is described in thesubsequent chapter Using WiNRADiO G3 SERIES Receiver. We hope youwill return to that chapter, as the WiNRADiO G3 SERIES receiver has manyfine features which it would be a shame to miss.Start the WiNRADiO G3 SERIES receiver application (double clicking on theWiNRADiO icon). The WiNRADiO G3 SERIES receiver control panel willappear as shown in the next page.Did you know?The first shortwave transmission across the Atlantic was accomplished bysix US radio-amateurs on December 11, 1921. The message was picked upby a Scottish radio-amateur. This achievement sparked a period of intensiveresearch and development which led to wide-spread use of short waves.(Before then, it was believed that frequencies over 1.5 MHz were useless.)
- 11 -WiNRADiO G3 SERIES Receiver Control PanelThe WiNRADiO G3 SERIES receiver control panel has some elementssimilar to from conventional shortwave receivers, and many additionalfeatures as well.The quickest way to get started with this receiver is to check its operation onlocal AM stations.Using the keyboard, type in the frequency of one your local AM stations:For example, for 774 kHz, type in 7 7 4 , then k for kHz, then press Enter.The typed-in frequency will appear on the digital frequency display. Thenselect the AM mode by clicking on the AM button. At this point, you shouldhear the station. You can adjust the volume using the two buttons next tothe small Volume display. (Note also the little slider between these twobuttons: you can drag it up and down to change the volume faster.)Manual tuning can be done in several ways. Let’s start with the tuning knob:Place the mouse cursor to the upper half of the tuning knob, at which pointyou will see the cursor change to a curved double ended arrow. Hold downthe right or left mouse buttons to increase or decrease the frequency, andthe knob will rotate clockwise or anti-clockwise, respectively. If you placeyour cursor in the bottom half of the tuning knob, the direction of the rotationwill reverse.
- 12 -The rotation increment of the tuning knob is 0.5 kHz. This can be changedeasily using the Shift, Ctrl or Alt keys: If you press the Shift key while tuning,the increment will increase ten times (to 5 kHz). Pressing Ctrl will increasethe increment a hundred times (50 kHz). On the other hand, if you use theAlt key, the increment becomes ten times finer: 50 Hz.If you are still unable to tune to any stations at this point, please refer toAppendix A - Troubleshooting.There are also several other ways to tune the WiNRADiO receiver otherthan typing the frequency or using the tuning knob. These will be explainedin detail in the Using WiNRADiO G3 SERIES Receiver chapter.Connecting the AntennaYour WiNRADiO G3 SERIES receiver comes with a start-up antennaconsisting of a 3-meter length of coaxial lead-in cable, with an additional 3meters of insulated wire. The thinner, insulated wire at the end is the actualantenna. The lead-in cable is necessary for the antenna to be as far awayfrom the PC as possible, to reduce interference from the PC.Please note that this start-up antenna is supplied for immediate gratificationonly and is not intended to replace a good shortwave antenna.The best placement of the start-up antenna depends on your actualsituation, and will often involve some experimentation. However, the basicrule is simple: Place the antenna as close to the window as you can, andkeep the active part of the antenna as far away from the PC, and otherelectronic and electrical devices, and metal objects, as possible.Did you know?The first commercial shortwave station was Radio Luxembourg. It was thefirst station to target areas outside of its own country with programs in otherlanguages. For most of the 20th century, this was the most powerfulshortwave station in Europe.
- 13 -An example of WiNRADiO start-up antenna placementNo matter how good a radio receiver is, the performance of the entirereceiving system will depend on the quality of the antenna. The sameapplies to a WiNRADiO receiver. To make most of your WiNRADiO receiver,you should install a proper shortwave antenna. There are many vendorsoffering shortwave antennas. WiNRADiO may also be able to assist – checkour Web page www.winradio.com.Did you know?During the cold war, the Soviet Union and other Communist countries usedto jam shortwave transmissions such as the BBC, Voice of America, RadioFree Europe and Deutsche Welle to their own citizens. The Soviet Unionalone was spending about $1 billion per year on jamming, and had 200jamming stations that were continuously pumping out 600 Megawatts ofpower.
- 14 -Using WiNRADiO G3 SERIESTuning to a FrequencyTo change frequency, simply type the new frequency into the keyboard. Assoon as you press a number or decimal point, the frequency display willactivate, waiting for a frequency to be typed. You can also click on thedisplay to type in a new frequency. After typing the new frequency, pressEnter and the receiver will instantly retune. To abort, press Escape.To enter units, such as kHz or MHz, simply press K for kHz or M for MHzafter entering the digits. Any invalid keystrokes are ignored. Frequenciesoutside the receiver limit (9 kHz to 30 MHz) will not be accepted and thedisplay will revert to the previous frequency.WiNRADiO G3 SERIES Receiver Frequency DisplayThe up/down buttons under the individual digits make it possible to quicklystep up or down the frequency in the corresponding positions. (The littleslider buttons between the up/down buttons can be used for fasteradjustment.)Under these buttons there is a band description window. This shows theband allocation of the currently tuned frequency. These band descriptionsare based on those applicable to North America. However, theseallocations are based on international treaties and therefore are generallyapplicable worldwide.Note that the default band allocation can be overridden with a call sign or auser-defined description of a frequency stored in memory. The default banddescription is also user modifiable: it resides in the file bands.csv in theWiNRADiO installation folder. This file can be edited using a spreadsheetapplication, such as Microsoft Excel.
- 15 -Fine TuningThe Fine Tune knob makes it possible to finely adjust the frequency in0.5 kHz steps.WiNRADiO G3 SERIES Receiver Tuning KnobTo use the tuning knob, position the mouse cursor over the knob (the cursorwill turn into a curved double ended arrow) and click on either the left or rightmouse button. If the cursor is on the top half of the knob, the left button willdecrease the frequency, and the right button will increase the frequency. Ifthe cursor is in the lower half, the opposite will occur (and the cursor willinvert its shape).Using the keyboard only, the frequency can be similarly adjusted using theup/down cursor keys.To speed up tuning, the step size can be increased ten or one hundredtimes by holding the Shift or Ctrl keys respectively, while clicking the tuningknob with mouse button or using the up/down keyboard keys. This is avery convenient feature if you wish to tune quickly across a frequency range:hold the mouse button and accelerate the movement by pressing the Shiftor Ctrl keys. On the other hand, pressing the Alt key will reduce the tuningstep ten times (to 50 Hz).Did you know?Most Space Shuttle astronauts are radio amateurs and the first elements ofa permanent amateur radio station in space have already been despatchedto the International Space Station.
- 16 -Setting the Modulation ModeTo select the modulation mode, click on the appropriate Mode button in theDemodulator panel:WiNRADiO G3 SERIES Standard Demodulator PanelThe real-time spectrum display shows the output of the receiver (i.e. theintermediate frequency signal) as it is applied to the PC sound card. Whenyou press the mode buttons, you will note that the central highlighted regionof the spectrum changes its width. This corresponds to the IF (intermediatefrequency) filter bandwidth associated with the different modulation modes.For example, standard AM mode has 6 kHz bandwidth, while narrow AM(AMN) uses 4 kHz bandwidth. The CW mode uses a narrow bandwidth of500 Hz. You will see the trace color change from white to yellow where thespectrum falls within the filter bandwidth. This indicates that you are onlyreceiving the yellow part of the displayed spectrum and the surroundingfrequencies are rejected.If you mistune the receiver somewhat, you will see the spectrum shifting.This assists you to tune the receiver right to the center of the transmitterfrequency, and to select the correct AM mode to avoid interference fromadjacent signals.
- 17 -If you also purchased the optional Professional Demodulator, you can selectthis demodulator from the Demodulators top bar menu. The basic functionssuch as volume control, audio muting and mode selection are identical tothe Standard Demodulator.WiNRADiO G3 SERIES Professional DemodulatorFor details of the additional functions such as continuous IF bandwidthadjustment and other special features of the Professional Demodulator referto Appendix E - Professional Demodulator.Volume ControlThe Volume control is also located in the Demodulator panel. The volumecan range from 0 (no sound) to 31 (full volume). To enter a value directly,click on the display and type in the new volume level. The volume can bealso increased or decreased by clicking on the up/down buttons next to thevolume display.Another convenient way of changing the volume is by using the small sliderbutton between the up/down buttons. Place the mouse cursor on it and seethe cursor shape change, to indicate a ‘slider’ type of control. Hold down theleft mouse button to drag the slider up or down and the volume will changeaccordingly.
- 18 -Finally, another convenient way of changing the volume is using the left andright cursor keys on the keyboard.Mute ControlNext to the Volume control is the Mute button, which allows you to switch offaudio output quickly. It is faster to use than setting the volume to zero, withthe added benefit of not changing the set volume level. To use the mutecontrol, simply click on this button. Click again to release.AGCThe AGC (Automatic Gain Control) has four settings: Off, Slow, Medium andFast. These make it possible to disable the AGC, or to select the speed withwhich the AGC reacts. Typically, the AGC would be in the Medium position.AGC ControlThe receiver must process a considerable variation of signals, ranging fromvery weak to very strong. This requires the sensitivity of the receiver to varyaccording to the incoming signal strength.The incoming signal can vary in intensity, with changing propagationconditions, and also depending on the modulation type and content. Forexample, with CW signals (where information is transmitted by keying thetransmitter on and off), the signal strength will vary substantially during thetransmission. The demodulated signal will then sound better with a slowAGC (so that the receiver will not have time to increase the gain during the“off” intervals, and so increase the background noise and causing a raspysound).On the other hand, use fast AGC when listening to especially weak signalsburied in static and noise. Otherwise, each new burst of noise woulddesensitize the receiver for a long time and you could miss long periods ofuseful transmissions.If unsure, use the medium speed AGC setting.
- 19 -IF GainThe AGC can be turned off entirely, using the AGC Off button. The receivergain must then be adjusted manually. This is done using the IF Gain setting.Note that by setting an excessive gain, the receiver will overload and thedemodulated signal will be distorted. On the other hand, if the gain is toolow, it will make the receiver appear “deaf”.Manual IF Gain setting is useful for hunting for very weak signals buried innoise.Manual IF Gain ControlThe IF Gain control is only enabled when the AGC is switched off. The gain“value” ranges from 0 to 100, where 100 corresponds to maximum gain.Audio AGCThe Audio AGC facility is available in the Demodulator panel, and provides asupplementary function to the main AGC. (The main AGC employs ahardware circuit, while the Audio AGC works in software.)Audio AGCAudio AGC is useful to compensate for audio volume changes when theantenna signals are so weak that the main AGC is not yet activated, or whenthe main AGC is disabled and the manual IF gain is used.
- 20 -AttenuatorThe Attenuator makes it possible to reduce the receiver sensitivity by 18 dB(i.e. 6 times).AttenuatorWhy would you ever need to reduce the sensitivity? This is becauseunusually strong signals from local stations may occasionally causeoverloading. This overloading can make the reception worse, and evencause stations to appear on frequencies, where none exist (ghost stations).See Appendix C - Dealing with Interference for more information on thisphenomenon.If a received signal is too strong, causing overloading, distortion or theappearance of ghost stations, you should reduce its level by pressing theAttenuator button.Squelch ControlThe Squelch control can be used to mute the receiver when no signal isbeing received. Without a signal, all you will usually hear is noise. Squelchis provided to cut out the noise until a station is found, making the receivermore comfortable to use.Squelch Control and Squelch Defeat ButtonThe squelch setting controls the signal level at which muting occurs. Mutingwill occur when the signal level drops below the squelch level. When asignal of a higher level returns, the sound will be restored immediately.
- 21 -The squelch is always shown in dBm units. To adjust the squelch control,first tune to an unoccupied frequency that produces only noise. Increase thesquelch until the receiver is muted. You will see the red-colored segment ofthe S-meter growing until it gets higher than the current S-meter value. Atthat moment the receiver will be muted. Add a few dB extra (to allow amargin for background noise fluctuation on the band). Now when you tune toan occupied frequency, if its signal strength is higher than the squelch level,the receiver will be unmuted.Next to the squelch setting is the Squelch Defeat (Def) button. Whenactivated, the squelch action will be turned off (it is the same as if thesquelch was set to its lowest level, but more convenient). The red segmentin the S-meter will turn blue to indicate this condition.It is easy to forget that squelch is active. If the receiver doesn’t seem to beoperational (no sound from the speaker), check the squelch and mutesettings first.Frequency SteppingThe Frequency Stepping facility makes it possible to specify an arbitraryfrequency step size. To change the step size, click on the associated displayand enter the required value (from 1 Hz to 1 MHz). You can also use theup/down buttons on the right of the display, to select from commonly usedstep sizes. For convenience, you can also use the small slider between thetwo buttons.Frequency Stepping PanelWhen the step size is selected, you can step up/down from the currentlydisplayed frequency using the left/right arrow buttons under the Step sizedisplay. The double-arrow buttons further down will cause stepping by astep size ten times larger. Stepping can also be done using the keyboard PgUp/Down keys.
- 22 -For example, if you wish to browse the AM broadcast band (approx. 530 to1620 kHz), set the step size to 10 kHz (for North and South America) or9 kHz (for the rest of the world), which is the channel separation for AMbroadcast stations. Tune manually to any station first, then step up or downto browse the band. To browse the shortwave broadcast stations (2.3 to30 MHz), 5 kHz works well.This type of fixed-size stepping is convenient if you wish to explore afrequency band where the channels are equally separated. However, youshould ensure that the stepping frequencies fall on the actual channelfrequencies in the band. If you know the channel separation but are unsureabout the exact frequency of the first channel, tune to an active channelusing manual tuning first, and only then step up or down in fixed steps.The Auto button engages Auto-stepping, which provides a significantenhancement over fixed stepping. When properly configured, auto-steppingwill automatically set the step size according to the frequency you are tunedto. Auto-stepping can be also used to associate particular mode and squelchsettings with specified frequency ranges.To configure the auto-stepping ranges, go to Options | Autostepping in thetop bar menu. The following window opens:You can use the New button to add a new range. For each range, you needto specify the start and end of the range, step size, and optionally mode,squelch and description. You can specify as many such bands as you like.When done, close the window.Next time when you tune to a frequency, and the Auto button is pressed,the step size (and optionally mode and squelch) will be set to the predefinedvalue if the new frequency falls within a specified auto-step range.
- 23 -Frequency MemoryThe WiNRADiO G3 SERIES receiver has the ability to store up to onethousand frequencies in one memory file. It also allows you to load and savedifferent memory files for a huge amount of total storage, limited only by thesize of your hard disk.Memory Control PanelStoring a Frequency into MemoryWith each frequency, you can store several attributes: mode, callsign, usercomment, group assignment, squelch and a hotkey.To store a frequency into memory, the receiver must first be tuned to thatfrequency (and the appropriate mode must be selected if you also wish tostore the mode). Next click on the S button in the Memory Control Panel asshown above.A Store frequency dialog box will pop up, allowing you to assign a memorynumber to the current frequency.Did you know?The first shortwave message from the UK to Australia was received onMarch 6, 1924. On April 8, 1927, the regular Australia-Britain wirelessservice started operating, and the AWA company (Amalgamated WirelessAustralasia Ltd.) built a shortwave receiving station at La Perouse, a suburbof Sydney (named after the French explorer La Perouse, who in 1788 wasthe first Frenchman to arrive in Australia).
- 24 -Storing Frequency to MemoryAt the top of the dialog box is the frequency you are storing. The next lineshows the next available memory number. You can change this to anothermemory number if you wish (including one which is already allocated).The third item contains the group assignment buttons. You can assign thefrequency to one or more of 16 different groups (whose meaning you defineyourself). When you are searching or scanning for a particular type offrequencies (for example “Airforce”), the group assignment will allow you toconfine the searching and scanning to that particular type.Note that a frequency may be associated with more than one group at thesame time.There are also several additional items that can be optionally stored witheach frequency:
- 25 -• Most stations have a name or callsign. You can store up to 11characters in the Callsign field.• For quick tuning to your favorite stations, you can assignHotkeys (function keys F2 to F12) to up to eleven differentfrequencies. If you then press a hotkey, the associatedfrequency will be instantly recalled. Hotkeys which are alreadyassigned will be shown in this dialog box as ‘used’, howeveryou can overwrite the previous assignment with a new one ifyou wish.• User Comments can also be stored with a frequency. The sizeof the comments is limited to 31 characters.• The Mode and the Squelch values can also be stored, whichwill be then set automatically when the frequency is recalled.• Finally, a Memory Scan Lock-out can be set for eachmemory, which means that the memory will not be included in amemory scan. In the memory Recall window, such memorieswill be shown with a small ‘x’ preceding the memory number.Finally, when everything has been set, click on OK or press Enter, to savethe new frequency.Recalling a Frequency from MemoryThere are several ways to recall a frequency from memory:• Using Memory Recall• Typing a number into the memory number display• Using a hotkey• Memory steppingTo recall a frequency, click on the R button. A dialog box will pop upshowing a list of all memory frequencies.To select a frequency, click on an item in the list, and the frequency will betuned. Then close the window. Alternatively, use the up/down cursor keysto choose the frequency and press Enter.
- 26 -Recall Frequency from MemoryThe assigned memory groups are shown as color bars for a quick visualoverview of which frequencies are associated with which groups (see thecorresponding colors in the Store frequency window). When you position themouse cursor over a highlighted memory, the actual group numbers will bedisplayed in a floating ‘hint’ box.Editing MemoryTo change the settings for a particular frequency, open the Recall frequencydialog box as described in the previous section. Select the item you want toedit and click on Edit (alternatively, double-click on the item). A dialog boxwill pop up showing the current settings. All the settings (except thememory number) can be edited. After the entry has been edited, click onOK.Deleting a FrequencyTo remove a frequency, open the Recall frequency dialog box. Select thefrequency you wish to delete, and click on Delete. You will be asked toconfirm that you want to delete this frequency from memory.To delete all frequencies, select Clear from the Memory file sub-menu inthe File menu. You will be asked to confirm that you want to clear all thefrequencies in the memory.
- 27 -Saving a Memory FileEach memory file, containing up to one thousand frequencies, is storedseparately, allowing different memory files to be loaded and saved. To savethe current memory file, simply select Save from the Memory file sub-menuin the File menu. If you wish to save it with a different name, select Save asinstead, and a dialog box will pop up allowing you to specify the file name.When you exit the WiNRADiO G3 SERIES application, all memory changesareautomatically saved; there is no need to use the Save command before exit.Opening a Memory FileWhen WiNRADiO starts up, the most recently used memory file will beopened automatically.To open a different memory file, select Open from the Memory file sub-menu in the File menu. A dialog box will pop up allowing you to choose amemory file to load.Memory SteppingMemory stepping makes it possible to step through frequencies stored in thecurrent memory file.To step through memory frequencies use the left/right arrow buttons locatedunder the memory S and R buttons. The double-arrow buttons locatedfurther down make it possible to advance ten frequencies up or down (or tothe start/end of the memory list if it is less than ten frequencies away).Memory stepping will only work if there are frequencies stored in memory. Ifno frequencies have been stored, nothing will happen if you try to stepthrough the memory.ScanningThe WiNRADiO G3 SERIES application contains a comprehensive set ofscan functions to enable the user to search for stations which are currentlyon the air. There are three basic types of scanning: Immediate Scanning(Searching), Range Scanning and Memory Scanning. The scanning methodis selected using the appropriate button in the Scanning Control Panel:
- 28 -Scanning Control PanelImmediate Scanning (Searching)This is the simplest scanning method. Click on the Search button to selectthis scanning mode, then use the [>>] or [<<] buttons to scan either forwardor backward from the currently tuned frequency. To stop scanning, press theStop button (marked with a green square). To pause, press the Pausebutton (marked with two vertical bars).A signal is considered ‘found’ when the signal level is higher than squelch.Correct setting of the squelch value is therefore essential for scanning.If you set the squelch level too low, then scanning will stop even if there isno signal (the background noise will be higher than the squelch level). Onthe other hand, if the squelch level is set too high, then a useful signal maybe missed because it will fall short of the squelch level. With a bit of trial anderror, you will need to adjust the optimum setting for the squelch level(usually a few dB above the background noise floor).Scanner ConfigurationWhen a signal strength level is higher than the squelch level, this indicatesthat a signal has been found. You can configure the software to specify whataction you want to be taken at this point. To access this configuration facility,go to Options | Scanning in the top bar menu.Did you know?The survivors of the Titanic disaster owed their lives to shortwave. The SOSsignals transmitted by the sinking ship’s spark-gap transmitter were pickedup by the Carpathia 58 miles away, proving that radio saves lives.
- 29 -Scan SettingsThere are two basic actions the software can do when a signal is found:Pause scanning or Stop scanning. If Pause is selected, then you need tofurther specify the conditions under which the scanning will Resume. Theconditions to resume can be one of the following:1. When the signal disappears (i.e. the scanning resumes immediatelywhen the signal disappears);2. After a certain user-defined Delay time (i.e. no matter if the signaldisappears during this Delay Time or not, the software will always waitfor the Delay Time interval, then resume);3. When the signal disappears during Delay time (i.e. the scanning will notresume if the signal returns within an interval shorter than, or equal to,Delay Time);4. When there is no signal during the Delay time (i.e. the scanning willresume if there is a no-signal gap equal to, or longer than, Delay time).The Delay time interval can be set from 1 to 100 seconds.The Scan rate controls the speed at which scanning occurs, and specifiesthe maximum number of scanning steps per second.
- 30 -Note that the upper scanning speed limit may be restricted by the actuallyavailable CPU resources of your computer.When signal is found and scanning pauses, waiting for the pre-set Delaytime to expire, the countdown timer will appear inside the [<<] or [>>]buttons. If no Delay time was set and scanning is pausing until the signaldisappears, then the [<<] or [>>] button will flash.GroupsThe Groups setting is useful for Memory Scanning, which will be describedlater: it serves to restrict Memory Scanning to particular memory groupsonly.ExclusionsSometimes it is desirable to exclude certain frequencies from scanning. Thismeans that such specified frequencies should be ignored even if the signallevel on these frequencies is higher than the squelch.The WiNRADiO G3 SERIES receiver application makes it possible formultiple frequency ranges to be excluded. This is done using theExclusions button. When you press this button, you will open anExclusions editor window, allowing you to enter a range of frequencies tobe excluded.For these exclusions to become active, check the Enable excluding whilescanning checkbox in this window.Frequency Range ScanningTo be able to use Frequency Range Scanning, you need to set up thedesired scanning ranges first. This is done using the Ranges button in theOptions | Scanning top-bar menu.Did you know?Unlike medium wave or FM broadcast stations, shortwave stations changetheir frequencies and program schedules very often. One of the bestpublications providing regular frequency updates and transmitting schedulesis the Monitoring Times magazine (www.monitoringtimes.com).
- 31 -Setting up Scan RangesEnter a new range using the New button. This will open a dialog box, whereyou will be asked to specify lower and upper limit frequencies of the range,the modulation mode, squelch level, and, optionally, a description. You canenter as many such ranges as you like:Adding a New Range
- 32 -When the range definition is done, close this window, then close the scannersettings. Then activate the Range button in the Scanning control panel:Scanning Control PanelWhen you press the Scan Forward button [>>], the scanner will commencescanning from the start frequency of the first range. When the last frequencyof the first range is reached, it will then continue onto the next range, etc.When it reaches the end of the last range, it will go back to the start of thefirst range and continue looping infinitely until a signal is found, or untilmanually stopped or paused. If you use the Scan Backward [<<] button, theprocess will be exactly reversed (i.e. starting from the top frequency of thelast range and working its way downwards).You can stop or pause this activity using the Stop or Pause buttons. If youuse the Pause button, then restarting scanning using Scan Forward or ScanBackward buttons will resume the action from the paused frequency. If youstop scanning with the Stop button, then using the Scan Forward or ScanBackward buttons will recommence scanning from the initial (or the last)frequency again.If no ranges are specified in the Ranges list, then activating scanning in theRange mode will result in no action.An additional useful feature of frequency range scanning is that all foundfrequencies can be automatically stored in memory, even if the receiver isleft unattended. To do this, enable the Auto Store checkbox in the Scanranges set-up window, and specify the memory range to which thefrequencies should be written. You can also specify a special Group Numberto be assigned to such frequencies.When using the Auto Store option, you should also set the appropriateconditions for scanning when the signal is found (for example, Pause whensignal found, and Resume after the minimum delay time will provide thefastest scanning and writing into memory).
- 33 -Note that if more signals are found than there are allocated memories, theexcess frequencies will not be stored.Memory ScanningThe last scanning method is Memory Scanning. Here the receiver will stepthrough memory frequencies, starting from the first one to the last one, andrepeating the loop until a signal is found or until manually stopped.If a squelch value is stored with a memory this value will be used tocompare with the current signal level. If there is no value stored, the currentsquelch value will be assumed.It is possible to restrict scanned frequencies to particular memory groupsonly. These groups can be selected from the Options | Scanning | Groupswindow, accessible from the top bar menu. Groups can be enabled/disabledusing the check box Enable group restriction in the same window.S-meterThe WiNRADiO G3 SERIES receiver Signal Strength Meter (S-meter)makes it possible to measure signal strength in either S-units, dBm or µV(microvolts). The units are selected by correspondingly marked buttons onthe right side of the display. In the microvolt mode, the p-p button is alsoenabled, making it possible to select peak-to-peak values rather than thedefault RMS (Root Mean Square) values.S-meterThe S-meter also shows the currently selected value of the squelch (the redsection at the bottom side of the scale). When the signal strength falls under
- 34 -the squelch level (i.e. the needle falls in the red region and turns red also),the receiver audio will be muted.The squelch value is always indicated in dBm units (even if the signalstrength is displayed in S-units or microvolts).Note that when the AGC is off (and manual IF gain control is activated), theS-meter is disabled. This is because the S-meter relies on the AGC for itsproper function.Tuning PadA unique fast-tuning facility is located under the Attenuator, IF Gain andSquelch settings.Tuning PadIf you place the mouse cursor inside the long horizontal window of theTuning Pad, you will see a frequency increment displayed, which can varyfrom 1 Hz to 1 MHz in convenient steps. The value of this increment can bechanged quickly by moving the cursor mouse horizontally within the TuningPad. The current increment value is always shown under the pad. You canquickly change between incrementing and decrementing by alternating theleft and right mouse buttons. The sign of the displayed increment value willalso change accordingly.By combining horizontal movement of the mouse with alternating theleft/right mouse buttons, you can quickly tune to any frequency, and stepthrough the band with the appropriate step size.
- 35 -The row of yellow squares under the Tuning Pad serves a similar purpose,providing convenient increment sizes in a narrower band between 1 Hz and10 kHz. These increments are selected by placing the mouse cursor overthe yellow squares, and using the left or right mouse buttons forincrementing or decrementing.Power SwitchThe Power switch, located at the bottom-right corner of the applicationwindow, controls the receiver power. When it is off, the receiver circuitry willbe powered down and no sound will be heard in the speaker orheadphones.When you exit and restart WiNRADiO application, the power on/off status atexit will be remembered.Date and Time DisplaysThe clock displays, located under the Tuning Bar, indicate the current timeand date.The UTC clock shows Universal Coordinated Time, formerly called GMT(Greenwich Mean Time), which is the standard time used around the world.This is provided because most shortwave stations announce their broadcasttimes in UTC. Both displays derive their information from the PC clock. Thetime difference is determined by Windows Time Zone setting (Start |Settings | Control Panel | Date/Time Properties | Time Zone tab).Spectrum ScopeClick on the yellow triangle button on the left of the On/Off switch and theSpectrum Scope display will slide out at the bottom:
- 36 -Unlike the spectrum display window inside the Demodulator panel, which isreal-time and narrow band, the Spectrum Scope is wide-band and the graphis created by fast tuning the receiver across the specified frequency range.To set up spectrum sweeping, enter the Start and End frequencies, tospecify the start and end of the sweeping range, respectively. Next specifythe frequency step.Spectrum ScopeThe sweeping is controlled using a set of buttons similar to a tape recorder:The Start button (with a triangle) starts sweeping. The Stop button (with asquare), stops sweeping, while the Pause button pauses it. The button witha red round arrow selects continuous sweeping, which means that thesweep will continue from the start frequency when the end frequency isreached, and continue in this loop until manually stopped.The Min, Man and Diff buttons enable the display of minimum, maximumand differential values when continuous sweeping is selected. (A scale forthe differential trace will be displayed on the right-hand side whenever theDiff button is pressed.) The differential trace is very useful when examininglong-term activity on a given band. The receiver can be left unattended inthe continuous sweeping mode, and any activity on the band will be clearlyvisible on the differential trace.There are also two Zoom in/out buttons performing their self-explanatoryfunctions, and a Clear button, which clears the graph and the min/maxvalues.Clicking anywhere on the spectrum graph tunes the receiver to thecorresponding frequency. You can also drag the mouse horizontally acrossthe spectrum and continuously tune the receiver.To hide the Spectrum Scope, use the yellow triangle button next to thepower switch again.
- 37 -Appendix A - TroubleshootingProblem: The WiNRADiO application installed OK, but there is nosound coming from the speaker.Solution: Check if you see any noise appearing in the spectrumscope in the Demodulator panel (under the AM, AMS, etc., mode selectionbuttons). If there is a flat line or only very little noise visible, check thefollowing:• The receiver output is connected to the sound card Line input using thesupplied cable. (If your PC sound card does not have a Line input, youcan use alternative inputs such as Aux or Microphone, but the softwaresettings need to be changed accordingly.)• The sound card has been set up correctly. Especially make sure that theRecording Line input has been enabled (you will find this panel underOptions | Recording in your sound card volume control panel – click onthe speaker icon in the bottom bar to get to the volume control panelfirst):Note: If you have difficulties accessing the sound card control panels (forexample if there is no speaker icon), refer to Appendix B – Sound CardControls.
- 38 -• The receiver demodulator has not been set up properly. Make sure thatthe sound card type and the audio input are properly selected (this panelis accessible under the Setup button in the Demodulator panel):• The sound card has the Left and Right inputs reversed. Normally, theG3 SERIES Demodulator expects the receiver to be connected to theRight input. Using the reverse input makes the Demodulator use theLeft input instead. (This is a very rare problem, so use this only when allother possible remedies have been explored.)Problem: I can tune the receiver and see the signal peaks in thespectrum scope, but I can’t hear any sound at all.Solution: Check that your speaker or headphone is connected to thespeaker output of the sound card. Set the volume to medium (say 15), thesquelch to the lowest value (-130 dBm) or defeat the squelch by clicking onthe Def button. Make sure the Mute button in the Demodulator panel isreleased, too, and the speaker output of the sound card is unmuted in thesound card control panel.
- 39 -Problem: I can hear the audio, but it is not a pleasant sound. There isan interfering high pitch tone.Solution: You need to mute the Line input in the sound card controlpanel - see the panel on the next page. (What you are probably listening tois the intermediate frequency signal mixed with the demodulated audiosignal.)Sound Card Volume Control PanelProblem: I can hear the audio and tune the receiver, but the sound isdistorted.Solution: Check if the AGC is switched on (i.e. either the Slow, Medor Fast buttons are down – typically the Med setting is used). Check theInput gain in the Demodulator Setup panel: it should be set just below theclipping level. If both settings are correct, try to reduce the sampling ratefrom 48000 samples/second to 44100 (also in the Demodulator Setup).(Some sound cards do not provide good quality sampling at 48000 samplingrate.)
- 40 -Problem: I can hear the audio and tune the receiver, but the volume istoo low, even if I adjust the Volume control to maximum.Solution: Check the Input gain in the Demodulator Setup panel: itshould be set as high as possible, just below the clipping level. Also, engagethe Audio AGC in the Demodulator front panel.Problem: I can hear the audio and tune the receiver, but the audiodrops-out occasionally, and the display is very sluggish, sometimes it evenfreezes.Solution: Close all other simultaneously running programs to reducethe burden on the CPU. If the CPU usage shows consistently more than80%, this may indicate insufficient CPU resources for the G3 SERIESapplication. (Check the CPU usage under the Settings button in theDemodulator window. The CPU resource meter is at bottom left.)Problem: I can hear the audio and tune the receiver, but the audio isvery noisy. The background noise level displayed on the spectrum scopeappears very high.Solution: Make sure the Attenuator is switched off. Check that yourantenna is properly connected, the connector is not loose and that theantenna cable is not damaged. Does the noise floor drop significantly if youdisconnect the antenna? If so, then the antenna is picking up too muchambient noise. Try to improve the antenna, or move it further away from thePC. (Additional noise-defeating measures may be in order; see alsoAppendix C – Dealing With Interference.)
- 41 -Problem: Reception is obscured with a buzzing interference.Solution: Check for the sources of interference in your surroundings:it could be fluorescent lights, a lamp dimmer, or some other householdappliance. Your PC (especially the monitor) could be also the culprit.Unless you can suppress the interference at the source (which is not alwayspossible), the only solution is to install a better antenna, preferably anoutdoor one. Computer networks are especially noisy and if your PC isconnected to one, you will almost certainly need an outdoor antenna. If theinterference level varies periodically with peaks about 40-50 kHz, apart, themost likely culprit is the monitor or the video card. Switch the monitor off - ifthe interference disappears then the cause is the monitor. Modern LCDmonitors generate much lower levels of interference than CRT ones. (Seealso Appendix C – Dealing With Interference.)Did you know?The WiNRADiO G3 SERIES software is XRS (Extensible RadioSpecification) compatible, making it possible to add additional softwarefunctions to your receiver. There are many XRS Plug-ins to choose from.You can download them from http://xrs.winradio.com.
- 42 -Appendix B – Sound Card ControlsSound card control panels and their settings can be somewhat confusing.They are also rather inconsistent from one version of Windows to another.WiNRADiO G3 SERIES receivers require a full duplex sound card, meaningthat the card must be able to simultaneously process signals in twodirections (i.e. record and playback) at the same time. The majority ofmodern Sound Blaster compatible cards are indeed like that. However,some older cards may not be full duplex.The Recording section of a sound card is used to input and digitize the IF(Intermediate Frequency) signal arriving from the receiver (only the Rightchannel is used, of the Left and Right stereo channels). The Playbacksection is then used to output the demodulated audio signal to thespeaker(s).For the WiNRADiO G3 SERIES application, there is a need to independentlycontrol both sound card sections: The Recording section volume needs tobe adjusted to provide the correct IF signal level for the demodulationprocess; the Playback section control is needed to be able to control thespeaker volume.Typically, you would access the Playback volume control panel by clicking aspeaker icon in the Windows task bar. From this panel, you can get to theRecording control panel by selecting Options | Properties | Recording in thetop bar menu.However, the speaker icon may be missing. An alternative way of accessingthe Recording/Playback controls is via the Windows Control Panel. Here youcan also enable/disable the speaker icon.The table on the following page shows how to enable/disable the speakericon, and how to get to the recording/playback controls from within theWindows control panel. The methods vary depending on the version ofWindows you are using.
- 43 -Windows Enable “speaker” icon Recording/playback volume controlsNT Control Panel |MultimediaAudio-tabCheckbox: “Showvolume control on thetaskbar”Make sure speaker icon is displayed, then double-click on speaker icon in task bar to display theVolume Control dialog.Sound Playback: Select Options | Properties |PlaybackSound Recording: Select Options | Properties |Recording98 Control Panel |MultimediaAudio-tabCheckbox: “Showvolume control on thetaskbar”Control Panel | MultimediaAudio-tabSound Playback: Click on buttonSound Recording: Click on buttonME Control Panel |Sounds and MultimediaSounds-tabCheckbox: “Showvolume control on thetaskbar”Control Panel | Sounds and Multimedia Audio-tabSound Playback ! Volume buttonSound Recording ! Volume button2000 Control Panel |Sounds and MultimediaSounds-tabCheckbox: “Showvolume control on thetaskbar”Control Panel | Sounds and MultimediaAudio-tabSound Playback ! Volume buttonSound Recording ! Volume buttonXP Control Panel |Sounds and Multimedia |Sounds-tabCheckbox: “Placevolume icon in thetaskbar”Control Panel | Sounds and MultimediaAudio-tabSound Playback ! Volume buttonSound Recording ! Volume button
- 44 -Appendix C - Dealing with InterferenceElectromagnetic Interference (EMI) is what prevents us from receiving aclear signal, even when the receiver should be sensitive enough to receiveit. There are many types of interference you can experience with radioreceivers, emanating from both natural and man-made sources.Natural interference is produced by atmospheric phenomena such as stormsand sun activity.Not so surprisingly, man-made interference is often worse. Sources includeelectric motors, power lines, passing cars, welders, fluorescent lights, faxmachines, computer networks, etc. Receiving antennas should always be asfar away from sources of electromagnetic interference as possible.One significant source of man-made electromagnetic interference is thepersonal computer, and the video monitor in particular. Since theWiNRADiO G3 SERIES receiver requires a personal computer to operate,this creates a potential paradox. The WiNRADiO receiver itself is designedto be substantially immune to PC interference. However, any receiver needsto be connected to an antenna, and antennas can’t discriminate betweenuseful signals and interference. The interference from your PC can eitherradiate directly to the antenna, or it can be conducted to it along the outerconductor of the lead-in cable. Even in professional radio receiving stations,a lot of care and effort is always needed, if this type of self-interference is tobe avoided.Some computers are worse than others in terms of generatedelectromagnetic interference. The worst culprits are usually video monitors,which radiate radio frequencies at multiples of horizontal deflectionfrequencies. These frequencies range from about 30 to 100 kHz, and youcan sometimes hear their harmonics right across the entire shortwave band.If you find strong signals sounding somewhat like a tractor engine, spacedbetween approximately 30 and 100 kHz apart (on modern hi-resolutionmonitors, the typical frequency is around 94 kHz), your monitor is most likelythe cause.To check this, tune to one of the interfering signals, then switch off themonitor and see if the signal disappears. You could continue using theWiNRADiO receiver, and live with the fact that some useful frequencies willbe obscured by your monitor’s interference, or you can replace your monitorwith a ‘quieter’ one (modern LCD displays are far quieter than old CRT
- 45 -monitors), or you can try to relocate your antenna further away from yourcomputer.A good remedy to try is to wind five to ten turns of the antenna lead-in cablethrough a large ferrite core (the doughnut shaped toroid type), near the PCend of the cable. This suppresses common-mode interference, which is atypical but curable problem with PC-controlled receivers.Another type of interference which you may encounter is intermodulationinterference. This is usually caused by strong local stations, whosefrequencies combine to create ‘ghost’ signals on frequencies which arearithmetic combinations of the stations’ frequencies. These ‘ghost’ signalscan sometimes coincide with useful frequencies, rendering them partially orcompletely unusable. They will usually disappear when you switch on theAttenuator in the receiver control panel. You may also try shortening theantenna.If you live very close to a strong local transmitter, these measures may beinsufficient. In such case, you should be able to eliminate intermodulation byfitting a special filter to your antenna, to reduce the level of the signalscausing the interference. The design and application of such filters fallsbeyond the scope of this book, since the large majority of WiNRADiO usersshould not experience this problem (after all, not too many of us live nextdoor to a radio station). However, broadcast frequency filters and tunablepreselectors are standard items and can be obtained from good radioequipment suppliers.Did you know?The first shortwave transmission from space took place on October 4, 1957,when the first Russian satellite, the Sputnik, was launched. The Sputniktransmitted amplitude modulated signals on 20,008 kHz. The characteristicbeeping of Sputnik’s telemetry was listened to by millions, ushered in a newera of political, military, technological, and scientific developments, andmarked the start of the US-USSR space race.
- 47 -Appendix D - Inside WR-G3 SERIESTechnically minded users may like to explore the WiNRADiO G3 SERIESReceiver and experiment with some of the innovative concepts of SoftwareDefined Radio.The WiNRADiO G3 SERIES Receiver is the world’s first commerciallyavailable Software Defined Radio, where the Demodulator function is fullyperformed in software running on a standard PC. It is also the world’s firstshortwave radio on a PCI card. The potential for experimentation istherefore substantial. This receiver and its software have been indeeddesigned to promote and encourage such experimentation.The WiNRADiO G3 SERIES receiver represents only a half of the entireradio. The other half is your PC.The receiver hardware contains the following functional blocks:The incoming signal from the antenna (in the 9 kHz to 30 MHz range) isfiltered and amplified, then fed into a mixer. Here it is mixed with the first LO(local oscillator), which is performed by a DDS (Direct Digital Synthesizer),with a PLL (Phase Locked Loop). The resulting 45 MHz intermediatefrequency is filtered using a 4-pole 45 MHz crystal filter with an IF bandwidthof 15 kHz, and then amplified.
- 48 -The second mixer again uses a DDS with a PLL to mix the 45 MHz signaldown to the last intermediate frequency, which is 12 kHz.Both DDS circuits derive their reference frequency from a 20 MHz referenceoscillator.The 12 kHz IF output is then fed to the Right channel of the Line Input of thePC sound card. You can hear what it sounds like if you use the sound cardmixer panel to listen directly to this input (rather than using the G3 SERIESDemodulator software).The AGC is performed in the first IF stage, based on the level of the last IFoutput (at 12 kHz IF). As the IF bandwidth of the first IF stage is 15 kHz, theAGC action is delayed until the dynamic range of the first IF stage is fullyutilized – this is in order not to cause desensitization of the receiver in thepresence of neighboring strong signals, falling within the 15 kHz IFbandwidth. The resulting variation in audio output is then compensated for insoftware, using Audio AGC in the software demodulator.The final IF bandwidth is then adjusted entirely in software. If theProfessional Demodulator is used, this bandwidth is continuously variablefrom 1 Hz to 15 kHz.Did you know?The largest shortwave transmitters nowadays operate with 250,000 –500,000 Watts of power. Using the CW mode, and in suitable atmosphericconditions, radio amateurs make regular contact around the world with onlya very tiny fraction of this power: reports exist of round-the-worldcommunications achieved with less than five Watts of power.
- 49 -Appendix E – Professional DemodulatorThe WiNRADiO G3 SERIES receiver has provision for additionaldemodulators, in place of the supplied standard one. Installed demodulatorscan be selected via the Demodulators top bar menu. Check the WiNRADiOWeb site www.winradio.com periodically, for demodulators available.The Professional Demodulator which is available as an optional extra, takesthe concept of software-defined shortwave receiver a step further. The maindifferences between the Standard and the Professional demodulator are asfollows:• Additional demodulation modes (DSB and ISB)• Continuously variable IF bandwidth (from 1Hz to 15 kHz)• User-adjustable IF filter coefficients and other parameters• User-adjustable audio AGC• User-definable IF bandwidth presets• Interactive demodulator structure with two spectrum scopes and avector voltmeter• Additional instrumentation (SINAD and THD meter)• AF Squelch for FM modeWiNRADiO G3 SERIES Professional Demodulator
- 50 -The front panel of the Professional Demodulator looks similar to theStandard one. Note in particular the added DSB and ISB modes, thecontinuous IF filter bandwidth control, enhanced Audio AGC (the timeconstants are user definable in the Setup window), and a row of IFbandwidth preset buttons at the bottom. The numbers on top of the IFbandwidth preset buttons indicate the associated bandwidth (in kHz). Thesepresets, too, are entirely user-definable.To change the IF bandwidth, you can type the desired value (in Hz) directlyin the IF bandwidth editbox, or use the associated up/down buttons.Do not overlook the small but very significant slider button between thebandwidth up/down buttons: It allows you to change the IF bandwidth withina large range, by moving the slider cursor up and down, with a veryimpressive effect.In the spectrum scope, the selected IF bandwidth is shown using a differentbackground color around the center frequency. The portion of the signalspectrum falling within the IF bandwidth is shown in yellow.Adjusting Demodulator ParametersThe entire demodulation process can be observed in the demodulatorstructure window, accessible from within the Demodulator Settings (pressthe Settings button under the CW mode button), then the large ViewDemodulator Structure button). Each mode has its own associatedstructure. By selecting the mode either using the front panel or the tabs attop-right of the Demodulator Settings window, you can observe the differentstructures applicable to the selected modes. Each mode also has a numberof filter settings to experiment with.The meaning of each filter is best understood looking at the demodulatorstructure. All of these filters are linear phase FIR (Finite Impulse Response),with cut-off frequencies and lengths that can be adjusted and optimized bythe user, either by direct typing in the parameter or using the sliders,according to the received signal characteristics.Each filter length (i.e. the number of its taps), can be an odd numberbetween 3 and 255. The more taps, the better the filter characteristics, andthe better the selectivity of the receiver, but the computing task for the CPUis harder. Therefore, while increasing the filter lengths, always watch theCPU usage in order not to starve the operating system of CPU resources(80% is a good upper limit). Starving the system of CPU resources
- 51 -manifests itself by the computer becoming sluggish or possibly "freezing"entirely.The first parameter, the IF bandwidth filter, is the length of the first filter inthe digital path, which is responsible for much of the receiver selectivity. Thefactory default length is 63. Reducing this value will decrease the receiverselectivity and make the receiver more prone to interference from nearbystrong signals. However, for slower computers it may be necessary tocompromise on this figure if the demodulator appears too slow (to the pointof the panel "freezing" or drop-outs of audio) because of insufficient CPUresources.The post-mixer filters, which appear in all demodulators, are all of the low-pass type, their bandwidths being automatically related to the IF bandwidthfilter (whose center frequency is 12kHz). For AM, AMN, AMS, CW, DSB,ISB, FM3, FM6 and FMN, the post-mixer filters bandwidth is half of the IFbandwidth, while for LSB and USB both bandwidths are equal.If you have a preference for particular IF bandwidths, you can associatethem with any of the ten preset buttons (located at the bottom of thedemodulator front panel) by double clicking the Bandwidth column of the IFbandwidth presets table, and then typing in the numerical bandwidth value inHz. The buttons are numbered (1 to 10) from left to right. The factory defaultvalues can be restored at any time, by pressing the Restore defaultsettings button.For the AM, AMN, FM3, FM6 and FMN demodulators, a supplementarylow-pass filter was introduced in the audio output path, to reduce harmonicdistortions generated in the demodulation process. Its cut-off frequency (theupper limit of the pass band) and length adjustments can also improve theoverall signal-to-noise ratio under bad receiving conditions.Finally, a noise-derived squelch is implemented for frequency modulationmodes, FM3, FM6 and FMN. The energy of the noise present above theuseful voice baseband is used as a signal presence indicator. Theuser can modify the length of the high-pass filter separating that noise,squelch filter length. The squelch control appears on the demodulator frontpanel when any of the FM modes is selected. This makes it possible toadjust the noise threshold level at which the squelch will mute the audio.Finally, all demodulated audio output is scaled up by an Audio gain factor.The scaled audio signal level is further adjusted with the Volume control inthe demodulator main panel. When the Audio AGC is active, the fixed Audiogain is ignored. The attack and decay times for the three possible Audio
- 52 -AGC speeds (slow, medium and fast) can be also configured, under AGCSpeed Constants on the left of the demodulator settings window.Demodulator StructureThe G3 SERIES Professional Demodulator implements the generalquadrature representation of all narrow-band modulated signals. Suchsignals can always be considered as the sum of two amplitude-modulatedcarriershaving a 90 degree offset, usually referred to as I and Q. Users familiar withSoftware Defined Radio digital signal processing concepts, will find the G3SERIES Professional Demodulator to be a useful tool for experimentationand study, where the effects of various filter settings can be easily observedand optimized.AM Demodulator StructureThe demodulator structure windows include two spectrum analyzers makingit possible to view signal spectra in real-time. Each analyzer can be"connected" to any of the test points shown as green dots in the diagram. To
- 53 -connect the left spectrum analyzer to a particular test point, left-click on thegreen test point. Its color will change to red. Right-clicking on a dot willconnect it to the right analyzer, and the color will change to blue. If bothdisplays are connected to the same test point, the point color will turnmagenta.Within the displayed spectra, a red color frequency cursor can be manuallydragged, using the left mouse button, over a particular spectral component.The two Vector Voltmeter displays labeled Left/Right indicate the relativeamplitude and phase difference between the two spectral components at thecursor frequency.There are two additional tools provided in this window: THD (total harmonicdistortion) and SINAD (signal-plus-noise-plus-distortion to noise-plus-distortion) meters. They can be used to test the overall receiver performanceas well as provide indication of the sound card quality. To use thesefacilities, a pure tone-modulated signal must be applied to the receiverantenna input, and the frequency of the modulating tone must be equal tothe Test freq setting.When either of the THD or SINAD buttons is activated, the right-handspectrum display will be automatically connected to the end of thedemodulator chain (i.e. right-clicking on any other test points will not workuntil both the THD and SINAD buttons are released).For synchronous demodulation of amplitude modulated signals (the AMSmode) without carrier or with a fluctuating one, the G3 SERIES ProfessionalDemodulator uses a PLL carrier recovery technique based on the Costasloop:Synchronous AM Demodulator Structure
- 54 -The LSB and USB demodulators have basically the same topology. ISB canbe thought of as a combination of LSB and USB, where each of the soundcard channels is used for one of the independent side bands.
- 55 -USB Demodulator StructureThe CW received signals are first down-converted to zero Hz, and then,after additional channel filtering, up-converted to a convenient audiofrequency. This frequency (a digital BFO) is user-adjustable, by changingthe value of the CW tone frequency parameter in the demodulator set-up.CW Demodulator StructureFinally, all frequency demodulators have the same block diagram. The onlydifferences between these demodulators are the bandwidth values of theinput IF filter and the two post-mixer filters:FM Demodulator Structure
- 56 -Appendix F - Developer SupportWiNRADiO has always extensively supported third-party softwaredevelopment efforts with all our receivers, and the WiNRADiO G3 SERIESreceiver is no exception. We provide technical details for developers to beable to develop the following:1. Third-party applications controlling the WiNRADiO G3 SERIES receiver.We do this by providing API information making it possible to access thereceiver hardware from third party software. (Seehttp://www.winradio.com/home/developer.htm).2. Plug-ins to provide enhanced functionality. For this, we have developeda special interfacing standard called XRS (Extensible RadioSpecification). All our receivers conform to this standard, and manyplug-ins are already available for various applications (seehttp://xrs.winradio.com).3. New types of demodulators. The G3 SERIES demodulators in factrepresent a special type of XRS plug-in. Detailed information is alsoavailable at http://xrs.winradio.com).4. Support under alternative operating systems. See for examplehttp://www.linradio.com.5. Support under Radio Basic, an easy to use specialized programminglanguage for radio receivers. See http://www.rbasic.com.Have you registered yet? WiNRADiO provides regular upgrades to ourapplication software. Use our on-line registration form onwww.winradio.com/register to take advantage of this free service.
- 57 -Declaration of ConformityThis device, trade name WiNRADiO Communications Receiver, modelnumber WR-G3 SERIES complies with Part 15 of the FCC Rules. Operationis subject to the following conditions: (1) This device may not cause harmfulinterference, and (2) this device must accept any interference received,including interference that may cause undesired operation.I have determined and warrant that the above described device has beenshown to comply with the requirements of the FCC Part 15, by having adevice tested at an accredited testing laboratory. Each unit marked isidentical to the device as tested. Compliance assumes no unauthorizedchanges will be made to the equipment and it will be maintained andoperated properly. A test report has been generated. A technical filecontaining the test report will be maintained for a period of at least 2 yearsafter manufacturing ceases. It is also understood that characteristics of thisequipment will require retesting.Milan HudecekManaging DirectorforRosetta Laboratories Pty.Ltd.15 Stamford RoadOakleigh 3166Australia+61 3 9568 2568

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