RF Technology T500B Base station transmitter User Manual Manual T500

RF Technology Pty Ltd Base station transmitter Manual T500

User manual with circuit diagrams removed

Eclipse SeriesRF Technologyrfinfo@rftechnology.com.auAugust, 1998T350 / T500 TransmitterOperation and Maintenance ManualThis manual is produced by RF Technology Pty Ltd10/8 Leighton Place, Hornsby NSW 2077 AustraliaCopyright © 1998 RF Technology
Page 2 RF Technology T350/T500 CONTENTS CONTENTSContents1Operating Instructions 51.1 Front Panel Controls and Indicators 51.1.1 PTT 51.1.2 Line 51.1.3 PWR LED 61.1.4 TX LED 61.1.5 ALARM LED 62Transmitter Internal Jumper Options 72.1 JP2: EPROM type 72.2 JP3: Dc Loop PTT 72.3 JP4: Audio Input Source 72.4 JP6: Input Level Attenuation 72.5 JP7: Audio Response 82.6 JP8: Sub-audible Tone source 82.7 JP9/10/11: dc Loop Configuration 83Transmitter I/O Connections 83.1 25 Pin Connector 84Channel and Tone Frequency Programming 85Circuit Description 95.1 VCO Section 95.2 PLL Section 105.3 Power Amplifier 105.4 600W line Input 115.5 Direct Coupled Audio Input 115.6Local Microphone Input115.7 CTCSS and Tone Filter 115.8 Audio Signal Processing 125.9 PTT and DC Remote Control 125.10 Micro-processor Controller 135.11 Voltage Regulator 136Field Alignment Procedure 136.1 Standard Test Conditions 146.2 VCO Alignment 146.3 TCXO Calibration 146.4 Modulation Balance 156.5 Tone Deviation 156.6 Deviation 166.7Line Input Level166.8 Output Power 16
RF Technology T350/T500Page 3CONTENTS CONTENTS7Specifications 177.1 Overall Description 177.1.1 Channel Capacity 177.1.2 CTCSS 177.1.3 Channel Programming 177.1.4 Channel Selection 177.1.5 Micro-processor 187.2 Physical Configuration 187.3 Front Panel Controls, Indicators and Test Points 187.3.1 Controls 187.3.2 Indicators 187.3.3 Test Points 197.4 Electrical Specifications 197.4.1 Power Requirements 197.4.2Frequency Range and Channel Spacing197.4.3Frequency Synthesizer Step Size197.4.4Frequency Stability197.4.5 Number of Channels 197.4.6 Antenna Impedance 197.4.7 Output Power 197.4.8Transmit Duty Cycle207.4.9 Spurious and Harmonics 207.4.10 Carrier and Modulation Attack Time 207.4.11 Modulation 207.4.12 Distortion 207.4.13 Residual Modulation and Noise 207.4.14 600W Line Input Sensitivity 207.4.15 HI-Z Input 207.4.16 Test Microphone Input 217.4.17 External Tone Input 217.4.18 External ALC Input 217.4.19 T/R Relay Driver 217.4.20 Channel Select Input / Output 217.4.21 DC Remote Keying217.4.22 Programmable No-Tone Period 227.4.23 Firmware Timers 227.4.24 CTCSS 227.5 Connectors 227.5.1 Antenna Connector 227.5.2 Power and I/O Connector 247.5.3 Test Connector 24
Page 4 RF Technology T350/T500CONTENTS CONTENTSAEngineering Diagrams 24A.1 Block Diagram 24A.2 Circuit Diagrams 24A.3Component Overlay Diagrams25BParts List 26
RF Technology T350/T500Page 51OPERATING INSTRUCTIONS1Operating Instructions1.1 Front Panel Controls and Indicators1.1.1 PTTA front-panel push-to-talk (PTT) button is provided to facilitate bench and field testsand adjustments. The button is a momentary action type. When keyed, audio from theline input is disabled so that a carrier with sub-tone is transmitted. The front-panelmicrophone input is not enabled in this mode, but it is enabled when the PTT line onthat socket is pulled to ground.1.1.2 LineThe LINE trimpot is accessible by means of a small screwdriver from the front panel ofthe module. It is used to set the correct sensitivity of the line and direct audio inputs. Itis factory preset to give 60% of rated deviation with an input of 0dBm (1mW on 600Wequivalent to 775mV RMS or about 2.2V peak-to-peak) at 1kHz. The nominal 60%deviation level may be adjusted by measuring between pins 6 and 1 on the test socket,and adjusting the pot. By this means an input sensitivity from approximately -30dBm to+10dBm may be established.An internal jumper provides a coarse adjustment step of 20dB. Between the jumper andthe trimpot, a wide range of input levels may be accommodated.WARNINGChanges or modifications not expressly approved byRF Technology could void your authority to operate thisequipment. Specifications may vary from those given inthis document in accordance with requirements of localauthorities. RF Technology equipment is subject tocontinual improvement and RF Technology reserves theright to change performance and specification withoutfurther notice.
Page 6 RF Technology T350/T5001.1 Front Panel Controls and Indicators 1 OPERATING INSTRUCTIONSLED Flash Cadence Fault Condition5 flashes, pause Synthesizer unlocked4 flashes, pause Tuning voltage out of range3 flashes, pause Low forward power2 flashes, pause High reverse (reflected) power1 flash, pause Low dc supply voltageLED ON continuously Transmitter timed outTable 1: Interpretations of LED flash cadenceIndication Fault ConditionFlashing, 8 per second Synthesizer unlockedFlashing, 4 per second Tuning voltage outside correct rangeFlashing, 2 per second Low forward powerFlashing, 1 per second High reverse powerContinuous dc supply voltage low or highTable 2: Interpretations of LED flash speed, for early models1.1.3 POWER LEDThe PWR LED shows that the dc supply is connected to the receiver.1.1.4 TX LEDThe TX LED illuminates when the transmitter is keyed. It will not illuminate (and anAlarm cadence will be shown) if the synthesizer becomes unlocked, or the outputamplifier supply is interrupted by the microprocessor.1.1.5 ALARM LEDThe Alarm LED can indicate several fault conditions if they are detected by the self testprogram. The alarm indicator shows the highest priority fault present. Receivers usingsoftware issue 5 and higher use the cadence of the LED flash sequence to indicate thealarm condition. Refer to table 1. Receivers using software issue 4 and lower use theLED flash rate to indicate the alarm condition. Refer to table 2.
RF Technology T350/T500Page 72TRANSMITTER INTERNAL JUMPER OPTIONS2Transmitter Internal Jumper OptionsIn the following subsections an asterisk (*) signifies the standard (Ex-Factory)configuration of a jumper.2.1 JP2: EPROM TypeCondition Position27C256 2-3 *27C64 1-22.2 JP3: Dc Loop PTTThis jumper enables or disables the keying of the PTT function by means of a dc signalpassed down the 600W line input pair. When enabled, JP9-JP11 control how the dcsignal is configured with respect to an internal opto-coupler.Condition Positiondc loop connected (enabled) 1-2 *dc loop not connected (bypassed) 2-32.3 JP4: Audio Input SourceEither the 600W or the high-Z balanced inputs may be selected.Condition Position600W Input 2-3 *High-impedance Input1-22.4 JP6: Input Level AttenuationThis jumper permits coarse input sensitivity to be set.Condition Position0dB attenuation 1-2 *20dB attenuation 2-3
Page 8 RF Technology T350/T5002.5 JP7: Audio Response 4 CHANNEL AND TONE FREQUENCY PROGRAMMING2.5 JP7: Audio ResponseCondition Position750 uSec. pre-emphasis 1-2 *Flat response 2-32.6 JP8: Sub-audible Tone SourceCondition PositionInternal CTCSS 1-2, 4-5 *External input 2-3, 5-62.7 JP9/10/11: dc Loop ConfigurationThese settings are only relevant when the PTT signal is to be used across the same wiresas the audio. Refer to setting of JP3. They control the levels and connection into theaudio balanced line circuitry.Condition JP9 JP10 JP11Current Loop Input ON OFF OFF *12Vdc Loop source OFF ON ON3Transmitter I/O Connections3.1 25 Pin ConnectorThe D-shell 25 pin connector is the main interface to the transmitter. The pinconnections are described in table 3.4Channel and Tone Frequency ProgrammingChannel and tone frequency programming is most easily accomplished with RFTechnology TecHelp software or the Service Monitor 2000 software. This software canbe run on an IBM compatible PC and provides a number of additional useful facilities.DOS and 32-bit versions are available.TecHelp allows setting of the adaptive noise squelch threshold, provides a simple meansof calibrating the forward and reverse power detectors, setting the power alarm presetlevels, and enabling transmitter hang time and timeout time limits. TecHelp can besupplied by your dealer, distributor or by contacting RF Technology directly.
RF Technology T350/T500Page 94 CHANNEL AND TONE FREQUENCY PROGRAMMINGFunction Signal Pins SpecificationDC power +12 Vdc 0 Vdc1, 1413, 25+11.4 to 16 Vdc GroundChannel Select 124810204080219221023112412BCD Coded0 = Open Circuitor 0 Vdc1 = +5 to +16 VdcRS232 Data InOut152Test and Programming use9600, 8 data 2 stop bits600W Line HighLow206Transformer IsolatedBalanced 0dBm Output150W / Hybrid 719Direct PTT input 3Ground to key PTTT/R Relay driver output 16 Open collector,250mA/30VSub-Audible Tone Input [+] 5>10kW, AC coupled[-] 18 (1-250Hz)High-Z Audio Input [+] 4>10kW, AC coupled[-] 17 (10Hz-3kHz)External ALC input 8 <0.5V/1mA to obtain>30dB attenuation, O/Cfor maximum powerTable 3: Pin connections and explanations for the main 25-pin, D connector.5Circuit DescriptionThe following descriptions should be read as an aid to understanding the block andschematic diagrams given in the appendix of this manual.5.1 VCO SectionThe Voltage Controlled Oscillator uses a junction FET which oscillates at the requiredtransmitter output frequency. A varactor diode is used by the PLL circuit to keep theoscillator on the desired frequency. Transistor Q20 is used as an active filter to reducethe noise on the oscillator supply voltage. The VCO is keyed ON by themicrocontroller through Q10. It is keyed ON when any of the PTT inputs are active andOFF at all other times.
Page 10 RF Technology T350/T500 5 CIRCUIT DESCRIPTION The VCO output is amplified and buffered by monolithic amplifiers MA2 and MA3before being fed to the PLL IC U6.Amplifiers MA1, MA4 and MA5 increase the VCO output to approximately 4 mW todrive the power amplifier. MA1 is not switched on until the PLL has locked and hadtime to settle. This prevents any momentary off channel transmission when thetransmitter is keyed.5.2 PLL SectionTemperature compensated crystal oscillator XO1 is the frequency reference source forthe PLL Synthesizer. The frequency stability of XO1 is better than 1 ppm and it can besynchronized to an external reference for improved stability. External reference optionboard 11/9119 is required when using an external reference.XO1 is frequency modulated by the processed transmit audio signal from U7b. Thisextends the modulation capability down to a few Hz for sub-audible tones and digitalsquelch codes. A two point modulation scheme is used with the audio also being fed tothe VCO to modulate the higher audio frequencies.The 12.8 MHz output of XO1 is amplified by Q22 to drive the reference input of thePLL synthesizer IC U6. This IC is a single chip synthesizer which includes a 1.1 GHzpre-scaler, programmable divider, reference divider and phase/frequency detector. Thefrequency data for U6 is supplied through serial data link by the microprocessor.The phase detector output signals of U6 are used to control two switched currentsources. The output of the positive and negative sources (Q3 and Q6) produces thetuning voltage which is smoothed by the loop filter components to bias the VCOvaractor diode D3.5.3 Power AmplifierThe 4 mW output from the main board connects to the power amplifier board through ashort miniature 5W coaxial cable.Q2 on the power amplifier board increases the signal to approximately 200 mW. Thebias current of Q2 is controlled by Q1 and the power leveling circuitry to adjust thedrive to the output module U2.U2 increases the power to 10-30 watts (depending upon options) before it is fed to thedirectional coupler, low pass filter and output connector. The directional couplerdetects the forward and reverse power components and provides proportional dcvoltages which are amplified by U1a and U1b. The forward and reverse voltages fromU1a and U1b are compared to the DC reference voltage from RV1. The difference isamplified by U1c, Q3 and Q4.
RF Technology T350/T500Page 115 CIRCUIT DESCRIPTION 5.3 Power AmplifierThe resulting control voltage supplies Q2 through R10, R12 and completes the powerleveling control loop.5.4 600W Line InputThe 600W balanced line input connects to line isolation transformer T1. T1 has two150W primary windings which are normally connected in series for 600W lines. Thedual primary windings can be used to provide DC loop PTT signaling or a 2/4 wirehybrid connection. All four leads are available at the rear panel system connector.The secondary of T1 can be terminated with an internal 600W load through JP5 or leftun-terminated in high impedance applications.5.5 Direct Coupled Audio InputA high impedance (10kW) direct AC coupled input is available at the system connector.The direct coupled input connects to U9a which is configured as a unity gain bridgeamplifier.The bridge configuration allows audio signal inversion by interchanging the positiveand negative inputs and minimizes ground loop problems. Both inputs should beconnected, with one lead going to the source output pin and the other connected to thesource audio ground.5.6 Local Microphone InputThe local microphone input is provided for use with a standard low impedance dynamicmicrophone. The microphone output is amplified by U9a before connecting to analogueswitch U10a. U10b inverts the local microphone PTT input to switch U10a ON whenthe microphone PTT button is pressed. U10a is OFF at all other times.The local microphone audio has priority over the other inputs. Activation of the localmicrophone PTT input switches OFF the audio from the line or direct inputs throughD16 and U10c.5.7 CTCSS and Tone FilterThe CTCSS encoder module H1, under control of the main microprocessor U13, canencode all 38 EIA tones and (on some models) additional commonly-used tones.The tone output of H1 connects to jumper JP8 which is used to select either H1 or anexternal tone source. The selected source is coupled to U9c which is a balanced inputunity gain amplifier. The buffered tone from U9c is fed to 300 Hz low pass filter U7c.RV3, the tone deviation trimmer, is used to adjust the level of the tone
Page 12 RF Technology T350/T5005.8 Audio Signal Processing 5 CIRCUIT DESCRIPTIONfrom U7c before it is combined with the voice audio signal in the summing amplifierU7a.Back to back diodes D4 and D5 limit the maximum tone signal amplitude to preventexcessive tone deviation when external tone sources are used.5.8 Audio Signal ProcessingJumper JP4 selects either the line or direct input source. The selected source is thenconnected to JP6. JP6 can be removed to provide 20 dB attenuation when the inputlevel is above 10 dBm to expand the useful range of the line level trimmer RV4. Thewiper of RV4 is coupled to the input of the input amplifier U9d. U9d provides avoltage gain of ten before connecting to the input of analogue switch U10c.The outputs of U10a and U10c are connected to the frequency response shapingnetworks C52, R133 (for 750ms pre-emphasis) and C61, R55 (for flat response). JP7selects the pre-emphasized or flat response.The audio signal is further amplified 100 times by U7d. U7d also provides thesymmetrical clipping required to limit the maximum deviation. The output level fromU7d is adjusted by RV1, the deviation adjustment, before being combined with the toneaudio signal in the summing amplifier U7a.The composite audio from U7a is fed through the 3Khz low pass filter U7b. Thefiltered audio is coupled to the TCXO voltage tuning input and the modulation balancetrimmer RV2.RV2 adjusts level of the audio used to modulate the VCO. This primarily effects thedeviation of audio frequencies above 500 Hz. RV2 is used to balance the high and lowfrequency deviation to obtain a flat frequency response relative to the desiredcharacteristic.5.9 PTT and DC Remote ControlTwo main PTT inputs are provided. The first, a direct logic level input, is connected topin 3 of the system connector. The transmitter can be keyed by applying a logic low orground on pin 3. Pin 3 connects to the PTT logic and microprocessor through D10.DC current loop control can be used for remote PTT operation. The current loop can beconfigured by JP9, JP10 and JP11 for use with either a remote free switch or a remoteswitched source.Opto-isolator ISO1 is used to isolate the loop current signal from the transmitter PTTlogic. The loop current passes through the input of ISO1 and the output of ISO1connects to the PTT logic.
RF Technology T350/T500Page 135CIRCUIT DESCRIPTION 5.10 Microprocessor ControllerA bridge consisting of diodes D6, D8, D9 and D14 ensures correct operation regardlessof the current polarity. Q17 limits the current and D7 limits the voltage input to ISO1.Any low voltage current source capable of providing 2 mA at 4 V or switching circuitwith less than 4.8kW loop resistance can be used to switch the DC loop.The test PTT button on the front panel and the local microphone PTT button will alsokey the transmitter. Both of these also mute the line audio input. The microphone linealso enables that audio input.5.10 Microprocessor ControllerThe microprocessor controller circuit uses a single-chip eight bit processor and severalsupport chips. The processor U13 includes non-volatile EE memory for channelfrequencies, tones, and other information. It also has an asynchronous serial port, asynchronous serial port and an eight bit analogue to digital converter.The program is stored in U5, a CMOS EPROM. U4 is an address latch for the low orderaddress bits. U2 is used to read the channel select lines onto the data bus. U11 is anaddress decoder for U5 and U2. U3 is a supervisory chip which keeps the processorreset unless the +5 Volt supply is within operating limits. U1 translates theasynchronous serial port data to standard RS232 levels.The analogue to digital converter is used to measure the forward and reverse power,tuning voltage and dc supply voltage.The processor keys the VCO through Q10, switches the 9.2 Volt transmit line throughQ14 and Q16, and the alarm LED D1 through Q1.5.11 Voltage RegulatorThe dc input voltage is regulated down to 9.4 Vdc by a discrete regulator circuit. Theseries pass transistor Q23 is driven by error amplifiers Q8 and Q18. Q9 is used to startup the regulator and once the circuit turns on, it plays no further part in the operation.The +5 Volt supply for the logic circuits is provided by an integrated circuit regulatorU14 which is run from the regulated 9.4 Volt supply.6Field Alignment ProcedureThe procedures given below may be used to align the transmitter in the field. Normally,alignment is only required when changing operating frequencies, or after componentreplacement.
Page 14 RF Technology T350/T5006FIELD ALIGNMENT PROCEDURE 6.1 Standard Test ConditionThe procedures below do not constitute an exhaustive test or a complete alignment ofthe module, but if successfully carried out are adequate in most circumstances.TCXO calibration may be periodically required owing to normal quartz crystal aging. Adrift of 1ppm/year is to be expected.Each alignment phase assumes that the preceding phase has been successfully carriedout, or at least that the module is already in properly aligned state with respect topreceding conditions.6.1 Standard Test ConditionThe following equipment and conditions are assumed unless stated otherwise:·AF signal generator with 600W impedance, 150-3000Hz frequency range, with levelset to 387mV RMS.·Power supply set to 13.8Vdc, with a current capable of >5A.·RF 50W load, 30W rated, return loss <-20dB.·Jumpers set to factory default positions.6.2 VCO Alignment1.Select a channel at the center frequency (half way between the highest and lowestfrequencies for the model in question).2. Disconnect the Audio input (no signal input).3.Key the PTT line.4.Measure the voltage between pins 9 and 1 of the test socket (TUNE V), and adjustC99 to obtain 4.5±0.25V, while the TX LED is ON and the ALARM LED is OFF.6.3 TCXO Calibration1.Select a channel at the center frequency (half way between the highest and lowestfrequencies for the model in question).2. Disconnect the Audio input (no signal input).3.Key the PTT line.
RF Technology T350/T500Page 156.4 Modulation Balance 6 FIELD ALIGNMENT PROCEDURE 4. Measure the carrier frequency at the output connector, and adjust XO1 until thecorrect carrier frequency is measured, ±50Hz.6.4 Modulation Balance1. Set RV3 fully counter clockwise (CCW) (sub-tone off).2. Set RV1 fully clockwise (CW) (maximum deviation)3. Set RV2 mid-position4. Set JP7 for flat response5.Key the transmitter on6. Set the audio input to 150Hz, 0dBm.7. Measure deviation and adjust RV4 (line Level) for a deviation of 5kHz (2.5kHzfor narrow band transmitters).8. Set the audio input to 1.5kHz, 0dBm.9. Adjust RV2 (Mod. Bal.) for a deviation of 5kHz (2.5kHz for narrow bandtransmitters).10. Repeat steps 6-9 until balance is achieved.11.Key the transmitter off.12. Return JP7 to its correct setting.13. Carry out the Deviation (section 6.6) and Tone Deviation (section 6.5) alignmentprocedures.6.5 Tone Deviation1. Remove the audio input.2.Key the transmitter on.3. Adjust RV3 for the desired deviation in the range 0-1kHz.1 If sub-tone(CTCSS) coding is not to be used, adjust RV3 fully CCW.____________________1 The factory default is 500Hz for wide band (5kHz maximum deviation) and 250Hz for narrow bandchannels.
Page 16 RF Technology T350/T5006FIELD ALIGNMENT PROCEDURE 6.6 Deviation6.6 Deviation1. Set RV4 (Line Level) fully clockwise (CW).2. Set the audio to 1kHz, 0dBm, on the line input.3.Key the transmitter on..4. Adjust RV1 (Set Max. Deviation) for a deviation of 5kHz (2.5kHz for narrowband transmitters).5.Key the transmitter off.6.Carry out the Line Input Level alignment procedure (section 6.7)6.7 Line Input Level1. Set the audio to 1kHz, 0dBm, on the line input, or use the actual signal to betransmitted.2.Key the transmitter on.3. Adjust RV4 (line level) for 60% of system deviation (3kHz or 1.5kHz for narrowband systems).4. If the test signal is varying, RV4 may be adjusted to produce a level of 234mVRMS or 660mVp-p at the audio voltage test connector pin 6 to pin 1.5.Key the transmitter off.6.8 Output Power1. No audio input is required2.Key the transmitter on.3.Adjust RV1 on the power amplifier PCB for the desired power level at the outputconnector. 24.Key the transmitter off.____________________2 Be sure to set the power below the rated maximum for the model of transmitter. If in doubt, allow1.5dB cable and connector losses, and assume that the maximum rated power is 15W. This means nomore than 10W at the end of a 1m length of test cable. This pessimistic procedure is safe on all modelsmanufactured at the time of writing.
RF Technology T350/T500Page 177 SPECIFICATIONS7SPECIFICATIONS7.1 Overall DescriptionThe transmitter is a frequency synthesized, narrow band FM unit, normally used todrive a 50 watt amplifier. It can also be used alone in lower power applications.Various models allow 2-25W of output power to be set across a number of UHFfrequency bands. All necessary control and 600W line interface circuitry is included.7.1.1 Channel CapacityAlthough most applications are single channel, it can be programmed for up to 100channels, numbered 0 - 99. This is to provide the capability of programming allchannels into all of the transmitters used at a given site. Where this facility is used inconjunction with channel-setting in the rack, exciter modules may be “hot-jockeyed” orused interchangeably. This can be convenient in maintenance situations.7.1.2 CTCSSFull EIA sub-tone capability is built into the modules. The CTCSS tone can beprogrammed for each channel. This means that each channel number can represent aunique RF and tone frequency combination.7.1.3 Channel ProgrammingThe channel information is stored in non-volatile memory and can be programmed viathe front panel test connector using a PC and RF Technology software.7.1.4 Channel SelectionChannel selection is by eight channel select lines. These are available through the rearpanel connector. Internal presetting is also possible. The default (open-circuit) state is toselect channel 00.A BCD active high code applied to the lines selects the required channel. This can besupplied by pre-wiring the rack connector so that each rack position is dedicated to afixed channel. Alternatively, thumb-wheel switch panels are available.
Page 18 RF Technology T350/T5007SPECIFICATIONS 7.1.5 Microprocessor7.1.5. MicroprocessorA microprocessor is used to control the synthesizer, tone squelch, PTT function andfacilitate channel frequency programming. With the standard software, RF Technologymodules also provide fault monitoring and reporting.7.2 Physical ConfigurationThe transmitter is designed to fit in a 19 inch rack mounted sub-frame. The installedheight is 4 RU (178 mm) and the depth is 350 mm. The transmitter is 63.5 mm or twoEclipse modules wide.7.3 Front Panel Controls, Indicators, and Test Points7.3.1 ControlsTransmitter Key - Momentary Contact Push ButtonLine Input Level - screwdriver adjust multi-turn pot7.3.2 IndicatorsPower ON - Green LEDTx Indicator - Yellow LEDFault Indicator - Flashing Red LEDExternal ALC - Green LEDExternal Reference - Green LED7.3.3 Test PointsLine Input – Pin 6 + Ground (pin 1)Forward Power – Pin 8 + Ground (pin 1)Reverse Power – Pin 4 + Ground (pin 1)Tuning Voltage – Pin 9 + Ground (pin 1)Serial Data (RS-232) – Pins 2 / 3 + Ground (pin 1)
RF Technology T350/T500Page 197.4 Electrical Specifications 7 SPECIFICATIONS7.4 Electrical Specifications7.4.1 Power RequirementsOperating Voltage - 10.5 to 16 Vdc with output power reduced below 12 VdcCurrent Drain - 5A Maximum, typically 0.25A StandbyPolarity - Negative Ground7.4.2 Frequency Range and Channel SpacingFrequency 25 kHz 12.5 kHz330-365 MHz T350C T350CN360-380 MHz T350A T350AN375-400 MHz T350B T350BN403-420 MHz T500A T500AN430-450 MHz T500D T500DN450-520 MHz T500B T500BN7.4.3 Frequency Synthesizer Step SizeStep size is 10 / 12.5kHz or 5 / 6.25kHz, fixed, depending upon model7.4.4 Frequency Stability±1 ppm over 0 to +60 C, standard±1ppm over -20 to +60 C, optional7.4.5 Number of Channels100, numbered 00 - 997.4.6 Antenna Impedance50W7.4.7 Output powerPreset for 2-15 or 2-25W depending upon model
Page 20 RF Technology T350/T5007SPECIFICATIONS 7.4.8 Transmit Duty Cycle7.4.8 Transmit Duty Cycle100% to 40C, de-rating to zero at 60C.100% to 5000ft altitude, de-rating to zero at 15,000ft.7.4.9 Spurious and HarmonicsLess than 0.25mW7.4.10 Carrier and Modulation Attack TimeLess than 20ms. Certain models have RF envelope attack and decay times controlled inthe range 200ms< tr/f <2ms according to regulatory requirements.7.4.11 ModulationType - Two point direct FM with optional pre-emphasisFrequency Response - ±1 dB of the selected characteristic from 300 - 3000 HzMaximum Deviation - Maximum deviation preset to 2.5 or 5 kHz7.4.12 DistortionModulation distortion is less than 3% at 1 kHz and 60% of rated system deviation.7.4.13 Residual Modulation and NoiseThe residual modulation and noise in the range 300 - 3000 Hz is typically less than -50dB referenced to rated system deviation.7.4.14 600W Line Input SensitivityAdjustable from -30 to +10 dBm for rated deviation7.4.15 HI-Z InputImpedance - 10KW Nominal, balanced inputInput Level - 25mV to 1V RMS
RF Technology T350/T500Page 217.4.16 Test Microphone Input 7 SPECIFICATIONS7.4.16 Test Microphone Input200W dynamic, with PTT7.4.17 External Tone InputCompatible with R500 tone output7.4.18 External ALC InputOutput will be reduced 20dB by pulling the input down to below 1V. (Typically morethan 40dB attenuation is available.) The input impedance is @10kW, internally pulledup to rail.The external ALC input can be connected to the power control circuit in Eclipseexternal power amplifiers.7.4.19 T/R Relay DriverAn open collector transistor output is provided to operate an antenna change over relayor solid state switch. The transistor can sink up to 250mA.7.4.20 Channel Select Input / OutputCoding - 8 lines, BCD coded 00 - 99Logic Input Levels - Low for <1.5V, High for >3.5VInternal 10K pull down resistors select channel 00 when all inputs are O/C.7.4.21 DC Remote KeyingAn opto-coupler input is provided to enable dc loop keying over balanced lines or localconnections. The circuit can be connected to operate through the 600W line or througha separate isolated pair.
Page 22 RF Technology T350/T5007 SPECIFICATIONS 7.4.22 Programmable No-Tone Period7.4.22 Programmable No-Tone PeriodA No-Tone period can be appended to the end of each transmission to aid in eliminatingsquelch tail noise which may be heard in mobiles with slow turn off decoders. The No-Tone period can be set from 0--5 seconds in 0.1 second increments. The No Toneperiod operates in addition to the reverse phase burst at the end of each transmission.37.4.23 Firmware TimersThe controller firmware includes some programmable timer functions.Repeater Hang Time - A short delay or ``Hang Time'' can be programmed to be addedto the end of transmissions. This is usually used in talk through repeater applications toprevent the repeater from dropping out between mobile transmissions. The Hang Timecan be individually set on each channel for 0 - 15 seconds.Time Out Timer - A time-out or transmission time limit can be programmed toautomatically turn the transmitter off. The time limit can be set from 0-254 minutesin increments of one minute. The timer is automatically reset when the PTT input isreleased.7.4.24 CTCSSCTCSS tones can be provided by an internal encoder or by an external source connectedto the external tone input. The internal CTCSS encoding is provided by a subassemblyPCB module. This provides programmable encoding of all EIA tones.Some models encode certain extra tones.Tone frequencies are given in table 4.7.5 Connectors7.5.1 Antenna ConnectorType N Female Mounted on the module rear panel3 The reverse phase burst is usually sufficient to eliminate squelch tail noise in higher-quality mobiles.
RF Technology T350/T500Page 237 SPECIFICATIONSFrequency EIA NumberNo Tone67.0 A169.471.9 B174.4 C177.0 A279.7 C282.5 B285.4 C388.5 A391.5 C494.8 B397.4100.0 A4103.5 B4107.2 A5110.9 B5114.8 A6118.8 B6123.0 A7127.3 B7131.8 A8136.5 B8141.3 A9146.2 B9151.4 A10156.7 B10159.8162.2 A11165.5167.9 B11171.3173.8 A12177.3179.9 B12183.5186.2 A13189.9192.8 B13196.6199.5203.5 A14206.5210.7 B14218.1 A15225.7 B15229.1233.6 A16241.8 B16250.3 A17254.1Table 4: Tone Squelch Frequencies
Page 24 RF Technology T350/T500AENGINEERING DIAGRAMS7.5.2 Power & I/O Connector25-pin “D” Male Mounted on the rear panel7.5.3 Test Connector9-pin “D” Female mounted on the front panelAEngineering DiagramsMost Eclipse transmitter modules contain two PCBs, a motherboard with the controland signal generation circuitry (the exciter board), and an RF Power Amplifier board.Certain models are equipped with optional functions on piggyback PCBs atop theexciter motherboard. The exciter PCB typically has a few components whose valuesvary from model to model depending upon operating frequency and local regulatoryconstraints. The RF PA PCB varies from model to model but to a greater extent. Atleast two different PCB layouts, and numerous variations, exist. This manual presentsthe circuits and parts lists for two representative variants. When ordering spare parts besure to specify the model exactly, in case the part you require is different in value fromthat specified in this manual.Older models (predating this manual) may not be covered by this manual. However,advances are evolutionary, and the information in this manual will be sufficient in mostcases to permit understanding and servicing of all models, past and present.Versions of more detailed circuit schematics, printed on A3 paper, may be inserted orbound with this manual towards the end. It is sometimes easier to work with these fold-out diagrams because of their larger format. In case the inserts / fold-outs are missingor damaged, the reader is advised that information in the figures included with the textshould be identical.A.1 Block DiagramFigure 1 shows the block signal flow diagram.A.2 Circuit DiagramsFigure 2 shows the detailed circuit diagram with component numbers and values for themain (exciter) PCB. Figure 3 shows the detailed circuit diagram with componentnumbers and values for the higher-power PA variation. Figure 4 shows the detailedcircuit diagram with component numbers and values for the lower-power PA variation.

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