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Manual for GRANDproto35 operationJacques Davida, Junhua Gub, Olivier Martineau-Huynha, David Martina, PatrickNaymana, Vincent VoisinaaLPNHE, Universit´e Pierre et Marie Curie, Universit´e Paris Diderot, CNRS/IN2P3, Paris,France.bNational Astronomical Observatories of China, Chinese Academy of Science, Beijing 100012,P.R. China.1 IntroductionIn this document we give details needed to set up, run and maintain the GRAND-proto35 acquisition, and (tentatively) fix possible issues.2 The Front-End UnitHere we give a brief description of the structure of the Front-End Unit and provideinformations needed to make sure it runs in a proper state and identify possibleproblems if should be encountered.2.1 Unit Set-UpThe unit should be fixed to the corresponding antenna pole as shown in Fig. 1:the front pannel is vertical, with the pressure valve facing ground.2.2 ConnectionsConnections to the Front-End Units should be carried out in the following order:i) First connect the three outputs of the antenna to the associated inputs ANT X,ANT Y,ANT Z of the Front End Units with the three dedicated coax cables.Make sure here that you connect the 75Ω F-type connector end (the thinner one),and not the 50Ω one (thicker). Inversion would destroy the plug. Also since the12 V DC power supply to the antenna LNAs is provided through these cables, itis in principle safer to plug/unplugg them only when the Front-End Unit poweris off.ii) Then connect the GPS antenna. By no means should the GPS antenna be con-nected when the power is on. This may destroy the GPS unit inside the board(see section 2.3.2) and make it unusable. The GPS antenna should preferablybe placed above ground. A magnet inside the GPS antenna allows to fix it to aclose-by metalic surface.Email address: martineau@lpnhe.in2p3.fr (Olivier Martineau-Huynh)Preprint submitted to Elsevier April 19, 2018
Figure 1: Front (left) and bottom (right) views of a GRANDproto35 Front-End unit casing oncefixed to an antenna pole.Giii) Then connect the optical fiber (which can however be plugged/unplugged at anytime, with no risk of damage).iv) Finally plug the power cable. Nominal value of the power supply should be 15 V,but values between xx and xx are still OK. A green LED on the front paneljust below the power plug allows to check if the board is powered on.2.3 Front-end board descriptionA picture of the board is shown in figure 2. It can be divided in 4 functionnalsections: analog, digitial, communication and power supply.2.3.1 Analog partThe description of the analog part of the board is given in details in [1] (in French).Here we just give a brief overview.The analog part lies in the top-left corner of the board. Signal input to the boardis done for each of the three channels through an MMCX 75Ω jack connected to thecorresponding F-type connector. From top to bottom we have X, Y and Z channels.The signal is adapted to a 50Ω impedance thanks to a dedicated amplifier placed justafter the connector, then fed into the 30-100 MHz filters tagged KR ELECTRONICS.Signal is finally processed through a power detector AD8310 [2], which acts as anenvelop detector. The power detector runs in differential mode. Its common modevoltage has a nominal value of 0.9 V adjusted thanks to a potentiometer (blue square,just above the filter). It can be measured between ground and the test point shownon Fig. 2 To Be Done.The analog section also provides the power supply to the LNAs placed inside theantenna nut through a bias-tee system connected to the MMCX plugs. This meansthat in normal operation, a 12 V DC voltage is applied to the input plugs, which the2

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