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s atv @ww #0 IC-471 ATV Cirquit ! Hello, it is possible to add an Upgrade to make the ICOM 471 a complete ATV and SATV TRX ! This Modification is not prepared by ICOM, so it's not only a 'plug in'- or 'cut Diode'-Modification. Because ATV is not "plug and play" i won't give Anyone a Circuit-Diagram, you have to find it out by yourself... (it's too easy). The Tricks are: 1) get some 70MHz-IF with a small pickup-C at the RX/TX-Commonpoint, that's on the RF.YGR-Board the Anode of D1, reamplify it (my picup is -24db, a MAR6 is +25db). 2) if ATV-TX: modulate your Signal (the Plessey SL5066 is UFB for this Job) (only modulate, NEVER make a new 70MHz-Signal (think abt PWR-Regulation)) 3) filter your Signal (i use the DC6MR-Filterdesign (5 Stages of 2 Tanks), if you want ATV and SATV you need 2 Filterbanks (wide / narrow)) 4) add the ATV-Tonecarrier behind the Filter 5) if ATV-TX: switch off the 70MHz-TX-IF-Stage, you are reinserting behind it. 6) reinsert though -10 db couple-resistor right before the 70->434-MHz TX-Mixer (at the hot Side of L11) 7) as ATV-RX do the same, but: pass an AMP instead of the ATV-Modulator, don't amplify to mutch befor the TV-Set (don't overdrive it). 8) a Switch to pass an RX-Signal through the ATV-Modulator allows you to check if ATV would be possible if your QSO-Partner would have ATV-Gear. 9) use the TV-Set-Output also as your ATV-TX-Monitor I's great to do 70cm ATV with the "IC-471ATV" like making normal Local-QSO's before, it's only switching on TV-Set and 'Cubic-Inch'-Camera or Camcorder, no wireing Touble like before. You can also use this Tricks to build a Highspeed-PR Modifikation, i suppose 2 Mbit/sec FSK should be possible this Way. Have Fun, 73 de Karl 1.Nov.1995 ***end

 

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