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Serveurperso

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About Serveurperso

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    RC-Cam Visitor
  1. Hi, From left to right, antenna on the left side, "ComTech" brand (and white BSS479LAIDFM sticker) on top. __------------ Antenna-__ | | | |___________| 1 234 56789 1 -> LNB or LNA power supply (only needed if you want to feed a preamp powered by coax cable) 2 -> Analog 0-5V RSSI level 3 -> 5V regulated logic power 4 -> Baseband out (mixed video + sound subcarrier) 5 -> I2C DATA 6 -> 9V PLL charge pump power (>9V for >1500MHz!) 7 -> I2C CLOCK 8 -> not needed (PLL programmable out) 9 -> not needed (PLL programmable out) Ground is the metal case. Remove the old tuner Use a multimeter to find 5V and 9V Use a headphone to find baseband (white noise) Use a headphone to find I2C data and clock (typical data burst noise only when you change the channel switch) Reverse I2C data and clock if the RX frequency dont change. 10 minutes operation and no risk for your baseband board IF you're used to "DIY". Pascal
  2. Hi, Here is the "1.0 final" stuff : Features (sorry for me english lol) : Rotary encoder and fast/easy to use OSD GUI. Decade Engineering BOB-4 OSD module @ maximum processing speed / maximum display optimisations / 50Hz refresh rate (my SPI bus run @ 1MHz) 4 (up to 16) "17mhz saw modded" tuners diversity Visual RSSI bargraph for each tuners / diversity selected tuner / usefull diy antenna or low noise preamp comparison tool Diversity algorithm that takes into account the background noise level /w manual or auto trim. Live "poor man's spectrum analyser" mode, PLL charge pump configured @ 170uA for spectrum and 50uA for normal tuning (In the future a dedicated tuner with a very narrow bandpass 480MHz IF filter give a better spectrum display / selectivity) Next I test a way faster refresh on an OLED display module. PPM output for the training cable, this receiver can synchronise any VTX PLL (1 cheap arduino mini pro for 1 modded TX) Manual frequency hopping + non standard RF usage/non standard CCTV channels = bulletproof/virtually undisturbable video downlink Individual AFT/AFC Automatic Frequency Control / Fine Tunning on each tuners -> A closed loop "servo" frequency control with individual bargraph + or - 2MHz -> compensate for tuners components tolerances, usefull @ long range/ for weak signal And there is still 90% free space in the groundstation ATmega2560 for telemetry / antenna tracking and more DIY stuff ! Next -> double conversion superheterodyne tuner ? Pascal
  3. I make my own FPV (or HAM/analog ATV) receiver with (saw upgraded) comtech tuners (Arduino replace the PIC for I2C, decade bob-4 for a basic spectrum analyser GUI). This is the first test of my homebrew RSSI diversity and PLL controler : http://www.youtube.com/watch?v=BU7yOY8PXqg I can also control any transmitter on custom frequency:) My five Comtech have exactly the same calibration, you can see only somes small clip when the multiplexer switch. (four tuners are tested on this video)... I use only One baseband PCB!! (3 wire only is needed, GND, baseband and 8V reg), 5V must be external, the onboard 7805 can't power 4 tuners. It's easy to recover pinout inside any receiver (to swap a crappy tuner with a good Comtech) -> GND, 5V and 8V. I2C CLK, I2C SDA can be reversed without damage. On Comtech, there are only two contacts remaining, RSSI, and LNB power (to power the new "EME" Ultra Low Noise preamp from MiniKit:))) Pascal
  4. Hi, My T-Rex 250 FPV (small heli without any stabilisation system) : For me flight agility is the best on (CP) helis:) Regards, Pascal
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