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Attention: RC-CAM.com will be closing down August 2021.

The RC-Cam.com forum was the very first online community dedicated to the advancement of wireless video cameras on radio controlled (R/C) models. This is now called "FPV" (First Person View). We are proud of the contributions that our members have made to the FPV hobby.

We've seen significant changes over the last twenty years. Initially there were a lot of eager R/C hobbyist that built their own video systems. Allowing these creative individuals to share their work was the purpose of this site. Now the FPV market is flooded with low cost systems; Sadly DiY FPV video projects are now rarely discussed.

RC-CAM.com (main site and forum) will be closing down August 2021. This is being announced now (March 2021) so that everyone has time to download any information that is important to them. After the site is shutdown the information will no longer be available here.

We appreciate every member's involvement with advancing the FPV hobby. It is indeed sad to say goodbye to all our online friends. Be safe and stay healthy.

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In my continuing hobby-level experiments I tried something today with crummy results that seemed kind of odd and I can't figure out what was going on.

I used both a 500mw 900Ghz TX and a 250mw 5.8Ghz TX on the same heli, mounted about 4" apart, both with the stock whip antennas facing straight down to the ground. My thinking was that if one frequency was not getting decent reception for whatever reason the other frequency might work fine. The wiring from the camera up front was spliced to feed both TX units and I ran all three devices from one 3 cell lipo, separate from the lipo for the heli's power. The two ground receivers were connected to an Oracle diversity unit and the resulting output was a fast flicker from with the image from one frequency shifted slightly out of registern with the other. The 900Ghz receiver was pretty standard with an 8dBi patch antenna and the 5.8 receiver was a Yellowjacket Diversity receiver with two 8dBi patch antennas. When I manually switched the output from one receiver to the other the image was indeed shifted. I'm no rocket scientist but it seemed very odd to me since both receivers were using the identical video signal (weren't they?). Needless to say, the heli never left the ground and I guess I won't be trying this again.

Any comments? Would it possibly have worked with both TX on the same frequency? Also, while I'm here... Has anyone used the DMD long range fpv equipment with better than usual results and is there any where you can get English documentation for their product?


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If you are seeing slightly shifted images then that is not normally a problem. However, it sounds like you have connected the camera in parallel with both video Tx's without the required buffer/amplifier to ensure video levels are maintained. If that is what you have done then you will invite problems and will usually freak out the Oracle because the video levels will be non-standard.

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