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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.


dalbert02

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About dalbert02

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    RC-Cam Regular
  • Birthday 03/31/1971

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    http://www.miamidade.gov/mdfr
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  • Location
    miami, fl
  • Interests
    saltwater flyfishing, uavs, biking, urban exploring
  1. dalbert02
    I started a little post on the history of FPV over at RCG. May you guys that don't frequent that site check it out and offer any corrections or additions or point out any errors. I won't be offended. Thank you. -dave http://www.rcgroups.com/forums/showthread.php?t=1585073
  2. dalbert02
    I'd like to send my GPS coordinates from my airplane. I currently use APRS via the audio channel and a TinyTrak but I would like an alternative to get the GPS sentences into my computer/ground station. Thanks, -dave
  3. dalbert02 started following telemetry radio, a maxstream alternative
  4. dalbert02
    Anyone ever hear of friendcom? http://www.friendcom.com/En/pro02.htm I could only find one distributor in the US, perhaps in Europe they are more available? https://www.argentdata.com/catalog/product_info.php?products_id=107 Do you think they may be worth a gamble as a cheaper alternative to Maxstream Xtend? -Dave
  5. dalbert02
    Any opinions on gray PVC used here and white PVC and effects on velocity factor? -dave
  6. dalbert02
    Finally, sorry for the low quality graphic. I changed to grayscale and made it as large as I could to fit within the 250k file limitation on this board. -dave
  7. dalbert02
    Finally, T3 is a narrow band sweep of the modified antenna. If anyone is interested, I can post the original data files and you can download the free Anritsu software so you can play with the position of the markers, plot Smith charts, or create a return loss plot. -dave
  8. dalbert02
    T2 is a narrow band sweep of the original.
  9. dalbert02
    Attached are the SWR plots of before and after. T1 was a wideband sweep of the original antenna.
  10. dalbert02
    Sorry for the long delay. Sometimes there is not much activity here so I forget to check often enough. Regardless, here are some pics of IBCrazy's helix antenna. Both before and after compressing the coils. I used a sharpie to trace the original wire path and to use as a guide while compressing the coil. -dave
  11. dalbert02
    One more I am curious about, what are your thoughts on this (if you do not mind)? http://www.trivec.com/landbased_av2055.html Obviously this would be a recieve only antenna and need to be built for your frequency. I like the idea of portability, circular polarization, and light weight. I'd love to build one for 2.5Ghz if I could find some plans on it. Thanks, -dave
  12. dalbert02
    Thank you very much for the idea of using an attenuator. I just won a bid on a really expensive Pasternack stepped attenuator on eBay (won for only $60!) but I don't think it is rated up to 2.5Ghz. The fixed attenuators are not that expensive so I will look at those. I know Meca and MiniCircuits mentioned make descent ones. Are there any other recommended brands or brands to stay away from? Thanks, -dave
  13. dalbert02
    Nigel, That link is awesome! Thanks! Thomas, Your link is not working. I tried searching the site but did not come up with anything. Perhaps I am over thinking this. I want a wide margin of error (+6db) for an upcoming mission. I need to fly several kilometers over ocean and can not have a video failure. Given: Rx sensitivity -80db for an acceptable picture Rx antenna +10dbi Tx +27 dbm Tx antenna 0db gain Cable loss 3db (1.5 on each side) 2510Mhz 10km Then I'll have 120db of path loss and an RSSI of -86.4dbm. http://www.distributed-wireless.com/calculators/pathl
  14. dalbert02
    Thank you very much for your insight. Now on to my next question. Assuming I go with a dish antenna, I would like to calculate the expected gain for a dish of d diameter. From Wikipedia (http://en.wikipedia.org/wiki/Parabolic_antenna) I learned that the Gain G of a dish can be expressed as G = ((4 π A) / λ2) eA or G = ((π2d2) / λ2) eA Where G = Gain A = Area λ = wavelength d = diameter eA = is a "dimensionless parameter called the aperture efficiency. The aperture efficiency of typical parabolic antennas is 0.55 to 0.60." So for an example, if I look at a dish from Hyperl
  15. dalbert02
    Here is a link straight to the tutorials. Complex to Real Tutorials -dave
  16. dalbert02
    If I had: a dish that claims 24db of gain a yagi that claims 24db of gain a patch that claims 24db of gain and they are all tuned to the same frequency, would you expect equal range out of each? Is one type of antenna any better than the other for any reason? Thank you, -dave
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