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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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Ive not played with the thing in a while but I think it had a trimmer. The guy that sent it too me said it was a good one as it was putting out 750mW instead of the 500mW that it was supposed to. I found the trimmer or what ever it was peaked right out, as soon as I backed it off it got more stable.

Ron, I think you are spot on.

Terry

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Just when I found a very good combination with the DPCAV antenna on the plane with a 500mw tx, 900mhz and the Future hobbies antenna on the headset, I make a hugh crash :(

It was windy, and with the wind on the back of my neck, I was placing the hood on my coat, I hit the power swicht of my goggle hat :o I lost the video at a worst moment, the plane crash at full speed near vertically...

I broke the DPCAV antenna and now the transmiter is defect. As you can see the antenna, I suspect the output transistor of the tx had burnt. If I come very close to the tx with my headset, I got a picture.

The output transistor is BLT80. They have it at Digikey and it cost only 0.99$, if you buy a reel of 1000 of course...

Do you think I probably only need to replace the BLT80 and do you know where I can get one?

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post-57-1237679681_thumb.jpg

Edited by Vrflyer
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Sorry to hear about the crash. It looks very bad.

Mouser the replacement transistor for under $2. But I have a feeling your transistor is still fine and that the problem is something else.

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Bad luck Denis, I crunched mine last week too.

Silly mistake as usual, the plane was in bad trim just after take off and I did not have enough left on the trims to trim it. I got it to a reasonable hight before putting my vr glasses on only to find I had forgotten to turn them on. In the time it took me to turn them on the plane had swung round 180 and was heading into a pilon. I pulled up and hard left but still hit it as the easystar dose not turn good. The wings were knocked off and the rest hit vertical but lucky for me it was all airframe damage and the good stuf was ok.

I should of landed when I could not trim it properly and again when I found the glasses turned off but........ http://www.vimeo.com/3798288

Terry

Edited by Terry
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Bad luck Denis, I crunched mine last week too.

Silly mistake as usual, the plane was in bad trim just after take off and I did not have enough left on the trims to trim it. I got it to a reasonable hight before putting my vr glasses on only to find I had forgotten to turn them on. In the time it took me to turn them on the plane had swung round 180 and was heading into a pilon. I pulled up and hard left but still hit it as the easystar dose not turn good. The wings were knocked off and the rest hit vertical but lucky for me it was all airframe damage and the good stuf was ok.

I should of landed when I could not trim it properly and again when I found the glasses turned off but........ http://www.vimeo.com/3798288

Terry

Just a fast question what´s that osd you´re using there?

BTW nice vids you have on vimeo, finally I see some of your videos online :)

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Thanks Wavess, all those videos are just raw test footage most or them for my 4way system and the 5.8Ghz gear. I don't aim for good videos as my main aim is for still photos. http://myweb.tiscali.co.uk/elevated/gallery.htm

The OSD is the Remzibi OSD but it seems the home point did not set correctly for some reason, its been ok on all my other flights but my video recorder has not :(

Terry

Edited by Terry
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Yes, the video Tx likes the simple monopole wire whip that is included by the manufacturer, but that antenna is not high performance. However, if you have time, you might want to put it back on the Tx and see how all the other antennas work out when they are used on the video Rx.

If you learn anything new then please share!

I've done some flights with the DPCAV antenna on the plane and the 200mw tx on channel 4, I was using Future hobbies antenna on the headset. I got less good reception with this tx compare to the 500mw. When the plane turn and the wings are not level, I noticed immediatly diminution in reception strenght, and when the plane bank at 30deg and more, I lost completly the video per intermitence.

I had replace the DPCAV antenna with the standard monopole antenna that come with the tx. I was highly sceptical, I was just turning my head on ground and was loosing completly the video while the plane was at my feet... I was ready to remove the headset in flight. Amazingly it perform better than the DPCAV, now the plane need to be at 90 deg in turn to lost completly the video, strenght was reasonable when flying beyond some trees. I lost also the video partially when I fly above my head.

I'm very please with the result, this tx is perhaps not enough powerfull for my kind of flying, aerobatic and true trees near ground, but will work very well with my small T-rex 450 helicopter or small plane. Also the original antenna is very small, light and can be bent easily without dammage, that will be a great advantage on helicopter, the antenna will exit under the helico and bent at landing.

I'm very please with the 500mW tx too, the flights I made last week end with the DPCAV on the plane and the Future hobbies antenna on the headset was very good, I did not loose the video at all even when the plane was turning tight or flying beyond the trees, but I had many video dropout, it was looking like flying inside a Canadian winter storm, so it's not a problem for me :)

Last week I was searching on the future hobbies website for another 900mhz antenna like mine, but sadly he don't sell it anymore. The next day while opening a package received from Deal extreme I was stunt to see this antenna inside the package :o

http://www.dealextreme.com/details.dx/sku.5241

This one is white but it is identical to the Future hobbies antenna, and it cost only $3 with free shipping. So everyone who fly or evaluate 900mhz rx/tx, I would suggest you to buy one and make some test. I don't understand why, but in every test I made, this antenna was performing better on the receiver than all other antenna, even the most expensive. Kept in mind I don't fly long range, it's not good for long distance flight but the best one to fly around inside 1/2km (not tested beyond). I also did not tested it on the plane yet, it comparable in size to the HG903RD

Edited by Vrflyer
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I had replace the DPCAV antenna with the standard monopole antenna that come with the tx. I was highly sceptical, I was just turning my head on ground and was loosing completly the video while the plane was at my feet... I was ready to remove the headset in flight. Amazingly it perform better than the DPCAV, now the plane need to be at 90 deg in turn to lost completly the video, strenght was reasonable when flying beyond some trees. I lost also the video partially when I fly above my head.

From what I have learned from my bench testing, the 900Mhz 200mW video Tx is not RF stable when a common dipole antenna is installed. There seems to be a design issue in the Tx that needs to be resolved. Until the design bug is fixed, I would highly recommend that you continue to use the simple monopole wire whip that the manufacturer provides.

Fortunately the 500mW Tx is a much better design and works great with a real dipole antenna like the ones you received from DPCAV. For sure, don't use the simple monopole wire whip with the 900MHz 500mW model if you want longest possible range and the least interference to nearby electronics.

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  • 1 year later...

I'm brand new to FPV hobby and all of gear from DPCAV and it is the 900MHz Pro-Series A/V Transmitter 500mW,and the question is, it came with the 900MHz Rubber Duck Omnidirectional with +3dBi gain antenna with SMA Plug. And my other FPV fliers told me to go with the half-wave monopole design would that be a good idea,omnidirectional with +2dBi gain, the rubber duck is a little big for my project it's a 60 size trainer. Any help would be nice.

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Antenna choice is all about compromises and you need to decide what is best for your situation. Regarding what is best for the video transmitter's antenna, if better performance is wanted then the dipole you already have is a good pick. If small antenna size is more important than performance then you might decide to use a OEM style monopole since they are very small. As far as the dipole being too big -- a .60 size trainer is a large model, so you should be able to haul a baseball bat size antenna with it. :)

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For the record, I built the Goof Proof Patch scaled to 1.2ghz. Fantastic. For the test I used the cheap stuff: the little mini cam/transmitter 1" cube with a pitiful little wire antenna. Yup, the RX with a TUNING knob. Works almost 100 yds with some video loss on the stock antenna. With the patch: unlimited. I flew all over with no video loss. I just forgot the patch was directional. I could fly behind it at close range. I never aimed it. Seems to have 180degree FOV. How far? I lost the plane about 1/2 mile out due to RFI hitting my 72mhz crystal RC RX. My bad. Took 2 days to find it. But the VIDEO was perfect right to the end. The plane, 55in. foam electric, was recovered (across the river) without a scratch. Only damage was 2 lipos discharged to the point of no return. So now, I'm building the 910mhz version for my PLL RX and 200mw TX. More on that later.

But all this just drives home your point about the neglected receiver antenna issue. BTW, I'll be using my bullet proof RC receiver for future tests. My RC can reach a mile, but I suspect the video link will eclipse that thanks to your patch design. Thanks for sharing your research.

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