900mhz or 5.8ghz for RealTime fpv video?

[aForcefulThrust]

Ok so I have a 2.4ghz spectrum radio. I plan to boost the signal and try to get atleast 2 mile range.

I have a 900mhz video transmitter now. Should I get a low pass filter for 900 and cloverleaf antenna, or just get a 5.8 video tx and just start over. I hear the 900 can cause interference with my 2.4 dx7s radio.

Thanks!

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[Madryan]

Firstly it depends how far you intend to fly this thing... 900Mhz is better, i have both a 900mhz and a 5.8ghz...the 900mhz has more range .....but it depends on hw many MW it puts out as well... I have a high wattage 2.4 amplifier i tried out...not saying how high cos i don't think its meant to be used here i just tested it thats all... but the 900 video works a treat .. 5.8 i found got more interference but thats just teh airwaves where i live....could be different for you..just depends how much money you want to burn testing things out...ok i re-read yer post....the 2.4 is more likely to swamp your video if you boost it... i actually bought a FM 36mhz radio and tried using the boosted 2.4 video from teh flight platform back to to base...that worked better but i just have a really uneasy feeling about using fm where i am.. just another or option... i haven't played around with this for ages...just saw your post and got me interested in it again...might dig it out one of these days again.


Just from my own experimenting ...

cheers

[aForcefulThrust]

Thanks! I would like to go uhf but.... I read on the Thomas scherrer site the dx7s has no ppm out or something lol. Im thinking this
http://diydrones.com/profiles/blogs/...ost-your-24ghz
May be my only option. So maybe 5.8 would be better with that? Idk... don't have allot of money to spend testing, just need to know what will work for me! Thanks for tips..

Edit: and my video tx is 500mw

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[zeeflyboy]

Boosted 2.4 is, in my opinion, not ideal.

You'd be better off getting an EZUHF/Dragonlink/Thomas scherrer and then as a super cheap option picking up a turnigy 9x to wire it up to. As a slightly more expensive option second hand modular futabas or JRs make a good choice...

Even cheaper still, you can pick up an old 72mhz radio which will be good out to a couple of km on it's own for peanuts.

alternatively, read this about the dx7 and LRS systems http://www.fpvmanuals.com/2011/03/17...ezuhf-or-tlrs/

for video link, if not using 2.4ghz for control it makes a better choice than 5.8ghz for video. 5.8Ghz is very clear but the transmitters are inefficient and get quite hot, it's quickly attenuated by atmosphere so range is limited, and it is seriously sensitive to obstacles... you have less interference issues than with 900mhz in general, and the equipment is generally more sensitive. 900 Mhz is better for longer range though and will pass obstacles more easily... really hard to answer the question for you. You need to decide what you want to achieve, read up about the pros and cons of each and then make a decision that best suits your goals.

The only reason to use 5.8ghz though imo is if you can't use 2.4ghz (due to using it for control, flying with other guys on 2.4 etc etc).

[aForcefulThrust]

I really want to go UHF if possible...

" Spectrum DX7SE DO NOT WORK,ONLY DSM MODE; NO PPM OUT MODE NOT EVEN INTERNALLY" Saw this on Thomas Scherrer site and got me worried....

did some research and aparently, The DX7SE is NOT the same as the DX7S that I have. Spektrum models can be a bit confusing: DX7, DX7SE, and DX7S(my model). From what I've read the DX7SE and DX7 are older models and have been discontinued. So maybe my DX7S will work?

Exactly what is PPM out and how can i find out for sure if my TX has it? Is that the trainer port?? I'm about to take my TX apart and investigate
I can't find anything over google about dx7S and uhf or ppm..

[Madryan]

Thi sexpalins PPM and PCM...i agree with above...900Mhz is a better option.. and he is right about teh poor performance of 5.8 my transmitter gets very very hot..and guzzles the battery... low power low frequencey.. efficent..less susceptible to atmosphere and obstrucition......anyway theres a lot out there on thsi stuff do your homework and you will be fine...dont pull your radio apart that will achieve nothing...PPC and PCM are both FM frequecy.. just explained different..nothing to do with your radio..your radi uses DSM ...

hope this helps a bit.

cheers

LINK HERE >>>
http://www.aerodesign.de/peter/2000/...M_PPM_eng.html

[zeeflyboy]

DX7S is a completely different radio to the DX7.... It's basically a dx8 with a few features and one channel missing.

Should have ppm out on the trainer port just like the dx8.... You simply need to plug the UHF system into the trainer port (may involve making your own cable, not hard) and then supply power (probably an external 3S lipo... Depending on system chosen) to the UHF. Job done.

[Adidas4275]

from my experience I have found that 1.2-1.3ghz with a low pass filter or bandpass filter is the best of both options.

It has the range and ability to go through trees and other objects like 900mhz but has better image quality and smaller antenna (CP) than 900mhz.

Also many of the 900mhz vRx are old tech that are not very sensitive and pick up a lot of other RF noise.



5.8ghz is high video quality and the vRx are newer tech that makes them more sensitive meaning you dont need as high of a mw output to go LOS distances.

5.8ghz is suseptable to reflections and WiFi noise. I have not had good range with 5.8 and get a lot of glitches. Other environments will dictate the frequency needed.


Never use the stock antennas. CP antennas like the ones IBcrazy makes are the best for multipath rejection and reflections.

1.3ghz CP antennas are a little large, 5.8 is better in terms of size.

My Lawmate 1w 1.3ghz vTx and lawmate 1.3ghz vRx work very well.

I also have a BOB 1.2ghz 800mw kit that works well also.


but with 1.2 you need to use a filter so you dont knock off 2.4ghz


I would not use 2.4ghz even when i use UHF because all the rest of the guys I fly with use 2.4ghz..... so that would not turn out well.


I use my dragonlink via trainer port on my Dx8 with out any issues.


some of my FPV flying with my Y-6s and Skywalker. Soon to add a wing to the mix as well.

[ame]http://www.youtube.com/watch?v=-eOaCWqxDL8[/ame]
[ame]http://www.youtube.com/watch?v=zz-moVAFA-Q[/ame]
[ame]http://www.youtube.com/watch?v=Zz1xRDgiBnI[/ame]
[ame]http://www.youtube.com/watch?v=s6gvzoaCWzw[/ame]
[ame]http://www.youtube.com/watch?v=IXSzdFa9yVo[/ame]
[ame]http://www.youtube.com/watch?v=KlCZUb0VNLY[/ame]


http://videoaerialsystems.com/produc...s/ibcrazy-vee/

Good info on 1.2-1.3ghz kits
http://www.rcgroups.com/forums/showthread.php?t=1279902