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-   -   2.4GHz Camera Systems with Spektrums (https://www.rcuniverse.com/forum/aerial-photography-video-81/6745736-2-4ghz-camera-systems-spektrums.html)

healthyfatboy 12-11-2007 11:26 PM

2.4GHz Camera Systems with Spektrums
 
I was wondering if there have been issues using the 2.4GHz camera systems with the newer 2.4GHz radios. I can imagine some problems especially if the camera output is high. What has been everyone's experiences with using these cameras with Spektrum, Futaba, and any other 2.4GHz radio systems?

JMSTECH 12-12-2007 10:44 AM

RE: 2.4GHz Camera Systems with Spektrums
 
Ahhh don't do it! [X(] Signals too close and will cross, then cause your bird to drop from the sky!!!!

healthyfatboy 12-12-2007 11:06 AM

RE: 2.4GHz Camera Systems with Spektrums
 
That's what I was thinking. Thanks for the information.

bkdavy 12-12-2007 11:13 AM

RE: 2.4GHz Camera Systems with Spektrums
 
Has there been any real testing of this? I have a 2.4 ghz video system, and I don't fly it when the 2.4 GHZ flyers are in the air because we don't have any real data. The only experience I've seen was one day at the field, I was getting the camera ready to fly, and noticed interference in the video signal. When i inquired, one of the Spectrum systems was operating. They didn't report any problems with their system. The spectrum systems are supposed to be pretty bullet-proof. Proximity could be an issue (flying spectrum system and video on the same plane) but it would be nice to seem some actual results.

Brad

wjglynn 12-12-2007 11:43 AM

RE: 2.4GHz Camera Systems with Spektrums
 
If you do a little research on the topic you will find that the Spektrum implementation of the 2.4gig frequency band divides that band into 80 channels. Each time a Spektrum transmitter fires up it scans the entire band looking for 2 unused channels which it then locks onto. Its receiver (that has been previously "bound" to the transmitter) finds its mate on those two frequencies and life is good. This is why they advertise that 40 Spektrum systems can be in the air at once. I am not as well read on the Futaba frequency hopping technology but the underlying FCC requirement that all manufactured devices be able to tolerate coexistance is probably the important factor.

I use a BWAV system on my airplane. It operates at a fixed frequency in the 2.4gig band. We fly fly the plane with Spektrum Radio gear. We use a 72mhz system to operate the camera mount. We have 20-30 flights under our belts with both gas engines and electric motor configurations without a single interference issue. The only question that might arise with the Spektrum system is what happens if a fixed frequency video transmitter fires up after a nearby Spektrum has selected the channel whose frequency matches the video transmitter? I posed that question to the Spektrum experts at the JR tent at Joe Nall and was reassured that the underlying technology will allow cohabitation of frequency by multiple devices.

I do not understand this underlying technology as well as I would like but I do know how computer ethernet technology works. When two nodes on an ethernet network generate data packets that collide, each node times out for a random length of time (milliseconds) and then attempts retransmission. Wireless ethernet networks do operate as FCC regulated 2.4gig band devices. I suspect that the rate of packet transmission is so high that a few dropped packets from collisions will not affect the reliability. Spektrum is also designed to use the packet from the best signal of the two channels so if one is intermittantly getting hammered it will merely use the other.


If I am correct with my theory then the only risk one runs is if the band gets saturated enough with traffic to cause a slow down in the service of messages between transmitters and receivers. While there are still some questions about specific scenarios I would not advise anyone to accept categorical dismissals of confidence in these systems. In time I believe that the track record will show that overall this technology poses less risk to your airplane than 72Mhz. technology. It is just not well understood yet.

For now I have both but all my new stuff will be Spektrum (along with my 2.4gig video xmitter).

(Coming to you today from under all the ice in NE Kansas!)

Bill

vince.b 12-19-2007 12:54 AM

RE: 2.4GHz Camera Systems with Spektrums
 
I use a 2.4 video system....
I have not flown it with the fasst system yet.
all the checks i have done show no signs of problems (rc link drops).
also from what i know about DSS modulation it will not be a problem.
when i move the rc tx between the video tx and rx there is alittle hum in the picture.
the futaba system is so fast it does not matter.
but i guess the other systems like spektrum could potencially have one if you fire your video system up after you power up the spektrum.
Futaba has been playing with DSS for along time. way longer then any of the other vendors. they have known this is where rc was heading for some time is my bet and they just waited until the hand was forced.
but for sure i will post here when we get some clear skies down here.
BTW on 72 megs from video off to video on i get a slight trim change on pcm and on ppm just alittle more servo noise untwised leads.
when i set up the test for the 2.4 futaba system i had the video tx and the rc rx togther... there was a little servo noise but no lose of link on a powerded down range test.
and mounted the video tx and the rc rx is 12" apart and 0 servo noise.
I can post here when i get a flight in.
for some video's on youtube check out
http://www.youtube.com/videocruzer
the DVD,s that i made from the last 2 flights are wicked clear and should look even better when the sun is in the right spot

JMSTECH 12-19-2007 02:44 AM

RE: 2.4GHz Camera Systems with Spektrums
 
Very nice Vince ;) Looks like Sannich area? :D I particularly like the trail of smoke from that glow, gives the video a nice touch!!! So did you ever get that video set up from Thomas working?

John

vince.b 12-19-2007 11:18 AM

RE: 2.4GHz Camera Systems with Spektrums
 
thanks
ohh yahh... thats the system. It would be nice if youtube told you what to compress it to b4 uploading.
I think i got the first video close on compression export but the 2nd vid they squished it alittle to much.
the ditail that you can see on the tv is awsome.... the tail braceses shake and vibrate at full throttle (more effect)
to the foot prints in the field.

THe plane I am puting together for the new season is a H9 Sundowner with a 220 in the nose.
the video should be more stable and alot faster.

vince.b 12-21-2007 04:05 AM

RE: 2.4GHz Camera Systems with Spektrums
 
YOu were right...
I tested the video 2.4 with the futaba fasst system.
I am pretty sure that I tried all 8 and was not happy at all with what i found.
range test without video on with low power boot on the radio was so far i could not see the controls move(about 250').
with the 2.4 1w video tx on the range looked to be cut by about 30% and when i walked away from the plane with body between the tx and the plane the range went done to about 50'. the most range i could get was about 150 to175'.that was channel 2 (2.430)
I should run into someone at the field this weekend if the weather holds. then i will be abale to get a true baseline on the low power boot.
I cant remember if I hit channel 8 . looks like its (2.510)
also the channel that had the longest range was alos the one that showed a clear video when there was a metal tailgate between the vidoe tx and the antenna.
other test i have done are when the other guys on 2.4 do a range test i put my camera model right beside there model and there is no lack of range at all.

I chose not to fly as the fields are very mucky this time of year.

JMSTECH 12-22-2007 12:46 AM

RE: 2.4GHz Camera Systems with Spektrums
 
Yeah I read that report before... considerably shorten range. That is why the FPV pros avoid the 2.4Ghz radios with their telementary gear. BTW this weekend is rain, rain and rain... we share the same clouds even though I live on the other side of the Malahat :D

JMSTECH 12-22-2007 08:52 PM

RE: 2.4GHz Camera Systems with Spektrums
 
Well the sun managed to peak through the clouds today but kind of windy. So I flew today and crashed my EZ* [:@], looks like back to the shop for glue therapy :D Actually I really should replace her since she's getting pretty warped from all the ...learning curves I've had in the past. :D:D

vince.b 12-22-2007 10:27 PM

RE: 2.4GHz Camera Systems with Spektrums
 
epp foam wing for the win...
mscomposite.com
the one i have is about 4' and I have flown it into all kinds of things on purpose :)
just use MG servos and one motor size up on the big one...
I have it set up right now with over 220 grams of glow wire and the inverter....

JMSTECH 12-23-2007 12:12 AM

RE: 2.4GHz Camera Systems with Spektrums
 
heh heh.. thanks for the tip Vince! I got my miss Frankenstein all fixed up! :D She looks so funny with all the signs of fractures on her nose, center fuse and now right wing! Maybe go for the record here and break the tail as well? Just to make things even better I reinstalled the lipo battery I use for A/V and guess what? I smelled that sweet smell of BBQ plastic! OH YEAH BABY I jumped and frantically ripped everything out of the fuse!!! The battery look fine after the crash but I think the nose impact must of crushed the wire leads inside the shrink wrap and when I pressed it into the fuse it must of shorted out! OH BOY!!! I guess no FPVing tomorrow, just traditional flying. More to come... the trilogy of JMSTECH FLYING ADVENTURE!! The CRASH, THE CHAOS, THE DESTRUCTION!!! That would make a great FPV video huh? Should make one of those next when I get into one of those destructive moods ;)

headhunter23 12-23-2007 11:13 PM

RE: 2.4GHz Camera Systems with Spektrums
 
Hey had been reading this thread and others. It seems there is a definite issue with spektrums and 2.4ghz video systems. Are there any controllers that do handle the 2.4ghz video systems well? Or is this overall?

Ivan.

JMSTECH 12-24-2007 01:07 AM

RE: 2.4GHz Camera Systems with Spektrums
 
Well Ivan let's just say 2.4ghz radio and 2.4ghz a/v tx don't like to share the same path. They fight and sometimes both loose at the end. ;) What's wrong with tradition radio anyways? I know jettpilot here get's 15 miles with a modded out antenna on his, even he would tell anyone not to combine the 2.4G radio along with 2.4G telementary gear as well.

headhunter23 12-24-2007 12:20 PM

RE: 2.4GHz Camera Systems with Spektrums
 
Yea had assumed that but it seemed to be more of an issue with the spektrums. I guess it applys to all the 2.4ghz radios.[:-]

Ivan


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