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Jun 09, 2011, 02:38 PM
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BEV 5.8GHz AV TX/RX Set


Hello, I have this FPV System but I cannot make it work!
Can you please help me?

Thanks!
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Jun 09, 2011, 06:27 PM
what goes up, must come down..
AussieHoppy's Avatar
Quote:
Originally Posted by Coyote64 View Post
Avoid channel 4 for the harmonics and you will be fine, seperate video channels by 100mhz
I am non-techo, but I am curious- would I be better off having some kind of filter thing on the Tx or Rx to close in on a given frequency so it isn't so broad?
I remember reading somewhere there is something that can be replaced to narrow the freq band... that is if I understood it correctly in the first place

I know when flying with other guys, all on 5.8, there's an amount of cross banding on different channels... unless we should be setting up our GS's further away from each other...
Jun 09, 2011, 10:15 PM
Registered User
Quote:
Originally Posted by OmarRG View Post
Hello, I have this FPV System but I cannot make it work!
Can you please help me?

Thanks!
Looking at your wiring and this http://www.bevrc.com/bev-58g-200mw-p...-fpv-p-18.html , it looks like your receiver ( if you have the same type) is not getting enough juice - - Working voltage: DC 9- 13 volts- Current consumption: 120mAh.

And using dry cells would be expensive

Kc
Jun 09, 2011, 10:43 PM
B to the O to the B
Ecibob's Avatar
Is there any real advantage to using a CCTV camera like the ones that are standard definition (DX-201, etc.) or an HD camera.

I see you can get these keychain cams for like $100... seems pretty reasonable and would be a new world over the others.

Is that true, are HD cams advantageous in practically every way?

Could I use it with a standard lawmate or other TX and RX?
Jun 09, 2011, 10:49 PM
Registered User
Thank you KCLeong18. I will change the power supply. I used this batt because I am still testing the system in my working table. Once on the plane I will use another one!. I will try tomorrow with more power and let you know the results!
Jun 10, 2011, 11:06 AM
Gig 'Em!
TexasAggie's Avatar
Very brief question - Of the FM frequencies (for RC control), does 72 MHz for offer the best combination of range and available receivers? I expect 35, 40, or 50 MHz would give better range, but it seems harder to find receivers and crystals.
Jun 10, 2011, 04:59 PM
Nevermind...
isaacintheclouds's Avatar
Had a successful first flight today viewing through a t.v. All went well thanks to all the good advice I got here. My VTX battery is a little heavy though, a 3s 910 mah. lipo. Someone here said it would be good for an hour or so. Since I dont need that long yet,could I lose a little weight with a 450mah battery or even less and still get 25 or 30 minutes with it? Thanks all!
Jun 10, 2011, 08:10 PM
Nakelp
nakelp86's Avatar
Need some help,
I tried three different microphones and everyone of them causes severe interference while working
Toroids do not help, dont know what to do anymore, any suggestion maybe for better microphone?
Jun 11, 2011, 12:42 PM
Registered User
Quote:
Originally Posted by QiW View Post
quick question ...
i am flying with futaba 2.4rc and currently using 900mhz video
i just acquired another video tx rx with the following frequencies ... which one will best suit my futaba 2.4rc without too much damage in the secondary harmonics ??
1 1080MHZ
2 1120MHZ
3 1160MHZ
4 1200MHZ

thanks
I would guess that 1080 would be the best and 1200 the worst. As always, please use frequencies that are legal in your country if only to avoid interference to yourself and other users of the frequency.

I recall that 900mhz may be cell phone frequencies outside the USA.

Cliff
Jun 11, 2011, 12:53 PM
Registered User
Quote:
Originally Posted by QiW View Post
another quick question
how far apart does the video frequencies have to be in order not to interfere with each other (assuming range between 900mhz to 1.2ghz) ?
planning on flying FPV together ...
Standard FPV links have an audio sub-carrier on 5.5mhz or 6.5mhz. Figure that the video is using as much as 3.5mhz in the center of the channel and you get a deviation of +-10mhz for a bandwidth of 20mhz; so that is the bare minimum.

The width of the IF in the receiver is generally a little wider than 20mhz (think of it as +- 10mhz), so you can get interference from a transmitter that is only 20mhz away that is transmitting +-10mhz.

Most FPV links have at least a 40mhz channel separation to avoid the possibility of cross channel interference. Some receivers will lock on to an adjacent channel if the signal is strong, but loose lock at any flight distance or if the correct channel is broadcasting.

I hear reports of adjacent channels on 5.8g bleeding through. To be honest I have little experience with multiple FPV links flying at the same time.

Cliff
Last edited by theothercliff; Jun 11, 2011 at 01:07 PM.
Jun 11, 2011, 01:05 PM
Registered User
Quote:
Originally Posted by AussieHoppy View Post
I am non-techo, but I am curious- would I be better off having some kind of filter thing on the Tx or Rx to close in on a given frequency so it isn't so broad?
I remember reading somewhere there is something that can be replaced to narrow the freq band... that is if I understood it correctly in the first place

I know when flying with other guys, all on 5.8, there's an amount of cross banding on different channels... unless we should be setting up our GS's further away from each other...
Filters on the transmitter are really only good for reducing harmonics, e.g. reducing the 2560 from a 1280 transmitter.

The IF filter in 910 and 1280 receivers can be replaced. The stock one is something like 22.5mhz and the replacement one is something like 17.5mhz. The major effect of this is to reduce noise and increase range, although it would help keep adjacent transmitters out too.

Cliff
Jun 11, 2011, 01:13 PM
Nakelp
nakelp86's Avatar
Quote:
Originally Posted by nakelp86 View Post
Need some help,
I tried three different microphones and everyone of them causes severe interference while working
Toroids do not help, dont know what to do anymore, any suggestion maybe for better microphone?
Anyone pls?
Jun 11, 2011, 02:12 PM
Registered User
I've just had my first ever FPV experience, and it hasn't gone particularly well. Im running a KK quad copter, a Markus Zingg vTX with his SPW and clover leaf antennas. It's a 5.8ghz system, 2.4ghz radio, and I managed about 20 feet range before the video signal was unworkable. I've connected the power through the easyOSD current sensor only, and this powers the vTX, EOSD and sony CCD Cam. I understand that ferrite rings may help reduce interference, but where, and how?

I'm going to go and try over again but with the OSD removed from the system.
Jun 12, 2011, 09:43 AM
Registered User

Do not adjust your FPV transmitter.


Quote:
Originally Posted by nakelp86 View Post
Need some help,
I tried three different microphones and everyone of them causes severe interference while working
Toroids do not help, dont know what to do anymore, any suggestion maybe for better microphone?
What FPV sender/receiver do you have? Have you adjusted it in any way? These systems require amplified audio that puts out standard "line level" audio of about .5 to 1.0 volts.

One of the first FPV systems that I bought was from r2hobbies and although it has a place for audio and comes with audio cables, the text of the ad does not mention audio and the audio does not work. Taking the transmitter apart, there are components missing in the audio section.

Do not adjust your FPV transmitter. Experimentation is tempting, but you will only do it more harm than good. Too much one way and both your bandwidth and harmonics go up past the limit. Too much the other way and your sync level and intensity may become unusable. Also, adjustments to the transmitter should be complimented with opposite adjustments to the receiver.

Cliff
Jun 12, 2011, 09:51 AM
Registered User
Quote:
Originally Posted by Jamiem View Post
I've just had my first ever FPV experience, and it hasn't gone particularly well. Im running a KK quad copter, a Markus Zingg vTX with his SPW and clover leaf antennas. It's a 5.8ghz system, 2.4ghz radio, and I managed about 20 feet range before the video signal was unworkable. I've connected the power through the easyOSD current sensor only, and this powers the vTX, EOSD and sony CCD Cam. I understand that ferrite rings may help reduce interference, but where, and how?

I'm going to go and try over again but with the OSD removed from the system.
You should get more than that for range.

Did you know that you must run CP antennas on both Tx and Rx.

Does this copter have significant metal or CF structures that might block the signal? Generally, you must always be able to see the transmitter antenna from the receiver antenna. Is the aircraft rotated so that the aircraft blocks the signal?

Do you know what the antennas should look like and do they look like that? They should be very symmetric with loops poking up at like 45 and 45 degrees (don't know exact numbers) each.

I would put the stock antennas back on for a test, and test it off the aircraft. 5.8ghz is the worst for line of sight and multi-path, but you should get at least several hundred feet.

I would PM Markus and ask for help.

Cliff


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