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Jul 26, 2011, 02:56 AM
Registered User
RocketMouse's Avatar
Anybody! Please!

What is the best channel to use for Fox800 (with FRSky)?

For better range and less interference.
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Jul 26, 2011, 03:18 AM
Registered User
bingo17's Avatar
Theoretically the lower channels should be better but the fox unit is very noisy.
What you NEED is a low pass filter from DPCAV

Quote:
Originally Posted by RocketMouse
Anybody! Please!

What is the best channel to use for Fox800 (with FRSky)?

For better range and less interference.
Jul 27, 2011, 02:36 PM
Registered User
Adekamer's Avatar
i make filter coaxial resonator
http://adekamer.webs.com/tech.htm#frsky (lenth 20mm cover - not total lenth)


video before coaxial resonator
164146.AVI (12 min 36 sec)

after coaxial resonator
164146.AVI (12 min 36 sec)

look right corner signal strength
Jul 28, 2011, 02:37 PM
Registered User
Quote:
Originally Posted by RocketMouse
Anybody! Please!

What is the best channel to use for Fox800 (with FRSky)?

For better range and less interference.
the best are 1160 and 1280 means channel 6 or 9.

Last time I made 5.3km on frsky:
- hack module no telemetry installed in 13 years old graupner mc12
- Fox 800 on channel 6 1160mHz + self made vee
- designed by myself rssi module (top left corner)
- booster + 5dbi frsky antenna

No filters, not even a good bec (I use the swithing one from turnigy plush 40)

My plane is designed and built from scratch by myself - 2m wingspan


FPV FrSky 5290m (28 min 31 sec)


I had some interruptions in link but with good panel antena and tracking this setup could reach 10km.
You can start watching from 15:20 - before I was flying without any destination until I found nice clouds to catch
Last edited by Mieciu; Jul 28, 2011 at 02:42 PM.
Jul 28, 2011, 05:08 PM
Navigator
volto's Avatar
Mieciu, I am having trouble with my RSSI I got from uav.org.pl. I made a post in the UK fpv forum here, pictures on page 2 of that thread. I left a message on the live support on uav.org.pl and also posted in the polish fpv forum, but no response. Any help getting this working would be much appreciated.
Jul 29, 2011, 02:16 AM
Registered User
Quote:
Originally Posted by volto
Mieciu, I am having trouble with my RSSI I got from uav.org.pl. I made a post in the UK fpv forum here, pictures on page 2 of that thread. I left a message on the live support on uav.org.pl and also posted in the polish fpv forum, but no response. Any help getting this working would be much appreciated.
maybe mistake in connection? that's really simple circuit. I saw you soldered a wire to green diode but what about the rest?
Jul 31, 2011, 10:44 PM
Navigator
volto's Avatar
Quote:
Originally Posted by Mieciu
maybe mistake in connection? that's really simple circuit. I saw you soldered a wire to green diode but what about the rest?
I re-soldered to the green LED and now it works. Go figure. It passed the continuity test but still wasn't a good enough solder joint I guess. Thanks!
Aug 02, 2011, 08:17 PM
Registered User
Adekamer's Avatar
sorry!
vid1
164146.AVI (12 min 36 sec)

vid2
132904.AVI (9 min 47 sec)

look low-right corner: "rssi"
Aug 02, 2011, 11:32 PM
Registered User
Quote:
Originally Posted by Adekamer
look right corner signal strength
quite a strong improvement!

This is a quarter wave coaxial resonator (trap)? so acts like a notch filter rejecting all other frequencies?

That RSSI is signal strength of command RC, not video received RSSI, yes?

Did you find the coaxial resonator improved video quality?
did you install one on ground station video antenna?

thanks.
Aug 02, 2011, 11:57 PM
Registered User
Adekamer's Avatar
Quote:
This is a quarter wave coaxial resonator (trap)? so acts like a notch filter rejecting all other frequencies?
yes

Quote:
That RSSI is signal strength of command RC, not video received RSSI, yes?
yes, it RC signal from GREEN LED receiver Frsky

at ground system i not install coaxial resonator , i use lawmate 1.2 gHz video receiver & 1watt traceiver
tranceiver with custom V-e antenn
at graund 2 receiver and diversiti Eagle stantion and 2 custom antenn too.
Aug 05, 2011, 03:00 AM
Houba ! Houba !!
rcmonster99's Avatar
Quote:
Originally Posted by Adekamer
i make filter coaxial resonator
http://adekamer.webs.com/tech.htm#frsky (lenth 20mm cover - not total lenth)

Adekamer... I am not sure to understand. I clicked the link you offered and unfortunaly my Russian is very poor

I see you made the 1/4 resonators, then solder those to the aerial U.FL connector. then there is another picture of what looks like an V aerial with a coaxial cable connected at 90 degrees. I guess this has nothing to do with the FRSKY as there is a SMA connector at the end of this assembly?

So my questions are:
1- what aerial did you connect to the FRSKY ? was it the stock antenna?
2-I understand the Quarter-wave (λ/4-wave) coaxial resonators is constructed by shorting the center conductor of a coaxial cable to the shield at the far end of the circuit. The length of the cable is exactly λ/4 at the desired resonant frequency.
Could you draw exactly what you did ? is the grey cable length 31.25mm ? what is under the black heatshrink? is it the short between the coax centre and the shield?

sorry to be a pain but I would love to try this and want to make certain I am not going to blow up something
Aug 05, 2011, 07:26 AM
Registered User
Adekamer's Avatar
http://www.rfcafe.com/references/ele...-resonator.htm
1 -yes - it stock antenn,but i cut little him (~27-28mm)
2 -no! Quarter-wave (λ/4-wave) -not true! λ/4-wave * 0.69 = ~20-21mm
0.69 - approximately for coaxial cable
black heatshrink - true: short between the coax centre and the shield
Aug 05, 2011, 01:03 PM
Houba ! Houba !!
rcmonster99's Avatar
Thanks adekamer, Don't understand why the 0.69 factor but hey, If it works for you it will work for me
Aug 05, 2011, 01:37 PM
Registered User
Adekamer's Avatar
Quote:
Originally Posted by rcmonster99
Thanks adekamer, Don't understand why the 0.69 factor but hey, If it works for you it will work for me
0.69 - this average value for most coaxial cables (usualy range is 0.65-0.71)


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