Turnstile UHF RX antenna tutorial

[IBCrazy]

Foam should be no problem. The antennas bandwidth is huge, so the dielectric effects of the foam should be minimal.

-Alex

[Jameson]

Hi Alex,

thank you very much. I placed it this way - I can't wait to see how it will work!



God bless you for all your ideas and help!

Rastislav

[IBCrazy]

Beautiful installation!

[kenkos68]

How much would I lose if I spliced the connection from the receiver to the antenna? In other words, I have a two piece wing and want to mount the antenna under the wing. The receiver is in the fuselage. I would just need to quick connect once the wing was mounted. I wouldn't be connecting directly to the receiver (Dragon Link) each time, but a short piece coming from it.

-Ken

[Jameson]

Hi Alex,

on Sunday I made a test flight. I positioned my two antennas (turnstile and standard dipole) as shown on this picture:

Turnstile is flat on the bottom of wing, Dipole is in 90 degrees, half above the plane, half under it. My radio antenna is pointed up (for vertical polarization). I flew about 3km, airplane was pointing away from me and a little to left, altitude about 400m. When I bank right, RSSI went down - for a little while RX went into failsafe. When I bank left, RSSI went to full signal strenght. Please, may it be something wrong with my antennas instalation? Or it may be just some kind of local interference?

Thank you very much for any advices!

Rastislav

[IBCrazy]

Sounds to me like a conductive ground problem. What you are getting is interference, not weak signal. It's hard to explain how it works, but basically conductive surfaces near the transmitter side will cause distrurbances in the RX. The signal bounces off the conductive surface and confuses the RX side as the reflected signal gets there a few microseconds late.

This is short lived and will be momentery in most every case. If you're sitting down when flying, the problem will be worse than when standing up. It's just the nature of RF unfortunately.

-Alex

[Jameson]

Thank you very much for your reply. In fact, I'm flying in the direct vicinity of TV tower (it's in 5.5 mile away, on the hill), so I have to count with some UHF interferences... I'll continue in testing when the wind calms...

[M'ck'y]

Is it okay to put fibreglass and laminate over the turnstile? it's currently mounted inside the foam on the top of the wing.
Attachment 1808

[IBCrazy]

That's ok. It will do fine.

[M'ck'y]

Thx, laminate going on tonight!