Larger antenna
#1
Jim,

I have an airplane with a narrow fuselage that is filled with a motor, ESC, motor battery, X10+RFU and servos.  The fuse also has a large metal landing gear bracket for the two main wheels.  I had signal blocking problems with this airplane with two different radio systems, including XPS.

Even when I placed the receiver antennas away (as much as I could in the small fuse) from those interfering parts and oriented them at 90 degrees to each other, there were still angles at which the receiver couldn't see the transmitter.  I would experience momentary lockouts until the airplane's orientation changed enough for the receiver antenna to come back into view of the transmitter.

I eventually placed one of the RFU antennas facing vertically down and sticking though the bottom of the fuse and this solved the RF blocking problem.  However, the little nub sticking out under the fuse sometimes gets knocked around by the occasional rock, or I bend it if I pick up the fuse by grabbing it at the wrong spot.

I ideally would like to locate a Nano or RFU back near the tail, away from the main part of the fuse.  Regrettably the fuse is narrow back there and it would challenging to install the Nano or RFU and route the antennas.  I could put a Nano or RFU out near a wingtip, but I can't run the serial cable to it because the wing is sealed.

Is it possible to have an alternative "larger" antenna than the standard "one inch" elements?  Could a longer wire antenna be tuned to receive the 2.4GHz signal?  I'm thinking of something like an old school 72MHz 39 inch wire antenna that could run from the back of the canopy out to the top of the tail fin.

(This is kind of an ironic request, given that for almost twenty years we've enjoyed the convenience of installing small 2.4GHz receivers with their tiny antennas and not having to deal with long wire antennas.)

Thanks,

Paul
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#2
You can't have any of the white part (tip) of the antenna longer (or shorter) than 31.23mm, which is the proper length for the 2.4GHz wavelength. You CAN have longer coax before the antenna tip though. You will see about 0.75dB attenuation for every 12" of coax length. Your antenna (white tip) length is by far more critical. You can have several feet of coax length which is result in a drop a few dB in receiver sensitivity. When it comes to receivers and their sensitivity, every 6dB of gain doubles the effective range. This also applies to loss. So, you don't want much loss anywhere in your setup, but using longer coax lengths (which are not a normally stocked item by anyone) would work.
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#3
Interesting. Thank you Jim, Paul
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