Help!! Rx Antenna Attenuation???
06-05-2002, 03:01 AM
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Help!! Rx Antenna Attenuation???
Hey guys,
A friend of mine has just finished a TGA F-15, now with a half dozen flights on it. We have a strange problem, though and are wondering if anyone has seen this in the past...
Initially, the Rx antenna was routed internally along the top of the left nacelle longitudinally. When we did a rangecheck, it was only about 50'!! After scratching out heads a bit, we pulled the antenna out of the nacelle and laid it on top of the fuse - still longitudinally, no change in range. Then I grabbed the antenna and lifted it up - Immediately the plane came out of failsafe, and the range check increased to over 200' - more normal for the field where we fly.
The surface tested on is ashphalt, 50' wide. The F-15 is epoxy fiberglass (or close to it, we think), and it is painted with TopFlite gloss paint and foam core (factory sheeted). There is also a servo lead that runs parallel to the antenna to the tail elevator servo, about 1" away from the antenna. We can find no source for EM interferance - no metal on metal, etc. The radios are JR, on Channel 16, with a Z-PCM 9ch Rx and an XP8103 Tx with antenna collapsed for the range test.
Why would this happen? We do fly it with the antenna clipped to the fin, but it looks kind of weird. I don't remember seeing too many military jets with external antennas, so what are we doing wrong?
Any help is appreciated. Thanks!!
A friend of mine has just finished a TGA F-15, now with a half dozen flights on it. We have a strange problem, though and are wondering if anyone has seen this in the past...
Initially, the Rx antenna was routed internally along the top of the left nacelle longitudinally. When we did a rangecheck, it was only about 50'!! After scratching out heads a bit, we pulled the antenna out of the nacelle and laid it on top of the fuse - still longitudinally, no change in range. Then I grabbed the antenna and lifted it up - Immediately the plane came out of failsafe, and the range check increased to over 200' - more normal for the field where we fly.
The surface tested on is ashphalt, 50' wide. The F-15 is epoxy fiberglass (or close to it, we think), and it is painted with TopFlite gloss paint and foam core (factory sheeted). There is also a servo lead that runs parallel to the antenna to the tail elevator servo, about 1" away from the antenna. We can find no source for EM interferance - no metal on metal, etc. The radios are JR, on Channel 16, with a Z-PCM 9ch Rx and an XP8103 Tx with antenna collapsed for the range test.
Why would this happen? We do fly it with the antenna clipped to the fin, but it looks kind of weird. I don't remember seeing too many military jets with external antennas, so what are we doing wrong?
Any help is appreciated. Thanks!!
06-05-2002, 05:50 AM
#2
Help!! Rx Antenna Attenuation???
Randy,
You should've checked out the article on TGA set up tips located in the US RC Jet Command site located at: http://www.usrcjc.org/howto/TGF15Mods.htm
The recommended antenna routing is down one of the leading edges and through a yellow nyrod (pre-installed behind the leading edge). Mine has flown glitch/lockup free using this system for over two years. I guess you could still tape the antenna to the outside and along the bottom of your wing to keep it out of view. Also, consider one of those vertical whip antennas that the turbine guys use. I use the silver one on my HotSpot and it is not visible in flight. They did increase my range significantly.
Good luck!
You should've checked out the article on TGA set up tips located in the US RC Jet Command site located at: http://www.usrcjc.org/howto/TGF15Mods.htm
The recommended antenna routing is down one of the leading edges and through a yellow nyrod (pre-installed behind the leading edge). Mine has flown glitch/lockup free using this system for over two years. I guess you could still tape the antenna to the outside and along the bottom of your wing to keep it out of view. Also, consider one of those vertical whip antennas that the turbine guys use. I use the silver one on my HotSpot and it is not visible in flight. They did increase my range significantly.
Good luck!
06-05-2002, 12:38 PM
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Great stuff!
Thanks - That's quite the list! I was unfamiliar with that site, and we will try some of those suggestions - unfortunately the jet is completed at this stage and some will not be possible.
But I am still curious why the signal attenuation would happen???
But I am still curious why the signal attenuation would happen???
