[DaveV]

NOTE: ALTHOUGH SOME INTERESTING COMMENTS IN THIS THREAD IT IS ALL FOR NOT. THE PROBLEM APPEARS TO HAVE NOT BEEN RELATED TO THE CHROMEKOTE. PLEASE SEE MY FINAL COMMENT BY DaveV (ME).

I bought a used P-51 mustang (ws57") totally covered in nice shiny chrome last year. The seller warned me about placing the rx as the 'foil' may shield the signal. With that in mind I installed a Lemon RX LM0034 receiver with replaceable diversity antennas and equipped it with their 20cm antennas which I led to the outside of the fuse, behind the wing, one sticking out on each side. The plane was a handful but I managed a few minutes in the air and an ok landing. While in the air it felt like perhaps the signal cut out for a split second occasionally but it may have been unfamiliarity with the plane. Not too much wind but wind gusts may have contributed.

I installed this receiver in another plane and zero issues.

Spektrum has a couple of Carbon specific receivers that are designed to help overcome a shielding problem in carbon covered planes and I'm wondering if that may be worth a try. Carbon however only shields while the chrome may shield as well as bounce the signal??
The chrome cover is nicely shrunk on but I don't know who makes it.

Does anyone have experience with this cover and/or have advise for going forward?

[Max]

Hey, that plane looks familiar....

Here is a thread I started on the same issue when I had it:

https://www.rccanada.ca/rccforum/showthread.php?t=126828

[HAL9KPCM]

I might crazy with my thinking here.... but how wide is the fuselage at the approximate location of the antenna? Just wondering if by freak coincidence if the width, or even height, is approximately the same as the wavelength.

[DaveV]

Originally Posted by HAL9KPCM

I might crazy with my thinking here.... but how wide is the fuselage at the approximate location of the antenna? Just wondering if by freak coincidence if the width, or even height, is approximately the same as the wavelength.

Thanks for the thought but that can't be an issue as these diversity antennas only use one antenna at a time. They switch intantly to the one that has the best signal.

[HAL9KPCM]

I get that, but if the covering is creating a full wavelength antenna encapsulating the receiver antennas, while you are receiving a signal, it may not be a reliable signal. I wouldn't rule it out. Reading Max's thread, everything worked fine with the antennas exposed.

Edit... LOL... although I totally missed that you said yours were outside.

[DaveV]

Originally Posted by HAL9KPCM

I get that, but if the covering is creating a full wavelength antenna encapsulating the receiver antennas, while you are receiving a signal, it may not be a reliable signal. I wouldn't rule it out. Reading Max's thread, everything worked fine with the antennas exposed.

Thanks, I'll make sure that the antenna ends are 110% outside of the chrome and glue them at the exit.

[DaveV]

Originally Posted by Max

Hey, that plane looks familiar....

Here is a thread I started on the same issue when I had it:

https://www.rccanada.ca/rccforum/showthread.php?t=126828

Thanks Max!! Wonder why I didn't find that thread??

It looks like I did everything correct before the maiden.
I had started out by having the two antennas outside but above the wing. The range test went excellent but I was cautious and placed the bird on the balcony and did my range test from the ground. Sure enough, no range. Hence the antennas now sticking out the sides just behind/below the wing.

I was thinking perhaps the antennas touched the chrome when flying, causing the split second glitches but putting an Ohm meter on the chrome I don't get continuity on the surface...

Not to take any chances I’ll add a satellite with two additional antennas sticking out front/above the wing to see if that eliminates glitches.
Where exactly did you have your antenna(s) exit?

[stegl]

This is were good planning may have helped. One ant wire verticle and one horizontal longitudinally inside the canopy should have work well.
Before the canopy is glued on , plastic ant tubing could have been positioned with access from inside the fuse. Just thread the wire into the tubing.

[Max]

Originally Posted by DaveV

Thanks Max!! Wonder why I didn't find that thread??

It looks like I did everything correct before the maiden.
I had started out by having the two antennas outside but above the wing. The range test went excellent but I was cautious and placed the bird on the balcony and did my range test from the ground. Sure enough, no range. Hence the antennas now sticking out the sides just behind/below the wing.

I was thinking perhaps the antennas touched the chrome when flying, causing the split second glitches but putting an Ohm meter on the chrome I don't get continuity on the surface...

Not to take any chances I’ll add a satellite with two additional antennas sticking out front/above the wing to see if that eliminates glitches.
Where exactly did you have your antenna(s) exit?

It was a while ago but I'm pretty sure I had them come out the bottom where the back of the wing joins the fuse.One on the bottom left and one on the bottom right side. They were protruding out to the side on either side of the bottom of the fuse. Not straight down but to the sides.

You gotta remember, when the plane is in the air, the signals are going up to the plane. Putting them up top means the signal has to come up through the bottom of the fuse. The metal foil would act as a shield.

I recall around that same time period, a student had problems with his plane- it would always dead-stick. He didn't know why, and his instructor(at the time) insisted it was the engine. I suggested he was getting radio cutout and the throttle was going to idle when it lost the signal. The instructor claimed he range checked the plane on the ground and it always passed. Engine fiddling by his instructor continued for weeks.

After it dead-sticked for the umpteenth time and fell into the woods 200 yds away, his "instructor" bolted on the guy and left him to find his model on his own. I helped him out and we found the plane. Luckily it was in good shape. When we got back, we got back to the reasons why the engine kept quitting. I suggested he take his wings off so I could look inside. I was surprised to find that his RX was sitting ON TOP of his ni-cad pack. There wasn't a lot of room in there and that was where the instructor told him to put it. On its wheels, it passed the range test with flying colours. Then I told him to hold the model with the nose down while I did a range check walking away from the bottom of the model (Throttle up, not running) . Sure enough, I got a few steps away and the throttle when down to 0. We relocated the RX to below the battery and off to one side and range tested it level and nose down and it passed in both positions. Then we flew it- never had his engine quit since.

[Cougar429]

I have seen a few instances where signal loss contributed to either the complete loss of the craft or at least some pretty "Entertaining" moments.

What I often tell my students is to create contrast on their covering to help orientation, often with the distinctive differences on the top of the wing. When you look at flying patterns often the plane is turning towards or around the pilot, which orients the top that way. Vary rarely, (and I try to teach never) should the aircraft be directly above the pilot.

Same with the antenna. Best set either the long 72 MHz or now the more common 2.4 setups so that they can capture the signal from the side or above.

I built a Polaris foamie years ago and used one of my fave Berg receivers with a base-load antenna to keep everything internal. Went to range check the first day on snow and it went crazy. Talked to the Castle tech and found the Bergs are already internally base-loaded so simply cutting the antenna to fractional length would work fine. In fact, the receiver was so sensitive he suspected the reflection off the snow was overloading the Rx since holding the A/C even a foot or so off the ground settled it down and in flight it was fine.

Brought that up to relate the following: That covering would likely blank a signal, similar to a C/F fuselage or hiding behind equipment in the plane. Not sure if reflections would create issues, as well.

ps. Some receivers record signal events, along with noting if they had any power related LOS. Spektrum in particular can be vulnerable to power brown outs so another place to check.