Wiring (RF interference) question

[billythefish]

Hi, I don't see where my other posts went...

I have tried terminating at the radio connector (to the feedline) - no noise.

I have tried terminating at the aerial's connection - no noise.

I've bought and installed a new COM antenna (a CI-121) - connected, same amount of noise as before.

:'(

The obvious explanation is that the radio system is working correctly, and that the antenna is picking up a massive amount of interference from SkyView. What am I missing?

 

[cperry]

Bill,
I've believe I've traced my similar issue to a faulty LCOM capacitance filter.
Even with my skyview screen connected only to a battery on the bench (no connections to the aircraft), I get radio interference on both my aircraft radio and on a handheld A24 when the antenna is within about 10ft. Wiggling the connector on the filter causes the interference to become intermittent, which is something I can't replicate without the filter installed. Also tried three different harnesses, two different radios, and two different antennas.
As its much easier to get a new filter here at my door than it is to send the screen from Canada back to Dynon, or the radio back to Icom, I figure I'll just get a new filter and try it first. I'll let you know how that works out.
Chris

 

[billythefish]

Thanks Chris.

 

[billythefish]

@ Dynon support, given the previous posts in this chain, do you have any further suggestions for this particular problem? As you'll see from reading my posts above, I have tried your suggestions #1 and #2 (both 'pass'); although I have a backup battery I am unable to use it as it does not ever reach the state at which it is capable of running the SV components on backup charge, probably because the engine in my aircraft has never been run and voltages are correspondingly low (from a trickle charger into which the airplane battery is plugged).

I will try to source another 12v power source to run the unit from a separate power source (and test that) but I think that the fact that #1 and #2 exhibit no RF rules out electrically-conducted noise? Is this not the case?

WRT #4, my aircraft is still in my workshop (only because of this issue) so I do not have another aircraft/radio against which to test the interference. That was the original point of using the iCOM unit :-/

On the basis of this information, do you have any other suggestions I could try?

thanks for your help.

 

[dynonsupport]

Nothing further to suggest at the moment.

The on-battery test is a really critical one.

@ Dynon support, given the previous posts in this chain, do you have any further suggestions for this particular problem? As you'll see from reading my posts above, I have tried your suggestions #1 and #2 (both 'pass'); although I have a backup battery I am unable to use it as it does not ever reach the state at which it is capable of running the SV components on backup charge, probably because the engine in my aircraft has never been run and voltages are correspondingly low (from a trickle charger into which the airplane battery is plugged).

I will try to source another 12v power source to run the unit from a separate power source (and test that) but I think that the fact that #1 and #2 exhibit no RF rules out electrically-conducted noise? Is this not the case?

WRT #4, my aircraft is still in my workshop (only because of this issue) so I do not have another aircraft/radio against which to test the interference. That was the original point of using the iCOM unit  :-/

On the basis of this information, do you have any other suggestions I could try?

thanks for your help.

 

[billythefish]

I've tested the SV unit running from a separate 12v battery and, as before, it creates a massive amount of RF Interference picked up by my radio. I think this means it's not conducted interference.

NB: I think the SV unit connects the casing to ground, which means that ground is shared between the SV unit (running off an alternate 12v battery source) and the airplane / radio.

Any further suggestions? thanks

 

[dlloyd]

Bill,
I was chasing another type of noise problem several weeks back and read through your posts. After flying I will pull up to my hanger, swing the tail around and into the hanger. A couple times the squelch on my Garmin SL30 will break and will produces a noise like on your video. It stops when if I let the plane roll forward just a couple feet. I can duplicate this. But that has never been a problem once my tail is out of the hanger door. Can't tell you why this is, only that it is. Your video shows being inside a building, can you push your project outside, away from the building?
I had an ignition noise that was solved only when shielding the EMS module tach pickup wires to the ignition switch. I have not read of anyone else having that problem.

 

[sunfish]

I wouldn't assume that this is a Dynon problem and not an Icom preblem. By coincidence a poster on another thread at another website made reference to the Icom A210 being sensitive to interference.

I also think I rememberr discussing the subject with a tech at the airport who mentioned the same. The squelch can, I think, be adjusted by a dealer.

I'd buy an XCOM over Microair. The XCOM was invented locally to fill the gaps of what the Microair was missing. The XCOM is dual frequency and has a built-in 2 place intercom (as noted above). The XCOMs are Australian made in the US by Narco. I used one for 6 years and loved it. There were some issues with the early models out of the origianal manufacturer but they are long gone.

I'm getting many mixed reports on the new Icom with the digital screen, many are having trouble getting them functioning without interference but I know many are very happy with them in factory built aircraft. (Not to say that they aren't any good when self-installed)

thread here, post #6:

http://www.pprune.org/pacific-general-aviation-questions/495668-what-vhf-radio.html

 

[jakej]

I've tested the SV unit running from a separate 12v battery and, as before, it creates a massive amount of RF Interference picked up by my radio. I think this means it's not conducted interference.

NB: I think the SV unit connects the casing to ground, which means that ground is shared between the SV unit (running off an alternate 12v battery source) and the airplane / radio.

Any further suggestions? thanks

Bill
GET THE PLANE OUTSIDE THE BUILDING then tell us if you still have an issue.  I can't believe I missed that, probably was lead astray by your "I'm an engineer" quote :-?

Jake J

 

[billythefish]

Jake, I'm not an RF Engineer :-[

 

[jakej]

Bill
Sure helps knowing that   would have asked more pertinent questions earlier if I had known 

The symptoms you were/are seeing would not have made sense IF the plane was outside the building - this may be an opportunity, for those not flying yet, to point out that there can be 'issues' with systems when inside a building - do the final tests outside  ;D  :

Jake J

 

[cperry]

Bill, have a look at the pic I posted here: http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1361460985
If your antenna is similar, you might have a very difficult time finding a quiet enough place for it.
Chris