Radio Noise

[bakerde36]

Once I go above 2500 RPM I get an annoying static. I have tried different headsets and same results. I have turned off the secondary no help but when I turn off the mag it improves about 80 percent. I have the spark plug wires shielded that go to the mag and just wondered if there was anything else I could do. Other pilots say they hear me fine. I have the Flightline FL 760 radio.

[phenry]

I had been very careful to shield my p-leads in the initial construction and there was little to zero radio noise.
Later on, during the testing phase I tidied up the wiring loom under the cowl and suddenly lots of radio noise at around 2600 rpm and above.
What I found to be the problem was that I had laid about two inches of the p-lead fly ends (unshielded) into the loom.
When I separated out the the unshielded fly leads creating a small airgap all the noise went away.

Hope this helps

[sonex892.]

Do you have the shielded P leads grounded at one end only?
Steve
Sonex 892

[Jim B]

Do you have the isolation washers on your female plug ?
Jim

[bakerde36]

I believe I only have the P-leads grounded on end I will check and see.
I do not recall using an isolation washer I will check that also.
Thanks for your help. Densil

[bakerde36]

I will check my wiring under the cowl also. Thanks

[Bill Sargent]

I was flying my Sonex #160 with a very early Jabiru 2200 and a hand held radio connected to the A/C power supply. It was marginal at best but usable for 12 years.
I upgraded to the very last Camit 2200 ever made ( what a difference, but that is another story ).
The Camit has the small 15Amp belt driven alternator . Rx on the radio was fine but push the TX button and all Hell broke loose.
I purchased a DC Filter here in New Zealand from Jaycar Electronics. It is a Response 10 A Part # AA3074.
A/C power in and radio on the output.
Brilliant!!! works like a charm.I have NO other suppression ie large capacitors etc.
I have my radio mounted on a piece of wing rear spar channel hinged from the bottom of the panel between my legs. Aerial is an old ELT mounted on the turtle deck.The filter is mounted on the rear of this piece of channel.
If you google AA3074 it will come up. It was about $18 .
Might be worh a try!

[Titanium Cranium]

I have the same issue, except that when I turn off the electronic ignition, the noise almost entirely goes away. I have the shielded p-leads that appear to be grounded at each end, but it's still very bad. I have an ICOM IC-A200 radio mounted just below my mag and electronic ignition switches. I can hear everyone else's transmissions, although the static is horrible. My transmissions are barely audible to others though. I wondered if it's because my plane has the headset jacks mounted just behind my shoulders, so there's 4-6 feet of un-shielded wiring that could be picking up the noise. I bought a Sporty's SP-400 handheld radio to see if that worked any better, and I was amazed to find that the electronic ignition even feeds through into the handheld despite no connection to the plane at all. When I switch the electronic ignition off, the noise goes away in the handheld too. I'm going to try to get shielded wiring for the headset jacks and I'll move them under the panel to reduce the amount of wiring that's exposed to the electronic noise. If that doesn't work I'm not sure what to do short of ripping the entire panel out and starting over from scratch with a new radio and all new wiring to everything.

[kevinh]

I have the same issue, except that when I turn off the electronic ignition, the noise almost entirely goes away. I have the shielded p-leads that appear to be grounded at each end, but it's still very bad. I have an ICOM IC-A200 radio mounted just below my mag and electronic ignition switches. I can hear everyone else's transmissions, although the static is horrible. My transmissions are barely audible to others though. I wondered if it's because my plane has the headset jacks mounted just behind my shoulders, so there's 4-6 feet of un-shielded wiring that could be picking up the noise. I bought a Sporty's SP-400 handheld radio to see if that worked any better, and I was amazed to find that the electronic ignition even feeds through into the handheld despite no connection to the plane at all. When I switch the electronic ignition off, the noise goes away in the handheld too. I'm going to try to get shielded wiring for the headset jacks and I'll move them under the panel to reduce the amount of wiring that's exposed to the electronic noise. If that doesn't work I'm not sure what to do short of ripping the entire panel out and starting over from scratch with a new radio and all new wiring to everything.

My plane isn't flying yet, so take this with a huge grain of salt but search the posts for mentions of NGK plugs. Supposedly NGK DR8ES plugs on the primary side has helped fix the radio interference problem for a couple of people. YMMV ;-)

[peter anson]

I have the same issue, except that when I turn off the electronic ignition, the noise almost entirely goes away. I have the shielded p-leads that appear to be grounded at each end, but it's still very bad. I have an ICOM IC-A200 radio mounted just below my mag and electronic ignition switches.

I think that the point that Steve was making in an earlier post was that the shielded cables should only be grounded at one end or you can create earth loops which are great at transmitting and receiving noise.

I purchased a DC Filter here in New Zealand from Jaycar Electronics. It is a Response 10 A Part # AA3074. A/C power in and radio on the output.

I'm pretty sure this is the same part that I fitted to supply all my instruments. What they don't tell you is that it includes a 12V regulator, so guess what voltage my voltmeter always showed? As Bill used it just supplying the radio, it will do a great job of cleaning up the supply.

Peter