Jiott,

I have been reading this post with a degree of intrigue..........and I haven't responded till now because my line of thinking might be percieved as voodoo........


Your comment about the response from Dynon....."I submitted this "problem" to the Dynon tech support people and they think it is due to the RF energy from the radio interfering with the very sensitive ammeter sensor wires (unshielded). The sensor uses only a few millivolts/amp." I think has validity......although what they did not say, according to your post, exactly how or where the RF may be coming from.

Here is my voodoo story.......none of our aircraft are exactly the same; and, consequently, none of our experiences are likely to be identical...... So.....when I was assembling our aircraft and doing final testing while not everything was quite complete...I was playing with the radio.....everytime I keyed & held the PTT.....the little red LEDs I had mounted up by the wing roots for nightime cockpit illumination came on!.....Voodoo because the LED wires were not yet connected to anything!....just the unshielded electrical wires laying across across the carrythrough tube by the front of the turtledeck. This was not my imagination...it happened......suspected cause.....the location of the com antenna behind the turtledeck was just a few feet from where the loose wires were laying was apparently enough to induce enough voltage in the wire to light up the LEDs (which have an extremely small draw in order to light up). With the LED feeds rerouted under the sheetmetal & connected to the buss/switch the issue went away - since I really, really wanted to have the LEDs come on at times in addittion to when the PTT was activated!

With my little light voodoo story.....although different equipment is involved from your situation...you might consider the RF source interfering with the ammeter reading could be coming right off the exterior comm antenna and not from the antenna cable leading through the airframe. Might be just the way ammeter sensor wires are run through the aircraft in light of the fact that the whole aircraft is bathed in concentrated radiation from the comm antennae when the PTT is activated.

Can't say that it is possible to diagnose stuff like this from a distance...lord knows we can't see RF waves with out eyes....just a thought for consideration.....The Dynon folks might be onto something with their RF interference comment.....location of the unshielded ammeter sensor wires might be worth considering....or using a shielded wire.

Just a thought for consideration.

Dave S
KF 7 Trigear
912ULS Warp Drive