So we have a comm made by Dynon. We have great success with tx/rx in the higher frequencies. The 118.... range SUCKS in transmit quality, rx is good. Dipole antenna has been the best for us on the SWR meter, have tried others. Have same in the S20 no issues. Dynon says they have had this issue and are working on it, might have a fix for us in a couple of weeks. Great folks there. We’ve been through 3 radios so far.

Any pearls of wisdom? Radio juju is not in our collective skill set.

SWR is only one indicator of antenna health. Many things can influence it. What you need is an antenna analyzer. find out where the antenna is resonate. You may need to add or subtract the length to resonate it on the lower frequencies. Check with a local ham, they probably have an analyzer they can teach you to use and borrow.
Pete

I dislike radio gremlins. We've been trying to fix some major RF interference for a few weeks, nothing has helped so far. We are now stripping out all our intercom wiring and redoing it. Not fun.

If you are a nerd you may find this manual interesting.

What antenna are you using?

I don’t remember the brand of it right off. It’s not an expensive one. It’s perfect on the SWR and works like a champ in the S20.

We also have tried antenna analyzer. It’s resonance is best at like 125-something. All we can do is shorten it. We wonder if we cut it if then it will be messed up somewhere else.

Rag airplanes, usually experimental, and junk radios (non-Icom) are a real mixture for a good ass chewing from the tower. ☹️. I really dislike comm issues.

pouellette wrote:SWR is only one indicator of antenna health. Many things can influence it. What you need is an antenna analyzer. find out where the antenna is resonate. You may need to add or subtract the length to resonate it on the lower frequencies. Check with a local ham, they probably have an analyzer they can teach you to use and borrow.
Pete

Good info. Most antenna problems are due to termination issues. Make sure that the cable you are using is the right stuff. If the radio calls for 50 ohm then that's what you must use. Same for 75 ohm. The BNC connectors at the radio and sometimes antenna end are cable specific. The terminal manufacturer will spell out exactly which transmission cable can be used. Don't substitute. If you use stranded cable for instance and the connector is made for solid wire it won't work right. The shielding wire sometimes frays at one end or the other of the assembly and shorts to the center conductor or frame of the airplane can take out the finals in the radio or cause other intermittent problems. The right cable, the right terminal (BNC), the right routing (no sharp edges or turns) and it should work.

Put in another new radio from Dynon today. We had ordered it while original was away for “upgrade”. The new one works fine at the 118 range, tonight when I tested it in real-time I was readable further out than our handheld on the ground could transmit.

I’ll go test the Juneau tower out again, maybe tomorrow. See if they can hear me.