What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Radio Problem Garmin SL40

A

airtractor

I'm New Here
I have installed Garmin SL 40 , with no interphase just simple Ptt in both sticks. it all works fine, except when I transmit TX, It interferes with my Manifold pressure guage & my Ray Allen trim indicator. Everything else works as advertised. Radios are not my thing. Any ideas greatly appreciated.

Regards Fuzz.
 
Grounding Problem?

I have an SL-40 in My plane as well and it works very well with no interference. I suspect that there is a grounding problem of some sort but that is one of those things you just have to trace down and fix.

Bob Axsom
 
Radio Waves

If you are you building in a garage, the signal from the radio bounces all around and can effect the instruments and Ray Allen LEDs. I had the same problem and could only minimize it by shielding the push PTT wires and adjusting the antenna cable. Once I moved the plane to the airport and wide open spaces the problem went away.

Good luck,

Roger Ping
RV-9
Engine almost back together
 
Last edited:
radio problems

I suggest you post your question on the AeroElectric list. The problem with Ray Allen indicators has been discussed, so do a search first (I don't remember the actions recommended).

Dennis Glaeser
 
I had the same problem

I am using the Van's manifold pressure guage. I called and apparently this is a known issue, not specific to the Apollo series radios. The Van's manifold pressure guage is RF sensitive and there is really no easy way to fix this. Van's said all their demonstrator planes have the same behavior. They just ignore it or you can get a more expensive MP guage if it really bothers you. they said just don't look at the MP guauge when you are transmitting! :rolleyes:
 
Antenna?

Fuzz,

One thing you didn't mention is your antenna installation. I originally was going to go with a simple bent-whip belly antenna for my #1 Comm - the kind that doesn't have a BNC connector, just a threaded post end that you attach the center lead of the cable to with a ring connector. This was right under the pilot seat on my -8. (Why? Because I was being CHEAP!)

I installed the thing, and when I went to transmit, every LED-based indicator in the airplane went nuts!

Fortunately, I have low friends in high places in the avionics world where I work, so I consulted them. They laughed at my antenna connection and said "Well THERE'S your problem!" They said so much of the RF was "leaking" out of that lousy joint that I probably was making a giant radio cavity out of the cockpit. (Not too good if you're planning on having children someday?) :eek:

I replaced the antenna with a decent unit, finished with with a good BNC connector on the end of the cable, and the problem disappeared...

Somethign to check...

Paul
 
Something very similar happened to one of our local guys, except his whole EIS would reboot when hitting PTT. He had a very similar setup as Paul, and after getting a Comant antenna and re-routing coax problem was solved.
 
Sl40

First, I must admit I'm not tecky type at all, so my wiring was guided by my "low friends in high places," as Paul mentioned.

One of the areas that was made extremely clear was to use high quality BNC connectors. I even changed out my RG58 with RG400 coax.

I am proud to say that everything on my panel works as advertised. Only the SL40 side tones needed to be turned down. All radios and the Transponder (330S) were checked with Phx Tracon. (Neighbor works there and is building a 7).

Check your antenna and also retrace your grounds. Push the plane out into an open area and out of the garage.

Good luck, this is a great radio.
 
Problem Solved

Thank you all for your suggestions. I have fixed the problem, by moving the MAP sensor around in the dash I have found one point that it does not interfere. It has wasted two or three days but it is fixed.

Regards Fuzz!!!!!!!!!! :D
 
You must log in or register to reply here.
Back
Top