Question for those with dual Coms and belly mounted antenna's

Brantel · #1 08-16-2011, 06:18 PM

Question for those with dual Coms and belly mounted antenna's....

Did you install the xmt/rx interlock wires that reduce the one com's rx sensitivity when the other is xmting?

If not do the radio's bleed over or has anyone ever damaged one?

Pat Stewart · #2 08-16-2011, 06:22 PM

I have had duel bent whip com antennas on three RV's mounted on the belly with no problems,

Pat

Pat Hatch · #3 08-16-2011, 06:37 PM

Same experience for me on all three RVs, dual CI-122s on all of them, no problems.

Chappyd · #4 08-16-2011, 06:55 PM

I have the 2 on the belly also, CI-122's. IIRC, you have the Icom A 210? I have a Garmin SL30, and an Icom a 210. When I was wiring my radio's in the basement, sometimes when I would transmit on the sl30, the Icom "rx" light would come on. I remember seeing the interlock function and trying it, and I saw no difference. That was a couple years ago.

I'm flying now, and the good news is both radios are working very well. I will remember to pay attention to the "rx" light on the Icom when I transmit, and see if it still does it.

scard · #5 08-16-2011, 06:56 PM

Quote:

Originally Posted by Brantel

Question for those with dual Coms and belly mounted antenna's....

Did you install the xmt/rx interlock wires that reduce the one com's rx sensitivity when the other is xmting?

If not do the radio's bleed over or has anyone ever damaged one?

I'll chime in. I think the question is around the split com functionality in our audio panels and radios. If not, parden me for being out of place. Yeah, single pilot monitoring multiple radios, no problem. However, when we split the radios, which we do often, there is a real problem with rx/tx on either side of our aircraft 'sometimes', depending on frequencies. (430W, SL40, PSE audio panel) I assume this is because I didn't do the interlock, or the antennas are just too close, either side of a side-by-side. I'm guessing that we have a rare situation in our community where we rx/tx on two radios at the same time in the same cockpit by two pilots often with the audio panel split. The electronics definitely struggle.

For those wondering why you would want to do such a thing... We're on an IFR flight, I'm talking with center getting/reading back a reroute, and Tanya is on the other radio yapping with another gaggle of RVs a couple of hundred miles ahead VFR. I've had to punch her button on the audio panel and drop her com instantly before. OR, we just land at a large class C or B airport, she is talking to ground on .9 for the taxi, and I'm talking to the FBO on another freq. coordinating our parking (don't park me where you'll have to move me with a tug in a few hours when I'm not there...). I've been punched in the shoulder to shut up.. We do it all the time, and on the next airplane, I'm going to make sure I have the interlock wire hooked up

.

Brantel · #6 08-16-2011, 07:13 PM

Yes I have an A210 and thanks to Stein, I am soon to install a new 430W.

I already have dual belly antenna's. I have been using the second one for my handheld. One day I was xmitting with the A210 and it was causing the SP-400 to light up even though it was turned off!

I don't want to smoke the receiver in either radio so I was thinking of using the interlock.

PS Eng says this must not be used to enable split mode to work so that is the only reason why I would not want to.

Brantel · #7 08-26-2011, 08:42 PM

Well I got my 430W installed and at this time I am using a dpdt switch to select transmitters. No time or money right now for an Audio Panel.

I connected the 430 com, 430 nav and A210 com audio outputs to the PSE3000 intercom by way of three 100ohm resistors.

All works well except I cannot xmt on one radio without it bleeding over on the other no matter how far apart the freqs are nor does it matter if the freq. is active or not.

I have dual belly mounted com antennas. They are under the seats in the center of the outer most bay. They are Don Pansier antennas.

I used RG-400 coax.

I did not connect the xmt interlock wires.

Why do so many not have a problem with this but my install does?

My next step is to connect the interlock. Hope it helps!

Brantel · #8 08-27-2011, 01:50 PM

Installed the interlock wires....problem solved!!!!

Richard Connell · #9 08-27-2011, 05:09 PM

Quote:

Originally Posted by Brantel

Installed the interlock wires....problem solved!!!!

Quick question.... I have a 430w and a 300xl. Belly mounted commants. I get xmit bleed regularly so am thinking about using interlock.
Are the interlocks just connected together or are they each grounded to the ptt for the other radio?
Cheers

Brantel · #10 08-27-2011, 05:18 PM

In my case:

430W Interlock Input <---- A210 PTT line (gets grounded during xmt of the A210)

A210 Interlock Input <---- 430W PTT line (gets grounded during xmt of the 430W)

Works like a charm. It will however not allow the SPLIT mode (pilot xmt on com1, copilot on com2) of most audio panels to work since it cuts the reciever gain of the non xmitting radio way down. This is of no concern to me since I have no audio panel.