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ACRO E-mail Archive Thread: [Acro] Re: Help with some radio education

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ACRO E-mail Archive Thread: [Acro] Re: Help with some radio education


Thread: [Acro] Re: Help with some radio education

Message: [Acro] Re: Help with some radio education

Follow-Up To: ACRO Email list (for List Members only)

From: Jeffrey Lo <jlo at>

Date: Tue, 20 Aug 2002 05:50:58 UTC


  I have an ICOM A-21 as my backup radio in my Pitts mounted just below the
panel on the right side.  The coax from the antenna on the turtledeck passes
under the right side upper longeron and then down to the primary (Terra)
radio.  Where it passes by the ICOM, there is a break in the cable, with BNC
connectors and a barrel coupling.  If the Terra quits, I can just unplug the
coupling and plug the cable from the antenna into the ICOM.  Granted, I
can't use both radios at once, but it is only intended as a backup.  As for
the hassle of changing cables, well, I have to move the headset cables as
well, so what's one more cable.  I'm not even trying to use any NAV
functions.  It has seemed to work fine the couple of times I tested it out.

Jeff Lo
1988 Pitts Special S1S N230MP

-----Original Message-----
From: John Harlan [mailto:jmharlan at]
Sent: Monday, August 19, 2002 7:51 PM
To: bob at; IAC List
Subject: [Acro] Re: Help with some radio education

I agree you can't practically put two transmitters on one antenna.  However,
if the original handheld rubber antenna has a BNC on it, you can just mount
a bulkhead BNC connector to the belly skin somewhere and use your original
hand held antenna.  I did this with mine and it works just fine.  Maybe the
range isn't as good as with a "real" antenna, but it works ok.  The antenna
won't work very well for the nav side, however, because it needs to be
horizontal instead of vertical.

----- Original Message -----
From: Bob Scherer <Bob at>
To: IAC List <acro at>
Sent: Monday, August 19, 2002 8:13 AM
Subject: [Acro] Help with some radio education

> I could use some help in understanding some radio issues so I can
> a practical installation.
> One Design with a Microair Com and handheld GPS for Nav - single com
> An ICOM A-22 as backup com & nav.
> Problem is locating and/or using the Icom if needed.
> The Icom attached antenna works satisfactorily for nav when held up, but
> mounting pretty much dictates inside cockpit where nav range is very
> deteriorated.
> So if placed inside, that necessitates using an external antenna
> Can the existing comm. antenna be used with a splitter satisfactorily?
> If so, can the leads be left in place, but not connected?
> Will either radio be harmed by transmission from the other, if both
> connected to the same antenna
> Have seen splitters in Spruce cat, but most seem to be designed for nav
> freqs - will this seriously affect the com operations?
> Would a second com antenna be a better solution - will it work
> satisfactorily for the nav functions in the Icom?
> Thanks for the help educating me.
> Bob Scherer


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