Gary-
I'm new to the list. My kit is on order so I can't talk to anything
specific to the Eurpoa, but I do know communications. If you are just
getting 15 miles, you decidedly have a problem (opportunity). Have you put
a wattmeter of standing wave bridge into the circuit and checked? If you
have a problem, your VSWR should be very high, probably above 2/1. If there
is a problem with either the antenna or the coax, it should show up in a
high VSWR. If so, it may be a question of optimizing the antenna you have.
The other thing I would do is check the coaxial cable, possibly replacing
it. There are multiple grades of coax and you want to use high grade coax
and "type N" fittings. The other thing I would do is build a simple
vertical dipole and jury rig a piece of cable to the radio and try it. You
should be able to fit the antenna in the cockpit. It might even be worth
trying a dipole made of copper wire taped to the inside of the canopy to see
if the antenna is the problem. As far as a groundplane goes (or a dipole,
as far as that goes), you can find all the formulas in the "Radio Amateurs
Handbook" at the local library. It might be worth a trip to read up on vhf
antennas. It would take no more than 10 minutes and only a couple of
dollars worth of wire and cable to build a simple dipole. I'd not punch a
hole in the skin until you know that it is a problem. An antenna should not
even see the figerglass.
Jim Puglise, FL
>From: "STOUT, GARRY V, CSFF2" <garrys@att.com>
>Reply-To: europa-list@matronics.com
>To: <europa-list@matronics.com>
>Subject: Europa-List: RE: Com Radio Antenna Problem
>Date: Fri, 24 Oct 2003 14:23:50 -0500
>
>
>Hi guys,
>
>I'm hoping some of our very talented team of builders can give me some
>advice on a unique Com radio antenna setup I am planning. I've been
>flying my trigear now for 4 years and have never been happy with the
>transmit and receive distances I'm getting from my radio......a Garmin
>250 XL GPS/Com unit. Initially I installed the Bob Archer antenna, but
>after a year or so I wasn't happy with the performance and switched to a
>Comat "general aviation" type antenna. I built an aluminum ground plane
>about 8" wide and 20" long which I installed inside the fuselage behind
>the bulkhead. The Comat antenna was mated to that ground plane. I got
>better performance than with the Bob Archer, but still I think I should
>be doing better than a 15 mile maximum range. I had the radio bench
>checked, and the coax cable checked by an avionics shop, and they
>pronounced everything in good working order. Their suggestion was to
>glass in a copper wire mesh ground plane to the bottom inside of the
>fuselage, and then to mount the antenna EXTERNALLY under the belly of
>the plane. A couple of questions arise. Has anyone else ever tried
>this? What were the results? and more importantly, what should the
>dimensions be for the copper wire mesh (screen)? I was thinking that
>the larger the better, but there may be some technical calculation that
>I'm unaware of that would dictate a particular size. Any and all
>comments and advice will be appreciated. Thanks!
>
>Regards,
>
>Garry V. Stout
>N4220S Tri A060
>
>
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