Jim Weir - Rubber 'Baby Belly Baluns

First Ron you want to make sure it is YOUR problem not the other guys
receiver. A bad antenna pattern usually won't "garble" a transmitter. It
can reduce signal strength which would cause your signal to go into the
noise.
two questions how far away was the other aircraft and what was his
orientation to you?
Also what is the swr on your antenna?
My suggestion first is if you have a buddy with another plane (prefer two
seater with a helper installed in the second seat!). Have him monitor your
signal with a know good receiver/antenna and try different orientations and
distances to see it it is indeed your problem.

As far as antennas go my first impression would be an inverted 'V' type
antenna, which is basically a dipole with the feed end forming an angle
(between 45-90 degrees, not real critical) it isn't as directional as a
dipole is. Then make sure you have it matched properly and separate the
receive and transmit antennas by as much as possible to decrease likelyhood
of your transmitter feeding back into your receivers.

I hope this helps a bit!
John

On Sun, 03 Apr 2005 21:13:04 GMT, UltraJohn wrote:

First Ron you want to make sure it is YOUR problem not the other guys
receiver. A bad antenna pattern usually won't "garble" a transmitter. It
can reduce signal strength which would cause your signal to go into the
noise.

I've had enough separate cases of folks complaining about my radio. Not lately,
though...in fact I've done some fairly complex coordination with other traffic
on busy days in the pattern (e.g., "Fly Baby's on crosswind, and has the traffic
on the 45...I'll swing out and follow you") and no one complained.

two questions how far away was the other aircraft and what was his
orientation to you?

Don't know... just a voice breaking in and saying, "Hey, Ron, your radio's
unreadable." Weren't any of my "known buddies" in the air at the time, but the
FBO owner may have been flying one of his airplanes.

Also what is the swr on your antenna?

Never been checked... :-)

My suggestion first is if you have a buddy with another plane (prefer two
seater with a helper installed in the second seat!). Have him monitor your
signal with a know good receiver/antenna and try different orientations and
distances to see it it is indeed your problem.

In the past, I've set up an old Escort 110 in my hangar with a small tape
recorder and then gone and shot some T&Gs. There's definitely a higher noise
level when I transmit...but when you consider that a decimal meter reads about
109 dB chest-high, that's probably to be expected (and it's one reason I spent
the $$$ for an ANR headset...). But like my buddy yesterday, I felt my
transmissions were understandable albeit with high background noise.

Things may have admittedly changed; probably time to do this again. One email
suggested I check connectors; a good idea as I did have a BNC connector come
loose a few years back.

Or maybe I ought to pull the wind muff off my mike boom; maybe the microphone
got itself turned around.

On Sun, 03 Apr 2005 15:34:28 -0700, Ed Sullivan wrote:
] Ron, I have had pretty good luck with a stainless antenna on a .024
] metal panel on the belly of my Jungster II (all wood) It resides
] between the gear and in bent about 30° aft. I riveted on a doubler
] around the attach point.

I've done this with my transponder antenna... the builder of my plane used
0.040" aluminum in that area and it's probably strong enough. But...a) Do I
want it just a couple of inches from my transponder antenna, and B) The panel is
attached to the airplane with just a couple of wood screws. Don't know if I
want to add the twisting load from the drag of a long antenna.

And, again, I think antennas are ugly. I think the rubber duckie on the belly
would be less noticeable.

Ron Wanttaja