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[aprssig] Helmet Antenna - dont bother.

scott at opentrac.org scott at opentrac.org
Mon Mar 7 04:45:19 UTC 2005


Perhaps you weren't doing it right.  Here's a reference:
http://zapatopi.net/afdb.html#BUILD.

Scott
N1VG

-----Original Message-----
From: aprssig-bounces at lists.tapr.org
[mailto:aprssig-bounces at lists.tapr.org]On Behalf Of Robert Bruninga
Sent: Sunday, March 06, 2005 4:25 PM
To: aprssig at lists.tapr.org
Subject: [aprssig] Helmet Antenna - dont bother.


Today I was tail-bike on a marathon.
Lesson:  Dont bother with a helmet antenna
for voice.  (APRS maybe, but not for just voice).

I took one of those tiny 19" mag mount
whips with a small base (like a kisses chocolate piece)
stuck it inside the helmet protruding up through the
air holes, covered the inside with aluminum foil and
then let a can lid stick to the bottom of the magnet.

I also, carried an identical HT with its own
long whip.  Conclusion was generally no difference
after lots of side-by-side tests...
Therefore, dont bother.

An HT held to my mouth with a similar 19" whip is
going to work similarly as a 19" whip on the helmet at
the same height.  I had just hoped that the slightly
better ground  plane might work better than the HT with
no real  counterpoise.... dont bother.

Now, for APRS where you are not holding the HT to
your mouth, then maybe the extra height and lack
of body blockage is worth it.

Just 2 cents...
Bob



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