[Elecraft] Re: Mobile/portable antennas

[Sandy]

This is an interesting post!

As far as dipoles are concerned.....Some years ago, I was operating portable 
with a Ten-Tec PM3A (40/20m.) and then the first "Argonaut" they built. 
Some of my best results was with "loaded dipoles".  Dipoles very short for 
the given band I was operating on.  I remember the 40 meter one was about 
15' long overall.  It consisted of a center section of about 5-6' each leg, 
the loading coil (in each leg) then the last 12-15" of wire...mainly a 
"tuning stub" so to speak.  The loading coils were wound on 3/4" polystyrene 
tubing forms.  Antenna elements were #24 hookup wire.  Feeder was a short 
length of RG-74/U  (LOSSY on the higher bands!)  They were erected from 6' 
to around 15' high.  The tuning was VERY sharp, you could move maybe plus or 
minus 10-15 khz or so for around a 1.5:1 VSWR... They did work better than 
any vertical whip I tried.
 On the other hand 20 years later (NOW!)  I found it difficult to setup such 
an antenna EASILY in say a parking lot or a cow pasture (no trees!)  The 33' 
Fiberglass pole is easy to setup and does work, albeit not the best there 
is!

I have never tried the "commercial" loaded dipole antennas like the 
"Buddipole"?  Had an idea to use something homemade and similar using some 
telescopic "inner elements", easy to change "loading coils" and telescopic 
end elements in a "loaded rotating dipole" configuration, but never got 
around to doing this!  Something less than 20' long on 80 and less on the 
higher bands, light and easily transportable, easy to setup, maybe using the 
fiberglass mast not quite telescoped to full height...(25'?) to take 
advantage of the stouter section below the "fishing rod" tip sections. 
(This is the MGJ 33' pole)

The BIG disatvantage of the loaded antenna was a narrow bandwidth, 
especially with hi-Q loading coils.  Someday maybe I'll try it again 
configured as outlined above.

73,

Sandy W5TVW
----- Original Message ----- 
From: "Mike Morrow" <kk5f at earthlink.net>
To: <elecraft at mailman.qth.net>
Sent: Tuesday, March 04, 2008 6:23 PM
Subject: [Elecraft] Re: Mobile/portable antennas


.  I have used this very expensive combo a
> number of times in the past seven years at campsites in the Arkansas 
> Ozarks
> and the Tennessee and Alabama Appalachians.  For comparison purposes, I 
> also
> set up a simple home-made multi-band wire dipole ($20) at nine feet above 
> ground.
> I made contacts on 40m through 10m using both antennas.  In *EVERY* 
> instance,
> on *EVERY* band, the vertical installation was 2 to 4 **S-units** lower in
> receive and transmit performance, compared to the dipole.  I found NO 
> exceptions
> to this.