To: <tentec@contesting.com>
Date: Tue, 23 Sep 1997 14:42:39 -0400
From: bames@mecasw.com
Subject: [TenTec] antennas
> I have a large horizontal loop (1 wave on 80mt), needed for my QRP Argo
> (works really great), that would be a "resonant" antenna, right? Now
> suppose I had a really large loop, broke the loop as far from the feed
> point as possible and inserted a 75 ohm resistor. This would not be
> resonant but if the loop was big enough all the power would be radiated
> before it reached the resistor... so what kind of antenna would this be
> (other then a BIG antenna <G>?)
> Bill Ames
> KB1LG
Bill, I have the same antenna in a vertical configuration (but fed so
as to be a horizontally polarized antenna. My real estate is small (80
feet wide) so I have my loop flat across the top and bottom, and "X'ed"
across the center (fits nicely, works great!). I don't know about the 75
ohm resistor, but if you had one of higher value, say 600-800 ohms,
that would be (depending on the physical configuration of the antenna)
a RHOMBIC. I have a computer program that will output the correct
dimensions for them called ARIEL. It's available on various ham-related
web sites, such as http://www.qrz.com . If you put one up, (assuming you
have the real estate) I think you'll be happy with it's performance....
(A 75 meter antenna figured at a 10 degree wave angle works out to 4238
feet long, and needs to be 367 feet above the ground! Higher bands
obviously don't need this much real estate!)
NOTE TO LIST MEMBERS: I apologize for having brought into question all
this
antenna theory just because of my questioning the design of Ten Tec's
model
238 tuner (transmatch?). I've spent most of my "hobby career" learning
about
antennas, feedlines, and antenna "systems". What I've learned in the
past
week about tuners has added greatly to this knowledge. It is indeed a
pleasure
to be associated with such a fine mailing list. I appreciate the list
manager
being so tolerant as to put up with so many off-topic messages. Even
though
we're all learning something here, we really should get back to the
reason
the list is here- the fine equipment from Ten Tec! My apologies to the
list
manager ;-)
73 to all, Web Williams -KR4WM in Myrtle Beach, SC
P.S. I listen to 3.970 most of the day (when I'm not working) if anyone
wants to chat about antennas, Ten Tec equipment, etc.. I run a Corsair
II,
263 VFO, 229B tuner, Centurion amp, and 1209 transverter.
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