[TenTec] Rhombic antennas, tuners, and such...

[Webster D. Williams]

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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