[TowerTalk] halfwave verticals

[WA9ALS - John]

These are at http://www.amidoncorp.com/f_ham.htm

> David,
>
> Amidon makes a very effective tool to match the impedance of 50 ohm coax
to a
> variety of possibilities of do it yourself antennas. Their W2FMI UNUN
> (UNbalanced to UNbalanced transformer) model number 1.78:1-HMMU50 can
match
> 50 ohm coax to impedences of:
>
> 36 ohms  1.36:1
> 28 ohms   1.78:1
> 22 ohms   2.25:1
> 16 ohms    3.06:1
> 12.5 ohms  4:1
> 5.6 ohms  9:1
> 4 ohms  12.25:1
> 3.1 ohms  16:1
>
> My Inv L for 160 meters had a poor SWR (4:1 at resonance) due mismatched
> impedences until I inserted the UNUN and now I have a flat match at
> resonance.  The UNUN box is about the size of a deck of cards in aluminum
> casing and inserts between the coax at the feedpoint using PL259 females.
It
> works well with shotened verticals, vertical beams, shunt fed towers,
slopers
> and Inverted L's.  These devices are awesome and you can run high power
> through them-
>
> I think I paid like $50 for mine a few years back.  Amidon can be
contacted
> at 714-850-4660.  I got my UNUN back in 1995.  I assume that Amidon is
still
> around-
>
> If anyone is using a vertical whereas the minimum SWR reading is higher
then
> 2:1, you might consider using a UNUN to better match your feedline to the
> antenna- They are remarkable devices that don't get a lot of attention-
They
> make low power UNUN' for matching beverages too- and a whole bunch of
other
> devices for matching ladder line to coax etc.........GL
>
> 73  Paul  N0AH
>
> List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
> Trylon Titan towers, coax, hardline and more. Also check out our self
> supporting towers up to 96 feet for under $1500!!
http://www.anwireless.com
>
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>


List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 96 feet for under $1500!!  http://www.anwireless.com

-----
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com