[TowerTalk] High power 2:1 transformer was Re: 16om vertical and the number of radials

[Grant Saviers]

The capacitors are on the 25 ohm side so the transmission line 
transformer sees a low swr.  Hence, the caps need to handle 2x the 
current.  The details are in my QEX article "Broad-banding a 160m 
Vertical Antenna"  QEX May/June 2019.  (errata - pin #'s on the 
connecting cable are incorrect).

No problems with the match since putting it up, now at 101 confirmed on 
160m :) all on this antenna.

The 8 elevated aluminum electric fence wire radials are all still 
original. The top support (center of the T) was broken off by a falling 
branch which was replace 10/2022.  However, I'm sure there is a lot of 
loss (4+ db?) from being in a forest.  That's the price of free antenna 
supports (110ft fir/cedar trees).

I currently have 10-12" of snow (YUK a record) on the ground and heavy 
snow on the radials (and droop).  That has changed the resonance up 
about 50KHz.  So another nice capability of the tuner.

Grant KZ1W

On 12/3/2022 06:57, Chuck Dietz wrote:
> Grant, where is the series capacitor, before the un-un or between it and 
> the antenna?
> 
> Chuck W5PR
> 
> On Fri, Dec 2, 2022 at 7:53 PM Grant Saviers <grants2 at pacbell.net 
> <mailto:grants2 at pacbell.net>> wrote:
> 
>     I've been using the 2:1 one for 7 years at QRO for a good match at the
>     antenna as I don't have a tuner at the amp.  I can match < 1.4:1 the
>     entire band by switching in series capacitance in 50KHz steps to the
>     1.83 resonance.
> 
>     Grant KZ1W
> 
>     On 12/2/2022 13:05, marsh at ka5m.net <mailto:marsh at ka5m.net> wrote:
>      > Yes, match at the feedpoint.
>      >
>      > You might check out Balun Designs:
>      > https://www.balundesigns.com/1-2-balun-25-to-50-ohms-3kw-1213/
>     <https://www.balundesigns.com/1-2-balun-25-to-50-ohms-3kw-1213/>
>      >
>      > Marsh, KA5M
>      >
>      >
>      > -----Original Message-----
>      > From: TowerTalk <towertalk-bounces at contesting.com
>     <mailto:towertalk-bounces at contesting.com>> On Behalf Of Pete Smith N4ZR
>      > Sent: Friday, December 02, 2022 2:39 PM
>      > To: towertalk at contesting.com <mailto:towertalk at contesting.com>
>      > Subject: [TowerTalk] High power 2:1 transformer was Re: 16om
>     vertical and the number of radials
>      >
>      > A somewhat related question - as the R component at the feedpoint
>     of my inverted L goes down toward 25 ohms, I've begun wondering if I
>     should do some matching at the feedpoint, rather than using my tuner
>     in the shack, even though feedline losses at 160 are relatively
>     low.  Can someone point me toward a good way to do a 2:1 downward
>     transformation?  I already have a common mode choke at the feedpoint.
>      >
>      > 73, Pete N4ZR
>      > Check out the new Reverse Beacon Network web server
>     at<https://reversebeacon.net <https://reversebeacon.net>>.
>      > For spots, please use your favorite
>      > "retail" DX cluster.
>      >
>      >
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