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@pacbell.net
<mailto:grants2@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@ka5m.net <mailto:marsh@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@contesting.com
<mailto:towertalk-bounces@contesting.com>> On Behalf Of Pete Smith N4ZR
> Sent: Friday, December 02, 2022 2:39 PM
> To: towertalk@contesting.com <mailto:towertalk@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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