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

[Chuck Dietz]

Thanks for the info. I think I am going with 60 radials on the ground. I
want to use the 160 vertical tower to support an 80 meter array around it.
Elevated radials might make adjustments way more complicated. I have a
tractor and a good welder guy to weld a bracket and tube to a single plow
shear to make a radial plow.

Chuck W5PR

On Sat, Dec 3, 2022 at 11:59 AM Grant Saviers <grants2 at pacbell.net> wrote:

> 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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