Topband: Air wound coil

[GEORGE WALLNER]

If that antenna is resonant at 1900 kHz, and you have a suitably sized 
inductor between the bottom of the vertical wire and ground, there will 
likely be a tap-point on the inductor that will give you a low SWR. No need 
for a transformer.
I think that is probably the simplest and most solid solution.
Further to Clive's point, I believe that inverted L-s can have substantial 
high-angle radiation when the horizontal wire is a large portion of the 
antenna. I always use a T, even if the wires have to slope down. Keep the 
top symmetrical! (It also allows the antenna to be used on 80 and 40 meters 
-- if you can match it. A 160 m inverted L will probably have mostly 
high-angle radiation on those bands.)
Looking forward to the season!
73 and CU,
George

On Sun, 2 Sep 2018 19:29:51 -0000
  "Clive GM3POI" <clive at gm3poi.com> wrote:
> Or better still, Shorten the L until it is self resonant 
> at 1.9mhz, thereby
> lowering the amount of horizontal polarisation. Then use a simple hairpin
> coil across the feedline typically around 5microhenries. This will then when
> chosen correctly match at your chosen ideal spot say 1825.
> And provide a DC short to ground for the antenna. No Caps needed.  73 Clive
> GM3POI
>
> -----Original Message-----
>From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Tom
> Boucher
> Sent: 02 September 2018 18:20
> To: 160 reflector
> Subject: Topband: Air wound coil
>
> Bob W7RH - you don't need expensive hard-to-find vacuum capacitors to match
> a quarter wave 'L' or 'T' on top band. I use cheap multilayer high voltage
> disc ceramics and these have been working perfectly at QRO levels with my
> inverted 'L' for years.
> I use 1600pF made up from 1000pF + 470pF + 220pf all rated at 6.3KV and
> available (over here) from CPC at less than $4 for 10.
> Antenna is slightly longer than a quarter wave so it is inductive and the
> capacitors form the other part of the L-match network.
>
> 73,
> Tom G3OLB
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