Message-ID: <7A6010C0609B43C19622305C656A7FD7@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <4BAF2B2D.1010300@dsl.pipex.com>
In-Reply-To: <4BAF2B2D.1010300@dsl.pipex.com>
Date: Sun, 28 Mar 2010 19:43:34 +0100
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Subject: Re: LF: Antenna Matching
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Tim,

I Started  using a  parallel  tuner  , with a  4  gang tuning  capacitor , 
this was  fine up to  about  45  watts , with the  tx tapped 2 or 3  turns 
up and the  Ae  fed  from the  top  of the  coil  .. classic   top  band 
tuner. Using my  HF swr  bridge. which actually  works fine at  500  and 
reads the  correct power as well , I simply  tuned  for  minimum reflected 
power.

Then  thanks to  E-bay and others came  powers  over  100 mW erp  and blue 
lights from the  tuner ..

At  that  point, the  original  coil, now with  new  pespex spacer's, the 
ww2  (cellulose  ?)  spacers  having burnt out ...  I made a  variometer 
out of a length  of  brown drain pipe  and  some  marly  fittings  from b&q 
, the  original coil is  now  tapped  7  turns up and  acts as  the  feed 
auto  transformer ... this set up  works well  and will  take 200  watts  of 
carrier  , latest slight  improvement  was to  tap the  capacitor down the 
coil and  tune  for  minimal reflected power , good  swr but  requires a  re 
tune  if I qsy more than  50% of the  band  ..may be  too  higher  Q as the 
tune changes with the  wind  blowing the  wire about ....still  use the  swr 
bridge, but  take it  out  before running  wspr ..

Its not what  is in the  air ...its what's in/is the ground that  matters

GL - 73 - G ..

--------------------------------------------------
From: "tim hague" <m0afj@dsl.pipex.com>
Sent: Sunday, March 28, 2010 11:10 AM
To: <rsgb_lf_group@blacksheep.org>
Subject: LF: Antenna Matching

>
> I'm just about to apply for my 500kHz NoV, I've got around 100W of Tx 
> power available and I'm looking for some information on antenna matching, 
> my Tx antenna is just going to be a 132ft Marconi T with a 50ft vertical 
> section, can I get away with just a series tuned matching cct or are the 
> voltages across my matching C going to be very high, I have a wide spaced 
> C approx 200 to 700pF.
>
> Thanks  Tim M0AFJ
>
>