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From: "Dave Sergeant" <dave@davesergeant.com>
To: rsgb_lf_group@blacksheep.org
Date: Sun, 01 Jul 2007 17:10:24 +0100
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Subject: Re: LF: 500 kHz - G4GDR - Please listen
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On 1 Jul 2007 at 5:02, G3vtt@aol.com wrote:

> 
> I have taken to tuning the band low to high and high to low after
> calling  CQ. (Where have I heard that before?).
>  
> Incidentally how is your set up going? I've not heard you on for a
> week or  two maybe more. Any changes to your ground system and
> vertical to improve  matters?
> 
> 73
> 
> Colin G3VTT

Thanks for the QSO this afternoon Colin, we are getting there, 
admittedly a little slowly. I suppose this answers your last 
question, I have certainly been around and putting out the odd CQ 
call etc, but have to some extent been diverted by other things - 
sporadic E openings on 10m (they will soon be gone..), chasing DX 
(what little there is of it) on the other bands, and not least a bit 
in the way of TV and VCRs which needed repair - you can't turn away 
jobs which bring in the pennies!!

But more importantly over the past few days I have been exploring 
impedance measurement techniques on 500kHz, mainly with Peter G3LDOs 
3-meter method. I seem to have got that perfected now and can do 
reliable and repeatable impedance measurements on my vertical from 
the shack. It told me that it actually resonated at 492kHz (not good) 
and also that I have too many turns on my variometer - it is 
currently tuned to 499kHz. I had overestimated my terrible earth loss 
resistance - it is not 350 ohms which I had thought at first, rather 
a slightly better 150 ohms! I could even see it dropped slightly 
after yesterday's rain... I hope to document this on my website in 
due course.

I now need to readjust the turns ratio on my matching transformer (at 
the vertical base) so I have 50 ohms there instead of 22 and which 
will give a proper 50 ohms at the shack end, when hopefully the TX 
will produce a bit more umpth into it.

I still need to reduce the earth losses in due course, at least I now 
have a scientific way of actually measuring them and will be able to 
see the effects of any changes.

As for tuning high to low when we have only 3kHz to tune it is no 
great problem. I use the twin vfo's on the K2 - I monitor my own 
transmission on one VFO for sidetone and switch to the other one to 
tune. I wondered whether I should have netted on to you, maybe it 
would have confused you, but occupying two frequencies does seem 
slightly anti-sociable. I called CQ in the middle of the band to 
avoid Tom G3OLB who was in QSO around 501.5 (possibly with GW4HXO?). 
If it gets any busier I guess we will need bandplans...

73 Dave G3YMC

http://www.davesergeant.com