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Date: Wed, 14 Oct 2015 15:04:41 +0200
From: DK7FC <selberdenken@posteo.de>
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References: <858532982.20151012141313@chriswilson.tv> <561BC13C.6070603@posteo.de> <1893481215.20151013103725@chriswilson.tv> <2880411444781466@web29g.yandex.ru> <282008608.20151014123548@chriswilson.tv>
In-Reply-To: <282008608.20151014123548@chriswilson.tv>
Subject: Re: LF: First LF TX's from 2E0ILY
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Status: O

Hi Chris,

Am 14.10.2015 13:35, schrieb Chris Wilson:
> [...] It's far from optimal right now, 

...but your first signals are better then that of many other UK stns in 
the past few years (except G3KEV :-) ).
We could easily have a QRSS-3 QSO with good SNR.

Could, if i would be QRV :-(
My coil needs to be built up again. The RF litz is laying here in the 
cabinet, waiting for a new body. I plan to use at least 40 cm diameter, 
better 50 cm. Then i'll be on air again. The season is already there but 
there are many other time consuming projects :-/
But i'm watching what you're doing and how things are developing on your 
side.

Tell use the power and antenna current. I recommend to build a simple 
ANALOG amperemeter, a ferrite core with high mu (AL abt 4000 nH), a 
single turn primary, maybe 40 or 50 turns secondary, a bridge rectifier 
(1N4148 or maybe UF5404 or similar), a 10 Ohm shunt resistor, a 100 uA 
amperemeter, a 10nF C and a potentiometer and a switch. The switch is 
for different ranges, maybe 1A and 5A? Calibrate it by using a dummy 
load in series with a 1 Ohm resistor (metal oxide layer R is best). 
Measure the voltage across the 1 Ohm resistor with the scope. Then you 
know the current and can calibrate the meter.
Then you can put the meter in series to the antenna wire and align your 
variometer to a maximum current. This is resonance! Once you know the 
current in the wire, you can calculate the losses in the system and see 
if it worth to add more ground rods or if it's better to cut the 
sourrounding trees and the trees of the neighbours! :-)

73, Stefan

> but I
> have  plans  to  improve things! Right now I am just fascinated by how
> far  it  gets  "as  is".  It's  taken me ages to get this far, and the
> novelty  has  not worn off even with a poor antenna. Hopefully one day
> you might hear me out there.
>
>
>
>
>