Message-ID: <4D1BC000.5070507@toya.net.pl>
Date: Thu, 30 Dec 2010 00:10:56 +0100
From: Piotr Mlynarski <sq7mpj@toya.net.pl>
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Subject: Re: LF: "NM" on 136177.5
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Stefan Sch=E4fer pisze:
> Hello Piotr,
>
> Nice to see that you enjoy the LF receptions :-) Generally its nice to=
=20
> see new upcoming stations and a never ending interest in LF operation.=
=20
> Soon, i will be one of the active TX stations with a fixed antenna=20
> too. I am looking forward to this :-)
>
> 73, Stefan

Hi Stefan,

First of all i thank you for your response due to my LF reception=20
reports. Sure, it does not happen very often as i live in a really=20
hostile environment as far as  receiving long waves is concerned.
Nevertheless, i do enjoy every single lf reception even if it is a very =
=20
'short'  distance ( according to 'standards'  established by  current=20
T/A observations, transpacific qso etc...) so i was really happy to see=20
for the first time Markus,
DF6NM and Gus, SM6BHZ  tx'ing in the EU   '177 window . I even managed=20
to  set up LF grabber:   http://www.toya.net.pl/~mlynarski/  which i=20
will be switching on ocasionally or upon request.
you may regard this as a 'lower bound' of RX observations   i.e.   if=20
something is seen on my grabber it means whole world is already watching=
=20
this :)
( btw , abt 21 utc.. Markus started TX'ing as i can see veeeery weak=20
traces at 136.1775 kHz )
the distance to Markus is abt 640 km , to Gus abt 817 km so when you=20
will be qrv on 137 frm  Heidelberg ( 801 km ) i am pretty sure that , on=
=20
statistical average, i will be in position to receive your signal, so=20
likely,
 we may have a x-band qso on 137 kHz - it would be a great pleasure for=20
me if this would have happened !

on VLF issues.... just today, Ken, M0KHW asked you abt possible=20
replacement of  bf862 jfet. i can confirm your answer that J310 also=20
works in your VLF antenna  - i have already built it  and tested shortly=
=20
during
Christmas Eve  SAQ transmission  - it worked but i had too much qrm so i=
=20
it had to be replaced by the loop which nulled some of the qrm.=20
Of course, the placement of the antenna ( i.e. on my balkony)  was=20
absolutely inappropriate but i did it only for checking purposes etc...=20
i have also used your idea of separating  jfet along with 1M, 10M R's=20
and 20nF cap into a waterproof box while placing the remaining parts in=20
a separate box and  used abt 20 m of pair cable between.
i am preparing for your next kite vlf experiment but this time i will=20
be  /p station abt 10 km away  frm my qth  so  i will try to check if=20
the numerical model of earth-ionosphere waveguide works in practice .. :)
i plan to use your VLF active antenna along with the SDR-IQ receiver .
At this moment i have completely no idea how to make 'the calibration'=20
of such setup in order to have the readouts comparable with some=20
theoretical predictions
 but the 'long winter evenings',  hopefully, will provide some solutions=
  :)

                                                             Yours,=20
Piotr, sq7mpj
qth: Lodz /jo91rs/