Message-ID: <5B3BB75F.9030305@posteo.de>
Date: Tue, 03 Jul 2018 19:50:23 +0200
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <A905714CEEED4F84A38B62B60939952A@MPC>, <Pine.LNX.4.64.1806302043050.405@plato.ucs.mun.ca>, <Pine.LNX.4.64.1807010624110.1371@plato.ucs.mun.ca> <5B38A763.17452.850587@roelof.ndb.demon.nl> <Pine.LNX.4.64.1807030917560.9723@plato.ucs.mun.ca>
In-Reply-To: <Pine.LNX.4.64.1807030917560.9723@plato.ucs.mun.ca>
Subject: LF: Summer games / EARTH ANTENNAS
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Hi Joe, VLF,

You seem to like to 'play' on the very low frequencies during the sunny 
days :-)

Same here! My YL bought a house in JN39XI and we are spending almost 
each weekend there in the peaceful silence. The forest is really great! 
I guess you know that, as a Canadian.
Now i'm planning to receive some signals in JN39XI07 
<http://k7fry.com/grid/?qth=JN39XI07> .  BTW a most useful distance for 
analysing my own signals from Heidelberg (about 55 km QRB).
Oh and i think about playing with earth antennas again, you know!

BTW did someone (of the group) ever tried to build a full size dipole 
for 137 kHz? I mean for transmitting! On a stony mountain/hill it could 
be better than expected. With a Raspi + GPS module one could build up a 
simple WSPR beacon and a ICL7667, which can be driven by the 3.3 V GPIO 
output voltage could make a simple and effective 5W PA running at 12V.
The wire just needs to be 1000m long or so. In a low frequented forest 
it could lay there for some days...

I remeber experimenting with a full size dipole on 630m in 2012, when 
the band was quite young. It worked well although the antenna was just 
4m above the ground and the soil conductivity was not ideal (medium 
conductivity). A few CW QSOs were done out of a 7 Ah gel battery and 
just 50W or so, in July!

And what about VLF and ULF using earth antennas? I remember making 45 km 
distance on 8.97 kHz from the 700m long wire antenna, grounded at each 
end (250W RF power if i remember correctly). That was about 15 dB in 3.8 
mHz. But what would be possible on lower frequencies if the far end of 
the wire is well grounded?

Time to fill that summer hole (activity)!

73, Stefan


Am 03.07.2018 14:03, schrieb jcraig@mun.ca:
> This was the first time SAQ was heard here using a mobile RX.  It was 
> in a quiet location, a km  from mains lines and other RF pollution.  
> SAQ became quite weak when
> the RX was in the forest however.  The trees must be good conductors 
> at VLF.
>
> Is the low-power miniwhip mentioned below the same new one designed with
> help from G4COL with a J310, Rs= 47-270 ohm and the FT-37-43 xfmr?  
> I'd like
> to try that at VLF.

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Hi Joe, VLF, <br>
<br>
You seem to like to 'play' on the very low frequencies during the sunny
days :-) <br>
<br>
Same here! My YL bought a house in JN39XI and we are spending almost
each weekend there in the peaceful silence. The forest is really great!
I guess you know that, as a Canadian. <br>
Now i'm planning to receive some signals in <a
 href="http://k7fry.com/grid/?qth=JN39XI07">JN39XI07</a> .&nbsp; BTW a most
useful distance for analysing my own signals from Heidelberg (about 55
km QRB).<br>
Oh and i think about playing with earth antennas again, you know! <br>
<br>
BTW did someone (of the group) ever tried to build a full size dipole
for 137 kHz? I mean for transmitting! On a stony mountain/hill it could
be better than expected. With a Raspi + GPS module one could build up a
simple WSPR beacon and a ICL7667, which can be driven by the 3.3 V GPIO
output voltage could make a simple and effective 5W PA running at 12V.<br>
The wire just needs to be 1000m long or so. In a low frequented forest
it could lay there for some days...<br>
<br>
I remeber experimenting with a full size dipole on 630m in 2012, when
the band was quite young. It worked well although the antenna was just
4m above the ground and the soil conductivity was not ideal (medium
conductivity). A few CW QSOs were done out of a 7 Ah gel battery and
just 50W or so, in July!<br>
<br>
And what about VLF and ULF using earth antennas? I remember making 45
km distance on 8.97 kHz from the 700m long wire antenna, grounded at
each end (250W RF power if i remember correctly). That was about 15 dB
in 3.8 mHz. But what would be possible on lower frequencies if the far
end of the wire is well grounded?<br>
<br>
Time to fill that summer hole (activity)!<br>
<br>
73, Stefan<br>
<br>
<br>
Am 03.07.2018 14:03, schrieb <a class="moz-txt-link-abbreviated" href="mailto:jcraig@mun.ca:">jcraig@mun.ca:</a>
<blockquote cite="mid:Pine.LNX.4.64.1807030917560.9723@plato.ucs.mun.ca"
 type="cite">This was the first time SAQ was heard here using a mobile
RX.&nbsp; It was in a quiet location, a km&nbsp; from mains lines and other RF
pollution.&nbsp; SAQ became quite weak when
  <br>
the RX was in the forest however.&nbsp; The trees must be good conductors at
VLF.
  <br>
  <br>
Is the low-power miniwhip mentioned below the same new one designed
with
  <br>
help from G4COL with a J310, Rs= 47-270 ohm and the FT-37-43 xfmr?&nbsp; I'd
like
  <br>
to try that at VLF.
  <br>
</blockquote>
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