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LF: Re: 137 kHz WSPR-2 on a 900m long ground loop, this weekend

To: <[email protected]>
Subject: LF: Re: 137 kHz WSPR-2 on a 900m long ground loop, this weekend
From: <[email protected]>
Date: Sat, 8 Sep 2018 16:24:03 +0100
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Nil to report at my QTH ur QRG 136 USB ie 137.425 RF FREQ
73 GL MAL/G3KEV


-----Original Message----- From: DK7FC
Sent: Saturday, September 8, 2018 1:45 PM
To: [email protected]
Subject: Re: LF: RE: 137 kHz WSPR-2 on a 900m long ground loop, this weekend

RR,

Now, since 12 UTC the TX is in its final position and runs each 10
minutes. It will run for 24 hours or so.
So far the results are quite satisfying, for just 10 watts. With 100 W,
we could have a CW QSO in the groundwave range. Did you expect that?

Let's see what the night brings. Also the radiation pattern will be
interesting...

More reports from more stations are welcome :-)

73, Stefan



Am 08.09.2018 14:02, schrieb Clemens Paul:
Hi Genosse Stefan,

2018-09-08 11:56 DK7FC 0.137425 -17 -1 JN39 1 DL4RAJ JN68kj 449 103 2018-09-08 11:56 DK7FC 0.137425 -11 0 JN39 1 DL0AO JN59vk 349 89 2018-09-08 11:08 DK7FC 0.137425 -10 0 JN39 1 DL0AO JN59vk 349 89 2018-09-08 11:56 DK7FC 0.137425 -22 0 JN39 1 PI4THT JO32kf 306 359 2018-09-08 11:08 DK7FC 0.137424 -22 0 JN39 1 PI4THT JO32kf 306 359 2018-09-08 11:56 DK7FC 0.137429 -18 0 JN39 1 DC0DX/RF JO31lk 218 0 2018-09-08 11:56 DK7FC 0.137425 -26 0 JN39 1 DC5AL-R JO31lk 218 0

73
Clemens
DL4RAJ





-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of DK7FC
Sent: Saturday, September 8, 2018 1:18 PM
To: [email protected]
Subject: Re: LF: RE: 137 kHz WSPR-2 on a 900m long ground
loop, this weekend

Genossen!

I just matched the antenna and run some WSPR-2 transmissions
on 137.425 kHz.

I'm getting 260 mA antenna current at 10 W RF power. So the
overall loss
resistance should be 150 Ohm (the wire has about 30 Ohm). For
resonating
i need about 2.5 nF in series to the wire.
So the feed point impedance is Z = 150 Ohm + j450 Ohm, still
behaving as
a loop. Quite a comfortable managable impedance. I had to wind
an output
transformer on a "RIK20" core (Reichelt!), which works very well. The
secondary number of turns was unknown at the beginning ;-)

Regular transmissions will start in an hour or so.

73, Stefan

Am 08.09.2018 12:07, schrieb Clemens Paul:

Hi Genosse Stefan,



Will someone catch the signal at all? At least i'm already
asking for RX
stations!


I've just resonated my antenna aa inverted L on 137.5kHz (with 502µH)
and wil be ready to receive in WSPR-2 as soon as you start.

73
Clemens
DL4RAJ





-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of DK7FC
Sent: Friday, September 7, 2018 1:49 PM
To: [email protected]
Subject: LF: 137 kHz WSPR-2 on a 900m long ground loop, this weekend

Genosse Roman, LF,

Yesterday i built a small LF PA providing 10 W at 50 Ohm. It
consumes 1
A at 12 VDC. I intend to run an over-night WSPR-2

transmission (20% TX

rate) on saturday night, using the ground loop or earth antenna in
JN39WI. The signal generator is a Raspberry Pi running on a

separate 7

Ah lead gel accu. The PA has its own 7 Ah accu. The PA can

switch from

2.5 W to 10 W :-)

Will someone catch the signal at all? At least i'm already
asking for RX
stations!

I'll carry some measuring equipment there, like my M0BMU LF tuning
meter, some Cs, a T106-2 and some wire, also a small ferrite core to
build a transformer if necessary.
What could the feed point impedance be? I have no idea! My modified
MFJ-259B covers LF but i expect it will be overloaded with strong
signals on the antenna, so i try to match the antenna with the
transmitter.

More soon :-)

73, Stefan

PS: Oh, i'm also going to connect two anti-parallel LEDs to
the antenna
to see if they shine. It is all a big game for old children!


Am 05.09.2018 23:54, schrieb Roman:


OK Stefan.
Try it to do. may be wonderful results.

Roman




Hello Roman,

Yes maybe i'll build a quick PA tomorrow for LF and will


transmit on LF


for 24 hours, each 10 minutes, WSPR-2. I have no idea at


all how this


antenna performs on 137 kHz. Is it still a loop or rather a


dipole or a


mixture? At least it has about the length of a full size


dipole for 137


kHz. I would TX at 10 W RF power only, so that a small accu


covers some


hours. But i'm not yet sure if i can find the time to do it


tomorrow.


73, Stefan

PS: If the antenna acts as a dipole, then it is beaming to


Russia directly.


Am 05.09.2018 21:42, schrieb Roman:




Congrts, Stefan!

We are follow by your success!
Listen, do you planning to operate 136 kHz, I hear, tell


me pse - do you planing try to TX with that ant on 477 kHz and 160M?


I will be interestin to hear about results.

73!
Roman



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