Date: Mon, 17 Apr 2017 17:28:36 -0230 (NDT)
From: jcraig@mun.ca
To: rsgb_lf_group@blacksheep.org
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Subject: Re: VO1NA on VLF:
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Hi Markus,

Happy to get your email -- it is encouragment for those lamenting a fried=
=20
helix!  Without a signal, the DF7FC probe and SL gives about -143 dB.
The LHS of SL says 8.27 kHz 3.8 mHz 60s with the config file being used.
It was actally -70 dB at 1 km;  at 5.8 it should be -115 dB which will=20
be easy to detect -- if I can arrive at that distance before the coil
fails.

Transmissions last about 30 mins until the coil arcs over.  Work is
underway towards increasing this number.

I chose 8277 to avoid interference with the serious work being done
on 8270!

73
Joe VO1NA

On Mon, 17 Apr 2017, Markus Vester wrote:

> Hi Joe,
>
>> Then the coil arced.
> Welcome to the club! I'd count that as a success: A real VLF amateur shou=
ld always be running close to the voltage limit of the antenna and coil! Yo=
u probably had around ~ 7 kV at 0.2 A?
>
>> -60 dB readings at 1 km
> What was the SNR and FFT bandwidth at that point? Scaling by r^-3 from 1 =
km to 5.8 km, the signal would be expected to drop by 45 dB at the far fiel=
d boundary.
>
> How long did the transmission last? Maybe it would make sense for Paul to=
 inspect Mike's data from Forest/Virginia.
>
> Any special reason why you use 8277 rather than 8270 Hz?
>
> Best 73,
> Markus
>
>
> -----Urspr=C3=BCngliche Mitteilung-----
> Von: jcraig <jcraig@mun.ca>
> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
> Verschickt: So, 16. Apr 2017 23:58
> Betreff: Re: LF: 2017-04-16 03:15:13 VO1NA AA PA0RDT JO11TM 0 477 -25Op8_=
||||||||||||||_~25dB
>
>
> Hi Roelof, G.. and Group,
>
> The delayed curtain up on the opera was due to VLF tinkering.
> There was much excitement when a pc with a properly working
> sound card was deployed. Today I resurrected the low 100m aerial
> (Happy Easter to all) and fed 30 watts 200ma on 8277 and
> got some lovely -60 dB readings at 1 km. Then the coil arced.
> A far field detection was almost a certainty up to this point!
>
> OP8 on 479.477 kHz will resume at 2200 tonight. Good luck
> to all and keep up the good work with the RTL Roelof and
> thanks for the reports Graham.
>
> 73
> Joe
> ...
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