Date: Sun, 8 Oct 2017 10:13:56 +0200 (CEST)
From: Jacek Lipkowski <sq5bpf@lipkowski.org>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <15ef8d7f085-c0b-23128@webjas-vae177.srv.aolmail.net>
Message-ID: <alpine.DEB.2.11.1710081007010.734@mailn.lipkowski.org>
References: <15ef8d7f085-c0b-23128@webjas-vae177.srv.aolmail.net>
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Subject: Re: LF: VO1NA in Todmorden on 8270 Hz
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If you choose to use the NEO7 fractional pll output directly, then pick 
frequencies which are 48MHz/N where N is an integer. This will lead to a 
much cleaner signal. 8.27015kHz is one possibility (48000kHz/5804).

Another option is to use Paul's ebsynth, and feed it a clean reference 
frequency from the NEO7. I use a 20kHz reference (48000/2400). This can 
generate an arbitrary frequency.

VY 73

Jacek / SQ5BPF

On Sat, 7 Oct 2017, Markus Vester wrote:

> Date: Sat, 7 Oct 2017 17:57:36 -0400
> From: Markus Vester <markusvester@aol.com>
> Reply-To: rsgb_lf_group@blacksheep.org
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: LF: VO1NA in Todmorden on 8270 Hz
> 
> Hi Joe,
> 
> good to know that you are on air again. The DL0AO grabber in Amberg (East Bavaria) includes your frequency in one of
> the 31 uHz instances.
> 
> > Yes, the high wire for 630m (~5 W EIRP) and the low for 36000m.
> Shouldn't that be the other way round, maximizing the important VLF radiation ? ;-)
> 
> > Yes, pps and NMEA to SpecLab but evidently no discipline yet
> Getting the SpecLab samplerate detector to work will lock your frequency but not the phase. To avoid the risk of
> phase jumps due to soundcard glitches or buffer underruns, I would then strongly recommend to set up the software PLL
> with audio feedback from a pickup probe. This method also has the advantage of maintaining absolute
> phase despite variations in the antenna circuit. But I have to admit that setting up SpecLab that way is a bit more
> involved, especially when you also want to apply PSK modulation for EbNaut.
> 
> With the programmable ourtput frequency from the NEO7, you may have two other, simpler options: 
> - You could tell the NEO to output the desired transmit frequency directly. For EbNaut, you can later add the
> traditional XOR or balanced mixer circuit.
> - You could use the NEO with high frequency output as a clock source for your DDS. EbNaut could be generated either
> by XOR or by manipulating the DDS phase word.
> 
> Best wishes,
> Markus
> 
> -----Ursprüngliche Mitteilung-----
> Von: jcraig <jcraig@mun.ca>
> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
> Verschickt: Sa, 7. Okt 2017 18:46
> Betreff: Re: LF: VO1NA in Todmorden on 8270 Hz
> 
> Paul Markus and Group,
> 
> Thanks Paul for the reports. The radiation gives more gratification than the efforts to get a stable carrier.
> 
> On Sat, 7 Oct 2017, Markus Vester wrote:
> 
> > Great result!
> 
> Truly astounding that Paul can receive 10 uW at 3600km with 10+ dB S/N.
> 
> > Hmm I thought that VO1NA had been on 477 kHz during those nights. Joe are you transmitting MF and VLF
> simultaneously, on two antennas?
> 
> Yes, the high wire for 630m (~5 W EIRP) and the low for 36000m.
> 
> > Do you already have GPS lock available on 8.27 kHz?
> 
> Yes, pps and NMEA to SpecLab but evidently no discipline yet. The pps pulse looks strange on the SL scope and there
> are 'PPS zero-crossing too
> flat' debug errors on SL SR correction. This is all the NEO7M seems willing to provide at the moment; connecting the
> raspi3 to the tiny USB
> pins on the NEO7M was fun, but otherwise unproductive. I'm hoping it's possible to send commands directly to the
> neo7m via usb without a special chip.
> 
> RSNTP is running on the SL pc.
> 
> 73
> Joe
> 
> >
> > 73, Markus
> >
> >
> >
> > -----Ursprüngliche Mitteilung-----
> > Von: Paul Nicholson <vlf0403@abelian.org>
> > An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
> > Verschickt: Sa, 7. Okt 2017 10:36
> > Betreff: LF: VO1NA in Todmorden on 8270 Hz
> >
> >
> >
> > VO1NA on 8270.00709 is a good nighttime signal at Todmorden
> > recently. Here are the last three night's spectra in 34.72 uHz
> > (8 hours 23:00 to 07:00 UT) using combined E-field and H-field.
> >
> > http://abelian.org/vlf/tmp/171007b.gif S/N 12.6 dB
> > http://abelian.org/vlf/tmp/171007c.gif S/N 14.5 dB
> > http://abelian.org/vlf/tmp/171007d.gif S/N 11.4 dB
> >
> > Not bad for 8uW ERP at range 3575 km and an undisciplined
> > OCXO.
> >
> > --
> > Paul Nicholson
> > --
> 
>
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