Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February

[Chris Osborn <g3xiz@yahoo.co.uk>]

Roger, Jim, Marcus, LF

I shall try to stabilize the shack temperature and keep frequency drift to a minimum.

The new TX uses a 10.000 MHz oscillator followed by a G4JNT divider (RadCom Sept 2010)
Thus I can transmit frequencies of 10.000 MHZ divided by even numbers e.g. 1112, 1114, 1116  . . .

I intend to build an off-air standard, 10 MHz output and locked to Droitwich (198 kHz) but the PLL IC's
have taken weeks to arrive (from Korea via E-Bay).

My TX OCXO is an ex-equipment unit (from China via E-Bay)

PIEZO, Carlisle, PA.
Mod 29201326
10.000 MHZ

I must confess that I'd assumed that the frequency stability with changing ambient temperatures would be
better than it seems to be.

73 Chris G3XIZ

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From: Markus Vester <markusvester@aol.com>
To: rsgb_lf_group@blacksheep.org
Sent: Thu, 10 February, 2011 21:32:25
Subject: Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February

Hi Chris, what sort of 10 MHz OCXO do you have? The little canned industrial types (eg. http://www.kvg-gmbh.de/10.0.html?&L=3 ) will stay within about a couple of ppb over hours, translating to some 10 microHz at VLF. 

 

Best 73, Markus (DF6NM)

From: Roger Lapthorn

Sent: Thursday, February 10, 2011 10:02 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: VLF Transmissions - G3XIZ - 12th / 13th February

The stability of "within a few mHz" could be a problem for those of us using extremely narrow Spectrum Lab settings to dig your signal out if the noise Chris. This is where absolute locking to a GPS source is so valuable as one can screw the bandwidth right down. A few mHz could mean the carrier drifts and is not detected. Still, I'll be looking!

73s

Roger G3XBM

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