Re: LF: G3XBM - very long carrier VLF transmission test Dec 15th

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Wolf (et al)

My frequency source is an HF crystal divided by 512. This is in the same box as the PA and stabilises at a temperature of about 60 deg C after about 15 minutes. Unfortunately I do not know how stable the frequency is, although I will attempt to measure this on Wednesday using Stefan's suggestion of locking Spectrum Lab to an MSK signal as I did for his recent tests.

In all honesty I doubt that my signal will be detected at any range and I've not heard of anyone within possible range who will definitely be monitoring yet.

73s
Roger G3XBM

On 13 December 2010 18:54, wolf_dl4yhf <dl4yhf@freenet.de> wrote:

Hello Roger,

Do you have an estimate about your transmitter's frequency stability (mHz per minute or similar) ?
This would help to guesstimate a half-way matched FFT bin width, or -if you prefer- QRSS speed index. Anyway, even for listeners/viewers in your neighbourhood, I'd suggest to use a setting for QRSS 120, or, if soft/hardware permits, even slower mode to sequeeze the last fraction of a dB out of the equivalent receiver bandwidth.

Unfortunately no good site for RX reception here, otherwise I'd like to test a new GPS-stabilized receiver. Maybe in a few weeks, using a remote VLF site with wideband FM link.

Good luck with the test,
  73,   Wolf DL4YHF .

Am 12.12.2010 23:51, schrieb Roger Lapthorn:

This Wednesday, Dec 15th, I will run tests on 8.7608kHz with very long continuous TX periods of several hours interspersed with gaps of 0.5 to 1 hour. Transmissions will start at 0900GMT and finish at 2300GMT. I will reveal the TX pattern after the test so the test is done "blind".

I'd be most grateful if suitably equipped stations could look for any possible signs of the signal, even though I shall only be using the 20m spaced earth electrodes and 5W as used for my local earthmode tests. Those able to screw the bandwidths right down may just be able to detect something, although I think it is unlikely at any great distance.

15.12.10    
0900-2300z 
8.7608kHz   
Carrier "on" periods of 30mins or more

Good luck to anyone having a go.

73s
Roger G3XBM

--
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.com/user/g3xbm
G3XBM   GQRP 1678    ISWL G11088

-- 
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.com/user/g3xbm
G3XBM   GQRP 1678    ISWL G11088