----- Original Message -----

From: Vernall

Sent: Sunday, May 19, 2002 10:40 PM

Subject: LF: Re: pegelmesser

Mal,

The frequency stability of any selective level meter with a VFO for a local oscillator makes them suspect for staying tuned within a fraction of a Hz for long periods. The digital display on a Siemens D2019 I have merely counts the VFO (with a constant 100 kHz offset to give passband centre frequency) and numbers actually change with VFO warmup. The display is to 10 Hz, so it can not be used for pre-setting to a QRSS signal that is expected to be below the noise and therefore impractical to try tuning by "ear". As well, the BFO is a free-running RC oscillator so the recovered audio can have further drift of centre frequency.

There are some selective level meters with master oscillator arrangements for tuning and demodulation, and can have fractional Hz stability.

In saying the obvious, selective level meters are primarily intended for determining signal levels.

Hello Bob

Look for a pegelmesser with phased locked loop oscillators, synthisized etc the same as mine and you will find they make a great LF receiver, especially the models with the 20 hz filters.

Even the free running osc type are useful if kept switched on all the time and inside the house with a fairly constant temperature and not outside in the bicycle shed!!

I do not have any trouble resolving and keeping signals within the 20 hz bandwidth for hours at a time. I especially like the W&G SPM-12, with the 10 khz IF output. I built an external product det, audio stage and it works extremely well, very sensitive and the filters are well suited to LF work.

73 de Mal/G3KEV

Bob ZL2CA