Jim and others, Thanks for getting the numbers straightened out. I've been hasty with email recently due to "not enough minutes in the day". The mains harmonic situation is that "very high" frequency
I made a numerical mistake in my last posting. 25 Hz shift at 136 kHz is a ratio of about 0.009, or 0.9%. Of course, we would like the "QRM deviation" of 50 Hz lines to be much less than plus or minu
Hi all, I made a numerical mistake in my last posting. 25 Hz shift at 136 kHz is a ratio of about 0.009, or 0.9%. Of course, we would like the "QRM deviation" of 50 Hz lines to be much less than plus
Hi Jim, Alberto, Rik and others, I agree that the frequency stability of the mains network is a point to consider further. However, I think there are two interference mechanisms at play in the LF ban
The picture seems to confirm Jim's remark, a variation of 1-2Hz at the 53rd harmonic results is a variation of 50-100Hz at the 2740th harmonic (137kHz) 73, Rik ON7YD At 15:43 24/03/2003 +0100, you wr
James Moritz wrote: Not sure about ZL, but here in the UK the 50Hz nominal mains frequency drifts around quite a bit - perhaps a few tenths of 1%. Seen on a fairly coarse resolution spectrogram, the
Dear LF Group, At 17:09 22/03/2003 +1200, Bob wrote: So my suggestion for selecting frequencies for long haul DX between amateur stations is to avoid multiples of 50 or 60 Hz (50 Hz mains being used
Hi all, I originally thought that 137.7000 kHz was clear of QRM in this corner of the world, however lots of capture time on trying to find a UA9OC signal (with success on 13 March) found a weak QRM