In reply to a post by dect:

In reply to a post by gary333:

What I found odd was at bang on 10pm the power started to reduce in 0.1db increments every 10 seconds until it made it's way down to 2.3db (from 6.2db) where it remained flat until after midnight. Not sure when it returned as went to sleep.

Did you mean power as thats not normally measured in decibels

Power is usually labelled as dBm, decibel-milliwatts.

Almost certainly talking about the SNRM, as those figures are the same as posted in the OP for noise margin.

Whoops, yep, I meant the Noise Margin.

In reply to a post by j0hn83:

Power is usually labelled as dBm, decibel-milliwatts.

Thanks for explaining, helpful as always

I tried AM 612khz tonight in the car outside. I noticed a pulsing hum sound going up and down with the muffled sound of voices in the background. As soon as I pull off the drive and move 20m away I then start the get a foreign broadcast (possibly Spanish). The broadcast becomes very clear (well as far as AM ever is) and is present all around the village I live in. Whoever is broadcasting is speaking constantly.

The pulsing up and down sound is loudest (and the voices become very muffled and low volume) around my house.

As I pulled off my street in the car I heard beep, beep, beep (5 or more times). Sounded like the ones to announce the time or start of a broadcast.

Should I be getting a radio station on this frequency, as if so, how are you supposed to test for noise?

Cheers guys.

I would say that where the foreign station is clear, is good evidence of no local noise drowning the signal out.