[600MRG] Rx noise 630m

[Tom W8JI]

Hi Dave,

Relative performance or noise performance is very difficult to measure 
in a meaningful way.

8dB is meaningless. 8 dB is just a ratio, what is the 8dB ratio against 
and under what condition?

The 13dB difference between a short and an antenna doesn't mean very 
much of anything either. It only means the antenna is picking up 13dB 
more noise than a short. That doesn't mean anything about ambient noise 
or antenna receiving performance. It only means is the antenna system 
has 13dB more background noise than a short in some test. It doesn't 
tell us anything about how well something is working, how poorly it is 
working, or what the ambient noise level is unless there is some good 
reference.

Now if we have some reference signal it might mean something. My full 
size inverted L antenna in January was about -73 dBm in 3.1kHz bandwidth 
daytime at this time of day, and -70 dBm average on a quiet night just 
before sunrise.

I just measured it now and it is -72 dBm in the same 3.1 kHz bandwidth. 
Some digital signal on right now is -86 dBm, 14 dB below the 3.1kHz 
noise floor.

My guess is that is N4WLO, my level meter can't decode digital signals.

Even this does not mean much.

73 Tom




On 3/18/2023 3:11 PM, Dave Riley via 600MRG wrote:

> Saying good bye to seasonal DX..
>
> Think the bulk of QRN has been nulled out here but still, the 
> difference between antenna and a short is about 13db
>
> Not much difference in noise level with loop spun around either..
>
> Maybe there is 8 db ambient noise average, some say that is low..
>
> What you say??
>
> TNX Dave @ W1FRV
>
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