[600MRG] QRN or conditions?? BACKGROUND NOISE

[Dave Riley]

Thanks Tom,

I measured the relative noise while in the SSB mode, same as WSPR with 
no agc..

The loop is 5 turns resonated and fed to the receiver directly with 50' 
of ultra low loss 72 ohm TX twin lead with no amp. in line..

The R75 receiver with preamp2 normally registers S0-1, then it may rise 
to about S5 or so at times with noise and I use the line level out noise 
voltage as reference..

So far it is helpful inseeing what is ahead as far as DX goes.. Still 
gathering the numbers..

TNX es 73 from Dave, W1FRV



On 2/6/2023 4:51 PM, Tom W8JI wrote:
> Hi Dave,
>
> My noise on an accurate selective noise meter increases 5dB here when 
> the sun sets and the band opens. It increases 25dB or more from 
> distant storms, sometimes 40-50dB from close storms.
>
> In my opinion, 4dB of noise change isn't anything. This is especially 
> true the way you are measuring noise.
>
> If you listen to the noise on a wide bandwidth and AM does the noise 
> sound change? Does it sound "buzzy" or raspy?
>
> 73 Tom
>
>
>
>
> On 2/5/2023 2:10 PM, Dave Riley via 600MRG wrote:
>> Was easy to see that last night was going to be deadsville for DX on 
>> 630..   IT WAS
>>
>> Normally with the RF input to the receiver shorted and the AGC turned 
>> off, I set the audio voltmeter to the line out voltage.. ZERO DBM
>>
>> Then apply the passive loop antenna and will normally see around +7 
>> dbm.. Am lucky that the power lines are tangent to the DX path..
>>
>> Late yesterday afternoon it read about 11+ dbm background noise.. 
>> Bummer, no DX tonight... AND THERE WAS LITTLE
>>
>> Now I have to find out if 4 more dbs of noise is partially the cause 
>> or just band conditions..
>>
>> Always with the negative waves Moriarty!!
>>
>> Any collaboration here??
>>
>> TNX de Dave/W1FRV
>>
>>
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