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 PC interference 
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Post PC interference
I thought I'd have a blitz on tracking down some interference in the 2 meter band as I had a S5 noise across most of the band.

First guess was the shack SDR server PC and indeed it was !!

However on further investigation I discovered it was the GPU card - a GT750.

Removing this card and using the built in Intel HD GPU fixed the problem - no more nasty noises !

Makes me wonder if other GPU cards are just as noisy ?

It was noisy even with no video cable attached to it and the noise seemed to be coming from the 12V power feed.

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G8GIW licensed in 1972 (C&G RAE), then G4WIM in 1984 (12 wpm CW test), then KT6UK in 2000 (USA Extra Class), now safely back in the UK and retired early (Google bought the company I was working for !)


Tue Nov 06, 2018 7:05 pm
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 PC interference 
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Post Re: PC interference
More likely the PSU, than the GFX card itself, they do draw quite a chunk of power and if the PSU isn't up to the job then it'll get stressed and noisy.


Tue Nov 06, 2018 9:23 pm
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 PC interference 
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Post Re: PC interference
I thought that myself - but discarded it as the source for two reasons

1. The PSU is overkill wattage wise
2. Tried a different GFX card which didn't use a 12V power feed and still got the problem.

Just tried another GFX (again made by NVIDIA) and same broad band noise.

Just seems to be this one PC causing a problem - I have three other PCs in the shack, but only this one is noisy.

On reflection I think I'll try switching out the PSU just to be sure.

73 Tim

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G8GIW licensed in 1972 (C&G RAE), then G4WIM in 1984 (12 wpm CW test), then KT6UK in 2000 (USA Extra Class), now safely back in the UK and retired early (Google bought the company I was working for !)


Wed Nov 07, 2018 8:48 pm
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 PC interference 
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Post Re: PC interference
Tim,
It could be the voltage regulators on the Motherboard and nothing to do with the gfx cards at all.

Maybe try underclocking it?


Wed Nov 07, 2018 11:27 pm
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 PC interference 
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Post Re: PC interference
It could be the motherboard as it's a new design an Asus H370 supporting an i7 8700 at 3.6GHz with 6 cores - quite the beast so could easily underclock and still have CPU cycles to spare.

However running the on board graphics adapter seems to fixed the problem but from an academic aspect it'd be interesting to get to the root cause.

73 Tim

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G8GIW licensed in 1972 (C&G RAE), then G4WIM in 1984 (12 wpm CW test), then KT6UK in 2000 (USA Extra Class), now safely back in the UK and retired early (Google bought the company I was working for !)


Thu Nov 08, 2018 8:33 pm
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 PC interference 
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Post Re: PC interference
That's a nice processor and motherboard combo, shouldn't anticipate any trouble with an ASUS board I've used them for years. Currently on an X299 with an i9@4.4GHz.

If you can swap out the PSU easily, then that'll be a good starting point.

KustomPC's (www.kustompcs.co.uk) always do a great deal on parts, and they'll recomend a suitable PSU without trying to rob all your pocket money.


Thu Nov 08, 2018 11:33 pm
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