UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - MW hum - higher frequencies only

Skywave · 21st Jun 2021, 11:53 pm

Having read all the posts so far, to my mind, post #4 seems highly relevant

From that - and what you have said, quote: hum is much worse if I am near the set, but if I move away by at least 5 metres then the hum becomes barely audible, unquote, leads me to wonder if it may be that the mains wiring radiation is being picked up by your body and re-radiated. Yes, really weird, I do appreciate - but you do seem to have a very strange fault condition.

However, this may be of assistance:
https://www.vintage-radio.net/forum/...ad.php?t=42507

If it isn't radiation from the mains, then it must be that where you are located there is a strong radiated electro-magnetic field that could be coming from a nearby radio transmitter - or some other source. Perhaps it's coming from a high-voltage street step-down transformer: it's entering your body and re-radiating.
Perhaps, with the aid of a portable transistor radio that shows same problem, a travel around your vicinity - which might be a few miles - might locate said transmission source.

I'll be intrigued to discover the cause - as I expect you will be - and other member here also!

Al.

21st Jun 2021, 11:53 pm	#11
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: MW hum - higher frequencies only - 200Hz Having read all the posts so far, to my mind, post #4 seems highly relevant From that - and what you have said, quote: hum is much worse if I am near the set, but if I move away by at least 5 metres then the hum becomes barely audible, unquote, leads me to wonder if it may be that the mains wiring radiation is being picked up by your body and re-radiated. Yes, really weird, I do appreciate - but you do seem to have a very strange fault condition. However, this may be of assistance: https://www.vintage-radio.net/forum/...ad.php?t=42507 If it isn't radiation from the mains, then it must be that where you are located there is a strong radiated electro-magnetic field that could be coming from a nearby radio transmitter - or some other source. Perhaps it's coming from a high-voltage street step-down transformer: it's entering your body and re-radiating. Perhaps, with the aid of a portable transistor radio that shows same problem, a travel around your vicinity - which might be a few miles - might locate said transmission source. I'll be intrigued to discover the cause - as I expect you will be - and other member here also! Al. Last edited by Skywave; 22nd Jun 2021 at 12:16 am. Reason: General additions, subtractions, etc.