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 AM radio noise
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 Return to top of page · Post #: 1 · Written at 7:55:43 PM on 10 June 2018.
Muzzery's Gravatar
 Location: Maleny, QLD
 Member since 28 February 2018
 Member #: 2218
 Postcount: 95

I just have to say this noise floor thing is rather a nuisance. I cannot get a radio to play much more than buzz and fizz at my place. I’ve tried my tecnico fortress in Brisbane western suburbs- I was out on a job so I took it with. It played beautifully there. Back home, it returns to the fold of all my radios, am fuzz. With the exception of one evening late a few weeks back, It was receiving 2nm hunter valley , around 950klms away... But nothing local..
I’ve done the rounds of the house, turned EVERYTHING possible off. So I’m sitting in the dark listening to very faint 4kq. Last night I had the wallabies game for a short while, and I even set it up in the living room and watched state of origin midweek, with the Tele on mute and the radio playing commentary. That was cool.
Tonight I have an insulated cable about 15 to 20 metres long out the window and along the neighbours fence top. No improvement.
I might even venture to build one of those timber crosses with wire wrapped around.
It seems a shame to repair a radio and not be able to use it...
Tomorrow I will try to attain a portable radio to “sniff” out sources of noise. All that’s left is smoke alarms , a gas water heater, and the fact that I’m in a hinterland crater.


 
 Return to top of page · Post #: 2 · Written at 9:23:28 PM on 10 June 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

Tomorrow I will try to attain a portable radio to “sniff” out sources of noise

That would be my suggestion. A while back I used one to track down some very bad RFI on AM. Turned out to be a variable frequency drive on the parking garage's air supply fan transmitting crap through the un-earthed current loop cables used by the CO detectors. The shields of those cables had not been terminated to earth, making them wonderful antennas for the RFI generated by the switch mode VFD.


 
 Return to top of page · Post #: 3 · Written at 9:53:14 PM on 10 June 2018.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

Do you have Wireless NBN & forgot to turn it off?


 
 Return to top of page · Post #: 4 · Written at 10:28:57 PM on 10 June 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

I’ve done the rounds of the house, turned EVERYTHING possible off.

Suggest you do that by switching off each of the breakers (or pulling the fuses) one by one. If the interference is still there after that exercise, then switch off the main switch itself. If it's still there after that, then the source is either battery operated or external and nearby your house, and could include the incoming mains itself.

BTW: do you have a smart meter? They are among the RFI suspects, too.


 
 Return to top of page · Post #: 5 · Written at 10:39:53 PM on 10 June 2018.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1575

Mobile phones, whether they are charging or not generate a lot of interference. I noticed with my samsung if I am charging it then it needs to sit flat on the table to stop most of its crap.


 
 Return to top of page · Post #: 6 · Written at 3:48:59 PM on 11 June 2018.
Simplex's Gravatar
 Location: Bathurst, NSW
 Member since 7 August 2008
 Member #: 336
 Postcount: 336

Watch out for plugpacks seem to power everything nowadays. I came across one which had a large capacitor in it and even when unplugged still ran for about a minute generating interference before stopping.

This particular plugpack had me foxed for a while before I worked out what was going on.


 
 Return to top of page · Post #: 7 · Written at 10:27:54 PM on 11 June 2018.
JamieLee's Gravatar
 Location: Clare, SA
 Member since 27 March 2016
 Member #: 1894
 Postcount: 508

My wife has a TV and a DVD player in our bedroom, if either of these are plugged in, the radios go to fuzz!


 
 Return to top of page · Post #: 8 · Written at 5:49:42 PM on 13 June 2018.
Muzzery's Gravatar
 Location: Maleny, QLD
 Member since 28 February 2018
 Member #: 2218
 Postcount: 95

Thanks for the pointers everyone! I went through the house today, with a little 9 volt battery radio. Oddly, it received quite well. I learned that some rooms are better than others, and there are hotspots within those rooms. I will try tonight, after everyone hits the sack, to see how much it quiets down with stuff turned off.

I do wonder whether the footy field lights, 500 odd metres away, have any effect.

This afternoon, I put a 20 metre length of single speaker wire across the top of the house roof, one end of the house to the other. I made sure it was insulated from the metal roof.. It improved reception out of site as opposed to the similar length along the neighbour fence. This will make it interesting late at night, I might be able to grab some distant stations.


 
 Return to top of page · Post #: 9 · Written at 5:58:44 PM on 13 June 2018.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6353

I do wonder whether the footy field lights, 500 odd metres away, have any effect.

If they are metal halide, probably not but it is possible to get electronic chokes for metal halide, mercury vapour and sodium vapour lamps these days. Unless the lights are fairly new it isn't likely though. If the lights are LEDs then their controllers will be electronic.

I can't see RFI from a few lights that far away causing issues though.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 10 · Written at 10:51:26 PM on 13 June 2018.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

Don' forget the Fridge mine generates quite a bit of RFI & a few years back one was wiping out Internet for quite a distance in the town. I also have an Omron timer that I use for killing the battery chargers especially the plug pack ones so they are not running well after the battery is charged.

I ended up putting a resistor in its active feed and putting a line cap between it & the resistor.

If you have overhead power lines, and no street lights, Farm here no street lights, you may have a dud insulator close by? These can cause hissing & crackling, when its damp & the arc can often be seen. I have heard some going off like a rifle when it rains.

Marc


 
 Return to top of page · Post #: 11 · Written at 6:49:12 PM on 19 June 2018.
Robert69's avatar
 Location: Western Victoria, VIC
 Member since 14 November 2009
 Member #: 579
 Postcount: 109

I mainly listen to 774 in Melbourne from my home in western VIC, but as soon as I put in a camera security system - buzz exactly at 774 on the dial - and no other spot! I've tried toriods and RFI tuned filters around all the camera wires without luck. The only solution I can think of now is to make a linear power supply for the camera feeds...

How did these units ever pass RFI testing??


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Robert

 
 Return to top of page · Post #: 12 · Written at 10:12:46 PM on 19 June 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

How did these units ever pass RFI testing??

Like hundreds of pieces of gear these days, they were never tested in the first place. So much for "self regulation".

The CCTV system at my workshop is powered by a battery with float charger attached.


 
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