Re: Maybe for this group or if not...where


Geoff Eden
 

It is back interference from the modern switching power supplies. We used to use Transformers to render different voltages for the radio/television etc., but since the early 90s, we use fancy transistors to chop up the line voltage into little time segments to get lower voltage. The noise we get is from those transistors which generate incredible peaks, valleys, and harmonics. Some of the signal comes back down the plug and wire and some of it is radiated. So it's always a challenge to damp it out. There a good thing, however, or wall warts and laptop power cables would have to be a lot bigger and heavier.

There are things called line chokes which are comprised of a ferrous metal hoop through which you can wind a line cord and it will help to dampen down interference coming back up the power cable. They're not very expensive.

Geoff

-----Original Message-----
From: Steve Jacobson
Sent: Saturday, August 01, 2020 1:04 PM
To: all-audio@groups.io
Subject: Re: [all-audio] Maybe for this group or if not...where

Tom,

Agreed completely. I had a sudden increase perhaps a month ago in the interference I am getting on the AM band from my DSL service. The phone company must have changed something either with the phone lines outside or with the DSL settings. While I know there is always DSl interference along the wires carrying the DSL signal, it is also getting radiated from the AC lines as well. I can't figure out how it is getting into those circuits.

I have a tuner with one of those little square loops and I made a larger loop on a piece of cardboard and added a length of cable so I could move it around more. That really helped me escape some interference until this new DSL problem started. I still like to look for long distance AM reception especially during the winter evenings, and this interference really decreases my ability to do that.

Best regards,

Steve Jacobson

-----Original Message-----
From: all-audio@groups.io <all-audio@groups.io> On Behalf Of Tom Kaufman
Sent: Saturday, August 1, 2020 11:36 AM
To: all-audio@groups.io
Subject: Re: [all-audio] Maybe for this group or if not...where

Steve and list: It's amazing to think of just how many things we have
around the house that generate noise; things that we "have" to have to help
us function, such as our phones (cordless or otherwise) chargers,
modems...etc.! My cable modem really reeks habic with my AM radio; my
stereo system is back here; so is my modem! So there's not a lot I can do
about that! Problem is that this modem definitely does create noise on the
AM band! So since I can't pick up and move my stereo, there's just not a
lot I can do about it! I can position that little antenna that is hooked
into my stereo and hold it there with my hand, thus, it does help with the
noise! Problem is, as soon as I remove my hand, then it goes right back to
the position where it picks up the noise, so there's just no real "getting
away from it!"
Tom Kaufman

-----Original Message-----
From: all-audio@groups.io [mailto:all-audio@groups.io] On Behalf Of Steve
Jacobson
Sent: Saturday, August 01, 2020 12:18 PM
To: all-audio@groups.io
Subject: Re: [all-audio] Maybe for this group or if not...where

Georgina,

If I take my cordless phone and put it near an AM radio, I find that it
generates a good bit of digital noise across the entire AM band, but there
are oscillations that occur here and there that are stronger than the
general noise. I would guess that on his system, one of those stronger
oscillations happens to hit WBBM. Unfortunately, it is all a bunch of
guesswork on my part and there is a lot we don't know about his system. I
might be totally wrong. I am struggling with a problem with noise and
interference on the AM band in my house which is very hard to track down, so
there might be something more to this problem as well.

Best regards,

Steve Jacobson


-----Original Message-----
From: all-audio@groups.io <all-audio@groups.io> On Behalf Of Georgina Joyce
Sent: Friday, July 31, 2020 12:08 PM
To: all-audio@groups.io
Subject: Re: [all-audio] Maybe for this group or if not...where

Hello Steve,
URRRRR, shows you how long since I listened and took note of the AM band.
Whoops. At least someone is there to put me right. Found it interesting that
other radio stations perhaps not on AM did not suffer in the same way.

Regards,
On 31 Jul 2020, at 16:55, Steve Jacobson <steve.jacobson@outlook.com>
wrote:

Since the radio station is 780 KHZ, it is likely that the interference is
not caused by the frequency used by the phone, but that it is getting
interference from the digital circuits in the phone. Usually this happens
if your radio is close to the answering system or that you have placed the
wireless headphones near your radio. If neither is the case, check to see
if the cords running to the answer machine might be passing close to your
radio. Gina is right that an external antenna probably would correct this,
but moving the answering machine or making sure your headphones are not near
the radio should help. If you keep your headphones in a charger when they
are not being used, check to be sure the cord to the charger does not run
close to the radio. Making sure the radio is plugged into a different
outlet from the answering machine or any headphone chargers might be worth
trying as well. If your radio has a separate square loop antenna, moving
that around can make a big difference as well.

I live in Minnesota but listen to WBBM occasionally, and I have heard them
announce that they are also on FM on 105.9. You might be able to avoid this
by trying the FM frequency instead. I do not know if the coverage of the FM
frequency reaches you, though, but it might be worth checking.

Best regards,

Steve Jacobson

On 31 Jul 2020, at 03:47, Morey Worthington <worthington@wi.rr.com
<mailto:worthington@wi.rr.com>> wrote:

Evening all.

This is a audio related question, but has to do with a certain radio
station and a wireless cell phone.


I live North of Chicago Il. and listen to a ceertain powerful all news
station on AM (WBBM 780). We have a phone answering system with 3 wireless
headsets.

If If I am listening to the Chicago station and the phone starts ringing,
usually for the wife, a loud whisteling noise happens and stays there till
the call is finished. This only happens on this one station . I have tried
unplugging radio, the phone system, but no change. If I change the radio
station to another, all is well. I have tried moving the direction of radio,
it is a digital one, with nothing any different.

I am really sorry to ask this group about my issue, but it is audio
related. If not for this group, can someone , maybe, give me direction on
where to turn??

Thanks,

Morey Worthington



Georgina


Call: M0EBP
DMR ID: 2346259
Allstar: 52178
Locater: IO83PS






Georgina


Call: M0EBP
DMR ID: 2346259
Allstar: 52178
Locater: IO83PS

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