Sources of RF interference in my home

[racin06]

Most people on this board know the potential sources of RF interferenece; however, the following information is to help newbies. The following is a list of RF interference sources I have indentified in my home that do or do not negatively impact my Icom IC-R75:

Furnace (located in basement about 20 ft. from R75) - Produces a high- pitched whining noise when running. Cannot be nulled out using loop antenna.

Ceiling light (located about 10 ft. from R75) - Produces very weak noise, but can be dulled out using loop antenna.

Other lights in my home - No detectable interference produced.

Microwave Oven (located about 25 ft. from R75) - Produces a loud and irritating crackling noise. Of course, the MW oven isn't running continuously, so this is no big deal.

Computer (located about 20 ft. from R-75) - No detectable interference produced.

Sump Pump (located in basement about 30 ft. from R75) - Produces an immediate crackling noise, about 0.5 seconds in duration, when the pump starts and stops.

Refrigerator Compressor (located about 20 ft. from R75) - Produces a weak rushing noise that can be nulled out with loop antenna.

Washer (located about 25 ft. from R75) - Produces a very weak rushing noise. No big deal.

Dryer - (located about 27 ft. from R75) - Produces a medium rushing noise that, most of the time, can not be nulled out with loop antenna.

Dish Washer (located about 20 ft. from R75) - Produces very, very weak interference. No big deal.

Cordless Phones, 2.4 Ghz and 900 Mhz - No detectable interference produced during use from any of these phones in my home.

44 in. LCD Widescreen TV (located about 12 ft. from R75) - This is the major culprit in the house, which is why I do my HF monitoring with this appliance off. Produces a very loud crackling and rushing noise that can not be dulled out with loop anntenna. When I say loud, I mean loud! It is worthless to try to use the R75 with the LCD TV on.

Just wanted to share my experience at identifying RF interference sources in my home in order to help the newbies out at indentifying their sources of interference.

 

[woody_461]

Good one...don't forget to check out flourescent lights&dimmer switches too.Computer monitors wil cause interference,usually.It comes in as a steady loud buzzing on some frequencies(confirmed by shutting them off).My radio is right next to my computer.

These lan cables are the worst culprit for me.Still waiting in my other post to see if shielded Cat5 will help.Only option now is to disconnect everybody from the internet..LOL! :wink:

 

[woody_461]

Oh...almost forgot bugzappers!

No worries right now,stupid snow everywhere!

 

[flyingwolf]

This is so weird. My wife wont let me run the cables under the bed becuase of the cat out to the window. (we live in an apartment so it has to be at the window and no further) So I run the cable from my scanner out to the window by way of the ceiling. I just have a couple of cheap plastic clicps holding it up there. When I rewired the bedroom for the lan figured I would use the same clips. Run them directly beside the scanner antenna cable. I have seen no noise issue from it.
The cable is sheilded cable so that may be why. So it should also do a good job for you.

The clips are strong too. The little one decided to use it for a swing a few days ago. Held up pretty good.

Jim

 

[Colin9690]

When my wife uses the treadmill which is downstairs, when i'm listening to my PRO-93 upstairs, it produces this REALLY annoying squeal that just repeats itself. Nothing big deal on UHF and 800MHz, but on VHF and VHF-LOW, it is really apperant. SO ANNOYING!!!! :evil:

 

[N_Jay]

When my wife uses the treadmill which is downstairs, when i'm listening to my PRO-93 upstairs, it produces this REALLY annoying squeal that just repeats itself. Nothing big deal on UHF and 800MHz, but on VHF and VHF-LOW, it is really apperant. SO ANNOYING!!!! :evil:

Treadmills have fairly large (and cheap) DC motors run by switching supplies.

 

[iceman47]

To be real honest with you I haven't had any interference of any kind since I got rid of my Wife.
Food for Thought?

 

[woody_461]

To be real honest with you I haven't had any interference of any kind since I got rid of my Wife.
Food for Thought?

*ROTFL*

Seems we overlooked the most important source.

 

[racin06]

To be real honest with you I haven't had any interference of any kind since I got rid of my Wife.
Food for Thought?

I don't have any interference from my wife. I have my wife trained and she certainly know her place in the house. :lol: :lol: :lol:

 

[N_Jay]

To be real honest with you I haven't had any interference of any kind since I got rid of my Wife.
Food for Thought?

I don't have any interference from my wife. I have my wife trained and she certainly know her place in the house. :lol: :lol: :lol:

Yea, and you have HER permission to say so! :twisted: :twisted:

 

[racin06]

Yea, and you have HER permission to say so! :twisted: :twisted:

Hey, I wear the pants in my family...my wife just tells me which ones to wear. :lol:

 

[kb2vxa]

"My wife wont let me run the cables under the bed becuase of the cat..."

There is a phrase that fits, something about a cat and a cat 'o nine tails. (;->)

 

[OutPost]

Ex-Wife

Major interference from my side of the woods about 1,000 feet away. Just happened to be scanning a group of freqs and whammo....the ex and my (now) ex-best friend talking on a low FM portable phone about how they wish I was dead, etc, etc, etc.

A total of 9 selected hours of recordings later, they both are sitting on pins and needles since February and I love it !! My lawyer loves it too, and these jerks wonder why I carry my .38 in my pants when I take walks.....are they stupid??? 8)

 

[Twister_2]

Your Central Air System or Heatpump causes all of my interference...on the cb you must be within 10-15 miles to even hear them!

 

[N1BHH]

Add to the list some of these: Old door buzzer transformer; Touch sensitive lamps; Electric fence transformers; Other scanners connected directly (as opposed to thru any splitter/preamp) to the same antenna; Thermostat; Loose wire or coaxial connector, one disconnected from a radio; Electric blanket/heating pad. All of these are sources of interference.

 

[k4pbn]

Electrostatic air cleaners are the biggest culprit in my house.

 

[mtindor]

For anybody experiencing RFI, here is a great publication...

http://www.audiosystemsgroup.com/RFI-Ham.pdf

A lot of this will go over the heads of a lot of people. But, using many of the techniques in this publication you can successfully live in an environment of varied RFI and still enjoy your hobby (i.e. have your cake and eat it too).

Mike

 

[mtindor]

My Linksys WRT54G generates a carrier that is S9+ at 32 khz intervals across, at the very least, 6-8 Mhz. I didn't bother checking exactly how far up and down HF it extended.

It's a pain in the rear if you're into digital modes since the carrier falls right on 7035 and 7070, popular frequencies for digital modes.

So I've got some work myself to take care of.

Mike

 

[mtindor]

My Linksys WRT54G generates a carrier that is S9+ at 32 khz intervals across, at the very least, 6-8 Mhz. I didn't bother checking exactly how far up and down HF it extended.

It's a pain in the rear if you're into digital modes since the carrier falls right on 7035 and 7070, popular frequencies for digital modes.

So I've got some work myself to take care of.

Mike

I don't have any ferrite beads or torroidal cores yet. I'm still confused as what is best to get. However, setting my hardwired computers [that are hooked to the Linksys] to 10 mbit / full duplex instead of 100 mbit really cuts down on the ethernet trash. The RFI list on contesting.comc clued me in to that - http://lists.contesting.com/_rfi/

When I plug my laptop into its power supply, I get a little trash. I haven't scanned 0-30 mhz to see just how much trash and where, but definitely it makes a little noise in certain places. My desktop computers don't seem to do too bad though.

My sister has some office space in my basement - her computer is connected via CAT5 to the linksys. Her computer equipment emits a good deal of trash. If I turn it all off, there is still some underlying noise. I then went nad turned off her 6-port power strip / surge protector and it eliminated most of the remaining nasties that i heard on HF. So I'm not sure if the power strip itself was a culprit or if her computer / printer / monitor, even though they were off, were emitting some extra garbage while off.

At any rate, last night is the first night in 13 years where I was able to tune below 80 meters and have nearly total quiet. I could actually pick up a ton of nondirectional beacons below 500 khz last night. I never could do that before. Cleaning up the RFI (and of course being free of the AEP trash from their overhead power lines, associated equipment and distribution lines that surrounded my _old_ property) are a huge help.

I was copying vy weak signal CW DX on 160 m last night. It used to be that I couldn't even listen to 160 m because I had constant S20+ noise.

mike

 

[VernM]

Don't leave out fish tank heaters. One across the street from me in my novice amateur days would have spelled the end of any operation from 3-29 MHz were it not for an understanding fish fancier. We killed the culpret and he got one he would't pay for until he knew it was not going to interfere with other things.