NOAA Interference

[btritch]

I need a bit of help and info...

I am listening to certain frequencies in my scanner...It always happens around the 150 - 160 spectrum...It only happens for about 5 or 6 seconds at a time...It sounds like someone keys up but instead of hearing them I actually hear the the NOAA Weather Channel (s) talking and then it just cuts off like it's unkeyed and every so often amidst all this noise and talking you hear a click and a busy signal like on a telephone...

Repeater To Close? The closest repeater for this service is about 25 miles away, the other about 60

Bleedover? NOAA is on the 162 range and it's interferring on the 150-160 range of channels?

But what else could cause this? Anyone know? Anyone?​

 

[rfradioconsult]

You are experiencing classic intermod interference; most likely 3rd order. Do a search on intermodulation interference, its a very common and very mis-understood. Simply stated the NOAA transmits a continious signal that is easly identifiable, a second transmitter keys up and the resultant "mix" of the two signals can cause a third signal; most likely that is what you are hearing.

 

[btritch]

I SEE! I did research on the subject!!! http://en.wikipedia.org/wiki/Intermodulation THIS is what I found!!! I NOW understand what it is! I have heard it in both mobile and base invironments and never knew what it was caused from!! Now I DO! THANKS rfradioconsult!!!!!

 

[rfradioconsult]

Lots of folks lump most radio interference under intermod; sometimes it is, sometimes it isn't. Do you know where Fitzgerald mountain is, east of Springdale. Never mind, I thought you were in NW Ar.

 

[btritch]

I've heard of it, Usually the interference isn't that bad, I can deal with it but today, It's been BAD, Every few minutes!! Yes, I have heard of the mountain in springdale...Why do you ask?

 

[Twister_2]

that happened to me once or twice on a cb with 162.55 mhz...also on 163.xxx mhz i can hear the weatherradio along with something in 900 mhz.

 

[rfradioconsult]

I've heard of it, Usually the interference isn't that bad, I can deal with it but today, It's been BAD, Every few minutes!! Yes, I have heard of the mountain in springdale...Why do you ask?

That area was settled by my ancestors and it was named after them, my paternal grandfather was born between Springdale and Fayetteville.

 

[N4GKS]

My BCT15 started doing this. Even my cheap scanner never had a problem so imagine my surprise at the highly touted 15 doing it.

 

[btritch]

My BCT15 started doing this. Even my cheap scanner never had a problem so imagine my surprise at the highly touted 15 doing it.

Going out on a limb here but I have noticed it is doing it way more than usual...Going out on a limb here but could it potentially be the type of year/weater/atmospheric conditions?

Just a thought, I have noticed it more now that before...On my cheap 2025 AND on my pro 97...Both..

 

[ka3jjz]

I'm pretty sure PAR electronics makes a filter that would knock out the NOAA signal. Their filters are a bit expensive but well worth it 73 Mike

 

[rfradioconsult]

It depends on where the intermod mix is occuring; if its happening in your receiver then it may help. However, it can happen external to your receiver, something as simple as a rusty fitting on a tower can cause it. Tower operators have to constantly fight this problem, they will hire a crew every few years go up and remove old hardware and replace it with new. Paging and NOAA transmitters are the one's most heard because you can listen and easly identify them. Paging transmitters are a real problem; most operators are shoestring to begin with and don't spend much on maintenance.

 

[N1BHH]

When WBZ AM 1030 had a fire at their transmitter in Hull, MA., the results afterwards were pretty radical. Even though the fire was at the base of one of it's antennas, it made for some strange reports. People were able to hear them on their toasters, radiators and even their telephones. It was so bad that the Police Department which was over a mile away heard it on their telephone system, without picking up the phone. They fixed all the problems and got everything back and running properly, but it was funny hearing some people complain about it coming from the radiator in one room and a toaster in the kitchen.

 

[rfradioconsult]

When WBZ AM 1030 had a fire at their transmitter in Hull, MA., the results afterwards were pretty radical. Even though the fire was at the base of one of it's antennas, it made for some strange reports. People were able to hear them on their toasters, radiators and even their telephones. It was so bad that the Police Department which was over a mile away heard it on their telephone system, without picking up the phone. They fixed all the problems and got everything back and running properly, but it was funny hearing some people complain about it coming from the radiator in one room and a toaster in the kitchen.

Thats not uncommon if a station has a problem the FCC will allow them to operate with a modified antenna pattern. Here is a link that shows their licensed pattern, so if the were non-directional for a time they could cause problems is other directions.
http://www.fcc.gov/ftp/Bureaus/MB/Databases/AM_DA_patterns/10513-5756.pdf