Interference on VHF frequencies ?

[ham1946]

While monitoring frequencies around 151.xxx I am hearing every 65 seconds a 5-second sound that sounds like a vibrating tone (sounds like a metal vibration machine sound). It can be heard on several frequencies but mostly on 151.625 and 151.655 MHz. It is not something in my house or even in the local area as I can hear this on my scanner in my car 30 miles away from my house. It happens every 65 seconds and lasts for about 5-seconds and is very loud. I'm located in the Canton , Ohio area.
Any ideas what this is or where it might be coming from ?

 

[JamesO]

Often with interference you need to look very close to yourself and sometimes you actually need to verify the problem on more than one radio.

Suggest you try a different car as well, assume this may be a hand held radio?

Find it odd you are hearing the same problem 30 miles away, if the signal level is still as high when you are at home, I would be looking possibly at the car.

If this is a repeater output, then maybe the problem is with the repeater or on the input to the repeater.

You may have to use a directional antenna to triangulate to the location of the transmission if you feel the problem is over the air.

For example I have a car charger for my cell phone and the moment I plug it in I get a lot of noise on the HF bands, when I plug the cord into the phone, even more noise in the HF band.

I have not addressed this yet, I just unplug the power adapter for my phone for now, but I will probably either try other car chargers or work on filtering or shielding the car charger.

 

[bob550]

A bit of detective work shows that 151.625 MHz is licensed to Domer Communication, a two-way radio company in North Canton, OH. 151.625 is an itinerant business-band frequency. 151.655, however, does not seem to be licensed to this company. Can you determine whether this "interference" is heard simultaneously on multiple frequencies? A spectrum analyzer, or SDR, would be helpful here.

 

[jonwienke]

It's more likely a data transmission than interference.

 

[nd5y]

While monitoring frequencies around 151.xxx I am hearing every 65 seconds a 5-second sound that sounds like a vibrating tone

Some types of DMR systems do that.

 

[ham1946]

This definitely is not a car related interference problem. Other people can hear it from there house and also when we are 30 miles away from home. It's not just my radio or my car or my house interference. It's a powerful signal that is broadcast over a large area over many VHF frequencies and 151.625 and 151.655 are just two of them which it can be heard.

 

[bob550]

If you're hearing this in your car as well as at home, that would rule the car out. Next, try shutting your cell phone off to see if that may be the source. Phones are a device we tend to have with us everywhere.

 

[bob550]

What make and model of scanner(s) are you using? It's possible you're receiving images of the original frequency.

 

[ham1946]

It's not my phone, I turned it off. Other people hear it on other brand name scanner's too. IT's not the scanner's. I'm wondering now if it isn't some type of digital data transmission. I know nothing about digital data transmissions.

 

[montana1975]

does it show enc/dmc/nac/ other detail?

 

[montana1975]

does it show enc/dmc/nac/ other detail?

i mean dmr ,, lol

 

[montana1975]

security murs/bussiness etc device do entermittent i her too