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Interference on 462.5325 MHZ Oakland Co Michigan


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Just now, markskjerve said:

I spotted that as well but figured it was highly unlikely. 90 miles away from Clark County (where the OP said he was) - also licensed for 2 watts.

Agreed - this is the closest possibility yet. The signal is hitting -22db as far west as Normandy and Woodward and as far east as Delmere and 14 mile. It’s hitting -40db by the tech center in Warren. 

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1 minute ago, markskjerve said:

I spotted that as well but figured it was highly unlikely. 90 miles away from Clark County (where the OP said he was) - also licensed for 2 watts.

I wondered the same thing. I wouldn't be surprised if radios got swapped around between plants.

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2 minutes ago, SignallyCurious2 said:

Agreed - this is the closest possibility yet. The signal is hitting -22db as far west as Normandy and Woodward and as far east as Delmere and 14 mile. It’s hitting -40db by the tech center in Warren. 

You can try removing the antenna on the radio. That's a cheap kind of signal attenuater. Do that when the signal gets real strong with the antenna connected. When you get close enough to the source the radio should respond even without the antenna connected.

One other trick is flip the radio over so the antenna is horizontal. The source antenna is likely vertical and the cross polarization results in may cases another 20db attenuation. Then rotate in a circle. When the signal is minimum either the end of the antenna is point nearly towards the source or directly away from it. Try that in several locations and that can help pin down the area.

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23 minutes ago, Lscott said:

You can try removing the antenna on the radio. That's a cheap kind of signal attenuater. Do that when the signal gets real strong with the antenna connected. When you get close enough to the source the radio should respond even without the antenna connected.

One other trick is flip the radio over so the antenna is horizontal. The source antenna is likely vertical and the cross polarization results in may cases another 20db attenuation. Then rotate in a circle. When the signal is minimum either the end of the antenna is point nearly towards the source or directly away from it. Try that in several locations and that can help pin down the area.

Awesome - gonna do this now. 

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I did some more searching on another site. Assuming the frequency is really 462.5125 I found the following:

462.5125    DMR    MO    4    ROCK SECURITY & EVENTS INC.    WRAK353    PONTIAC    IG    SECURITY COMPANY: RADIOS WILL BE USED FOR COMMUNICATION BETWEEN EMPLOYEES
462.5125    DMR    MO    4    United Parcel Service, Inc.  WPMR963    MADISON HEIGHTS    IG    APPLICANT IS A DELIVERY SERVICE. THE RADIOS WILL BE USED TO COORDINATE THE ESSENTIAL ACTIVITIES OF THE BUSINESS.
462.5125    DMR    MO    5    X-Cel Industries, Inc.    WQTT460    Southfield    IG    Radios used to coordinate activities around a coating facility.

 

               
                 
                 
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38 minutes ago, Lscott said:

I did some more searching on another site. Assuming the frequency is really 462.5125 I found the following:

462.5125    DMR    MO    4    ROCK SECURITY & EVENTS INC.    WRAK353    PONTIAC    IG    SECURITY COMPANY: RADIOS WILL BE USED FOR COMMUNICATION BETWEEN EMPLOYEES
462.5125    DMR    MO    4    United Parcel Service, Inc.  WPMR963    MADISON HEIGHTS    IG    APPLICANT IS A DELIVERY SERVICE. THE RADIOS WILL BE USED TO COORDINATE THE ESSENTIAL ACTIVITIES OF THE BUSINESS.
462.5125    DMR    MO    5    X-Cel Industries, Inc.    WQTT460    Southfield    IG    Radios used to coordinate activities around a coating facility.

 

               
                 
                 

I’ll check these out, I’m leaning heavily into the 14 mile and Coolidge intersection. American axle has been written up for this before. 
 

the two addresses with strongest locations have been:

 

4250 Normandy Ct, Royal Oak, MI 48073 -21.3db

 

2600 W 14 Mile Rd, Royal Oak, MI 48073 -29.3db

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4 minutes ago, markskjerve said:

Might check this location out around 6 miles away from where you have been checking...
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That’s too far. I’ve got it narrowed down to a 2 square mile radius. The signal is fixed and hits the same power at my home address daily. 
 

it’s within .5 mile of this water tower that has antenna arrays on it. 
 

 

2725 Samoset Rd royal oak mi 48073

 

it also is not 462.5125, it’s closer to 462.53125 confirmed on 3 different SDR’s and a handheld. 

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2 hours ago, SignallyCurious2 said:

I’ll check these out, I’m leaning heavily into the 14 mile and Coolidge intersection. American axle has been written up for this before. 
 

the two addresses with strongest locations have been:

 

4250 Normandy Ct, Royal Oak, MI 48073 -21.3db

 

2600 W 14 Mile Rd, Royal Oak, MI 48073 -29.3db

Yeah, their plant is on 14 mile right next to the railroad overpass. I've been by it enough times.

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I did some checking on AAM and there is only one possible. It's an expired license and the plant is located in Three Rivers. That's a long way away.

https://wireless2.fcc.gov/UlsApp/UlsSearch/licenseFreqSum.jsp?licKey=1905276

The frequency listed is 462.3125. Hum, if some radio tech miss typed the frequency entry he could have hit 462.53125, added in the extra "5" after the decimal point.

Somebody could be using an unlicensed frequency, never licensed, or continues to use one on a long expired license. It happens. The FCC seems really lax in cracking down on this crap.

For example the ding-dongs at the Lakeside Mall, house keeping, are doing it. They are on the same frequency as the Troy GMRS repeater but a different PL tone. Their license expired in 2015, never renewed from what I can see in the FCC database, and they still use the frequency!!! Geez!!??

Oh, if you want to "test" their, illegally operating, GMRS repeater out its 462.575MHz/467.575MHz with a PL of 186.2Hz. You can key it up about 4 to 5 miles away with an HT easy enough.

Anyway you narrow the search down and locate the likely source of interference keep us informed!

 

ULS_License - Expired Mall FCC Licenses.pdf ULS License - General Mobile Radio (GMRS) License - KAB1523 - LAKESIDE GENERAL GROWTH PROPERTIES - Administration.pdf

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3 hours ago, SignallyCurious2 said:

it’s within .5 mile of this water tower that has antenna arrays on it. 
 

 

Do yourself a favor & search the term "intermod" as it relates to RF.  What you're seeing is likely a product of 2 (or more) frequencies mixing & creating an un-intended 3rd frequency. I'd bet dollars to donuts that the water tower has some high powered stuff that's throwing out birdies & mixing with something else nearby.

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1 hour ago, Radioguy7268 said:

Do yourself a favor & search the term "intermod" as it relates to RF.  What you're seeing is likely a product of 2 (or more) frequencies mixing & creating an un-intended 3rd frequency. I'd bet dollars to donuts that the water tower has some high powered stuff that's throwing out birdies & mixing with something else nearby.

If that would be the case I would think I would be unable to decode the DMR messages, even though they’re encrypted, I am decoding DMR message blocks with subscriber info, AES key info, talkgroup info and color tables. 

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1 hour ago, SignallyCurious2 said:

With my gain set all the way down, the strongest signal reading yet is behind AAM, next to the water tower. 
 

it’s either on the water tower at 2725 Samoset Rd royal oak mi 48073

inside AAM

On the rail tracks proper, owned and operated by CN - maybe this is a Canadian system?

Try running the address on https://www.antennasearch.com/ . It maps out both registered and unregistered towers that the FCC doesn't show, might give you a bit more to go on.

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1 hour ago, SignallyCurious2 said:

On the rail tracks proper, owned and operated by CN - maybe this is a Canadian system?

I would not suspect the railroad. They would either be FM, or they were moving to NXDN, but that's on VHF, not UHF.

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12 minutes ago, markskjerve said:

Try running the address on https://www.antennasearch.com/ . It maps out both registered and unregistered towers that the FCC doesn't show, might give you a bit more to go on.

Looks like it’s owned by the SE Oakland county water authority, I tried calling them an hour ago but their prompt says they left at 3. 
 

comparing that location with the readings I have make sense too. 

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2 minutes ago, SignallyCurious2 said:

I agree, they’re still NBFM and the police are P25, but you can’t rule anything out when it comes to Canadians.

Maybe. They still have to operate under US rules. Plus they need to communicate with other railroads, yards etc. That's likely going to be on VHF.

 

Railroad - Scanner Frequencies and Radio Frequency Reference.pdf

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Had to do some reverse engineering but found the FAA study approval for the water tower. 
 

it was some time ago, I’m going to follow up with the water authority tomorrow morning. With that height, it’s no wonder I can hear the signal everywhere I go. Some days it blows through all the way to 467 MHz. My home is line of sight as well. 

IMG_0050.png

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