What is this bleed? 155.550

[riveter]

Been having an interesting situation here at UMBC in SW Baltimore for a long while. My agency has as our primary frequency 155.550. Most of the portables here and the repeater are programmed with PL and don't get any interference at all. However, my mini-portable at and our mobile radios are not PL-squelched and have for a very long time had bleed interference when at relatively high altitude from an unknown police agency using the same frequency at what sounds like very long range. I didn't think much of it until this evening, when I heard the bleed agency have a MAJOR situation involving multiple vehicles being read out by a very stressed officer and discussions of at least one gunshot wound victim. I had initially thought this to be a small-town agency, but this isn't the sort of thing that happens frequently in those places, and this channel is a little too trafficked for that.

To help ID: The station is only heard when I'm near the top of the hill here at ~300-320' elevation. However I am able to receive it with a small but very effective 6" whip antenna on this portable (though interestingly not on my PSR800 with a usually very effective Austin Condor antenna). It sounds like they are using motorola portables (and they keep stepping on eachother so you get funny keyup and release squawks- sounds like NYPD Midtown sometimes) and possibly a harris base station.

I tried searching through the DB to find a relevant station at the proper range, but I couldn't find anything. Does anybody have any enlightening answers?

 

[Jay911]

Too bad you can't get it on the scanner - it'd be useful to know if you are getting a tone of 123.0 and/or 131.8. A number of provinces in Canada use 155.55 as one of the repeater frequencies for the Royal Canadian Mounted Police. Here in Alberta it's used in multiple communities (the frequency is re-used with the different tones to isolate them as different "channels"). Besides the potential to hear more than one station due to there being multiple channels, users DO have the ability to walk all over one another on this system somehow without heterodyning - just sounds like you are in a room full of people.

You would also hear MDC1200 squawks followed by a ~820hz tone lasting around 0.35 second, which is their way of signaling the dispatcher that they want to talk to them. The dispatcher's transmissions would be prefixed with a ~1950hz tone lasting roughly 0.1 sec.

Sound like a match?

 

[riveter]

No unfortunately. Partly because of the truly extreme range from Canada to Baltimore- I don't think this is tropo skip, more likely standard ground level propogation from something less than 100 miles away. There's also no actual walkover of two simultaneous transmissions either- this is more people keying up instantly as soon as another user is done talking. Like with NYPD's systems, this seems to generate some wacky end-of-transmission squawks sometimes which I would guess is just to provide a differentiation between transmissions. I don't hear any talk request tones associated with that kind of system either, just the standard masked MDC1200.

Worth noting is that they use plain speech (no 10-codes) and the NATO/ICAO alphabet. So, they're too modern to be another MD agency (ha ha).

 

[jmarkey]

Could be Frederick County, VA Sheriff's Department. They're about 80 mi southwest, and have a transmitter up on the ridge (2,200ft).
ULS License - Public Safety Pool, Conventional License - WNNQ983 - FREDERICK COUNTY OF VIRGINIA SHERIFFS DEPARTMENT

 

[riveter]

Ooh good call. That's it- incident I was hearing involved Church St, Main St and some numbered streets: following your choice, found those in Middletown VA... in Frederick Co. Very good call.

I didn't think it could be VA (aka I assumed), but apparently that's possible. Still a hell of a stretch, but I'm on one of the highest hills around Baltimore and that's got some beastly elevation too, so I guess that's enough for a 100W transmitter to punch it all the way to UMBC.

Thanks!!

 

[phillydjdan]

I was going to suggest the Bridgeton, NJ Police with a 179.9 PL. Up here in Philly one of our suburban counties (Bucks) tones out their fire and EMS on 155.550 (123.0 PL) and 90% of the time if I disable my PL on my mobile and base, I pickup Bridgton Police. They use MDC signalling also, so at first I thought this could be the comms you were hearing

 

[reconrider8]

it helps if you can read and understand the fcc database also and how it relates to your area

 

[riveter]

I did do a ULS search a while back... but I was looking mostly for results in PA because of various factors that made me suspect something up there. Simply turned out I was looking in the wrong direction.