912.125

[Spleen]

Caught this little treasure today....I couldn't get Scanner Recorder fired up until their radio check was all but finished, but caught his signoff....never heard any responses...this of course could be an image of a 400MHz-band frequency, and all I ever heard mentioned was towns in PA...I was using a little whip today, not the usual discone...

 

[Spleen]

Followup

Followup: Turns out to be Federal Protective Service, doing radio checks every four hours....anyone know if the frequency is really 912.125 or did I get an image of a 400MHz transmission? New mp3 is attached...

 

[doctordave]

Spleen,

I used to regularly tune the FPS in our area on 415.2 .....might be worth plugging in at your location to see if it matches what is coming through on 912.125. Our wiki has some additional FPS freqs - but I have no idea if they are active around here.

http://wiki.radioreference.com/index.php/Federal_Protective_Service

 

[ka3jjz]

While it's always possible it's an image, it might also be a transmitter link. Usually these are very directional, and you have to be in the path to hear them. I would have thought they'd be up in the microwave region, but just maybe that's what you have here.

73s Mike

 

[Whistler]

This is a repeater RX? Is it a plus or minus offset??

 

[Spleen]

After listening to the mp3 again and consulting the Wiki (thanks for that BTW, I didn't know we had a FPS entry there), I guess I'll try 413.875 and go from there:

FPS operates four megacenters:
• Philadelphia, PA (FPS Regions 1, 2, 3)
417.200 Dispatch - Region 1 - P25 - logged in CT, ME, MA 417.200 Dispatch - Region 2 - P25 - logged in NY 413.875 Dispatch - Region 3 - analog,CSQ - logged in PA, MD

 

[Spleen]

After listening to the mp3 again and consulting the Wiki (thanks for that BTW, I didn't know we had a FPS entry there), I guess I'll try 413.875 and go from there:

FPS operates four megacenters:
• Philadelphia, PA (FPS Regions 1, 2, 3)
417.200 Dispatch - Region 1 - P25 - logged in CT, ME, MA 417.200 Dispatch - Region 2 - P25 - logged in NY 413.875 Dispatch - Region 3 - analog,CSQ - logged in PA, MD

It's 413.875....I caught the 0030 radio check. I'm just amazed it comes in that strong here in downtown Bawlmer...thanks for the help fellas.

 

[Whistler]

Are you able to pick up traffic in the Region 11, Suitland? I would have thought that would be easier to RX than Philly.

 

[Spleen]

I'll give the Suitland frequency a listen during "24" tonight...

 

[ka3jjz]

Just for winks, I put the 413 mhz freq in my 245 while I was at work, and sure enough, several units with a 3 prefix were obviously doing some sort of testing - someone had a receiver in the backround, and had the typical hollow tunnel sound. Big signal there - and that's saying something. Right in that area there are several 800 towers (some are BGEs), at least 1 or 2 pagers and the FBI microwave tower, all within a 2 mile or so radius. Can you say 'desense'?

For those that might not be aware - I'm referring here to the area in Woodlawn around Security - the mall, and the boulevard. The big SSA building is not the only SSA building in that area. They lease several other buildings for the contractors (of which I am one - I work for Lockheed) with a 10-20 minute driving time radius. It wouldn't surprise me at all if a repeater was being installed in the area, accounting for the big signal.

73s Mike

 

[TinEar]

413.875 is being received very well here in Glen Burnie. Just heard a mention of W. Pratt Street which would appear to put the unit in Baltimore - unless, of course, there's a W. Pratt Street somewhere else also. I'm running it CSQ as you suggested Spleen. Wait a minute...that's not a good idea. I'll leave it in tone search in case someone does use a PL/DPL.

3S111 unit mentions checking something out at "Security" to a female dispatcher.
3-SAM-111
Later enroute to 1500 Woodlawn Drive

3P359 mentions Woodlawn Drive
3-PAUL-359

 

[Spleen]

Should probably hear more of them now that baseball season has started....DHS, FPS, and scads of other agencies' troops like to congregate at Camden Yards....you see them running the doggies through the MARC trains, having "meetings", etc.

Today should have been a great day to pick up TX from them because of the (home) Opening Day (probably explains the Pratt Street locale).

I'm going to scan the FPS frequencies tonight with the discone, but I don't have high hopes because of the long cable run....and if I think about it, I can turn on the CTCSS decoder module in the Winradio software and see if it registers anything...

As I was typing this, I caught a TX to 3 Sam 311 on 413.875, but couldn't hear the other side at all...

 

[TinEar]

Should probably hear more of them now that baseball season has started....DHS, FPS, and scads of other agencies' troops like to congregate at Camden Yards....you see them running the doggies through the MARC trains, having "meetings", etc.

Today should have been a great day to pick up TX from them because of the (home) Opening Day (probably explains the Pratt Street locale).

I'm going to scan the FPS frequencies tonight with the discone, but I don't have high hopes because of the long cable run....and if I think about it, I can turn on the CTCSS decoder module in the Winradio software and see if it registers anything...

As I was typing this, I caught a TX to 3 Sam 311 on 413.875, but couldn't hear the other side at all...

I'm hearing both sides of the conversation 5x5. Both ends are really blasting here.
Is the base station IDing as "Mega-Center?"

 

[Spleen]

Yes...megacenters...that jives with the Wiki entry for FPS...I'm actually getting decent reception with the discone, but I'll have to switch back to the whip to get a CTCSS decode (if it exists)...

 

[TinEar]

Yes...megacenters...that jives with the Wiki entry for FPS...I'm actually getting decent reception with the discone, but I'll have to switch back to the whip to get a CTCSS decode (if it exists)...

I'm not seeing any tone for what's been up so far - at least the net with the 3 Sam and 3 Paul units. They seem to be running CSQ. That dispatcher is so loud here that it's almost overmodulating. I can't believe the transmitting site is very far away from me.

Starting 2032, the same dispatcher/controller did radio checks with Woodlawn units (the ones we heard). She then went to Pittsburgh units (3G). Of course, I couldn't hear any of the mobiles but she was still loud and clear so obviously is simulcasting across several cities. She then does Philadelphia radio checks with the units there (3S and 3P in one area and 3G in another.)

 

[Spleen]

The 20:30 radio check on 413.875 (seem to be four-hourly) did not contain a tone. I put a loop antenna that's sensitive on UHF on the Winradio and got the best signal with it oriented in a general North-South direction, S9+10, so you must be sitting right next to the txmitter, TinEar...

 

[TinEar]

The 20:30 radio check on 413.875 (seem to be four-hourly) did not contain a tone. I put a loop antenna that's sensitive on UHF on the Winradio and got the best signal with it oriented in a general North-South direction, S9+10, so you must be sitting right next to the txmitter, TinEar...

I almost want to look in the back yard to see if they erected a tower there for this system. It's that loud.

Oops...time for 24.

 

[Spleen]

I can't find the thread, TinEar, but this "image" issue I was having almost solves the mystery a few weeks ago of those "other" 900MHz txmissions....I searched 400 MHz and sure enough, those empty carriers with PL of 64.7 showed up at 406.650, 406.425, and 407.050, S9+20.

Edit: These are the old Department of Commerce frequencies, which used to be a Motorola Type II system....I guess they're testing out something new...they never used it anyway, though I do remember hearing the control channel motorboat as recently as last summer...

 

[Whistler]

Can someone put me on the trail of understanding these "images". I don't quite understand and would like to do a little research. 900 images that are actually 400?

 

[Spleen]

These days, it happens a lot on wideband receivers connected to wideband antennas or antennas that are cut for one frequency but can resonate on another band...there's actually a formula you can use to determine where these "images" might occur....some Googling will probably lead to a definitive answer....