help deciphering frequencies

Status
Not open for further replies.

ryradio

Member
Premium Subscriber
Joined
Oct 28, 2011
Messages
88
I was looking at the FCC license search page and I found two 100mhz frequencies that I would like to monitor. Neither of which are listed on the RR database.

Unfortunately I am getting the "garbled" transmission that you would hear on a control channel or like when you try to monitor a digital/trunked frequency on a standard scanner.

So how do I decipher what type of system these frequencies are on?
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
10,994
Location
SNCZCA01DS0
Well, it would help if you could tell us what they are.
A link to the FCC license, the FCC call sign, etc.
 

teufler

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
2,348
Location
ST PETERS, MISSOURI
his could be am image frequency. On the extra class ham exam, there were a couple of questions about a frequency minus the mixer chip or something like that, you would get a frequency. Or if 100 mhz, it could be a 2nd harmonic of a low band signal. If so, divide the frequency by two to get the primary frequency. There are many ham 6 meters calling frequencies, 50.1 to around 51.0. These are SSB signals, which most scanners will not play back correctly. Now if a 6 meters signal, you got a band opening.
 

ryradio

Member
Premium Subscriber
Joined
Oct 28, 2011
Messages
88
I cant post audio. The frequencies are 154.something and 159.something which are in the normal band range of conventional public safety in our area. Its for a public works department. The FCC licenses says one is a mobile relay and the other is for 20 mobiles.

What does 'mobile relay' mean? ... I think I was only hearing the garbled sound on one of two frequencies... probably the 'mobile relay' frequency.
 

toastycookies

Member
Joined
May 29, 2010
Messages
722
Location
the far east
I cant post audio. The frequencies are 154.something and 159.something which are in the normal band range of conventional public safety in our area. Its for a public works department. The FCC licenses says one is a mobile relay and the other is for 20 mobiles.

What does 'mobile relay' mean? ... I think I was only hearing the garbled sound on one of two frequencies... probably the 'mobile relay' frequency.
most likely a crossband vehicle repeater.

exact definition can be found at 47 CFR 90.243
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
10,994
Location
SNCZCA01DS0
You really haven't give us any usable information. "154.something and 159.something" tells us the band. What you are hearing could be anything.
If you can link to the license or give us the call sign, the emission designator on the FCC license will tell you what kind of system they are running. Frequency alone doesn't do us any good.
 

ryradio

Member
Premium Subscriber
Joined
Oct 28, 2011
Messages
88
The emmsions designtors are a combination of these:

11K3F3E, 7K60FXE, 7K60FXD

which might be mototrbo but I am unclear on how to program such a system without all the specifics that I usually depend on the database for. Or alternatively, I am not sure if my Uniden 996P2 is able to receive that type of system at all.
 
Last edited:

Redneck0410

Member
Premium Subscriber
Joined
Mar 3, 2008
Messages
1,001
Location
Hutchinson, KS
MotoTRBO is the two 7xxxxx designators. The other is narrowband. Only a handful of scanners can monitor such a system.

Sent from my SM-G930F using Tapatalk
 

toastycookies

Member
Joined
May 29, 2010
Messages
722
Location
the far east
The emmsions designtors are a combination of these:

11K3F3E, 7K60FXE, 7K60FXD

which might be mototrbo but I am unclear on how to program such a system without all the specifics that I usually depend on the database for. Or alternatively, I am not sure if my Uniden 996P2 is able to receive that type of system at all.

What are the EXACT frequencies you are trying to monitor?
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
10,994
Location
SNCZCA01DS0
The emmsions designtors are a combination of these:

11K3F3E,
This is narrow band FM analog.

7K60FXE, 7K60FXD
As stated above, these are DMR/MotoTrbo



which might be mototrbo but I am unclear on how to program such a system without all the specifics that I usually depend on the database for. Or alternatively, I am not sure if my Uniden 996P2 is able to receive that type of system at all.
It's pretty common for the licenses to be set up this way.
Likely the original license was 11K3F3E FM analog originally. The DMR emissions were added later when they made plans to upgrade their radios. The 11K3 will stay there unless someone decides to remove it.

Since the time slot and color codes aren't part of the FCC license information, someone will need to put the effort into figuring out what they are. That might be you. When you do figure it out, submit it to the data base so others can access it.

And, since you seem to be reluctant to share the specifics of exactly who it is you are talking about, no one here can really do anything to help you. If you would post the call sign, agency, or something that identifies the specific user, someone just -might- have the information you are looking for.
 

ryradio

Member
Premium Subscriber
Joined
Oct 28, 2011
Messages
88
Thank you all for the information. Pointing out the "emmisions designators" is all I really needed to know.

I think it is apparent now that the garble I hear on one of the two frequencies I am trying to monitor is a DMR/MotoTrbo system which my scanner cannot decode. I do not hear the same garble on the other channel, which I assume means its still narrowband analog, but unfortunately it doesn't appear to have any traffic at this time.
 
Status
Not open for further replies.
Top