Emergency Frequencies Are All Just Static

[cschoe]

Hi! I'm new to radio in general and picked up an SDR radio kit today so I could tune into police dispatch. I've found my county's emergency frequencies (Louisville Emergency Communications Network: MetroSafe Trunking System, Multiple, Kentucky) but although I can see noise appearing at those frequencies, when I tune it only ever sounds like noise. Is there something obvious I'm doing wrong? So far the only thing I've been able to listen to is a few music stations.

 

[chrismol1]

You will need to use SDRTrunk program and input the red control channel so it will follow the voice channels

 

[a417]

just to forewarn you...


of the sample of 10 of the talkgroups that are broadcast on that trunked system, you will be able to pick up only one of them. You will notice that column of 'DE' - which means fulltime digital encryption is in use on those channels. The 'All Talk' group is the only one there that's not currently blocked from you.

Good luck.

 

[Spleen]

That system is P25 Phase II, you're going to hear digital noise until you apply a proper decoder...start with Simple APCO P25 Phase 1 Decoder Plugin Released for SDR# and maybe DSD. When you get up to speed it looks like a good excuse to learn SDRTrunk.

 

[sunwave]

DSD-FME for APCO P25 works well for C4FM type systems. SDR++ has it's own RIGCTL and AUDIO over TCP plugins which makes it easier to get up and running. APCO P25 is digital and digital always sounds like noise. That's the reason we use decoders.

 

[dave3825]

SDR++ has it's own RIGCTL and AUDIO over TCP plugins which makes it easier to get up and running.

That will not decode trunked systems, right?

 

[maus92]

Wrong tool to use to monitor the system. SDR Trunk is probably the easiest for a novice to set up but will require several RTL-SDRs or a single AirSpy.

 

[dave3825]

While his screenshot does reflects a freq from the first site (or close to it), if he was able to receive any of the last three sites, he could get buy with 1 dongle.

RFSS	Site	Name	County	Freqs
1 (1)	001 (1)	Jefferson County Simulcast	Jefferson	854.2125c	854.4875c	854.7375c	855.3625c	856.2125	856.4375	856.4625
				856.7625	856.9375	857.2125	857.4375	857.4625	857.7625	857.9375
				858.2125	858.4375	858.4625	858.7625	858.9375	859.2125	859.4375
				859.4625	859.7625	859.9375
1 (1)	003 (3)	Jeptha Knob	Shelby	851.475	852.475	852.950	853.225c	853.875c
1 (1)	004 (4)	La Grange	Oldham	851.1375	851.350	851.675	852.100	852.2875c	852.625c
1 (1)	005 (5)	New Bernheim	Bullitt	851.6375	851.8875	852.1375	852.3875c	853.125c