220 MHz Public Safety Interop use

[N9JIG]

I've seen weird packet bursts on the former HAME 1.25m range before when using my SDR down by the railroad tracks. Never managed to figure out what it was.

It almost looked similar to the bursts I see sometimes on 900 MHz from the FHSS power meters.

I think (but I am not sure) that some of the PTC data on the railroads is/was carried on 220 on some lines. That might account for the packet bursts.

 

[IC-R20]

It was likely amplitude companded sideband. There were some large trunking systems that used that back many years ago. Sort of died off. Used to be able to pick up the mobile radios pretty cheap on E-bay.

Very interesting. Those would be fun to get for amateur 1.25m use.

 

[IC-R20]

I think (but I am not sure) that some of the PTC data on the railroads is/was carried on 220 on some lines. That might account for the packet bursts.

Ah yeah that's it, I just looked it up and you are correct. I only ever saw on one of those generalized frequency range charts that there was railroad stuff there but never knew exactly what. That's really cool and an old mystery finally solved. Thanks.

 

[bigray246]

There is a 220 Mhz. analog trunked system based out of Staten Island NY. I know IMTT terminal in Bayonne NJ is on it.

 

[wtp]

i am too far away, but,

WPQA838

STATE OF NEW YORK, DIVISION OF STATE POLICE

0003438595

QM

Active

04/28/2025

QM..?

 

[mmckenna]

QM..?

QM = Non-Nationwide Public Safety/Mutual Aid, 220MHz