Anyone hear this tone before?

[devicelab]

Found this on an active federal VHF analog frequency. At first I thought it was some kind of MDC or a paging tone but now I'm wondering if it could be an older form of encryption? There is clear voice so not sure what this is...

https://www.dropbox.com/s/wk4d7g9e5ck8rtu/fedtone.mp3?raw=1

 

[nd5y]

What frequency?
It's not voice encryption. It sounds almost like PSK31. Probably a low speed data mode for SCADA or something.

 

[devicelab]

It's not voice encryption. It sounds almost like PSK31. Probably a low speed data mode for SCADA or something.

Data on the same channel as their voice comms using the same PL?

 

[ecps92]

Freq would help some, as the Federal Band is shared, there are plenty of Telemetry users also out there.

Found this on an active federal VHF analog frequency. At first I thought it was some kind of MDC or a paging tone but now I'm wondering if it could be an older form of encryption? There is clear voice so not sure what this is...

https://www.dropbox.com/s/wk4d7g9e5ck8rtu/fedtone.mp3?raw=1

 

[devicelab]

Today, I heard a dial tone and a long press of a DTMF key -- which may open a gate or an on/off relay. I think the original tone is probably a confirmation tone (i.e. vehicle passing thru gate)

When I get a chance, I'll head to the facility and see if my suspicions are correct.

 

[devicelab]

Freq would help some, as the Federal Band is shared...

Won't give out the frequency as it's their security patrols. I know the facility and the agency already.

 

[Giddyuptd]

If it's in clear, in Bothell WA im sure someone will search and run a discovery and find it.

 

[ecps92]

Talk about Self Centered.
You ask for help but when asked for more info, deny access

Congrats, you have triggered the IGNORE feature

Won't give out the frequency as it's their security patrols. I know the facility and the agency already.