Fed CC?

[mike_s104]

Just ran across these that sound like control channels.

409.0500
417.2750
408.4625

408.5375 - flips between a very weird sound (high pitch squeal) and what sounds like data or a control channel.

 

[ff-medic]

Probably Federal Freqs for the Federal Courthouse near you. I checked Virginia, Maryland and Pennsylvania and got no hits on the freqs you listed.

One freq I researched is assigned to the FBI.

Encryption ????

Search the Federal UHF band in 5 to 7 mhz increments , and other than playing with the squelch , adjusting it to get a distance possibility , I ..at this time , have no other answers.

FF - Medic !!!!




FF - Medic !!!

 

[mike_s104]

Probably Federal Freqs for the Federal Courthouse near you. I checked Virginia, Maryland and Pennsylvania and got no hits on the freqs you listed.

One freq I researched is assigned to the FBI.

Encryption ????

Search the Federal UHF band in 5 to 7 mhz increments , and other than playing with the squelch , adjusting it to get a distance possibility , I ..at this time , have no other answers.

FF - Medic !!!!



FF - Medic !!!

How do you think I found those? Searching HF?

I don't think it's encryption and nor I think it's FBI (they tend to stay around the 160MHz range around here). There's a lot more than just a Federal Courthouse in Berkeley. These might be from MD, PA, VA or DC. The signals were pretty strong so I would suspect they were some-what close.

 

[mtindor]

Check for an Fed prison facility within range of you. I'm betting it is one of them.

BOP: Maps of Facilities - Mid-Atlantic Region
BOP: Maps of Facilities - Northeast Region

Very common to have 400-420 mhz trunked systems (some still analog, most Type II digital). I'm not sure if they are all moving on to P25 or not. But around here two just converted from Type II analog to digital in the past couple of years.

Talkgroups for these systems seem to share a fairly common template. If you see a lot of use on talkgroups under 112 it's probably a prison system. TG 16/32/48/80 are very common on these systems.

Mike

 

[ChrisP]

Just ran across these that sound like control channels.

409.0500
417.2750
408.4625

408.5375 - flips between a very weird sound (high pitch squeal) and what sounds like data or a control channel.

These are not trunking control channels, but digital control links to various sites belonging to the National Parks Service in the DC/MD/VA area. They transmit multiplexed digital data and radio control to the VHF sites used by the NPS. I wrote about these links in the March, 2010 issue of Monitoring Times.

409.0500 MHz is a link from Boonsboro, MD to Cacapon Mountain, part of the C&O Canal National Historical Park. The link controls 170.3625 MHz.

417.2750 MHz is a link from Luray, VA to Hogback Mountain, part of the Shenandoah National Park system. This link controls 173.6750 MHz.

408.4625 MHz is a link from Hogback Mountain to Fork Mountain, also in Shenandoah National Park.

408.5375 MHz is a link used in the C&O Canal NHP, used to link Lambs Knoll with Great Falls. VHF tied into that is 170.3625 MHz.

- Chris

 

[OldDeadOne]

Chris so those are data only and not voice?

 

[mike_s104]

These are not trunking control channels, but digital control links to various sites belonging to the National Parks Service in the DC/MD/VA area. They transmit multiplexed digital data and radio control to the VHF sites used by the NPS.

- Chris

Chris so those are data only and not voice?

I'd say not.

 

[mike_s104]

These are not trunking control channels, but digital control links to various sites belonging to the National Parks Service in the DC/MD/VA area. They transmit multiplexed digital data and radio control to the VHF sites used by the NPS. I wrote about these links in the March, 2010 issue of Monitoring Times.

409.0500 MHz is a link from Boonsboro, MD to Cacapon Mountain, part of the C&O Canal National Historical Park. The link controls 170.3625 MHz.

417.2750 MHz is a link from Luray, VA to Hogback Mountain, part of the Shenandoah National Park system. This link controls 173.6750 MHz.

408.4625 MHz is a link from Hogback Mountain to Fork Mountain, also in Shenandoah National Park.

408.5375 MHz is a link used in the C&O Canal NHP, used to link Lambs Knoll with Great Falls. VHF tied into that is 170.3625 MHz.

- Chris

Thanks!

 

[ChrisP]

Chris so those are data only and not voice?

Correct - you will not hear analog voice over these links. The radio audio is digitized and part of the data stream...

- Chris