Wednesday, August 08, 2007

VHF Trunking Mysteries

There are a couple of mysterious trunking control channels that have been reported in the VHF federal bands and so far we have no solid information on where they are coming from or who is operating them.

First, a listener in New Jersey as been reporting what he believes is an EDACS trunking control channel on 170.7625 MHz. 172.6875 & 172.9875 MHz might be analog voice channels associated with this control channel. The signal comes and goes as if it's being heard via skip, but from which direction is unknown. EDACS federal trunked systems are rare, but a VHF system would be a first. Listeners in Philadelphia, where 170.7625 MHz is used as by DHS/ICE have not confirmed a trunked system there. The 172.6875 and 172.9875 are previously un-assigned frequencies.

The originator of this information has theorized that it's an ICE/DHS trunked system somewhere. But so far he hasn't reported any specific voice traffic heard. I find that difficult to accept with as little information as we have so far. It makes no sense to me that the DHS would set up an analog EDACS trunked system, totally incompatible with what they are doing everywhere else, and not using the P-25 standard, which has been mandated by specifications in federal budgets for interoperability.

In the south, another monitor in Florida is reporting a P-25 control channel on 170.1250 MHz. It is reporting a System ID of 910. Speculation is that it might be military or Department of Energy, but nothing is confirmed. This signal is also being heard via skip from an unknown location in the Southeast US.

Anyone else hear any of these signals? Let us know at the Fed Files!

New CBP A&M Units?

I've been receiving information that there is a new call sign being heard on some of the Customs & Border Protection radio nets in the Southwest US. Listeners in Arizona have started reporting references to "1100 TAC" units, sometimes in association with CBP air units. The call sign does not appear to refer to a base location or station, but mobiles that operate as a group under that call. Sounds like it could be a Task Force unit of some kind, perhaps National Guard units working along the border?

Also, the CBP division that we used to refer to as Air Marine Interdiction Division (AMID) is now simply Air & Marine:

And it appears that the CBP A&M has added two AgustaWestland AW139 helicopters to its aircraft fleet:

DoE / BPA Activity

The Bonneville Power Administration, headquartered in Portland, Oregon, is an agency under the U.S. Department of Energy. They operate a series of VHF repeaters in the Pacific Northwest that is normally used for transmission line and facilities maintenance. All of these repeaters operate on 172.5250 MHz.

Recently I caught a transmission from "KOD900 Denver" calling an aircraft (who's call sign I failed to catch) about his landing at Portland Internatnional Airport. I assumed that the aircraft was probably involved in aerial inspections of tranmission lines. I also had not realised that BPA had a centralized dispatch center that was NOT in Portland!