Thursday, October 22, 2009


I've been down in the Orange County, California area the last week and have come across some active channels that remain a mystery.

408.4000 MHz, 412.6500 MHz and 417.4000 MHz are all being heard in P-25 with a NAC of $167. It appears that 417.4000 MHz might be the input to 408.4000 MHz. Others have reported some surveillance and radio checks on the 408.4000 frequency, but what agency?

The 408.4000 frequency used to be a federal agency common, but that assignment changed at the beginning of 2005 when the UHF federal band began to be re-channeled. Many military bases have been heard using the 408.4000 frequency in the past. The 412.6500 frequency has some Justice Department assignments, as well as the 417.4000 frequency.

Some would probably look at the $167 NAC as proof of being the FBI, but there are plenty of other possible agencies that might use this NAC. And I still haven't seen enough evidence hat the FBI routinely uses their UHF assignments for surveillance operations, but things might be changing.

Further monitoring will be required. If anyone in the SoCal area has any further information on this activity, let me know!

Tuesday, October 20, 2009

Interoperability Channel Names

APCO International has released a draft copy of it's "Proposed Standard Channel Nomenclature for the Public Safety Interoperability Channels". The draft can be viewed here:

This is to help standardize the channel names for the federal and non-federal interoperability frequencies through out the US. The document also provides a complete list of the frequencies for reference.