Wednesday, October 10, 2018

TSA Moving to UHF Channels?

A recent posting in the Federal Business Opportunities website,
was sent to my attention.

It appears from the description that the Transportation Security Administration (TSA) is interested in changing out all of their radio equipment from VHF to UHF frequencies. The TSA has just recently gone through an agency-wide upgrade of their VHF radio infrastructure that included new BK radios and equipment. The information provided by the TSA includes this data on thier radio systems:

At the present time, TSA operates approximately 155 repeaters at approximately 150 airports, approximately 120 base stations at approximately at 120 airports, and over 21,000 handheld radios at approximately 415 airports located in the United States of America and its territories. TSA also has Bi-directional amplifier (BDA) and Distributed Antenna Systems (DAS) systems installed at approximately 10 airports. Currently TSA manually encrypts its handheld radios and base stations monthly.

Several folks have inquired as to why they are moving. One suggestion is that the FAA, who shares many of the TSA frequency allocations, was wanting the VHF channels back. I also think that there are more available channels in the federal UHF band (406-420 MHz) than there are in the VHF (162 - 174 MHz) band.

Monday, October 08, 2018

US Park Police in DC Move to P25 Finally

It appears from postings on the Scan-DC mail list that the venerable US Park Police analog radio system may have finally met it's demise.

For some time the Park Police in Washington DC have been using analog FM for their radio transmissions. They have continued to use analog radios long after nearly every other federal agency in the DC region has moved to various forms of digital radios. The analog Park Police frequencies also have long history of being heard over quite an large area around the DC area, and could often be heard into the Philadelphia and even New York City on some occasions.

The new, encrypted, P25 digital frequency lineup for the Park Police will include the following:

168.7875 - ADMIN
171.7750 - DISPATCH

No information yet on P-25 NAC or radio IDs for the Park Police. 

Special thanks to the Capitol Hill Monitor newsletter for keeping up with new developments on this:

New Federal Trunking in DC?

Over last weekend I noticed reports on Radio Reference of a new VHF trunking control channel being heard in Virginia around the Washington DC area.

The frequency of 173.1750 MHz was reported as having a P-25 control channel with a system ID of 981, Site 101 and a WACN of BEE00.  DSD+ shows an alternate control channel of 172.6625 MHz.

Keep an eye on this system as more information comes in:

Saturday, August 11, 2018

Unidentified Federal Trunked System A52

A quick update on the unidentified P-25 trunked sites I and others have heard in the Las Vegas area. Radio reference has updated the entry for this system and it now indicates that it is a multi-site, multi-state system, with sites in California, Arizona and Nevada.

I monitored the control channel data about a month ago on a visit to the area and it still only showed two sites active and no affiliations. But apparently they have been busy with this system build-out.

I suspect this is a Department of the Interior system that will support the Bureau of Reclamation and other DOI activities in the Lower Colorado region.

Although it is listed as "Clark, NV", I am certain that site 112 is at or near the Hoover Dam area, as I get close-call hits on that control channel when I am at the dam.

Here is what is showing at Radio Reference:

2-013     Site 13        Riverside, CA  172.1125
2-061     Site 61        Yuma, AZ       172.650
2-065     Site 65                       172.6502
2-075     Site 75                       172.1375
2-122     Site 112       Clark, NV      172.1125


Sunday, June 03, 2018

TSA Dropped 172.9000 MHz?

Back when the Transportation Security Administration (TSA) began operations in 2002, they were originally under the Department of Transportation (DOT). The radio frequencies that were first standardized to be used by the TSA nationwide included 169.3000, 172.1500 and 172.9000 MHz. These frequencies were culled from the Federal Aviation Administration (FAA) allocations, and they are still shared between the two agencies.

Since the new radio updates that the TSA has undergone, I have noted a distinct lack of any activity on the 172.9000 MHz frequency as I travel across the country. Most airports still have some activity on the 169.3000 and 172.1500 frequencies (as well as others), but mostly silence on the 172.9000. Anyone hearing activity on 172.9000 MHz, please let me know!

UPDATE - After reviewing my notes and talking with several other listeners, there are a few locations using 172.9 MHz for TSA activity, but it does still appear to be no longer the "primary" VHF repeater frequency that it once was for the TSA nationwide. 

Federal/Military use of NXDN

   I recently saw some discussions about some VHF federal frequencies being used for an NXDN IDAS trunked system in Southern California. Monitoring had provided clues to the system users and it appears to be utilized by the Los Alamitos Joint Forces Training Center in Orange County. So far, two frequencies have been identified as being used by this system, and updates can be found here:

163.4125 MHz - LCN1
163.4375 MHz - LCN2
? - LCN3
   While the use of DMR and NXDN digital modes is increasing in the federal VHF and UHF bands, it is a bit unusual for a military facility to go with a non-standard radio system type when other military bases around the world are joining large networked P-25 digital radio systems.


Tuesday, April 24, 2018

USS Portland HYDRA System

Here is a rundown of the Portland HYDRA shipboard trunked system:

USS Portland (LPD-27)
EDACS Wide-band 
System ID – 003
397.2625         LCN-3
397.6125         LCN-5
397.7625         LCN-6
399.1625         LCN-7
399.3125         LCN-8
399.5625         LCN-9
399.7625         LCN-10

LCN-1 and LCN-2 were showing as part of the system, but were not active, so I could not confirm the frequencies. There was no LCN-4 showing.

Dockside security was using 395.2500, N293 and 398.6500, N293 for simplex communications.

   And one item that came via “close-call” near field monitoring, a UHF air band beacon on 313.6250 MHz. It was a continuous AM carrier with Morse characters “A-I-A” being send every 10 seconds. My assumption is since this vessel handles helicopters and tilt-rotor aircraft, a navigation/homing beacon to the ship would be a must.

Tuesday, April 10, 2018


A quick update on an item I posted nearly a year ago:

At the time I heard the Site 2-122 control channel on 172.1375 MHz. During my most recent trip to the Las Vegas area, I caught the control channel on 172.1125 MHz. The site is still broadcasting the same system information and using a NAC of A52.

But during my times of watching the control channel activity, I have yet to see anyone using the system. I've not seen any affiliations to this site and no voice channel grants.

The general assumption is that this is a multi-site VHF P-25 trunked system for the Department of Interior, who manages the Lake Mead National Recreation Area. And with the disbanding of the Hoover Dam Police last year, it was also assumed that the Park Police would take over patrolling the Hoover Dam and related visitors centers. That activity has not yet shown up on the new radio system.

I'll continue to monitor this system as I make it into the Southern Nevada region.

Monday, March 12, 2018

More VHF Lo Band P25?

Last year I wrote about some VHF low-band (30-50 MHz) frequencies that were heard in the P-25 digital mode. The frequencies monitored were 30.0500 MHz, 31.2100 MHz and 35.1900 MHz, all in the P-25 digital mode.

A recent posting on Radio Reference indicated that 30.1000 MHz, N270 was heard in Ohio, possibly being used by the Ohio National Guard.

The wide-band, all mode radio systems being deployed by US military units are indeed capable of P25 digital mode on nearly any VHF or UHF frequencies.

 Anyone else looking for P25 in the VHF low band? Curious if anyone else has caught any.