Loudoun County (VA) TRS Technical Information

From The RadioReference Wiki

Basic Information

This trunked radio system provides communications for the Public Safety services of Loudoun County:

  • Loudoun County Sheriff's Office
  • Loudoun County Fire and Rescue
  • Town of Leesburg Police

Police in the smaller towns in western parts of the county utilize the Loudoun County Sheriff's Office talkgroups. It is also possible that some town police may be using conventional frequencies instead of this system.

Encrypted talkgroups are present on this system. These talkgroups are not able to be decoded with any standard scanner setup. It is believed that the Loudoun County Sheriff's Office utilizes these encrypted talkgroups for Sheriff's Emergency Response Team (SERT) communications, but it is not possible to verify this for certain.

Technical Information

This system has two transmitter sites that are simulcasting the same data on the same frequencies. One site is located in Ashburn, providing coverage for Central and Western Loudoun. The other site is in Sterling, covering the eastern portion of the county, and also possibly providing interoperability with Fairfax County.

This system was rebanded to new frequencies on February 15, 2012.

The control channel is a standard P25 9600bps control channel.

The system utilizes Motorola's X2 TDMA technology, as well as standard P25 Phase I FDMA, for voice encoding. As long as all radios that are associated to a talkgroup are TDMA-capable, TDMA will be used for that talkgroup. As soon as a non-TDMA radio associates, that talkgroup will then be transmitted using FDMA until that radio is no longer associated.

LCFR Zones for the new (December 2009) radio system

Zone 60 Zone 61 Zone 69
A - Dispatch A - Dispatch A - Dispatch
B - Response B - Command 40 B - RHCC6
C - Command 10 C - Tac 41 C - Lansdowne
D - Tac 11 D - Tac 42 D - Cornwall
E - Tac 12 E - Tac 43 E - Reston
F - Tac 13 F - Command 50 F - Fair Oaks
G - Command 20 G - Tac 51 G - Fairfax
H - Tac 21 H - Tac 52 H - PrinceWm
I - Tac 22 I - Tac 53 I - Fauquier
J - Tac 23 J - Command 60 J - Winchester
K - Command 30 K - Tac 61 K - Arl
L - Tac 31 L - Tac 62 L - Alex
M - Tac 32 M - Tac 63 M - Fred Mem
N - Safety1(TA) N - Safety1(TA) N - Medstar
O - Safety2(TA) O - Safety2(TA) O - Ares
P - Dispatch P - Dispatch P - Dispatch