FCC Long-Range HF Direction-Finding Network

Pirate radio transmitters, transmitting antenna systems, pirate radio equipment suitable for AM or shortwave broadcasting. Reviews, modifications, other info specific to shortwave pirate radio broadcasting.
Post Reply [phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1266: count(): Parameter must be an array or an object that implements Countable
User avatar
JohnPoet
Site Admin
Posts: 169
Joined: Mon May 23, 2011 7:05 am
Location: Lansing, Michigan, United States of America
Contact:

FCC Long-Range HF Direction-Finding Network

Post by JohnPoet » Mon Apr 01, 2013 6:57 pm

This map shows the monitoring station locations in the FCC's remotely-operated HF (shortwave) monitoring network, as well as their physical addresses:
http://goo.gl/maps/wD6iY" onclick="window.open(this.href);return false;

It is these monitoring stations which are used to get an initial fix on an unlicensed broadcaster's location (on shortwave and AM mediumwave frequencies), by triangulating whatever signals are received by the various monitoring stations. They are unmanned, and can be operated from a central location. In the past, this network was able to pinpoint a station's location "within about 10 miles", but recent technological advances in long-range direction finding may now narrow that down, to possibly within as little as a mile or less of the actual station location.

Once an investigation of a pirate station has been launched, the FCC would probably take several long-range DFs of a shortwave station (or a medium-wave pirate, if it can be heard over a large area) to determine whether it is operating from a fixed location or locale, before attempting close-range direction-finding.

Once the long-range DFing is complete, the FCC could send a vehicle with short-range direction-finding equipment to the presumed locale of the station to wait for it to come on the air. However, they would first need to be able to make a reasonable prediction of when that station would be on the air again.

These short-range DF vehicles are typically dark-colored SUV types with no visible DF antennas, since those are installed inside the roof of the vehicle.

The newest DF vehicles may be extremely accurate, and the readouts are very possibly interfaced with GPS mapping (global positioning satellites). With such a system, the vehicle *may* be able to pinpoint a location with as few as two good directional readings from two directions, which could bring them right to your front-door much more quickly than it used to take "in the old days" (They don't need "two or three" DF vehicles to do it, anymore!) From extremely close range, they would also use high-tech readings of signal intensity to help verify a location... as well as their eyes (can they see an HF antenna, or feedlines?)


(See also FCC Field Offices )
John Poet
"A treasonous voice of dissent"
Free Radio Cafe Board Admin

Free Radio Cafe on Facebook
Follow FRC Loggings on Twitter
.

Post Reply [phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1266: count(): Parameter must be an array or an object that implements Countable
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1266: count(): Parameter must be an array or an object that implements Countable
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1266: count(): Parameter must be an array or an object that implements Countable

Who is online

Users browsing this forum: No registered users and 3 guests