I just bought a Pro 106 Digital Trunking scanner from Radio shack and was wondering what system DPS uses and if I am able to hear all of their communications. I have programmed some frequencies in around my area for the dispatches but all I hear is dispatch. I can not pick up any of the trooper traffic from the cars all I hear is dispatch. Is it that im to far from the cars or am I not able to pick up the traffic from the cars?
Thanks for the help,
And ignore the name. Lol
Your Pro-106 is capable of receiving TX DPS, which uses digital (P25), on conventional frequencies (meaning not part of a trunked system).
However, whether you can hear both the base stations (the dispatch offices)
and the troopers in their cars is dependent on several things.
TX DPS uses what is known as a duplex system. The dispatch office will transmit on one frequency, while the mobiles (the troopers actually out on the highways) will respond on an entirely different one. Unless you're relatively close to that unit, say 10-15 miles, you probably will only hear the dispatch office. The actual distance that you could hear the mobile would depend on a lot of factors, such as whether you're using an external antenna, if the mobile unit is on top of a hill, or down below one. Bottom line, it could be hit and miss.
You did not list your location, so just take a look at DPS-Dallas in the
database for an example:
You'll see that the dispatcher is transmitting on 155.4525; the 128 NAC is information that you'd enter in your Pro-106 as well.
The troopers working off of that channel will respond on 154.7025. So, unless you're close to them, and your scanner moves from the 155.4525 frequency to 154.7025, you'd never hear them.
For units farther away from the dispatch office, however, you will usually hear both sides of the radio traffic on a mobile repeater. For instance, for the section of I-20 west of Fort Worth from the Tarrant County line through Parker County, you'll hear DPS Mineral Wells, and the troopers on the highway, on a repeater that's near Aledo, on 159.2100. (Look under Region V, DPS Mineral Wells, you'll see 'Aledo Dispatch' listed.)
At times, dispatch offices such as Dallas will switch to "repeater mode", and you will hear both sides of the transmission on the main channel. But this is not always the case.
You can look on the database page for the frequencies used in your specific area. Enter both the base & mobile frequencies (the mobile frequency is listed as the 'input' to the dispatch frequency), as well as any mobile repeaters in your vicinity. Alternatively, just enter the frequencies in the first section listed on the page, the Statewide APCO-25 channel plan. Yep, it looks like a boatload of frequencies, but look closely. The same ones, especially under the mobile repeaters, are used repeatedly, just with different
NAC codes.