US DoD Monitoring

[scannerizer]

Hello. I am trying to monitor the Department of Denfense P-25 radio system for the sites in King County. I know I need to set it up as a P25 system in the scanner, but what I don't know is whether the system is explicit or implicit. I program my radio by hand so would like any support I can get. I once tried to program the system but never received ti. Is there something special that needs to be done to receive the control channels in the 380MHz band? Thanks.

 

[Stavro35]

I'm not exactly sure what you're asking? Please let me know what radio you have . And which sites are of interest to you. Perhaps we can help each other? I'm trying to figure out who site 101 is from brief communications. I'm located in Bainbridge island. Post back to me o.k?!

 

[ChrisP]

Hello. I am trying to monitor the Department of Denfense P-25 radio system for the sites in King County. I know I need to set it up as a P25 system in the scanner, but what I don't know is whether the system is explicit or implicit. I program my radio by hand so would like any support I can get. I once tried to program the system but never received ti. Is there something special that needs to be done to receive the control channels in the 380MHz band? Thanks.

These 380 MHz systems have all been explicit so far, so no need to worry about anything except entering the frequencies. Implicit systems require you to enter the frequencies in the correct logical channel number order. I've only run into a couple of those and they were not military...


- Chris

 

[poltergeisty]

Question: What is explicit or implicit?

 

[ChrisP]

Question: What is explicit or implicit?

P25 trunked systems have the option of being "explicit" or "implicit". If they are explicit, they broadcast the system frequency information over the control channel. Most P25 trunked systems are explicit.

There are some that are "implicit", that is, they do not broadcast the actual frequency information over the control channel, but simply broadcast the frequency logical channel number and the frequencies themselves are contained in the subscriber unit programming (the radios themselves). If you run into an implicit system, and monitor it via PRO96COM, the system shows no frequencies but only channel numbers.

As I said, I have run into very few implicit systems, but they are out there…

- Chris

 

[ecps92]

Search of the RadioReference Wiki

Question: What is explicit or implicit?

 

[scannerizer]

I'm not exactly sure what you're asking? Please let me know what radio you have . And which sites are of interest to you. Perhaps we can help each other? I'm trying to figure out who site 101 is from brief communications. I'm located in Bainbridge island. Post back to me o.k?!

Stavro35 it's a BCD396XT.

 

[poltergeisty]

P25 trunked systems have the option of being "explicit" or "implicit". If they are explicit, they broadcast the system frequency information over the control channel. Most P25 trunked systems are explicit.

There are some that are "implicit", that is, they do not broadcast the actual frequency information over the control channel, but simply broadcast the frequency logical channel number and the frequencies themselves are contained in the subscriber unit programming (the radios themselves). If you run into an implicit system, and monitor it via PRO96COM, the system shows no frequencies but only channel numbers.

As I said, I have run into very few implicit systems, but they are out there…

- Chris

Thanks for taking the time to answer my question. I always thought the control channel gave the system frequencies. That's how I had my scanner programed by control channel only so I wouldn't miss anything. Just never heard of the terms explicit and implicit.