Question regarding Police Frequencies in Tucson

[Luis_C]

Well, so Swat and Surveillance frequencies are APCO-25 digital, but in the description it says "(mixed analog/digital)" does that mean that there might be FM activity? Or what is it?

Thanks

[Duditz511]

Do you have the link? And yes, I would think that it means that there could be FM activity as well as digital. I doubt they would use it when working incidents though. Anybody else have an idea?

-Dylan

[Luis_C]

Originally Posted by Duditz511

Do you have the link? And yes, I would think that it means that there could be FM activity as well as digital. I doubt they would use it when working incidents though. Anybody else have an idea?

-Dylan

Here is the link: http://www.radioreference.com/module...ame=RR&aid=524

Really thanks for the fast response, I hope it is, going to Tucson in about 2 weeks, preparing my radio scanner.

[Duditz511]

Yup, I believe that you are correct, it looks like they have the ability to transmit on digital as well as analog. (Anybody to confirm? lol)

-Dylan

[Astrak]

Yes they transmit sometimes in analog and sometimes in digital, its hard to tell why because I have heard them actually working a case in "normal" mode and sometimes they use digital for no apparent reason at all. Have fun monitoring TPD.

[STiMULi]

Depending on the team or the incident it may be all Digital/ all Analog or in some major activities, both.

Since we know what we know lets leave the rest of this conversation to PMs Please...

[Luis_C]

Thank you guys, probably they have the two kinds of radios spread in different teams, and depending what they have is what they use, but no doubt they are moving to digital slowly.

[biloxicoast]

When I listen to tpd, cross talk channels are not p25. These channels are used for surviving, cross talk and extra channels. When Swat uses 8c it is in p25 mode

[Ghstwolf62]

I have been on lay over in Tuscon on more than one occasion and actually submitted some info on this back a while. It may have changed but I can confirm as of a couple years ago they transmit both analog and digital. The few days here and there I was in town didn't let me figure out more than PL and NAC codes for the channels but they would be analog one second and digital the next.

I don't know if they have something like this or not but if they do then this might be it. Could the radio automatically transmit in the mode last heard on it? So if someone transmits digital the next user would automatically do the same when keying up etc? (or some version of that) Some units might be manually set to either too if its possible rather than an auto response.

Don't know about migration but they've been doing it this way for some years now.

[FLANO]

TPD has analog and digital capability for some users. Detectives and SWAT, for example, have the capability to swith to the "cyphered mode" or "8C" for example. The use of the term "cyphered mode" should not be confused with encyphered comms, as some of the TPD users believe. It is simply the term used for the digital mode of the radio. All transmissions are currently monitorable with the proper scanner.

[W2NJS]

P25 radios have the ability to receive both analog and digital transmissions on the same channel, but can only be programmed to transmit EITHER analog or digital on that channel. That receiving status is called "mixed mode." For example, if the dispatcher wants to transmit a wanted status for a person then the transmission might be done in digital, and unless the listener had a P25-capable receiver the listener would hear only "hash."

[Ghstwolf62]

Thanks W2NJS and Flano

[FLANO]

While doing some clean up on the database, I realized where the confusion is coming from. I've added the separate entries for TPD F7C, F8C, F9C, and F10C. This should help differentiate when they are digital vs analog. Sorry folks

[sfreiman]

I used to have a digital scanner here in Tucson. Now have all analog and doesn't seem like I am missing much so far. Sure wish I could monitor Marana though, but understand that is near impossible.