Mixed Mode?

[JethrowJohnson]

Pleasants County EMS in West Virginia have a radio system that operates in mixed mode, so one transmission could be analog while the reply is P25. Why do they do that instead of just using P25?

 

[IAmSixNine]

They may have users who have not updated radios yet and are analog only.
They may have some equipment somewhere that is not able to incorporate P25. (stupid example some colleges have poles set up with press here for emergency, those often are set up on the PD channel with a pre-recorded message that transmits on the PD channel OR some have 2-way capabilities, just a dumb example)
Ultimately to get the actual answer for just that dept you would need to ask them.

 

[KevinC]

Ultimately to get the actual answer for just that dept you would need to ask them.

A dozen other people will reply, but this is pretty much the only correct answer.

 

[JethrowJohnson]

Thank you. I don't think it would be because some of them still have analog radios, because then I don't think those ones would be able to hear any P25 transmissions. Idk

 

[ramal121]

Have been dealing with this for well over a decade now. Here's the scenario. Customer wants to upgrade/expand the radio system some. Sales jumps in and barfs all over them as they pound the benefits and whiz bangs of this new digital stuff. Customer says cool! Sales says replace everything for $$$$. Customer says that is kinda steep at this time, will have to think about it. Sales not to let the momentum falter says no problem, we'll use mixed mode. That way you can use your old analog radios while you gradually upgrade to digital and everything will be just peachy. Customer says cool and buys a mixed mode system.

Then the complaints start and I have to bring everyone down to earth.

#1 Analog radios will not receive digital transmissions no how no way.
#2 If an analog radios happens to be in monitor you will hear at times the loudest, rudest noise you will ever hear on the radio.
#3 Digital radios can receive both modes, however most users cannot distinguish between either mode and therefore cannot figure out
which channel they should respond on.

This boils down to yes there are mixed mode radios in use and yes it seems to be the biggest cluster in radio ever.

 

[JethrowJohnson]

Sounds like that's probably what it is. So in this type of system, there are two different channels they use? It sounds like the digital radios are on the mixed channel, and the analog ones are on the analog channel, and the mixed and analog ones simulcast, so everything the analog ones hear is of course analog, but what I have programmed in my scanner is the mixed one, so the reason some are analog is because those are the analog ones on that channel, and the rest are P25. Is that how it works?

 

[speedway_navigator]

If a user didn't have multiple key capability that radio might only have a key for a different system or talk group. Our system uses different keys for PD dispatch, narcotics and med talkgroups. Our PD had to buy the multi key upgrade when the extra keys were rolled out

 

[BMDaug]

I run our VHF repeater mixed mode so SAR can access it. I run our fleet encrypted P25C with a DFSI console. We give SAR priority during missions where they have no other comms option than our repeater.

This is the only “non-cluster” way of using mixed mode imo…

-B