Mixed Mode Operation

[RKG]

I would be interested in the experience of anyone who has operated a Quantar running in mixed mode.

Assume UHF Quantar, with P25 hardware and software, running in mixed mode. Wireline access is via DIU, on digital only. Voted system, using AstroTac comparator.

1) Subscriber is talking in on digital and being repeated in digital; another subscriber keys in analog. What happens?

2) Console is talking out on digital; a subscriber keys in analog; what happens?

3) Subscriber is talking in on analog and being repeated in analog; another subscriber keys in digital. What happens?

We're going to run a series of tests on these and any other likely scenarios we can think of, but I'm wondering what to expect.

[N4DES]

I would be interested in the experience of anyone who has operated a Quantar running in mixed mode.

Assume UHF Quantar, with P25 hardware and software, running in mixed mode. Wireline access is via DIU, on digital only. Voted system, using AstroTac comparator.

1) Subscriber is talking in on digital and being repeated in digital; another subscriber keys in analog. What happens?

2) Console is talking out on digital; a subscriber keys in analog; what happens?

3) Subscriber is talking in on analog and being repeated in analog; another subscriber keys in digital. What happens?

We're going to run a series of tests on these and any other likely scenarios we can think of, but I'm wondering what to expect.

To answer your questions....

1) The digital signal may or may not be corrupted depending on RF capture. If the analog radio is programmed not to PTT with a signal being received the issue is moot.

2) Don't know...maybe someone else can answer.

3) I believe a digital radio shouldn't PTT when there is another signal being received regardless of the format, or at least that is how mine works.

Mark

[515]

From what I've seen, I agree with KS4VT on 1 & 3, where the user with the significantly stronger signal would always be repeated.

For 2, I'd imagine it depends on the wireline priority set via the Quantar or Comparator RSS. If the wireline has priority over the reciever, the dispatcher would be able to continue talking, and the analog user would be heard by no one until the dispatcher unkeys. If the DIU was wired to the comparator with the hybrid link, the dispatcher could hear the analog user while talking in digital (full duplex).

It's too bad subscriber radios don't have more busy channel lockout options designed for use in mixed mode systems...

[chartofmaryland]

The selection has to be made in the Astro-Tac Comparator. It has settings for analog and digital and what would be the first in and first out. You have to tell it what has priority.

Without a comparator it would be a first in and first out for a standalone quantar.

In the terms of the console, the dispatcher will make the choice which mode they will transmit in with say on a gold elite, you would see a sine wave representing an analog transmisson, and a square wave that would be for digital transmissons.

CoM