MON effect on ASTRO private calls

[Ranger522]

On my system, 450 mile multicast ASTRO digital, I have all subscriber radios (ASTRO Spectra’s, XTS3000's and XTS5000's) set for selective squelch, and all ASTRO call options selected.

All portables operate correctly, only unmuting for the proper calls.

When a Spectra is set to MON on, it unmutes to all private calls, but when MON off, they only unmute to the proper calls. Getting users to keep the Spectra’s in MON off is going to be a problem.

Is there a separate MON type/setting that I have not found?
Am I missing something, can anyone help?

[RKG]

I take it that this is not a trunked system.

In non-trunked radio, "private call" is really only a different way of causing a receiving radio to unmute; it is logically the equivalent of transmitting with a different PL than the fleet PL. In monitor mode, a receiving radio unmutes on valid freq alone (and, in the Astro context, valid freq and correct data format), without requiring any other receive qualification. So I think you're going to be out of luck, unless things have changed lately.

All of which underscores what we have said a number of times, namely that "private call" is a bit of a misnomer. It was never intended to preclude interception by someone who wants to listen, but only to minimize intrusion upon those who do not.

[Ranger522]

Sorry, you are correct, a conventional system.

I was afraid that would be the answer, and that is why I have told all subscribers to consider this a call alert feature rather than a private call.

It works really well on the portables, so I had hoped there was a way to set the mobiles to default to the correct setting, oh well......

Thanks for the response

[tvsjr]

This may be simplistic, but do your field units have a use for Monitor? If not, just reprogram the subscribers to disable the monitor functionality... I know you don't want to hear the words reprogram with that many subscriber units, but it would solve your problem.

And, yes, private call is a misnomer, as already pointed out. If you need privacy, run crypto.

[Ranger522]

I did think of that. Stupid question, but will the radio default to MON off if the control head button is disabled.

The only use for MON has been to set the squelch level for analog channels in the radio. I have not found any way to set a default in the CPS. (3-4 seems to solve many interference problems.)

Thanks for the suggestion, it may work.

[Dale Earnhardt]

just reprogram that button for blank and it should not default to MON at all.

[Ranger522]

Thanks, it seems the brains are together; does anyone have any ideas about a "poor man's" simulcast?

Multicast ASTRO, 13 alternating Tx Quantars (A site, B site). Actually 26, for two parallel channels. Users must alternate the Rx channel as they travel though the area. With ASTRO, many are forgetting to change channels as they never "hear" the signal degrading, it just goes away.

Yes, I know, why not simulcast? Money, though after spending several million on this system, how much more could it be? Maybe an option later.

I do have to reprogram all 250-300 radios one final time, so I need to work all the bugs out now.

I have tried auto scan, priority 1, priority 2, but it always hangs on the priority 1, even though there is not enough signal to understand the traffic.

Thought about RSSI, but I have the need to scan other agencies, but never miss traffic on the primary channel.

Any ideas or more discussion for a simple solution? This is a serious problem for my agency, and they look to me for answers!

[Jason]

Since a Selective Call in astro conventional mode isnt truly a "private call" as in a trunked environment, you'll have to get creative on how to keep those conversations "private", as we all did in the community repeater days. Of course as I'm sure you know, there is no foolproof way, as a user could just get a scanner of his/her own, etc.

Programming the Monitor key as blank or unprogrammed button will be the best workaround, as tvsjr suggested.

I would also make sure "Disable PL on mic off hook" is also disabled, as this could be used to also monitor the sel call traffic. You may also want to experiment with Smart PTT (fancy name for busy channel lockout) to Keep users from keying up on a sell call in progress. My experince with the Smart PTT feature it isnt that great.

[mr.syntrx]

Can you use Conventional Voting Scan in ASTRO?

[Ranger522]

Thanks, Jason, and yes, I do understand that it will always be possible to get around in some way, but my goal is to make it as fool proof as possible for the, how do you say, less technologically savvy, personnel. If someone is smart enough to listen in, that is OK, because they will also know how to turn it off again. But monitor will be hard to get all of users to turn off, and keep off.
I have already had to build an extensive power point training program on radio usage, controls and functionality.

And again, yes, I disabled the "HUB defeats PL" and also set up the smart PTT with quick key override. Works great for my users, who before would key up three and four at a time, prompting an aggravated dispatcher to respond, "Multiple units at once", several times a day.

As it has been said before, you can learn more, and discuss more here than with M, even in Schaumburg where they could not answer any of my questions during our equipment staging.

[MattSR]

Can you use Conventional Voting Scan in ASTRO?

Of course - NSWPS have been doing it for years...

[Karl NVW]

Implemented for Stste of Kentucky back in 1999. UHF ASTRO conventional, common channels with tight re-use pattern and some channels at adjacent sites are +/- 12.5 kHz away. It's the same concept as your design, but covering the entire state, not just a linear service area. It works as designed.

The problem you are experiencing when NOT using CVS is that the radio detects activity on the priority carrier frequency and stops. Because that channel is set as priority 1, the scan will not release until the carrier goes away. The same thing would happen in analog with two different receive PLs on the same RF channel set as P1 in the scan list..

Also, note that Motorola named the finction Private CALL, not Private Conversation. The call is sent to a unique NAC, not to the fleet NAC. The conversations can be eavesdropped, and they also can be heard on a P25 scanner.

[mastr]

Implemented for Stste of Kentucky back in 1999..... It's the same concept as your design, but covering the entire state, not just a linear service area. It works as designed.

The KSP system is for all practical purposes 16 discrete systems. Each offers regional coverage to mobiles within a given area, so it is not a single "statewide" system. "It works as designed" is an accurate statement, however whether this is would be a positive or negative remark is open to interpretation.