How Do You Silence That Annoying MDC Squawk?

[4n6inv]

I've been told "Too bad!" about trying to silence the annoying SQUAWK that MDC emanates at the end of a radio transmission. It drives me batty! Everyone else out here is Astro Conventional for signalling, but the city? Oh, no! Squawk! Is there any setting in the codeplug (Surely there must be!) that I'm missing to silence this horrible scourage on public safety radio? I mean, Hey! I love affiliating the names in my MDC call list; but the noise is other-worldly.

Thanks!

Jim

[The Pager Geek]

Data Operated Squelch

What type / model radio are you using?

tpg

[jackhackett]

Does DOS muting work with end-of-transmission MDC?

[4n6inv]

The city PD uses Relm mobiles and Motorola XTS5000 portables in analog. Digital refusniks. FD uses all Motorola XTL2500's and XTS5000's and 2500's. FD will switch to digital soon, but PD won't have any part of it. SO is totally digital and use OFB encryption 50-60% of the time. They are top-notch!

I'm using an Astro Spectra W-3 in my vehicle, and an XTS5000 MIII handheld.

I've seen the DOS screen in my programming software, but never had any idea it had anything to do with MDC. They are using end of tx burst - simply for the fact that they are such idiots; they need the tone to "know" when the other party has de-keyed. I'd have it at the beginning, so you wouldn't need to wait until the end to tx to see who was talking when it affiliates with your MDC call list. It's not like we have a lot going on out here... that's why it's so annoying!

[jackhackett]

From the Astro portable software help on DOS:

DOS causes the radio to automatically mute when receiving MDC Signaling data. This helps to reduce unwanted noise.
DOS applies primary to Leading PTT ID voice calls and not Trailing PTT ID.

I rarely deal with trailing IDs, so I can't say I've ever taken notice of what DOS would actually do with one.

[4n6inv]

Well; it's worth a shot... I'll give it a try and let you know what the results are. I've got to read up on DOS, first. Like I said; I've seen the DOS tab, but never paid any attention to it. Stupid me; probably thought it had something to do with converting old DOS - based codeplugs to CPS based cones...

[4n6inv]

OK; so here's the poop... It's better, but still a PITA. I know that sounds odd, but it's down to a short "Chirp" at the end of the transmission. Why on Earth, Motorola decided it would be a good idea to add a distinctive squawk - or even a chirp - at the beginning, or end of radio traffic for public safety, is beyond me. OK; imagine you're a criminal and you're doing what criminals do... Most; of course, do their doings in quiet surroundings (ie: middle of the night in a deserted building), so ANY sound is going to alert them. But; suppose you're forced to commit your crime where there are people around - say - in a exhibit hall ful of people. It would be hard to distinguish regular voice radio traffic from other sounds around you. But; add that distinctive tone - that everyone pretty much everyone knows, and you know that the police are there. That gives you a "head start" on covering up what you're doing - or gives you a little bit of a lead on running away from the Po-Po's. Not every cop wears an earphone, and they become quite cumbersome when they're yanked out of your ear in the middle of a scuffle. Which is a whole 'nuther problem...

Thanks for the help, and any further suggestions would be greatly appreciated!

Jim

[4n6inv]

OK; I guess I spoke too soon. Evidently; it was only "Chirping" on a few of the transmissions. It's still giving a full squawk on the others. I should have waited for a little more radio traffic before I commented... But; it's Monday morning, and slow here - so ANY traffic was worth noting - so I thought...

[jackhackett]

Trailing IDs are generally a bad idea, not only do you get this problem, but suppose the department clown decides to play around on the radio, he can key up, make some rude noises or whatever, and then turn off his radio before unkeying and dispatch won't get his ID.

[wavetar]

OK; so here's the poop... It's better, but still a PITA. I know that sounds odd, but it's down to a short "Chirp" at the end of the transmission. Why on Earth, Motorola decided it would be a good idea to add a distinctive squawk - or even a chirp - at the beginning, or end of radio traffic for public safety, is beyond me.
Jim

It's not by design...you're virtually always going to hear a short chirp when using post-MDC. The reason is the receiving radio has no idea when the transmitting radio is going to release it's PTT and send that annoying MDC squawk...so, it has to wait until it sees the very beginning of the MDC data word...then mute the speaker. The 'chirp' you're hearing is the very beginning of the MDC data. The timer you want to adjust is the "DOS Coast Timer"...the lower the setting the quicker the annoying squawk will mute. I believe the lowest setting is 25ms.

[HLA]

most of the departments i work with like it at the end then they know that person is done transmitting. but everyone has a different opinion. if it's set for pre and post it will give a repeater time to fully activate before you start speaking too. plus like mentioned earlier, it keeps the rude comments down.

[4n6inv]

I checked the "DOS Coast Time" and the lowest setting(s) are "0" or 4.45 ms. I'm currently set on "0" - only becuase the help field came with a strong warning not to adjust the field unless you are totally familiar with the system that the radio is operating on. Weird times listed BTW... No 25 listed. It goes between 22.25 and 26.7. Is a lower number better? What do you think of the 4.45 ms setting?

[judoka]

Given that the MDC ID is one-shot (not repeated through the voice like Astro/P25), there is some merit in trailing ID because you are more likely to miss the start of transmission if there is some repeater squelch delay on CTCSS detect. (There is also merit in Leading and Trailing ID for maximum reliability of ID signalling).
I can see why trailing ID is harder to mute though.

[escomm]

EOT MDC1200 squawks are known as the "Rich Man's Roger Beep"

[4n6inv]

Not what I was hoping to hear, but; it's pretty much what I'd already suspected... Escomm- that's a good one. Only out here; it's a moron's "Roger Beep". Something must have happened long ago in the past in one of these souls lives that made them do it that way. I understand the logic - both ways; but, it's just damn annoying. And, when the ONLY logic behind it is: "So we don't start talkin' until the other feller's done..." - you can only shake your head and wonder "Why?"

[Jason]

Why on Earth, Motorola decided it would be a good idea to add a distinctive squawk - or even a chirp - at the beginning, or end of radio traffic for public safety, is beyond me. OK; imagine you're a criminal and you're doing what criminals do... Most; of course, do their doings in quiet surroundings (ie: middle of the night in a deserted building), so ANY sound is going to alert them. Jim

Well, motorola's engineers created Stat-Alert over 20 years ago, to give much needed features to conventional channels. It's not perfect, but it is widely used in public safety, and with the proper RSS and CPS settings on your subscribers, it is possible to completely eliminate the sound from your radio totally if it is deployed properly. (you wont mute MDC on a relm mobile, however )

I think you'll find the benefits outweigh the drawbacks, but if it is a danger in your application, remove the signalling. If XTS5000's are deployed and the MDC signalling is annoying your users, find someone who knows how to setup the radios properly.

[4n6inv]

Ironically; last night, we had a slew of tornados whirl through here. That meant that everyone went to analog! (Everyone has an analog and a digital channel for each frequency pair with mixed mode rx) The reasoning was so the hams could talk on the "digital" channels if need be. It was like my worst Hell, ever! It freaked me out completely, because they gave the "Everyone switch to analog" command while I was walking to my car. So when I got in; I was hearing the MDC squawk even on the digital channels. I thought I was living in some alternate universe for a few minutes! I'll wake up screaming for a week after that scare.

[motorola_otaku]

Ironically; last night, we had a slew of tornados whirl through here. That meant that everyone went to analog! (Everyone has an analog and a digital channel for each frequency pair with mixed mode rx) The reasoning was so the hams could talk on the "digital" channels if need be. It was like my worst Hell, ever! It freaked me out completely, because they gave the "Everyone switch to analog" command while I was walking to my car. So when I got in; I was hearing the MDC squawk even on the digital channels. I thought I was living in some alternate universe for a few minutes! I'll wake up screaming for a week after that scare.

Tch, you think you have it bad? From the mid-late 1980s up until 2003 Houston FD used MDC Status messaging on all of their voice channels. Unless you were MDC DOS-capable, every 2-5 seconds or so you'd hear SQUAWK...SQUAWK.....SQUAWK..SQUAWK.

As for pre/post IDing, I like to use post ID on base stations and pre ID on portables and mobiles but that's more personal preference than anything.

[Thomas]

(you wont mute MDC on a relm mobile, however )

Pre-MDC burst can be muted completely on a relm rm-800u. The post burst is another story.

[4n6inv]

If you live in Houston; you've already lost a bet with God, somewhere... They have some seriously funky radios there. You're right - I would lose my mind if I had to listen to that. That alone, should have been a catalyst enough for Motorola to find some other way to do the signaling - or quieting.

I remember the MDC600 back in the 70's and 80's in and around Atlanta. Of course I was still a weenie back then, so the noisier; the better. As you get older - or you're forced to listen to it - it's not as much fun...

Thanks for the replies, everyone. It's a little better the way it is now, but ideally; it wouldn't sound like a :o fight whenever you have a rapidly developing situation - which isn't too often out here, but annoying when you do.

The PD is not going to change. At least; not until they're forced to. I almost have the FD switched completely to P-25 - they're just nervous about it. All of the hardware is in place and programmed - I just have to convince them to change zones and give it a try.

[motorola_otaku]

If you live in Houston; you've already lost a bet with God, somewhere... They have some seriously funky radios there.

HA!! New sig quote get!

If by "funky radios" you mean 20-year old Sabers and crippled Astros on the PD side and XTS3500s on the FD side, then yes, we do have some funky radios. Fear not, however; the City drank the Kool-Aid and dropped $135m on a 700 Astro25 system, with final system acceptance slated for 2013 on the latest timetable.

[escomm]

I just have to convince them to change zones and give it a try.

Yeah, have them try it on the fireground so they really know how great P25 is. Especially the guys wearing SCBAs......

[linkinpark9812]

Well, My Scanner (Pro-164 from Radio Shack) doesn't mute it.

My Portable VHF Radio (Chinese Made) doesn't mute it.

But my Motorola High Power Spectra, IMO, does a hell of a job muting the POST-MDC. I have also heard my departments portables when standing next to an officer. Theirs mutes the POST-MDC just about as good as the Spectras. (I think the Portables they use are HT-1250, but not 100% sure).

I would say 70 % of the stuff in my area is POST-MDC, while the rest is PRE-MDC or none.

Here is a sample of my Local PD that uses POST-MDC:

http://www.sendspace.com/file/5ovlq4

What do you think? That doesn't annoy me, I like it MUCH better than the whole squawk!

[4n6inv]

escomm,

I got them (FD) switched over to 100% Digital and they love it. They have analog only XTS3000R's for the SCBA units operating on sx fireground. Everything seems to be going quite well. But; I'm an EVIL man to all of the townspeople and "hamsters". And, yes; I'm a "hamster", too. I just happen to have scads of Motorola equipment that allows me to listen. You can buy a used P-25 portable on eBay for less than a decent Uniden scanner, these days. The SO and FD don't even care if I program them for people that I know, or they know, for that matter. As long as I don't load the SO's secure keys in them, they could care less. Whatever it takes to give our guys the best coverage, reliability, and compatibility; I'm going to push it through for them. Let the Refusniks get mad...

Jim

[tcash158]

Is there a way to still have the features of the mdc signaling or number indentifiers on the cdm and ht seris radios and silence it in the programming?

[jclendenen158]

Is there a way to still have the features of the mdc signaling or number indentifiers on the cdm and ht seris radios and silence it in the programming?

I don't believe you can completely silence it, but you can get it down to a much less annoying chirp.

In order to do this, you must have MDC set as your receive system on the personalities where you want it to be silenced.

Once that is set, the Data Operated Squelch (DOS) should mute the radio as soon as MDC is detected.