MDC Question...

central150 · Post by **central150** » Fri Jul 08, 2005 7:22 pm

While listening to Springfield, MA PD, (460.100) I am hearing some of their units key up, start talking, then about 2 seconds into their transmit, their mdc burst goes through. It's like..."CP21, I'll be (MDC) out with..." It's not pre, it's not post, it's in the middle of the transmission. And I am noticing more units doing this... Are these non-M radios, or something else...

Tony

jim · Post by **jim** » Fri Jul 08, 2005 7:56 pm

It sounds like what they do around here: not holding the PTT button in tightly and it keeps re-keying.

central150 · Post by **central150** » Fri Jul 08, 2005 8:21 pm

No, it's not that... Thats what I thought at first...

Post by Pj » Fri Jul 08, 2005 8:50 pm

Knowing those guys, I would say someone is screwing around more than anything...especially with the zillion of recievers that have in the city.

central150 · Post by **central150** » Sat Jul 09, 2005 6:36 am

I'm gonna have to try and make a recording of it..

DPL · Post by **DPL** » Sat Jul 09, 2005 5:53 pm

I have heard the same thing, just with a different ANI format (don't even know what it is). It goes off right in the middle of what somebody is saying, seemingly at random times...

central150 · Post by **central150** » Sat Jul 09, 2005 6:01 pm

Yeah, it's kinda different.

jmr3865 · Post by **jmr3865** » Sat Jul 09, 2005 8:31 pm

i know my pd system which is repeated has a beep beep sometimes in the middle of your listening csq. could that be it? sounds like morse code.

JOHN 1807 · Post by **JOHN 1807** » Sat Jul 09, 2005 10:19 pm

Not being familiar with the system (repeated?) Is it possible that another unit is (intentionaly - or not) keying up over another in the middle of a transmission?

wa2zdy · Post by **wa2zdy** » Sun Jul 10, 2005 1:56 am

jmr3865 wrote:i know my pd system which is repeated has a beep beep sometimes in the middle of your listening csq. could that be it? sounds like morse code.

Or it could in fact be morse code - the repeater identying. Usually the IDer waits until there is no activity but not all.

nmfire10 · Post by **nmfire10** » Sun Jul 10, 2005 4:37 am

My bet is on the radio's post-ID and the user is letting go of the PTT for a microsecond. There is a distinct difference between a repeater morse call sign ID and an MDC burst.

muggsy09 · Post by **muggsy09** » Sun Jul 10, 2005 3:26 pm

I'm headed to Springfield this week to go to Smith and Wesson I'll have to throw them in the scanner and see what I hear, because that just doesn't make sense. MDC is post or pre or both no middle of transmission. Unless its a user issue that some folks said.

<baffled>

Post by Pj » Sun Jul 10, 2005 6:05 pm

Before I moved out of the area (6 months ago), Springfield PD is 99.99999999% pre-PTT. There is of course the possibiliy that a few are post-PTT.

There are a couple of guys at the local radio shop who are diehard post-PTT people and will program them to post-PTT unless directed otherwise. I don't know what their deal is.

central150 · Post by **central150** » Sun Jul 10, 2005 9:01 pm

It's definetley an MDC burst. No one is keying up during their transmissions. Could it be that they are using say another brand of portable or mobile radio, Kenwood, with some kind of MDC add on? I know their motorcycle units use Kenwoods, not Moto's.

-Tony

Post by **wavetar** » Mon Jul 11, 2005 4:47 am

I know you can set the MDC 'pre-time' for up to 4.5 seconds in radios such as the HT/CDM series. I've never tried it, so I'm not clear on whether the mic audio is muted during this time, but if it isn't perhaps the radios are just improperly programmed.

Todd

nmfire10 · Post by **nmfire10** » Mon Jul 11, 2005 4:57 am

I've never tried programming a pre-id without a sidetone so I'm not sure if the mic is muted without it. This goes for /\/\ and kenwood. I suppose that could do it if there is no sidetone and the user starts talking.