CM300

jwussler · Post by **jwussler** » Tue Jan 02, 2007 11:58 pm

I have a cm300 VHF i cannot seam to get the MDC-1200 to decode on the display. Once in a blue mood one will decode. Dose anyone have any ideas.

Joe

bundy125 · Post by **bundy125** » Wed Jan 03, 2007 12:40 am

I'm still kinda new at the CM300 but I'll try to give you a hand. In the CPS go to conventional personalities and check each of them ( if you want to decode on all) to see if you have the Signalling System set up for MDC SYS 1 ( or whichever MDC SYS you have programmed in). If I'm not mistaken, this will allow you to decode MDC 1200 calls.

Now another thought comes to mind. If not all the radios on the frequency you are monitoring are set up to transmit MDC1200, there will be nothing to decode.

Hope this helps,

Bundy125

ve3nsv · Post by **ve3nsv** » Wed Jan 03, 2007 7:48 pm

I think your problem is you need to be in expert view (at the top choose view then expert) and then you have to set your MDC system for TX and RX in the channel personality window WAY down at the bottom of the screen. That is assuming you have already set up the MDC parameters properly.

HLA · Post by **HLA** » Wed Jan 03, 2007 8:03 pm

i've seen that problem before and what the problem ended up being is that somebody got into the mdc parameters of the 1250 portables and changed the timing length of the mdc burst and they slowed it down so it sounds cool to them but what it did is make it so other radios couldn't understand it and display it. i don't know if this is your problem too but that's what i've ran across.

jwussler · Post by **jwussler** » Thu Jan 04, 2007 12:25 pm

What should be the default seting for the time in the MDC

Post by **wavetar** » Thu Jan 04, 2007 1:00 pm

Default "pretime" (the time the radio waits upon PTT before sending the MDC packet) generally varies between 350-500ms in most Motorola radios. This should be adequate in most situations. In simplex modes, I've gone down as far as 125ms with no issues. If you are using a repeater, this time may need to be extended in order for the MDC to pass properly, and will depend on repeater make & model.

Todd

jwussler · Post by **jwussler** » Thu Jan 04, 2007 2:49 pm

Oh when i posted the original post i should have said it is set on post PTT

Post by **wavetar** » Thu Jan 04, 2007 3:09 pm

jwussler wrote:Oh when i posted the original post i should have said it is set on post PTT

Your radio is, but how about the other radios in the system? What model(s) are they? Also, are you going through a repeater?

Todd

jwussler · Post by **jwussler** » Thu Jan 04, 2007 3:30 pm

The other radios are a mixture of xts3000 ht1250 going through a repeater for ID of the unit and it will decode on the 1250. All set for Post PTT

Post by **wavetar** » Fri Jan 05, 2007 5:05 am

jwussler wrote:The other radios are a mixture of xts3000 ht1250 going through a repeater for ID of the unit and it will decode on the 1250. All set for Post PTT

Ok, so first thing to check is to see if it can decode properly in simplex mode. If it can, then it's obvious something is happening to the MDC through the repeater, which the HT1250 doesn't mind, but the CM300 does. I don't see any CPS settings which would affect post MDC decoding, off-hand.

Todd

radio-link · Post by **radio-link** » Sat Jan 06, 2007 9:44 am

wavetar wrote:I don't see any CPS settings which would affect post MDC decoding, off-hand.

Todd

Channel bandwidth? Just an idea...having it set wrong may keep voice comms OK, but signalling could go wrong.