MDC Programming Question

[SnoForum173]

How do you shorten the MDC burst? I have an XTS5000 and I've heard other radios which had very short leading MDC bursts, its just like a short click. Right now my radio is giving out a longer MDC sound. I am using CPS Version 10, what should I do? Thanks

[HLA]

are you just trying to make is so you can't hear it? what kind of system are you using, simplex, repeater, digital, analog? if you shorten it up too much it may not get decoded on the other end.

[SnoForum173]

I have a couple of different systems which MDC will be used. The one that actually matters I will not shorten, but the others I would like to shorten. They are analogue repeat frequencies with leading MDC. How do you adjust the timing or what ever I need to adjust to get the desired shorted burst?

[jackhackett]

Do you mean the MDC signal that's being transmitted, or the sidetone that you hear through your speaker?

[SnoForum173]

The MDC 'chirp' being transmitted, not the side tone, I have the side tone turned off. Its not a big deal to me, I just thought there was a simple way to adjust the timing of the MDC chirp to make it shorter. Thanks for your help guys.

[RKG]

If I understand your query, there is no way to affect the length of an MDC 1200 PTT-ID string. The format and inter-digit timing are fixed in the MDC protocol, and if you could adjust them, you would make the MDC word unreadable. What you can adjust is the MDC pre-time, during which the radio sends a filler message to give repeaters, etc., time to key up. So far as I am aware, the rule of thumb "normal" pre-time is 500 ms; if you didn't care about readability on the other end, you could shorten than.

[escomm]

The MDC 'chirp' being transmitted, not the side tone, I have the side tone turned off. Its not a big deal to me, I just thought there was a simple way to adjust the timing of the MDC chirp to make it shorter. Thanks for your help guys.

The receiving radios will need to have DOS turned on in order to mute the MDC squawk, and not setting it to completely mute the entire squawk will result in as close as you'll get to the desired effect.

[HLA]

you can adjust the speed of the burst by changing the intersequence time down but it will affect the recieving radio and probablly won't decode it anymore. what you probablly want to do is adjust the dos muting on the recieve radios so they act quicker and cut off the signal faster so you won't hear it.

[W3MOT]

DOS mute to 0.5mS should work perfectly. Note that this has to be done on the RECEIVING radios (as stated previously).

[nmfire10]

He's talking about the length of the data burst, not the DOS muting on the receiving radios. Go the advanced tab of the MDC personality. Set the bitsync packets for 0.