[XPR7550E] How do I program DOS correctly?

[ShawnClitso]

Hello, so I've been trying to mess around with my settings on my 7550 to get it to play the full MDC 'chirp'; however no matter what settings I use it cuts it off at around a 1/4th of the way through. I've tried setting the AMD to anything between 0 and 500ms with the same end result. Is there anything I am missing?

 

[Skypilot007]

I don't have CPS in from of me now but I think it's the DOS mute setting you need to adjust. It seems the default value at 500ms completely mutes the mdc data burst which is what its supposed to do. If memory serves me correct I believe I kept lowering the value from the 500ms default and the radio started making that chirp sound. This was on my 7550 and 5550 non-E version radios. Not sure if it makes a difference or not.

 

[chrismol1]

I believe there is that coast time setting and I think maybe the one below it Expert view to see all settings. 0ms no DOS muting, 500ms full muting and try 275ms for the well known half MDC chirp

 

[IFRIED91]

Hello, so I've been trying to mess around with my settings on my 7550 to get it to play the full MDC 'chirp'; however no matter what settings I use it cuts it off at around a 1/4th of the way through. I've tried setting the AMD to anything between 0 and 500ms with the same end result. Is there anything I am missing?

the xpr7000 series for some odd reason never DOS muted MDC1200 correctly the way it was intended. Do be warned.. messing with the coast time may cause falsing and/or packet clipping.

 

[APX8000]

While we are on the MDC topic, is there a way to change how long the alpha tag for the MDC identifier stays on the screen ? Mine stays until the carrier drops.

 

[IFRIED91]

While we are on the MDC topic, is there a way to change how long the alpha tag for the MDC identifier stays on the screen ? Mine stays until the carrier drops.

in regards to which CPS? APX or TRBO?

 

[APX8000]

Well lets see...what's the thread about....oh, an XPR7550e....guess which one ? Lol

 

[K2NEC]

Well lets see...what's the thread about....oh, an XPR7550e....guess which one ? Lol

I wasn't gonna say it....

 

[IFRIED91]

Well lets see...what's the thread about....oh, an XPR7550e....guess which one ? Lol

But your profile thumbnail and username say otherwise

 

[GTR8000]

But your profile thumbnail and username say otherwise

So by that logic, every post I make is about a GTR8000 repeater? Huh? 🤦‍♂️

 

[APX8000]

Huh ? Does your IFRIED name mean you can only post about partaking in the effects of marijuana use ?

 

[IFRIED91]

Huh ? Does your IFRIED name mean you can only post about partaking in the effects of marijuana use ?

That’s actually my first and last names combined

 

[chrismol1]

the xpr7000 series for some odd reason never DOS muted MDC1200 correctly the way it was intended. Do be warned.. messing with the coast time may cause falsing and/or packet clipping.

Yea I'd say I have an 80+% good MDC coast time chirp on the XPR7550e. I mean it will decode the MDC ID 100% of the time just not always with the chirp and this non-scan as scan will make it worse of course. Any older XTS/MTS/MT the coast time was 267ms was made perfect for that MDC chirp we all know. Now only 275ms closest on the xpr

 

[Stretchman]

If r ied?

 

[IFRIED91]

let me ask.. shouldn’t DOS completely mute out the entire MDC packet? Also anyone know when DOS muting was created? I assume (Probably wrong) it was developed after MDC1200 signaling first came out..

 

[mbnv992]

So, at least with the Astro Saber, every XTS radio I’ve ever used, MTS, and anything that does DOS MDC to mute the squelch, I’ve only come across 2 radios that actually completely fully muted the MDC noise ( a VHF Astro Saber 1R and a VHF Astro Spectra ). I double and tripped checked all the radios programmed and all the coast times are all set to 267ms.

I tried to increase / decrease the coast time and all this does is mute the noise for longer so you end up missing transmissions if you set it for too long. The cost time in (ms) has nothing to do with the actual muting of the MDC chirp noise itself, just how long the speaker remains muted after it senses the MDC noise ( if that makes any sense ).


It’s all up to each specific radio as to how much of the noise it lets through. It’s very rare that I ever ran into a radio that, once DOS is checked, that it fully mutes the MDC packet from coming through.

 

[IFRIED91]

so if you would set the coast time to zero it would still mute? That must mean coast time is made for muting mdc preambles QUOTE="mbnv992, post: 3682151, member: 212028"]
So, at least with the Astro Saber, every XTS radio I’ve ever used, MTS, and anything that does DOS MDC to mute the squelch, I’ve only come across 2 radios that actually completely fully muted the MDC noise ( a VHF Astro Saber 1R and a VHF Astro Spectra ). I double and tripped checked all the radios programmed and all the coast times are all set to 267ms.

I tried to increase / decrease the coast time and all this does is mute the noise for longer so you end up missing transmissions if you set it for too long. The cost time in (ms) has nothing to do with the actual muting of the MDC chirp noise itself, just how long the speaker remains muted after it senses the MDC noise ( if that makes any sense ).


It’s all up to each specific radio as to how much of the noise it lets through. It’s very rare that I ever ran into a radio that, once DOS is checked, that it fully mutes the MDC packet from coming through.
[/QUOTE]

 

[mbnv992]

So, if you set the coast time to “0” it’ll still mute but it will unmute super quick and a lot of times the tail end of the MDC squalk will still get through. It’s pretty annoying.


And if it’s set to anything over 500, you’ll start missing bits of transmissions. The sweet spot I think is in the mid / higher end of 200 milliseconds.

I had an mts2000 way back in the day I was missing transmissions because it was muting way too long after the MDC was cut off. Hooked it up to CPS only to find out that the coast time was over 1000 something. Turned it back down to 267ms and problem solved.

 

[APX8000]

Played with the settings....Leave DOS coast duration at 100 ms and change DOS Auto Mute Duration to 150 ms and let me know if you like that chirp sound. This is for MDC POST.