MTS2000 Sawtoothing Receive Audio on Priority Scan

[jaypike]

Hello All,

I have a MTS 2000 VHF 48 channel (H01KDD9PW1BN s/w 06.58) that I swear to God is sawtoothing receive audio while in scan, as it checks the priority member.

I tested this using a real simple setup: 2 channels, and transmitted various tones on the non-priority channel.

At low volumes, the audio is fine, but as the audio level is increased, the sawtoothing becomes more and more pronounced. At near peak audio, the delay to full volume is 100ms - 150ms. At normal volume levels, the delay is right around 75ms - 100ms.

Some of the things I've tried or set:

* Rx Unmute Delay (ms): 0ms
* Unmute/Mute Type: Tried 'UnMute,Or Mute' and 'Standard'
* Squelch (Fine Tune): 0
* Carrier Detect Required: Disabled
* Priority Chan Marking: Disabled and Enabled (neither changed anything)
* Receive Audio Calibration: 203 (tried 128, but not enough volume)

I read in here that 'APF Volume Boost' might be another option to try, but I can't seem to find it in the RSS (06.07).

I've side-by-side compared this to a 160ch MT2000 and two MTX-838s that I have, and with the 2 channel setup, they work just fine at full audio with no saw-toothing.

Do I have a bad board? I just got this off eBay a couple of weeks ago from 'erac1' (who seems to be a very reputable seller).

Any help or suggestions would be greatly appreciated.

jp (AA8SS)
firefighter/emt
portage, mi

[MTS2000des]

Not sure what you mean by "sawtoothing" but any conventional radio will have a momentary dropout while it checks for activity on a priority channel. I believe the dwell time is selectable in CPS/tuner and that may be the problem. I have two MTS2K VHF's and use them both with the dual priority scan enabled and they work fine. Was the radio aligned properly? I have seen Jedi's with way off front end BPF's do weird things in scan but a full alignment made the issues disappear.

I am familiar with Erac1 he's pretty good and if there is something wrong with the radio he will take care of you.

[jaypike]

Not sure what you mean by "sawtoothing" but any conventional radio will have a momentary dropout while it checks for activity on a priority channel. I believe the dwell time is selectable in CPS/tuner and that may be the problem. I have two MTS2K VHF's and use them both with the dual priority scan enabled and they work fine. Was the radio aligned properly? I have seen Jedi's with way off front end BPF's do weird things in scan but a full alignment made the issues disappear.

"sawtoothing", I'm seeing something similar to the following type of graph where the X-axis is the volume and the Y-axis is time, and the dips are the priority channel seek every 500ms:

Time vs. Volume (on MT2K w/issue)

Code: Select all

*********     *****     *****     *****     *****     *****
*********    ******    ******    ******    ******    ******
*********   *******   *******   *******   *******   *******
*********   *******   *******   *******   *******   *******
*********  ********  ********  ********  ********  ********
*********  ********  ********  ********  ********  ********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********

Time vs. Volume (on a normal MT2K)

Code: Select all

********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********
********* ********* ********* ********* ********* *********

Dwell time seems about right, nice and short. I'm using the old archiac DOS RSS program to program the radio, and I don't have the tuner/CPS software. I didn't know you could adjust the dwell time, which makes me wonder if you can adjust the priority channel scan time too? 500ms seems to get a bit annoying.

I am familiar with Erac1 he's pretty good and if there is something wrong with the radio he will take care of you.

Good to hear. I might just end up shipping the radio back to him, I just wanted to make sure I wasn't doing something stupid in RSS with the radio before I pestered him. I'm still a Novice at this (even though I own about 45 Waris/Jedi/Radius portables).

jp

[jaypike]

An additional piece of information that I forgot to add: The issue becomes much more pronounced at higher volume levels.

For my test, for example, I muted the audio by placing my hand over the radios speaker (to keep myself from going deaf), and then turned the audio up to full volume. On the other MT2000 and MTS2000, doing the same thing with the hand and the volume up all the way, there is no issue with the audio. But, on this one MTS2K, it is still noticable.

I first noticed this issue while using the radio in my duties as a firefighter. While in scan mode, listening to dispatchers on other frequencies results in missing critical parts of their communications as nearly 120ms+ of audio is 'ducted' rather than just interrupted.

jp