MT1000 Scanning problems need help

[pcnet1]

Have a 16 channel MT-1000, trying to scan 7 channels that have tone
codes set. Have tried priority PL Scan, and priority scan, as well as
non priority PL scan and set channel two as fixed priority but am still
getting trash coming in on radio when in scan. This happens at lots of
locations, the only way I can get rid of most of it to scan is to take
scan squelch up to 14 or 15, this is hurting my receive sensitivity.
There got to be somewhere where you can tell a channel not to open
without a tone correct tone code.

Have individual channels set up with
quik call II alert tone disabled
scan channel lockout disabled
signalling disabled

Can someone help with this problem, have to turn radio switch to tpl to
stop problem.

[RKG]

I believe (somewhere I have a book that might confirm this but can't find it) that the MT1000 firmware forces CSQ scan on the priority channel. Bear in mind that these were public safety radios and come from an era when co-channel activity on a public safety frequency was uncommon.

[pcnet1]

Am using R03.01 to program it, does new versions like 3.02 help, maybe updated software corrected some of the problem. What is kicking it off isn't other radios in the are, its floursent lights at convience stores and even my laser printer.

Might try programming with newer RSS if I had a copy.

[kb0nly]

The newer RSS won't make a difference. The 3.02 just addressed computer timing issues and a few minor fixes according to the readme with it.

If you set it to Priority PL or Non-Priority PL and set either a static Priority, or have the Priority follow the channel select it will observe PL for the Priority, at least mine did.

Your problem is nearby interference drowning the receiver, the only way to fix this is fix the items causing the noise, which in your case isn't a simple matter. All HT's are susceptible to noise of this type, setting the squelch ultra high is just making up for the increase in noise level from those devices.

I have an inkjet that when it carriage returns to the next line sends a quick "BLIP" on VHF. UHF doesn't have a problem in here, but with an HT on VHF nearby i can hear this "BLIP" "BLIP" "BLIP" when printing. I have done everything possible to eliminate it. Problem is its being radiated from the internals of the printer and the entire printer, as always these days, being plastic there just isn't much to do about it, unless i wanted to break out the tin foil and spray adhesive, LOL...

I did that to a Linksys router once, spay glue and tin foil on the inside of the case then ground the tin foil with small braid to the PC board ground and it cleaned it up, to the point that a radio can sit on top of it or next to it and never open squelch.

It's not your radio, it's the crap around you!

If nothing else the only fault of your radio is being too sensitive.

[pcnet1]

Where is the setting to set it to follow the channel knob, remember seeing it but damn if I can find it now.

[kb0nly]

It's on the scan list screen where you set Priority PL, etc.

Just disable the fixed priority and it will follow the currently selected channel as the priority.

[pcnet1]

Tried it and am listening it scans ok, no trash, but when it is receiving another channel and traffic is on priority it doesn't goto the priority channel. Get trash in Priority PL, but not in Non Priority PL.

Am I missing something or I might to have to live with it.

[kb0nly]

Hmm...

I had to fire up the programming laptop and RSS to check how i programmed mine the last time. Because i know that it would revert to the priority channel when active.

Channel Scan : Priority PL
User Scan Program: Enabled
Ficed Priority Channel: Disabled
Scan Hang Time: 03 sec

So when scanning it's not reverting to the priority channel when receiving traffic? Do you hear it checking the priority channel when receiving traffic on another channel? I know on mine i could hear the "chunk" in the audio when it checked the priority channel for traffic.

If you have it set to Non-Priority PL then Priority scan is disabled. This is like running CSQ scan without priority except it keeps the PL on channels that have it assigned.

[pcnet1]

Tried like this and the trash comes thru, can you look in the radio adjustment and tell me what your squelch settings are set at. 3 adjustments.

Thanks

[kb0nly]

Carrier Squelch: 08
Tone Squelch: 08
Scan Squelch: 12

I'm guessing that your tone squelch is set too low.

[pcnet1]

That's what I had to do before was take scan squelch up to 14 to keep the trash out, but this does cut down on sensitivity when in scan. It must be as they say in scan the priority channel is CSQ, not PL. Guess that why my in car video system set it off on traffic stops and its 2.4 GHz.

Thanks for trying to help, guess these might be get sold and replaced with HT-1000.

[kb0nly]

Weird, i have never had this problem with it dropping PL on the priority channel while scanning. What was your Tone Squelch set too? You might want to try backing off the Scan Squelch and increase the Tone Squelch instead.

Or, if for some reason it truly is going into CSQ on the priority then back off the scan squelch and increase the carrier squelch.

If all else fails and you sell them let me know, i got some local FD's and PD's that keep asking me to find more used MT1000's. I have been paying about $40-50 each on average to get em off ebay to clean up, refurb, and resell to them.

[wa2zdy]

It has also been my experience that while in scan mode, it monitors the priority in CSQ. I've read somewhere that is how it was designed. Why yours doesn't do that is a good question and one I'm sure many folks wish they had the answer to.

I suspect pcnet's radio is going to continue as it is. Perhaps you can learn to live without the scan function, or as you suggest, perhaps it's time to update to a Jedi. They don't have this scan squelch issue.

[kb0nly]

I'm almost positive that my one 16ch radio i had kept the PL on the priority channel, but i have since sold that radio and can't check!

I've since sold all my MT's and moved to Saber's. Still working on, and buying and selling MT's just not using them myself now.

[wa2zdy]

16 and 99 ch, all the same with this one.

[Lake Effect]

Here in W. Michigan we have about 250 MT1000 radios still in use and I agree with wa2zdy. The described problem of carrier squelch on the priority channel is how all of them here operate. I've never found a way around it.

[kb0nly]

Now that i think about it, i don't think it was my MT1000, i think it was my HT600E that kept the PL on the priority during scan. Anyone else have a HT600E that can try to verify this? I sold my last HT600E.

[RKG]

The reason why the MT1000 scans the priority channel in CSQ has to do with the time required to determine whether or not PL is valid. This runs between 155 msec and 250 msec., versus about 20-25 msec. to determine that freq is valid. When the radio stops on a non-priority channel, it pauses (but with audio still squelched) while it checks tone.

If you did the same thing with the priority channel and there was co-channel activity, essentially that would shut down the scan altogether. So the engineers' solution was CSQ detect on the priority channel while in scan mode.

When the Spectra came about, they "improved" on this: the priority channel would not open audio absent valid tone, but it would stay parked on the priority channel until the co-channel activity ceased and freq dropped.

Neither was a very good solution, but remember: these were intended to be public safety radios, and in their era, co-channel activity on a public safety channel was the exception to the rule.

Later, Motorola came up with "channel marking." This feature scans the non-priority channels in PL. If freq is detected on the priority channel, the radio parks there and tests tone. If tone is invalid, the CM flag is set to true, the radio drops the channel, and resumes scan. The next time it checks the priority channel, it will test for freq only, and if valid, it will assume it is still the co-channel, and resume scan without opening audio. Once the test comes back no freq on the priority channel, the CM flag is reset to false, and normal operation resumes.

This is the best that anyone has come up with so far, but it has one hole. If the co-channel starts and the CM flag is set true, and then if your own dispatch comes up with a much stronger signal before the CM flag has been reset, the radio won't open up on your priority channel.

The only way around this would be to test for tone on every freq detect. This would reduce the scan rate to about 4 ch/sec, even when the radio was quiet, and this is considered unacceptably slow.

Neither the FCC nor the coordinating agencies seem to care about co-channel operation on public safety channels any more. The fact of the matter is that two or more public safety agencies can share a channel without any problems, given sufficient geographic spacing and the capture effect -- so long as they don't scan. Once you introduce scanning, problems surface.

Not to beat anyone's drum, but this is one of the nice things about SmartNet trunking. Scanning is now a data-driven factor, versus a sampling-based factor, and it works with far fewer errors.

[wa2zdy]

When the Spectra came about, they "improved" on this: the priority channel would not open audio absent valid tone, but it would stay parked on the priority channel until the co-channel activity ceased and freq dropped.

The Syntor X handles the priority channel the same way. It is indeed annoying. But thanks for the info, I can understand now why it works as it does.

[pcnet1]

Has anyone tried going in with a HEX editor and change the saved file to make it use PL like Non-priority PL does, but with Priority. You would think you could change your saved file somehow?

[likimkim]

Hello there,
Could yours tell me that which RSS is used to programme HT600e?
Thanks~~~

73`

VR2WTF

[pcnet1]

600e uses the MT1000 software, unless if is low band, see batlabs web page on model specific, and it will explain.

[wa2zdy]

Has anyone tried going in with a HEX editor and change the saved file to make it use PL like Non-priority PL does, but with Priority. You would think you could change your saved file somehow?

I'd worry about a corrupt codeplug error with this idea.

[Metradio]

Hello there,
Could yours tell me that which RSS is used to programme HT600e?

There is an HT600E specific RSS but it is a cut down version of the MT1000 RSS, it is designed to be run on a floppy and has no signalling options.. As has been said the MT1000 RSS will do everything you want..

[likimkim]

Thanks pcnet1 and Metradio.