Batboard

Today I ran into a VHF MSR2000 that will not work when a p.l. tone is present but does work when no tone is present. It has been working fine for years on carrier squelch. I put in a p.l. tone in a mobile in anticipation of the arrival of a new base which will have tone decoding. This tone seems to have given the MSR indigestion. I realized afterwards of course that I could have monitored the received audio on the UHF link connected to the MSR. Don't have physical access to the MSR.
Can someone explain?

Maybe the vibrasponder tone reed is bad in the pl card ?? I am far from an expert, but i'd try a different tone element.

No flames fo rthe use of "tone element" "tone reed" "vibrasponder" I know theres a difference but bascially the same thing

Matt N3IVK

MSR (Micor Simply Repackaged) Make sure the reed is in the RX side- the board has both a TX & RX socket. There are jumpers in the repeater that may not be correct - a common problem with the MSR & Micor, whether on the mother board or on the cards.

That should read "Mitrek simply repackaged", basically a Mitrek.
YES there are several jumpers that have to be installed or removed in the PL / Audio board.
Sounds like the PL from the mobile is "Choking" the audio in the repeater, because the PL tone is still in the receive audio/ transmit audio path. Adding the PL enc. dec. also puts a "suck out" filter to remove the PL tone from the audio path in the audio board.

Will's explanation makes sense. I did not know about the "suckout" filter. Others have called it a tone stripping filter. When I do finally get access, I will inventory the cards and report what I find.
I had better order the manual too.
Thanks for all the help.

My two bits worth:
I think Will has it exactly right.
I would guess that the link is wired directly to the audio bus in the MSR.
With no High Pass filter the pl would be heard on the link.
this tone would likely conflict with the existing linl PL tone.

The MSR came out in the mid 80's as a low cost alternative to the MSF5000. The MSF was not available in low, or VHF band in the "Analog" version.
The case as well as the 13V power supply are similar to the MSF, the power amps came from the high power Syntor, the exciter, and receiver came from the Mitrek mobile.

The control cards are similar to Micor. the pins are different

When you get access to the site, you should make very detailed diagrams
of everything on the site.
Not only your customers's system. Everything has the potential to
interfere with anything else on a site.
Once you understand how everything is presently wired, then future modifications are easy.

You never made it really clear, that if you key up the repeater with a PL, the repeater just stays dead or that it did repeat, but without a PL as possibly could be expected. It depends on the configuration as mentioned several places above, if it can pass an incoming PL. But you would expect that the repeater would at least key up and pass the voice audio.

The followings is strictly guessing by me, but I believe some tone panels will do CSQ and PL at the same time. If that is the case, CSQ would always work, but some PL’s may or may not work depending on the tone panel’s programming. If the above applies because there is a tone panel present, you may just not be using a programmed tone.

Just to add another possiblity to the mix.

The Railroads bought a lot MSR2000 Stations.

Some of them were modified by Motorola to have "Anti-PL."
That is the station was CSQ but it wouldn't repeat when PL was decoded.

The reason: They wanted there system to be CSQ but didn't want the co-channel user with PL to access there repeaters.

DOug Eaton
Douglas Technologies
http://www.dougtech.com

Nand, what I was trying to say (but evidently failing) is that the base was repeating garbled audio judging by comments from Dispatch. I had to remove the pl tone from the mobile I installed, to restore the repeated audio quality. I had assumed that the MSR would ignore the unwanted tone but such is not the case. I have been informed that I have to add a PL board to the MSR and move some jumpers.
I would assume most modern repeaters would filter out the unwanted tone since they all seem to have tone decoders now?

My two bits worth:
The MSR is a crystal controlled radio, All of the various functions such as audio processing, and various code formats, are performed by various modules.
There is not a microprocessor in a truck load.
The audio filter has to be located some where, and in this case it is housed on the PL encoder/decoder module.
These parts cost money, and there is no point in installing parts with no function in a carrier squelch station.
The MSF, and various microprossor controlled modern subscriber units have the audio filtering included on the main PC board.
The supervisory and encoding/decoding functions carried out by the micropressor.
So, it is a matter of the current technology of your equipment.
Incedently, no earlier base, such as the tube compa, Motrac, Micor, Mocom 70, or Mitrek have PL filtering in the audio path.

Because we don't exactly know how this remote base is connected to the link tranceiver, nor what kind of signalling, if any is on the link, I need to guess how the link is configured.

I presume that the problem was caused by un filtered audio entering the link audio input. Perhaps the pl tone from the subscriber unit effected the link in some way as to cause audio drop outs.
I guess that the tone is causing the pl decoder to drop out on the control
station receiver.
Fortunately, turning the PL tone on the subscriber unit off cures the problem.