Multiple PLs on voted receive link

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HumHead
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Multiple PLs on voted receive link

Post by HumHead »

OK- For the moment ignoring all of the issues with radio versus landline links, here is my question:

We are thinking of adding a second voted receive site to a repeater. The challenge is that the repeater currently supports several PL tones on the input, so I would probably need to pass PL data through the link.

The first solution that comes to mind would be running the remote receive CSQ, and passing any received tone along.

Unfortunately, I would bet that if the voter sees a strong signal from a non-affiliated co-channel user on one site, and a weaker signal from one of our users on the other site it will vote for the stronger signal and lock our user out, since it has no way of validating the respective PLs.

The other possibility that comes to mind is a seperate receiver for each valid PL (currently only three), but that seems like it could get expensive fast

Any suggestions for doing this over a radio link?

Thanks!!
RKG
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Post by RKG »

This is a recurring question. The notion of having the satellite unsquelch on CSQ and then doing the tone controlling locally to th repeater tends not to work because the low frequency PLs will not pass reliably over phone lines, and if the link from the receiver to the repeater is RF, you'd have to pass the PLs through three sets of analog circuits. Unlikely to work.

I'm told there is a device that will decode PL (or DPL) at a satellite receiver, encode its value in to a short FSK burst, and then pass it along to a termination panel on the repeater end, where the specified PL or DPL is then regenerated for use by the repeater controller -- designed exactly for this situation. 56X can you help us out with the specs?
kurt meltzer
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Post by kurt meltzer »

Not sure what you are using as the sat rcvr, or if it's capable of scanning, but if it scans (or can be made to scan) - then you could program multiple personalities, each with same freq but different PLs. RX will unsquelch for any of your desired PLs but not distant co-channel users.
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xmo
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Post by xmo »

I am assuming that your reason for having multiple PLs is that you are using them so that several groups of users can share the repeater and not hear each others traffic; i.e. security doesn't want to hear maintenance chatter, etc.

If that is the case, the repeater is functionally like a community repeater and the real problem is not just getting a remote receiver to respond to more than one PL but getting the repeater transmitter to follow the input PL.

I have never seen a community repeater voting system or a comparator that was equipped to deal with multiple PLs.

I have tried to conjure up a vision of how I would solve this problem if it were assigned to me. In the old days I was one of those who thought if you had the right modules, enough time and a big bag of diodes, you could make a Micor do ANYTHING.

Perhaps you could use a Micor Spectra-Tac voting receiver for the link receiver. You would replace the coded squelch module with a Micor base multi PL decoder. One of these would also be installed in the main repeater control chassis. Then the outputs of the active PL from these decoders would be routed [as logic signals] to a custom card driven by the comparator voted site indication to pass the current PL selection on to the multi-PL encoder card in the Micor control shelf.

The remote receiver would be set up as a cross band multi-PL repeater so the link would carry the same PL as the main channel saw.

This would also work with MSR2000. Doing this with newer products - that might take some serious head scratching.
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HumHead
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Post by HumHead »

No, I just have to be different. :roll:

This is an MTR2000 with a Zetron Model38 (and some custom interfacing). We are running two tones in, one tone out, with a PL selectable link to a second channel.

Since someone will ask, if you TX with PL "A" you will go through the repeater , and come out with PL "A". If you TX PL "B", you will still come out of the repeater with PL "A", but the auxiliary relay on the Zetron is enabled for PL "B", and is used (again with some interfacing) to also key the link TX. We are not yet using the third tone pair, but are looking to implement it to allow MDC selective calling through the repeater without disturbing other units.

Sounds like we may be stuck here- give up the selectable linking, or give up the idea of a second RX site. :(
MOEtorola
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What radios do you own?: APX7000, All XTS and XTL

The possible fix.

Post by MOEtorola »

I have the same setup, and it works good. I am using a MTR2000,
CSI TP154+ with EX-8, and doug hall voter. My links are RF, they are maxtracs with zeatron model 38's on them. So you can probably already see how i did it. It takes alot of community repeater controllers, one on the main and one on each rf link. I also put a audio delay board on the TP-154 to keep the squelch crash down.

Brian O'Dell Tech/Eng N0ZSG
MOEtorola
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What radios do you own?: APX7000, All XTS and XTL

Forgot

Post by MOEtorola »

Even though you are using one PL tone out , i think it should work, correct me if im wrong. Also I run MDC-1200 through my system and it works great. One thing too mention, if you use MRTI (autopatch) on this set up, you may have to hold your access tone (*) a little longer to make up for the inherent system delays, not much you can do about the delays when your going through 2 community panels. my delay is approx. 300ms.
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