[App_rpt-users] Motorola MSF / Voting / Receivers;

Sat May 9 17:22:40 UTC 2015

Thank you again, Jeff and Chuck as well. I appreciate your answers and will only wait in hopes of hearing from someone that has interfaced a CDM 750 as a 2nd receiver on the Motorola MSF 5000. The MSF IS DESIGNED for a 2nd receiver and has an additional connector for plugging one in. But we lack the schematic for *anything* that discussed this connector. This is why I thought of Allstar. We have a RTCM connected to a (Yaesu) Vertex VX-4200 off site that we’re using in half-duplex mode to access the repeater using SIP or the web transceiver. It works fine and yes, the audio quality is there. The 4200’s have reverse burst and so far works well. We’re thinking of placing a 4200 or a CDM 750 at our back-up site and using Allstar to bring it to the repeater. We can set the PL at the main site to a different value and not lose its coverage while benefitting from a remotely located receiver. Absent instructions on interfacing the MSF 2nd receiver this will have to o. I think this will actually work better in the long run.
From: Jeff Carrier 
Sent: Saturday, May 09, 2015 7:40 AM
To: R. Wayne 
Subject: Re: [App_rpt-users] Motorola MSF / Voting / Receivers;

you have to set your buffers for the latency on your "worst" voter so that's going to slow things down.  We kicked this around and decided against it.  You can do it but the delays will be more.  I'm running a 2 site voter and it works great once I realized I could turn the buffers down to the minimum value.  Throwing a controller in the mix will complicate things IMHO.  The RTCM will do all the work for you and it's a simple device and quite reliable.  I have an RC210 on the shelf that I may never use again, when it worked it worked good but when it didn't it was a total PITA.  The RTCM's really need their audio from the discriminator to vote (I think) at least that's how i'm doing it.  The CDM's just sound beautiful too.  The audio is full range and clean.  They're good even as a transmitter but you really have to take a 45 watt version and turn it down to 20 watts otherwise you'll fry the PA sooner or later.  I have a shelf full of CDM "receivers" since they no longer have a functional PA.  I am not familiar with the MSF but if you can still use it's transmitter and stick the CDM inside the cabinet you should be good.  I pulled the receiver tray out of a mastr II and stuck a CDM in it's place though some would call that GE blasphemy 

On Sat, May 9, 2015 at 8:19 AM, R. Wayne <allstar at controlservers.net> wrote:

  Great answer, Jeff! We KNOW that the MSF is designed for a 2nd receiver tray and it would be nice if we had some direction. At least a schematic on that sub-section. Nope. “It won’t work. Don’t waste your time... (or ours by asking.) Thank you for your reply.

  There is another say that we can go. We can use a RC-210 controller or even a Zetron 38, a RC-100 – any number of external hardware controllers. But then how will Allstar like this? With the RC210 we can put the repeater on port 1, the receiver on port 2, and the RTCM on port 3 and then tell them all to talk to one another? We even have some Vertex VX-4100’s that have 20 KHz channel spacing and similar spec’s as the CDM750. Wouldn’t it be great to just solve the problem rather than adding more hardware complexity?

  It seems that Allstar is the solution as long as we can speed up the audio delay. But then again if we vote will it matter? I mean , won’t they all have some delay caused by the internet itself? Our biggest concern is with the “primary” receiver going out to the internet and then back just for the repeater to TX. What if the internet goes down? So then would our repeater. Our site vendor has 25 sites connected over 5.8 GHz and if we used a VPN this wouldn't be an issue. But we have receivers that will be remoted and this will require internet rather than a VPN right?

  From: Jeff Carrier 
  Sent: Saturday, May 09, 2015 6:49 AM
  To: R. Wayne 
  Subject: Re: [App_rpt-users] Motorola MSF / Voting / Receivers;

  I'll leave part 2 to one of the experts but as for part 1  

  The CDM makes a great receiver.  Though it's less desirable to me than an MTR2000 those just aren't in the budget.  Its certainly easier to interface to than the MASTR III's that I have on the bench now.  It is a mobile radio but in my installation I have 12 commercial UHF DMR MTR3000's all running nearly 100 watts at the same site as my UHF receiver and they're only separated horizontally and not vertically.  My CDM receiver also has a preamp and I've had almost no trouble.  I did have a mixing product but only when a 2 meter remote base transmitted on 144.890.  I'll add I have a pretty crappy duplexer on this but it is BP/BR and also has a pre-selector between the preamp and the receiver.  Still, they seem to have a "decent" front end for a mobile radio.  

  73 de K0JSC

  On Sat, May 9, 2015 at 7:33 AM, R. Wayne <allstar at controlservers.net> wrote:

    We have learned the hard way that our Motorola MSF 5000 repeaters with 30 KHz channel spacing and a 2 MHz wide front-end just cannot handle southern California’s 15 KHz channel spacing. We’ve tried using the 15 KHz replacement crystals with miserable results. We have not located 20 KHz crystals and even if we could we don't know what circuit changes would be necessary to tailor the audio response. We have asked on a site how to interface a Motorola CDM 750 mobile transceiver with 20 KHz channel spacing and instead of an answer we’re told it won’t work. It’s a mobile. Don’t waste your time. Well, its our time to experiment. I know of several popular repeaters here on SoCal built using the CDM 750 / 1250.

    OK. About Allstar. It seems if we can’t get an answer about directly interfacing a second receiver to a MSF 5000 that is designed for a second receiver we need to look at how Allstar can allow us to use an external receiver. Besides the obvious of a USB or RTCM is there any way to create like a LOCALHOST situation at the repeater site where we can almost eliminate any audio delay? We know that, and plan to use, off-site voting to cover our rather large footprint. That will have to be on an external Internet IP rather than an internal IP (192.168.x.x). Can we have both? An internal network and an external network? Or do we have to use one network especially if we plan on doing voting?

    Thank you in advance.

    R. Wayne

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