Batboard

We have a site with a GE MastrII repeater that was damaged during a recent sprinkler malfunction and need to replace it with an MSF5000 analog repeater in a rush. The site has 4 voted receivers on a GE comparator (in a separate cabinet that was spared). Has anyone ever run in to having to do this set up before?

The current set up for the voter is keying via DC remote and the MSF is equipped for DC remote.

What are the possible scenarios for interfacing the GE Comparator to the MSF?

Do I need to program the repeater as a station in order to vote the MSF receiver?

Is it even possible to do this or am I just spinning my wheels?

TIA

If your MSF were a CXB or RLB series [with the RSS programmable station control] you could easily mate it to the GE voter.

These stations can be programmed for whatever status tone frequency and level your voter requires.

Since you said your station is the earlier CLB series [so called 'analog'] that programs with the R1800 suitcase - you have a bigger challenge. There was a Spectra-Tac option for these stations that consisted of a separate board that resides in an expansion tray.

First you would have to find one of these boards. They have showed up on ebay occasionally but I have not seen one there recently. You could try calling some used dealers to try to track one down. Then you would have to modify this board if your voter uses a non standard status tone[Motorola uses 2175 Hz].

It might be easier to convert your station to PC programmability. There have been low split UHF MSF CXB stations on ebay for around $400. Buy one of those and mate the new control tray with your RF. You would have all the necessary parts for not a lot of money. Then put the left over pieces back on ebay!

Ok,

What if I program this thing to act like a Duplex Base Station with 4 wire DC controll, pull my MSF receiver audio from the DC remote audio, COR from the 25 pin connector on the side and install a cheap controller the DC control card on the GE voter for hang time etc....?

An anlog MSF won't normally have a 25 pin connector on the side unless there is some sort of option installed.

Post the exact model number of the MSF and what options are installed to facilitate accurate assessment of your situation.

XMO,

here is the info I have, model # C74CLB7105AT: RPTR 1F DC REM RT MSF5000

Options: C675AA DUPLEX FILTERING RPTR

That model number is the "Analog" version of the MSF.

Your proposal to need COR from the station suggests that you may need to review the operation of the voter.

Commercial voters from Motorola and GE use a status tone on the audio line from each receiver to the voter. The status tone is present when the receiver is NOT receiving a signal and goes away when the receiver unsquelches. This status tone is used to indicate to the comparator that a receiver is idle, is used for line integrity verification and in Spectra-Tac systems is used for AGC level setting.

You can read about voters here:

http://www.repeater-builder.com/tech-in ... ators.html

You can also download a manual for the GE voter:

http://www.repeater-builder.com/ge/lbi- ... 30002l.pdf

The bottom line is that the Analog MSF does not have a way to send a status tone without the Spectra-Tac option board which is hard to find. Even if you found one you would still need to modify either a comparator module or the Motorola status tone encoder module to match the different systems to a common status tone frequency. Neither modification would be too complex, but the CXB MSF control tray can do any status tone with simple programming.

That is why I suggested the control tray swap as the cleanest and quickest resolution of your problem.

Thanks.

I wasnt aware that there was a status tone on a DC voter setup.

I have worked on some GE MASTRII repeater systems with the GE Voting Comparator located at the same site as the repeater. All the remote receivers were GE voting receivers with the idle status tone encoder. The repeater station receiver was the local "self" receiver and it did not have a status tone encoder. We did some type of modification on the Comparator card for that reciever and connected it to the local receiver COR to indicate activity on that receiver instead of status tone.

We also found that we had to add an "artifical line" audio rolloff network to the local receiver audio into the Comparator to match the audio respose of the remote lease lines. Without that, it would almost never vote "self" becuse of the high frequency noise present from a local receiver.

I just checked my manuals to see if I still had details of the local receiver to Comparator interface but I could not find anything.

K2HZ comments about the audio comparator never voting the colocated repeater's receiver site is also known as "Down Voting" to a noisier signal site. The Low Pass audio filter network installed and used passes 0~2 kHz and rejectes 2~6 kHz which is part of the white noise these comparators use for selecting the best signal to noise ratio and then voting that audio signal. These network circuit boards simulate a Telco conditioned line or circuit type RT2002, RT3002 or T1 providing the acceptable system characteristics for the audio comparator. The "Down Voting" conditions have been found not only on GE but also on the /\/\ S-TAC analog audio comparators.

I could have sworn I've seen the JPS now Raytheon comparator product line offer an option or kit for a Status Tone Generator module to install in receiver circuits to make them compatible with GE 1950 Hz or /\/\ 2175 Hz analog audio comparators.

The Raytheon PTG-10 Pilot Tone Generator is what Dan 562 is thinking about. I should have one kicking around here, Now if I could only remember where....

So far the set up looks like it will be as follows:

MSF5000 Programmed to Duplex Base with 4 Wire DC Control

Local Receiver from the wireline to the PTG-10 (hopefully I'll find a handy COR take off point) to Voter Position 1.

Between the voter and the DC keying module I will install something along the lines of an ICS basic repeater controller for hang time.

So far It looks good on paper!

Two things ... I'd look for either a COR detection on PL receive if your system utilyzes CTCSS or the basic Carrier Squelch COR detection.

Generally the MSF5000 repeater stations should have an internal "Hang Timer" in the Squelch Gate circuitry to prevent the Subscriber drop out on noisey signals. The other place you might find a similar circuit would be in the GE analog audio comparator. On the older /\/\ S-TAC analog audio comparators there's a similar circuit on the audio Command Module and a physical Jumper wire for setting up the delay for 0, 1, 2, 4 or 8 seconds.

Gosh ... I'm glad to hear that the Raytheon (JPS) PTG-10 Pilot Tone Generator is still available. Isn't it great when a plan comes together!

Gotta Love It

Ok anyone have an idea wher I can steal the COR from on the MSF.
I have to be able to control the PTG-10 for the local receiver and I should be golden.

also anyone have na 600:600 Ohm matching transformers laying around that they want to sell? I had about a dozen or so kicking around, I put them away so well I dont remember where I put them.
Thanks

Here is a post that I posted a little while ago while screwing around with the MSF5000. Some pins that you might need are listed, including the COS pin with info.. Get yourself a Doug Hall comparator, it doesn't need a tone to operate, then again you get no consistant indication that the link is in operation.

Hope this helps, Rob
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Here is the info that I have so far from linking a Cat 300dx controller to a UHF MSF5000 CXB model repeater.

Some of the info is already posted in another thread, so this would be the updated info as I have changed some things around.

Here is the pin outs for the J2 connetor located on the side of the repeater.
Most of these connections go the the TTRC board (I believe)

PTT- Pin 12 on the J2

COS- Pin 23 on the J2 "RDSTAT" will appear as RX1ACT on the test panel and mux bus diagnostics in the software. Originally I tried taking this from pin 1 of U1552 but for a regular controller this just provided a signal when the radio rx'd any signal on channel (which equates to no pl control) This is the pin you would use if you are using a "community deck" type panel where it will rx and tx it own pl/dpl.
** If I remember correctly the COS output provides an active low signal which I believe shows 5-6 volts DC and when the radio rx's a carrier with proper Pl/dpl it will drop to almost zero. Most controllers are selectable to some degree of which logic they will accept active high or low.

Audio from reciever- (Line 2) +++ Pin 2 on J2
(Line 2) ----- Pin 3 on J2

Audio to Transmitter- (Line 1) +++ Pin 6 on J2
(Line 2) ----- Pin 7 on J2

Audio Ground- Pin 17 on J2** Tie together pins 17-3-7

Logic Ground- Pin 19 on J2 (Ground for controller)

Repeater programming- In the software all "repeater controls" have to be set up as a base station operation " Half duplex" operation with ptt priority to the wire line.

- Set the "System Connector" to line and the "Spare output" to active low. This is in the advanced information section on page 8.

- Ideally the MSF will be functioning as a base station, so you would just program you channel info and pl info for what you need.

- All of the audio/dev/tonal quality adjustments can be adjusted with the softpots in the service area.

******** It is also noteworthy to mention that we found that the controller audion was not behaving properly because the controller didn't pose a large enough "load" on the Line 2 audio side. So we ran 2 1200 ohm (=600 ohm) resistors across the screw terminals of Line 2 +/- just below the J2 connector. This gave line 2 audio the 600 ohm load it would normally be looking for with a deskset tone remote type set up-*****

I hope this info helps you out. I am not an expert on this at all. Please test properly all of the connections before connecting to them. I also hope more people add to this post