mfs5000 repeater

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tsoun
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mfs5000 repeater

Post by tsoun »

Help, I have a few mf5000 digital repeaters and lots of Systems Saber portables. I can not make these two to talk to each other. The repeater won't repeat. Any ideas
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wavetar
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Post by wavetar »

I assume you have the necessary hardware & software to program everything to the proper repeater frequency? A few more details would be nice...ie: what have you tried so far to get things working? Otherwise we're grasping at a lot of straws.

Todd
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tsoun
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Post by tsoun »

Motorola equipment/ system is new to me. I have deal with G.E and Kenwood system for years.
I have programmed the MSF5000 for a repeater mode and there are no failure light or indicator. and it is on frequencies. I can manualy key up the repeater and get 120 Watts out, but it won't receive, not even a 100uV injected into the port.
I've checked the duplexer and bypassed that too, checked PL and frequencies many times.
Also this MFS5000 has DES incryption and I did not mess with that at all.
I wanted to use as a conventional system only.
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xmo
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Post by xmo »

Assuming you have just one "mode" programmed with the correct receive frequency, Pl, and repeater qualifiers programmed, check the PTT Priority setting. By default this would be DWRL. Make sure the letter R is present or the station will not repeat.

Also check the Station Type Information screen [F4 Change View, F8 Station Model / Options] to be sure the field "Repeater Operation" is enabled.
Dan562
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Post by Dan562 »

Did you change the repeater frequency pair from what these MSF5000 were originally programmed? Which leads to my next question, "What were the original frequencies programmed in the software and what are your requirements now other than conventional?"
tsoun
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Post by tsoun »

Yes I did, these repeaters were originally used by the IRS and I am using the same band as are, and sorry, I can't tell you the frequencies but I'm only a couple of MHz off the original programmed frequency. Single channel mode
I read the original program and it was programmed as a repeater. And I checked and verified the setting over and over, every setting are in the right mode to repeat, I even took all of the letter off and leave only "R" and repeater Op. is enabled
Anyway, I am using this repeater for the System Saber portables with DES board install but for the time being, DES is not enabled.

Do I need to Retune the front end? now I don't know much about the MSF5000 whether it has the front-end or not, but with the G.E Master II/III station, the front end need to be tuned for the programmed frequency.
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Doug
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Post by Doug »

Absolutely
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xmo
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Post by xmo »

Yes, you must align the radio if you change frequencies. The front end adjustments on all the other bands [UHF/800/900] are accessed through holes in the rf tray front cover. Since there are no holes on the VHF, one might assume that there is nothing to align.

Wrong. There are five adjustments instead of six, so the standard front panel won't line up with the adjustments. Instead of making a special front panet for VHF stations the cheap so-n-so's saved the $ and the service person must remove the front panel to access them.

There are also adjustments that need to be made to the injection and image filters, so I suggest you track down a VHF MSF service manual 6881092E75.
tsoun
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Post by tsoun »

Are you talking about the front of the MSF5000, labled L1 to L6?
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xmo
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Post by xmo »

You said ex-IRS so I assumed Feds = VHF, but regardless of freqency band you should obtain the correct manual and follow the recommended alignment procedure.

UHF CXB series manual = 6881092E80
800 CXB series manual = 6881092E85
tsoun
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Post by tsoun »

UHF Band, and I don't have a service manual for that, the guy in D.C did not sent me the service manual instead I've got the Ops. manual
Anyway I've got one of the station up and running. Thanks for all of your help, vey much appreciated and just one more question.
How do you by-pass the 40 lbs. PA. I just wanted to use the IPA.
Lifting the whole base station is not very practical. There are five wires attached to the PA, when I unplug that cable, the radio will not key up.
Is there a way?
Jason
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irs

Post by Jason »

IRS typically has/uses allocations in 406-420... Maybe DAN562, Bernie or XMO can elaborate on whether those Stations will even move to somthing you can legally use.
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xmo
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Post by xmo »

"...How do you by-pass the 40 lbs. PA. I just wanted to use the IPA. ..."
___________________________________________________________

Clarify that. Is the station a B84 model with 225 Watt PA and you want to run the station at lower power?

The 225 Watt station is rated for variable power, 110 to 225 Watts so unless the final PA is bad, just turn down the power control.

If you have a 40/75/110 Watt station and just want to run 6 Watts out of the IPA in the RF tray - that's a different matter. You have to convince the station's microprocessor that the PA is working. You can make a little circuit to fake it out.
tsoun
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Post by tsoun »

It is a low power radio 110-140 Watts PA. I can turn down the power but I would still have the Final PA in the case/cabinet. The whole ideas is to lighten up the load. If I take the final PA out, that's 40 lbs. lighter. These repeaters will be lift and carry by people when load and unload. I want to strip this repeater to a bare-bone and put it in a 24" x 36" case
I've got 17 Watts out of the IPA and I'm good with that.
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kcbooboo
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Post by kcbooboo »

The PA and power supply each weigh about 40 pounds. They can be removed from the station and carried separately, then put back into the box when it reaches its final destination.

The UHF IPA is rated for 0-9 watts. There's not much heat-sinking inside the RF tray, and very little air movement.

There is an "isolation network" (a.k.a. 6W PA) in the UHF manual that takes the IPA output, runs it through a 9W amplifier and a circulator, and feeds 5-6 watts to the antenna jack. They don't use the IPA output directly. You may need some filtering after it to reduce spurious emissions.

Bob M.
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xmo
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Post by xmo »

There is no "9W amplifier" in the TTE1591A/TTE1592A/TTE1602A series Isolation Network.

The RF input to the Isolation Network comes from the IPA in the station tray. It goes through a directional coupler, then through either a single or triple circulator resulting in either 5.5 to 7 Watts or 3 to 3.5 Watts output respectively.

The output of this deck then goes through either the station duplex filtering or a harmonic filter.

There is a 15 Watt PA that looks identical and does have a power amp in it.

Bob is right - the IPA is rated for 0 - 9 Watts. It would be unwise to operate it above rated level. Also, if you are running it barefoot without Motorola's Isolation Network you have no directional coupler or circulator to protect the IPA.

I recommend you follow Bob's advice. Remove the PA and power supply from the cabinet for easier transport and then reassemble the station at its operating location.
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kcbooboo
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Post by kcbooboo »

Sorry. My error in not checking it out more closely. I looked at the schematic and it clearly shows several RF stages, so I thought they were on the isolation network. For whatever reason, Motorola chose to show the full IPA schematic on the isolation network sheet. All that network has is the circulator(s) and an isolation network which senses forward power and feeds that signal back to the SSCB.

Bob M.
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