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Author Topic: MSF-5000 Help  (Read 10703 times)

AF6D

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MSF-5000 Help
« on: September 22, 2014, 01:51:50 PM »

I am a repeater rookie and my Elmer skipped town with some of my equipment and failed to teach me. He always just did it. So... I humbly ask for help and direction.

I am on a site next to Heap's Peak in southern California that gets the spewed garbage from Heap's. Our antenna is at the top of the tower (omni coverage) 1.2 miles from Heap's. 99.1MHz FM checks in on the spec analyzer at -1dBm from my home 1.7 miles east of Heap's Peak. It is hotter I think on site and my 8924C doesn't go lower. The vertical beam width of our antenna seems to match that of 99.1, which has down tilt to get to their coverage areas.

Now then. The MSF 5000 is tuned proper and the helical resonators on the front end knock down 99.1 as they should. We also use a Angle Linear dual bandpass cavity on the front-end that knocks everything down by 90dB outside of 1MHz window. There does not appear to be anything on our input.

With this said we get moderate stations that can key up the repeater but not pop the squelch. When I listen from home 1/2 mile from our site I can work a station on the reverse down to S1. When the MSF was at my home it was awesome. But rather confusing is the excellent station that checked in from Edwards AFB loud and clear from his mobile. Or another from down town Palm Springs. The MSF is an excellent repeater and I've heard too often "get rid of the MSF and go get a couple of CDM1200 mobiles..." Right. I'm already on Hell's Highway next to Heap's and I'm supposed to use a mobile radio for a repeater?

I suspect that the squelch may be too high. But I don't know how to adjust it so that it opens just above the noise floor. The MSF has a receive of about .13uV but I haven't measured the noise floor yet. Without an Elmer I don't know how to even use the software. I have the RIB and the software loaded on a 386 laptop but where do I go from here?

Thank you in advance. I appreciate all of you.
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AF6D

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RE: MSF-5000 Help
« Reply #1 on: September 22, 2014, 05:26:27 PM »

As a follow-up I've heard from Redondo Beach about 80+ miles away today. Previously a 5 watt HT was full quieting yet this KC9xxx station was only at about 80%. At the same time a mobile station at Edwards AFB was 100%. A mobile. Hmm... I've also heard a lot of unnecessary kerchunking that doesn't do more than annoy. Hmm...

I am so confused.
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K4JJL

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RE: MSF-5000 Help
« Reply #2 on: September 23, 2014, 09:45:37 AM »

VHF or UHF?  CLB or CXB?

Do you have one of these?

http://i1070.photobucket.com/albums/u485/radi0h3ad/2635b19f.jpg
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AF6D

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RE: MSF-5000 Help
« Reply #3 on: September 23, 2014, 09:53:27 AM »

Thank you for your reply. I appreciate it.

It is VHF and I have both CLB and CBX. I am told that I can use the MARTI but when the unit was purchased it has a Zetron attached to the main board. I am not the one to have removed it so I don't know where to reattach it.
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K4JJL

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RE: MSF-5000 Help
« Reply #4 on: September 23, 2014, 10:13:01 AM »

CLB controller won't work on a VHF station (believe me, I tried).

You can connect the repeater controller to the MRTI port.  That's where I usually recommend to others.

Here's a good article pointing out how to interface with the CXB SSCB.

http://repeater-builder.com/motorola/msf/msf5000-digital-interfacing.html

The CXB uses "soft pots" to control the squelch levels.  They're set in the software under the service alignment section.  Don't remember offhand the F-key combination to get to that menu. (Maybe F2-F3 from the main screen?)

See this article for info.  Squelch setting is detailed at the bottom.

http://repeater-builder.com/motorola/msf/msf-rss.html

Again, do you have one of the service panels?  You'll need it to see when the squelch opens because there are separate squelch settings for local RX, repeat, wireline, etc.  I set mine to open around -118 dBm.

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AF6D

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RE: MSF-5000 Help
« Reply #5 on: September 23, 2014, 10:24:17 AM »

Before my Elmer left town with some of my property he told me that it was a CLB. The two that I have here are CBX and use ePots. I do have the smaller test panel; do I need to full panel?

I think it is a waste of time. I live 1/2 mile below the repeater site and can hear almost the same coverage area as the repeater but minus the interference. I am at 6,300 feet-ish while the repeater is at 6,450 feet. Hardly a difference. More to the point I left my radio, a Yaesu FT-847 with excellent VHF RX, on the input all evening and overnight. I could hear the stations trying to access the repeater while listening to the repeater on my HT and not hearing a burp. I can hear and work stations at S1 and do to test the repeaters failures.

I think I am wasting time and money on the radio site and will be better served moving it back to my home. I have an 85 foot tower with a DB224e antenna already installed and a repeater vault. This was the original home of the repeater. I know that the RX works and damn well at that. I measured it at -13dBm for 12dB SINAD. Even with an Angle Linear site noise kills it. Oddly enough many distant stations can get in but most cannot.

Thanks for the links. I'll check them out.
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K4JJL

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RE: MSF-5000 Help
« Reply #6 on: September 23, 2014, 10:39:20 AM »

The panel with the LED matrix is invaluable for figuring out what's going on inside the SSCB.  It will show you when the different squelch circuits open, when PL is detected, when the TX is keying (and why), etc. etc.

I may have one around the house somewhere I'd be willing to sell for $50 + shipping.
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K4JJL

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RE: MSF-5000 Help
« Reply #7 on: September 23, 2014, 10:43:57 AM »

BTW, -13dBm for 12dB SINAD is pretty lousy.  It should do 12dB below at most -110 dBm.
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AF6D

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RE: MSF-5000 Help
« Reply #8 on: September 23, 2014, 10:47:34 AM »

I misstated the RX. It is .13uV not dBm. As I said I'm a rookie. LOL. It will go as high as -125dBm and still hear tone but won't open PL beyond -121dBm. These numbers are without the duplexer or bandpass cavities. Those deduct 3dB.

Good catch on my oops.
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