Batboard

Well i'm getting a UHF 10db station master vertical for $20.00.

i'm working on him about the db-408 sitting up on the tower. so eventually i hope to end up with that as well.

does anyone know if an msf5000 turned down to 50 watts would be legal on gmrs?

Batman wrote: does anyone know if an msf5000 turned down to 50 watts would be legal on gmrs?

Yes it should be 'legal' as the station is FCC type accepted for that service.

I'm surprised about it having type 95 certification, but it really does. I guess it's because back in the day, when the MSF5000 was contemporay, GMRS was a completely different animal than it is today. Anyway, it's good to know.

MSF5000-FCC Authorization

thanks,

i saved that to post it with the repeater when i put it up

Please let us local gmrs users know when its up & running - tnx

question?

since it's type accepted under part 95a and it states 110 watts on the certification form can i legally run 110 watts on gmrs with it or do i have to turn it back to 50 watts?

will this repeater go back to 50 watts from 110 watts without any adverse effects?


how well you think i'll do with a 21ft station master?

the address it would be at is 283 locktown seargantsville rd stockton nj.

antenna would be about 20ft above ground level.

use 462/467.675 as a proposed pair.

be nice if local gmrs user with the capability to do so help me tune the repeater and duplexer as well as locate a suitable pair.

if i get help setting it up, then i have no problem sharing the repeater free of charge.

"since it's type accepted under part 95a and it states 110 watts on the certification form can i legally run 110 watts on gmrs with it or do i have to turn it back to 50 watts?"

No - you can only run the maximum of 50 watts on GMRS.

"will this repeater go back to 50 watts from 110 watts without any adverse effects?"

Shouldn't be a problem, but look at it with a spectrum analyzer before putting it in service

"how well you think i'll do with a 21ft station master?"

I don't know anything about the topography of Stockton, NJ, but an antenna at 20 ft AGL in fabulous, flat Florida will be usable outdoors with handhelds for about 3 miles & mobiles about 5 - you can just about talk as far without a repeater as you can with it at that antenna height. Get it up, generate some interest, and then try to find a better location. You're not going to be impressed with that height.

"use 462/467.675 as a proposed pair."

Go to http://www.mygmrs.com and see if anyone else has published use of that pair nearby. With 8 pairs available, you prolly don't want to park on a pair that someone else nearby is using. I just looked, that pair is in use in Monroe Township; I don't know how close that is to you.

Hope this helps.

Robert

Batman wrote:question?
use 462/467.675 as a proposed pair.

That frequency is the National REACT pair, although the FCC rules make no mention of this.

Do MSF's suffer from leaky cap syndrome? I got this one from Joe (JRM5625). should have it next week some time.

Leaky caps? No but a couple of the caps on the logic board are known to dry out. Specifically the filter cap for the 5 volt switching supply.

Certainly replace the electrolytic cap on the logic board that has two leads coming out one end and a third lead coming out the other end. The end with the two leads has red epoxy...it is the one Will mentioned, and it is 1000 uF. It is not a bad idea to replace the one next to it also.

Also, if the logic board is old enough to have the metal cover over the switching power supply, take it off to prevent heat build up.

was $300.00 shipped a good deal?

it appears to have everything including duplexer, but what is an HSO drawer and what advantage does it give me over not having one? joe had sold that before i bought the repeater from him.

UHF MSF5000 repeaters usually do not have or require the HSO drawer. They have the reference oscillator on the RX board.

HSO is short for High stability reference oscillator.

Will wrote:UHF MSF5000 repeaters usually do not have or require the HSO drawer. They have the reference oscillator on the RX board.

HSO is short for High stability reference oscillator.

You don't need an HSO drawer unless you're running in 800MHz or 900MHz commercial service. Don't worry about it. I've never seen a UHF MSF 5000 with an HSO on it (not to say they don't exist, I'm sure they do, but I've seen a ton of MSF's and never a UHF one with an HSO).

I suggest you read the repeater-builder.com article on the MSF 5000 from top to bottom so you know what you're dealing with.

This station can be a major pain in the ass if you don't know what your doing, but with a little self-education, it should be a breeze. Just make sure you don't slam things around, as the plastic pieces of the SSCB/TTRC shelf like to break off, and the RF deck cast metal can be a little brittle.

Don't expect better than .40uV +/- .5uV or so receive sensitivity - remember, these things were built to be rugged mountaintop repeaters with a lot of RF immunity, not high-performance radios with "unbeatable" receive specifications. Remember, you sacrifice selectivity for sensitivity. The MSF is an excellent compromise.

Oh, and $300 shipped is a KILLER price, no question. Don't even question that, you did more than good. Even if it's the older "CLB" series that requires the R1800 programmer (which I have if you need help with programming an EPROM).

Batman,
Do yourself a favor, keep your eyes open for a test set and a service manual as well. Going at an msf without the proper tools can prove to be hazardous to the msf's health. I see them all the time at the big auction sites usually at a reasonable prices as well.

I kinda figured this old equipment would have a lot of quirks, but i'm on a fixed income and finding type accepted gear for GMRS on the used market cheap is not so easy.

I will be sticking it in storage till i can get my hands on the above items.

I still have 2 uhf sabers and 2 uhf spectra's i have to get will to look over as funds permit.

i figure by next summer barring any surprises i'll have the repeater up and running and the sabers and spectra's ready to go on the system.

as for sensitivity, well i figure that's the norm for all repeaters. like has been stated you are in a high RF environment so you want selectivity. there is no reason though that i could not put a prescaler on the receiver along with a preamp to kick up the sensitivity a bit later down the road. seeing as the repeater will be on the family farm on a mountain top as opposed to an actual tower site with other RF sources a preamp should help rather then hurt.

I have a 128 watt solar panel here also. considering hooking up a couple car batteries as backup system along the panel.

i'm assuming that 20.00 for a 10db station master is good and that these make good GMRS repeater antenna's, correct?

I may not be able to plunk 5k+ down on a top of the line repeater setup, but when i dive into something i don't play

I make everything is in top shape and set up correctly before putting it on the air

my contacts in the broadcast industry makes things a lot easier then it would be if i didn't have them. good source for free hardline old LMR antenna's and radios and even repeaters some times along with the traditional analog broadcast gear for my part 15 am station.

d119 wrote:Don't expect better than .40uV +/- .5uV or so receive sensitivity - remember, these things were built to be rugged mountaintop repeaters with a lot of RF immunity, not high-performance radios with "unbeatable" receive specifications. Remember, you sacrifice selectivity for sensitivity. The MSF is an excellent compromise.

Seriously? I've got one up on GMRS right now (see also: what radios I own), internally-duplexed, and it starts opening up at .15 and is damn near full quieting at .45. Another one I had up for a while with an external BpBr duplexer did almost that good, but lost a few microvolts going through the duplexer.

OP: Do you have the MSF5000 service manual with the alignment instructions, a metering panel, and access to a service monitor or spectrum analyzer/tracking generator combo? You really, really need all of the above items just to get it to play on your pair, let alone get it to work at its full potential. The first one I cut my teeth on only needed to move 300 kHz up from where it was to play on GMRS, and just that little move required a complete realignment to get it to transmit. Which brings me to my next point: the PA control circuitry in those stations is extremely sensitive, and requires precise alignment of the internal duplexer cans or it just won't transmit. I'm not trying to discourage you, and I do encourage people to learn things like this on their own, but the tools to do a complete alignment are an absolute must. On the plus side, once you have the tools the alignment itself is fairly straightforward.

On a more general-advice note, the best thing you can do in terms of antenna height is to get the base of the antenna up and clear of the tree line and any nearby structures. Also use corrugated Heliax feedline if at all possible and avoid braided cables like Times LMR-400 or 600 except for short runs. Braided cable doesn't like full-duplex operation, and you may find yourself chasing gremlins if you don't go with corrugated feedline.

as far as setting it up. if i can find people in the local gmrs community with the equipment and knowledge to set it up and they are willing to do so free of charge, as well as help maintain it, i will put the repeater up for all to use as needed. if i have to shoulder the full load on my own with no help from potential users it will be a closed repeater or i will have to charge a fee to help keep it maintained and on the air.

that is where i'm at on the issue.

it will also be able to go up a whole lot faster with help from the community then without it.

I will be scoping out service manuals and meter panels as funds permit and getting it serviced as funds permit.

motorola_otaku wrote:

d119 wrote:Don't expect better than .40uV +/- .5uV or so receive sensitivity - remember, these things were built to be rugged mountaintop repeaters with a lot of RF immunity, not high-performance radios with "unbeatable" receive specifications. Remember, you sacrifice selectivity for sensitivity. The MSF is an excellent compromise.

Another one I had up for a while with an external BpBr duplexer did almost that good, but lost a few microvolts going through the duplexer.

You lost a few microvolts going through the duplexer? WTF?!?!? Check your tuning!

Well i received my MSF yesterday. i saw a little chip on the board resembling an eeprom with a sticker that had the tx/rx freq's written on it.

i'm assuming i got CLB not a CXB.

Batman,
Earlier on Joe had sent me a couple of pictures of the station, I have to assume its the same one......
What you have is a C44CLB7106 station (note CLB in model number) with internal filtering option. The station should be somewhere around 40 watts output before it hits the filtering section.
Doug

it's the same one yes. i'm to assume that big silver thing with the 4 adjustments on front is not a duplexer, but a filter?

Batman wrote:it's the same one yes. i'm to assume that big silver thing with the 4 adjustments on front is not a duplexer, but a filter?

Correct, the receiver filter cavities. Also part of the duplexer.

Actually there should be 7 of them, basically the exciter cable feeds into the three on the left which shapes the signal before it hits the pa. The pa input attaches to the output of the 3 and then feeds the amp. The amp output feeds the 4 filter input and round and round we go......... Just a note, the internal filter option is very touchy, follow the tune up procedures from the manual and you should be ok.

d119 wrote:

motorola_otaku wrote:

d119 wrote:Don't expect better than .40uV +/- .5uV or so receive sensitivity - remember, these things were built to be rugged mountaintop repeaters with a lot of RF immunity, not high-performance radios with "unbeatable" receive specifications. Remember, you sacrifice selectivity for sensitivity. The MSF is an excellent compromise.

Another one I had up for a while with an external BpBr duplexer did almost that good, but lost a few microvolts going through the duplexer.

You lost a few microvolts going through the duplexer? WTF?!?!? Check your tuning!

Since the thread got moved, I didn't see this. That was sort-of a typo on my part; the insertion loss was .03-.04mV, not 3-4mV.

edit: Also, for the OP's benefit, you can convert that station to software-programmable CXB by robbing the controller shelf and station interconnect board from a CXB station in any band/range. For a while 800 MHz CXB shelves were going cheap on eBay and I used three to upgrade a handful of CLB stations.

i actually have the msf5k swapped to a UHF desk Trac w/ internal Duplexer.

Going to run on GMRS 600 frequency into a 21 ft station master.