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msf5000 HSO mod?

Posted: Sun Oct 21, 2007 6:41 am
by The Kreick
greetings all.......

i have an msf-5000 analog repeater on 900, but is missing the hi stability osc module.... i heard there is a work around where the HSO module is not needed....... anyone have any details?

tnx,

joe ki8hp

Re: msf5000 HSO mod?

Posted: Sun Oct 21, 2007 3:49 pm
by W6JK
I think you can cable several of them together to share an HSO. That probably doesn't help you, but it does explain why they're usually missing. Another reference oscillator could probably be cabled in instead, perhaps from a GPS receiver.

'JK

Re: msf5000 HSO mod?

Posted: Mon Nov 19, 2007 1:32 pm
by willbartlett
I have a spare HSO from a Purc5K. If you are interested, drop me an email and we can work something out.

Re: msf5000 HSO mod?

Posted: Tue Nov 20, 2007 7:53 am
by fineshot1
Will - if the original poster does not respond or declines please pm me as I am interested in an HSO as well.

tnx.....dan n2aym

Re: msf5000 HSO mod?

Posted: Tue Nov 20, 2007 10:06 am
by MSS-Dave
Just some info...

Every MSF 5K 900 MHz TRUNKED station I've come across did not have the actual 5MHz reference built in. Moto sites used a master Rubidium standard outputting 5Mhz to lock all of the stations to a common source since the freq error requirement is so tight at 900. Forgive me for not having part numbers here but these stations have the tray in the bottom of the cabinet that accepts the 5 MHz to phase lock a 14.4 MHz synthesizer that ultimately drives the station. You should have this tray in the station unless someone pulled it. Then you want a complete tray like Will has, the Purc used the same setup. If you can't come up with 5 MHz externally or the internal standard for the tray, the board is jumper selectable to use several frequencies like 100 KHz, 5 and 10 MHz. I have to look at my spare or the book to see some of the other freqs available. I've never tried to run any of these units at any thing but 5 Mhz since I had that available. Just letting you know there are a couple of options to explore if you want. The UHF station does the 14.4 MHz freq, it's intregrated on the UNiboard. I don't remember if the uniboard on the 900 stations could accept a 14.4 oscillator. Perhaps xmo or Bernie can weigh in if they have experimented with this...

Re: msf5000 HSO mod?

Posted: Tue Feb 12, 2008 6:37 pm
by willbartlett
Dave, if you could look up the jumper settings for some of the other frequencies, I, and a lot of other people, would be eternally grateful.....

Will

Re: msf5000 HSO mod?

Posted: Tue Feb 12, 2008 7:17 pm
by MSS-Dave
willbartlett wrote:Dave, if you could look up the jumper settings for some of the other frequencies, I, and a lot of other people, would be eternally grateful.....

Will
OK then... Dug in the garage and came up with this. The Reference Synthesizer Board is a TLF 6816A. It has a 14.4 MHz VCXO that is phase locked to the HSO which can be 100 KHz, 1 MHz, 5 MHz or 10 MHz. I have only run the stock config of 5 MHz in many sites but I have had 10 stations daisy chained to a single source when I had a failure. Jumper settings are: JU20 OUT, JU21 OUT = 100 KHz. JU20 OUT, JU21 IN = 1 MHz. JU20 IN, JU21 IN = 5 MHz (default) JU20 IN, JU21 OUT = 10 MHz. These jumpers are 0 Ohm resistors. The HSO has to be very stable due to the reference dividers that are in the chain. I've run stations using the output from a service monitor at +5 dBm but I don't think it will lock at 0 or less.

Looking at some of the latest posts, looks like there will be lots of 927 machines going all over the place. Good Luck with it!

BTW... If someone came up with the MSF 5K 900 TRUNKED station manual, the schematic and board descriptions are located in the reference synthesis tab. There should be simular in the PURC 5K book also.

Dave

Re: msf5000 HSO mod?

Posted: Thu Sep 11, 2008 12:37 pm
by n1das
The Kreick wrote:greetings all.......

i have an msf-5000 analog repeater on 900, but is missing the hi stability osc module.... i heard there is a work around where the HSO module is not needed....... anyone have any details?

tnx,

joe ki8hp
There is a simple workaround where you supply your own HSO in place of the real Moto HSO module. The repeater HAS to have a 5 MHz (or 10MHz if changing jumpers works) input from SOMEWHERE in order to generate the 14.4MHz reference needed for the station to operate.

I just recently picked up a MSF5K 900MHz repeater, one of the 150W trunking repeaters that came up to the New England area from the NJ power company upgrade. Batlabs thread: http://batboard.batlabs.com/viewtopic.php?f=3&t=63976

Mine does not have the HSO module and I too am on the hunt for one. Many of the GEMOTO guys in the Boston area have successfully put these repeaters on the air using a Vectron 5MHz OCXO. It's a da@mn good deal at $50:
http://www.alltronics.com/cgi-bin/item/ ... Oscillator
I'm waiting for mine which should arrive in about a week.

The New England 900MHz MSF5K repeater experience:
http://www.repeater-builder.com/motorol ... 0-msf.html

From looking at what people have done with the Vectron 5MHz OCXO, it should be easy to hook it up in place of a real Moto HSO. What I'm wondering about is there's a VCO control input on the Vectron OCXO part and I don't know if it's an enable/disable logic input or a 0 to 5V analog input to warp the 5MHz frequency slightly. There's also an adjustment hole (covered by a screw) to tweak the OCXO if needed.

People that are using the Vectron OCXO 5MHz part in place of a real Moto HSO have reported that it works quite well. Not bad for a $50 workaround! 8)

Good luck.

Re: msf5000 HSO mod?

Posted: Fri Sep 12, 2008 2:55 am
by kcbooboo
I believe the 0-5V VCO input (some are 0-10V) on the 5 MHz Vectron oscillator is a fine-tuning input. If you use it for that purpose, the voltage must be rock-stable and well-filtered. Of course it could also be used as a modulation input, but I don't know how fast the VCO will respond to changes. Some people just connect that line to +5V, others ignore it. You can still adjust the coil behind the big screw to get the oscillator within 0.1 Hz.

There are also a couple of MSF Experience articles on http://www.repeater-builder.com, in the Motorola section, MSF&PURC area, but since nobody on this board reads stuff on repeater-builder.....

Bob M.

Re: msf5000 HSO mod?

Posted: Fri Sep 12, 2008 3:45 pm
by n1oty
You do not necessarily need either an HSO or a Vectron 5 MHZ OCXO. Ken Campbell, WG1U, has developed a couple of mods for putting a 900 MHZ MSF5000 on the air without a 5 MHZ reference. You can check out photo's taken by N1IIC at Boxboro last month. These mods were introduced by Ken at the 902 seminar given at the convention. We currently have two MSF's on the air with his Maxtrac mod (very stable in conventional repeater operation). My MSF in Plymouth is on the air with his jumper wire mod. The following link will take you to some of the pictures:

http://www.flickr.com/photos/jasongreene/page4/

Ken has added comments to some of the pictures. He has also corrected some info on the maxtrac mod and the corrections are included in his comments.

His jumper mod is the simplest, but it seems to be temperature sensitive. That is not a problem for my repeater as it is located in a temperature regulated room at a commercial site. Ken offers some suggestions for trying this mod when temps are not very stable. His Maxtrac mod, currently running on the Taunton repeater and the W1WCF Bridgewater repeater, is VERY stable.

John
N1OTY

Re: msf5000 HSO mod?

Posted: Sun Sep 14, 2008 7:09 pm
by n1das
Hi John,

I was at that seminar (900MHz) at Boxboro! I remember the jumper wire mod mentioned. My g/f was also with me. What clicked with her during the talk about how hams got their radios was with how commercial radios are programmed (via PC & software, etc.). She's seen me do that enough times over the years. It makes a lot more sense to her now. Now all she needs to do is get her ham license.

I think I'm gonna stick with Vectron 5MHz osc since I'm already headed well down that path plus I want it stable with temperature and don't want to ever worry about it once the repeater goes into service.

73,
Dave/N1DAS

Re: msf5000 HSO mod?

Posted: Mon Sep 15, 2008 2:13 am
by n1oty
Interestingly, we have found the maxtrac mod is more stable than the 5 mhz Vectron oscillator. YMMV. Apparently, there is nothing magical about using a 5 mhz reference, since Motorola allows these repeaters to be jumpered for 100 khz, 1 mhz, 5 mhz and 10 mhz references.

John
N1OTY

Re: msf5000 HSO mod?

Posted: Mon Sep 15, 2008 7:33 am
by n1das
n1oty wrote:Interestingly, we have found the maxtrac mod is more stable than the 5 mhz Vectron oscillator. YMMV. Apparently, there is nothing magical about using a 5 mhz reference, since Motorola allows these repeaters to be jumpered for 100 khz, 1 mhz, 5 mhz and 10 mhz references.

John
N1OTY
HMMM....interesting! I'll have to look into the maxtrac mod. It's good that we have several options available for providing a stable reference.