Batboard

Can Ya'll tell me what it take to convert a MSF Low power analog from a base to repeater. Other than programming.

Thanks

R

Basically new information burned to the prom and a complete alignment. There's a couple guys here on the board that can program the prom. Andy Brinkley and Bernie come to mind.
Doug

antenna tx/rx relay?

My thinking is that I can put a small continous duty pa in between the IPA and the circulator (contained in the pa chassis, cause there is no pa in the chassis) out to a duplexer and then the antenna port. Is this correct?

Or do I actually need a duplexer. I have been told that the front end on the msf is so selective that you don't need one.

THanks
R

The receiver preselector has enough selectivity to serve as part of the in-cabinet duplex option in combination with additional transmit filtering and a special duplex phasing harness.

Without all the correct factory parts, you will require an external duplexer or two antennas with adequate isolation.

In addition to the correctly programmed personality PROM and alignment, you will need to remove the antenna relay assembly and provide cables from the receiver and transmitter to connections on the side of the cabinet. The receiver cable connects to the receiver front end with a right angle SMA connector, Amphenol part # 901-9531-1. The connectors on the side of the station [panel receptacle] are Amphenol part number 82-5372.

Am I correct in thinking that the Circulator (in the PA assembly) would handle somewhere in the neighborhood of 40 watts?

I could then go to the duplexer and out to the antenna port (removing the relay). If I wanted to keep it all inside the housing?

THanks

R

I'll be doing this to my 75w UHF MSF5000 soon. My plan is to just unplug the coil wire going to the antenna relay and use that connector for the receiver. I have made a short jumper that will connect to the transmitter's low pass filter and bring the transmit signal out to another UHF jack on the side. I am hoping that the unit will run 75 watts with a fan or two to move the air around the massive PA heatsink.

Rather than use the internal controller, I'm interfacing a commercial controller via the MRTI connector on the control board. This gives me touch-tone control of the repeater as well as timers, CW ID, messages, etc. I have no doubt that the MSF5000 controller can do the timing and CW ID for me, but it gives me no means of actual control. As long as the MRTI interface is enabled (via RSS), it seems to provide and respond to the signals present on J802 on the SSCB.

Bob M.

I have found the circulators on the PA's in MSF5000's to be poor and removed them on the 100 watters and used an external circulator AND lowpass filter until the site went combiner on transmit and the combiners have the circulators so I don't need them. got up to 40 watts more!!!!! Now the PA's just loof at 100 watts.
On the low power PA's same and if it had the triple circulators got 40to 60% more power out. I used the primo teflon cable to bypass the RF out to the connector on the PA.

Even the UHF MSF with internal in-cabinet duplex, removing the three cirulators in the 100 watt PA made no difference in noise on transmitt or noise back into the receiver, gota love that rx frontend filter. Of course I had to turn down the power to get 100 watts.

So basically on the 6 watt unit with the pa chassis with nothing in it but the circulator I can just take that out right? I need to install a circulator in the system between my pa and the duplexer to prevent damage from close in lightning strikes but thats about it, right?

Bob that is what I thought about doing then I decided to keep it all within the cabinet. I am going to be on GMRS so I can't run more than 50 watts out to antenna. I am going to be alone on my hilltop, so I won't have to worry as much about desense and such.

Thanks for tolerating my ignorance!

R

There are some componets in the PA chassis that are used in transmitter power and tempature control. So best to leave it there and remove the circulators and run a coax cable to bypass where the circulator(s) were and route the TX power thru it. The IPA will put out up to 9 watts to drive your external amp, then route the power back thru the PA chassis so the power control circuits will still work. If I remember there is a filter on the PA chassis also.

An external circulator will not do much for a lightning strike, it would just fry the duplexer. Best to use a good coax lightning protection device at the feed line before the duplexer or radio.

I plan on using a polyphaser mounted on a ground window. I was thinking about the harmonics that come off of a bolt. I have not idea what I am talking about, but have read about some ham repeaters setup this way and it made sense. So if I have a properly installed polyphaser the circulator is redundant?

The job of the circulator is to prevent RF from other systems from coming through your antenna backwards into the station PA where it could mix with your signal and create intermod products.

Circulators are generally considered necessary where you are located on a site with other systems and less necessary the farther you are away from other sources of RF.

Can anybody tell me the wattage driving the IPA?

looking to drive amplfier (non/\/\) without the IPA as the PA only needs 1/2 watt drive for ouptut.

Thoughts?

I know this is taboo here but I am trying to piece something together until I can get the funds to do it correctly.

Rather than butcher the MSF5000 - I would measure the power it puts out as it is. Then I would buy a cheap power attenuator [maybe off ebay] to pad it down to the requirements of the aftermarket amp.

The when you someday find an affordable MSF PA - all you will have to do is install it.

Put a fan or two on your aftermarket amp and you should be fine.

My two bits worth:
I am on vacation at the moment, so I do not have my manuals handy.

The IPA will put out about 15 watts or so.
The power control circuit wants to see an input from the power sampler circuit in the pa assembly. Otherwise it will an all or nothing situation with the power control adjustment.

One of the reasons for the circulator in the output is for protection of the PA transistors in the event of very excessive VSWR.

Eliminate it at your own risk.

I can make the code plug if you need one. I will be home next week.

the pa will run 15+ watt ... but i would lower it to about 9 watts i own a few of these.. for bases they might run ok at 15 watts but for repeater use idle them at 9 watts.. and don't Eliminate the fold back protection at any cost......just find a amp that needs 10-20 drive

Hello all!

I am new to the MSF 5000, I have a VHF R2-Conv-Base I would like to turn in to a repeater.

1. Is this possible

2. What do I need to do

3. What do I need to program in the RSS

I see the TX RX relay and it is connected as follows:

The Transmitter is connected to the PA then from the PA to the TX RX relay. The Receiver is connected to the TX RX relay and then the Relay is connected to a bulkhead mount N connector.

I need to know if I should remove it and route the PA output to an external connector and the same with the receiver. This looks to be the easy part as I do not see any circulators in the cabinet.

Is this all I would need to do to get the "Hardware" part out of the way?

I know I am asking a lot and thank all of you for your time in advance!

Thank you,

Yes, it is completely possible. You can disconnect the relay coil; it should just unplug. The existing antenna connection now only goes to the receiver, so that's how you should label it.

Disconnect the cable coming from the PA going to that relay. Use a bulkhead connector or a short jumper (you may have to make or buy an appropriate cable) to run the PA output to a new connector on the junction panel. Label this as the transmitter signal.

Connect your duplexer to these two connectors.

In the RSS, you can enable the REPEATER setting if you want to use the internal CW ID and timers. There will be several timer values you'll have to change depending on your use. Make sure the PTT PRIORITY field in the mode you'll be using has the letter "R" in it, to allow the repeater to key the transmitter. You should also make sure that same field has "L" for local control, so you can use a microphone to test the station.

There are hundreds of settings in the RSS. Go through all the fields, and refer to the RSS manual to see if it has any relevance for you. You'll need to set the frequencies and tone squelch, at a minimum.

I have done this on a UHF repeater and also connected an external controller to it, so I didn't use the built-in CW ID or timers.

Bob M.

Bob:

Just so I have this right, leave the receiver pluged in to the relay which goes to the bulkhead and lable RX. Add a new bulk and remove the cable coming from the PA and bring it directly to the new bulkhead and lable it TX?

One other question, the control line going to the TX/RX Relay, should I leave it pluged in or should I pull it? (Stupid question I know, my common sense tells me that telling the MSF it is a repeater will disable the relay but I have to ask!)

Seems almost too simple, I have looked at the RSS for this thing and my head was swimming but I am sure that I can navigate it.

It is currently programmed for 151.xxx, the deck says it is capable of 146 to 165 or 70. Should I be able to just program this thing in the ham band without having to retune it?

Thank you soooooo much!!!!

Craig

My two bits worth:
First obtain a manual.

Follow the alignment instructions.
The VCOs are not adjustable in the VHF unit, however the injection filter
as well as the RF pre selector need alignment.

The pre selector is hidden behind the front panel, you need to remove 3 screws to gain access.

You will also need the special alignment cable. One is shipped with every unit.
The cables are the same for all bands.

Craig:

You've got the cabling correct. You can't leave the transmitter going through the T/R relay because your external duplexer will only want one signal on its receive port. Nor can you leave the receiver going through an activated relay, because that would disconnect the receiver as soon as the transmitter keyed up..

Alternatively, you can run your own cable directly from the receiver (SMA plug, right angle) to a jack on the side of the station, but since that cable is already there, going to the T/R relay, there's no reason you can't use it.

I don't know if the station is smart enough to disable the T/R relay when it's configured as a repeater. To make sure that relay never activates, disconnect the two-wire control cable going to it.

I don't know if there's anything inside that peripheral box except the relay. If there's a low-pass filter in there for the transmitter, then it might be a good idea to utilize it. I'd have to take a closer look. There might be two versions of that box: one with the relay (base) and one without (repeater).

The unit should go down to cover the entire ham band. You will have to retune the front end if you move it more than a couple of MHz. The tuning cable is mandatory. You could make one but the original works the best. Manuals will be necessary, as Bernie pointed out.

The RSS is formidable, daunting to say the least. But remember that these stations were capable of a lot more than what a simple ham repeater would need or use.

Bob M.

The range 2 will cover most of the ham band, except for the very bottom. If your repeater pair is at or below 145.6 it probably will not work. You will have problems getting the receive vco to lock (if at all - not adjustable) below 145 mhz. as you will be using a minus offset.

Been there, tried that, got the t-shirt.

A range 1 is ideal for the entire ham band, if you can find one. Took me several years to finally come across one.

Bob/Bernie:

I am having an issue programming my VHF MSF and receive the following error when trying to push in an edited codeplug.

"SSCB Firmware Is Version# 03 The Codeplug You Are Programming Is Version# 05 Do You Wish To Continue"

If you choose to continue it comes back and says that it could not convert and that it would not continue.

This activity does not hurt the current programming

Please tell me what I need to do to get around this as I am used to the RSS not even reading a radio if it is not in the .MDF, not reading the station fine then telling me that it can't upload my changes.

Thanks,

You need to do one of two things and I like the second one better...

First, rebuild your code plug with a version 3 default file that is included in the MSF RSS.

The codeplug must match the firmware version in the base station.

Other option: Upgrade the firmware in your base station to version 5 and then you will be able to load your updated codeplug.

The question is, do you have a TTRC equipped or is it only the SSCB in your base? If you have only the SSCB, you need a 512K prom. If you have both, then you need a 512K and a 256K if I am not mistaken.

Then again, I have been changing spark plugs on my Park Ave and building MSF's myself so I am a bit on the tired and ragged side.

George

When I reset the unit which has both ttrc and sscb the versions that display are 5.45 and 5.34 so it sounds like the station already has the version 5 firmware in it.

Thanks,

That IS the latest firmware.

Is the codeplug you're trying to send to the station the same one you just read from the station and modified? There's no way that should fail.

If you're reading an older codeplug from disk, modifying that, and saving it out, I can see where that could give you problems.

Although it's obvious to those of us who've been playing with these a while, make sure you're running the program in a true DOS environment, not a DOS box under any version of Windows.

If all else fails, and the codeplug isn't important, then start by reading CONV3.DEF from the distribution disk, edit the various mode and channel info in that, make sure you tell it there's NO secure board, and write it to the station. Even though it has "3" at the end, it is a system 3 file meant to work with firmware version 5 (don't ask). That will put the station back to some known state and it should definitely accept that codeplug.

Bob M.