Building a public service/volunteer portable repeater for our club

[kayn1n32008]

Accept the suck; get a proper duplexer and fit the entire works into a truck box. You can even mount an NMO antenna on top of it. Just drop it off where you need it, padlock to a tree. At 7 watts maybe 4 cans will do the job.

View attachment 183943

Always a proponent of using proper equipment. Hence it's Codan, and either a 4 or 6 cavity duplexer on VHF.

 

[Project25_MASTR]

I've been to a lot of radio sites where I've found that exact sort of installation. Usually a local WISP, but have seen some federal type stuff set up that way in more substantial boxes.

I've seen some use the Podrunner from Rescue 42 as well. Throw in the onboard generator option...power draw wouldn't be a concern (because we can't just not use a Quantar). I am curious how some of the Amateur Radio clubs in California that have these afforded them though.
CommandRunner XT™

 

[mmckenna]

I've seen some use the Podrunner from Rescue 42 as well. Throw in the onboard generator option...power draw wouldn't be a concern (because we can't just not use a Quantar). I am curious how some of the Amateur Radio clubs in California that have these afforded them though.
CommandRunner XT™

I've seen a few of those, but never in amateur radio use. Probably a bit rich for most ham clubs.

What I often see at remote sites is one of these sitting on a cement pad and bolted down:

Jobsite Boxes

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[kayn1n32008]

I've seen some use the Podrunner from Rescue 42 as well. Throw in the onboard generator option...power draw wouldn't be a concern (because we can't just not use a Quantar). I am curious how some of the Amateur Radio clubs in California that have these afforded them though.
CommandRunner XT™

Ugg. Quantar. Uses more juice on standby than a Codan transmitting at 30w.

While they are good stations, I'd take a Codan station over a Quantar all day long.

 

[Project25_MASTR]

Ugg. Quantar. Uses more juice on standby than a Codan transmitting at 30w.

While they are good stations, I'd take a Codan station over a Quantar all day long.

I'd honestly take one as well I just have a bunch of Quantars laying around. The only things I didn't really like about the MT-4E was the lack of an integrated controller with ID function and the separation of RX and TX programming which makes sense to why it's done that way just a pain if you are going back and forth between TX and RX a lot and then the UIC being an oddball web UI.

BTW, that card that you haven't seen before was the new control module. That repeater was built in December of 2024 and those pictures were from February of 2025.

 

[kayn1n32008]

I'd honestly take one as well I just have a bunch of Quantars laying around. The only things I didn't really like about the MT-4E was the lack of an integrated controller with ID function and the separation of RX and TX programming which makes sense to why it's done that way just a pain if you are going back and forth between TX and RX a lot and then the UIC being an oddball web UI.

BTW, that card that you haven't seen before was the new control module. That repeater was built in December of 2024 and those pictures were from February of 2025.

I think its just the nature of it being so configurable, with out any sort of module control data between the various components.

The MT-4 Does have a rudimentary internal controller, you can set hang time and time out timer, but I don't think you can link and unlink the A & B pairs, or link and unlink A&B.

Haven't played with a UIC-5, but we do have a few of the 4x RJ45 audio cards, and it will be interesting to get into figuring them out. However, this build is going to just be a LVSD jumper from exciter to receiver, analogue only, 180sec TOT, and 750ms hang time with 120⁰ reverse burst enabled.

Do you still have that station? If so cod you post a photo of the front? I'm curious to see it. If you can't post publicly, PM me with an email address.

 

[Project25_MASTR]

I think its just the nature of it being so configurable, with out any sort of module control data between the various components.

The MT-4 Does have a rudimentary internal controller, you can set hang time and time out timer, but I don't think you can link and unlink the A & B pairs, or link and unlink A&B.

Haven't played with a UIC-5, but we do have a few of the 4x RJ45 audio cards, and it will be interesting to get into figuring them out. However, this build is going to just be a LVSD jumper from exciter to receiver, analogue only, 180sec TOT, and 750ms hang time with 120⁰ reverse burst enabled.

Do you still have that station? If so cod you post a photo of the front? I'm curious to see it. If you can't post publicly, PM me with an email address.

I don't still have the station but I do have a slightly better picture.

 

[kayn1n32008]

I don't still have the station but I do have a slightly better picture.

Interesting. Looks like it gives you the ability to control the channels of the modules. I like it. Did the displays stay on full time? I also notice you don't have a system regulator in that station, does that module replace it?

 

[n3obl]

So are these units programmable? Crystal? I seen ones that have transmitter and p25 transmitter.

 

[kayn1n32008]

So are these units programmable? Crystal? I seen ones that have transmitter and p25 transmitter.

MT-4E exciter and receivers are programmable with windows software.

MT-1 and MT-2 are crystal controlled. MT-3 are in between.

 

[kayn1n32008]

So are these units programmable? Crystal? I seen ones that have transmitter and p25 transmitter.

MT-4E exciters and receivers are P25 'capable' and need to be enabled if not purchased to be dual mode enabled.

 

[mmckenna]

MT-3 are in between.

Programmable crystal?

 

[Project25_MASTR]

Interesting. Looks like it gives you the ability to control the channels of the modules. I like it. Did the displays stay on full time? I also notice you don't have a system regulator in that station, does that module replace it?

You know, I'm not 100% sure. I controlled the channels through the web UI on the UIC-5. I think the UM rotary dial options are the same as the System Regulator so yes, it does replace it.

That machine also had the MT-4Z receiver in it so no more having to tune the filtering in the receiver. There is also a rumor going around the next hardware revision of the transmitter may allow the MT-5 chassis to succeed the Cascade as a bunch of customers have been requesting the *PSK capabilities on the MT series.

 

[kayn1n32008]

Programmable crystal?

It's synthesized, but not programmed via software running on a computer. I think... It's some sort of external programmer, but not entirely sure. I've never played with MT-3, but going to delve into them at some point because we have a few MT-3 exciter and receivers.

 

[kayn1n32008]

I think the UM rotary dial options are the same as the System Regulator so yes, it does replace it.

Nice. It's even skinnier than the thinnest 'normal' system regulator with out an antenna relay.

That machine also had the MT-4Z receiver in it so no more having to tune the filtering in the receiver. There is also a rumor going around the next hardware revision of the transmitter may allow the MT-5 chassis to succeed the Cascade as a bunch of customers have been requesting the *PSK capabilities on the MT series.

I saw that. It's a nice step forward, hopefully they are as good as the previous receivers in performance and current draw.

 

[AK9R]

Programmable crystal?

Put a crystal in a vice and tighten the screw. I think that will reprogram it.

It's synthesized, but not programmed via software running on a computer. I think... It's some sort of external programmer, but not entirely sure.

Maybe you'll have to write to an EPROM. Hopefully, it's not a matter of changing connections in a diode matrix.

 

[rescuecomm]

I came by a Sinclair flat pack VHF duplexer 40+ years ago. A call to the factory said it was usable down to 2 mhz. It was marked as tuned in the VHF Federal band. A workable repeater was constructed from a VHF Micor using 145.110 TX and 147.600 RX. The event the repeater was constructed for ended before we used it. Ten years later the duplexer was trialed on a VXR-7000U at 3.125 Mhz split. It was no go on that radio. The helical filter on the Micor was really adding to the system performance. Maybe finding a VHF Micor front end to add to your receiver could help.

 

[kayn1n32008]

I came by a Sinclair flat pack VHF duplexer 40+ years ago. A call to the factory said it was usable down to 2 mhz. It was marked as tuned in the VHF Federal band. A workable repeater was constructed from a VHF Micor using 145.110 TX and 147.600 RX. The event the repeater was constructed for ended before we used it. Ten years later the duplexer was trialed on a VXR-7000U at 3.125 Mhz split. It was no go on that radio. The helical filter on the Micor was really adding to the system performance. Maybe finding a VHF Micor front end to add to your receiver could help.

Codan/Daniels VR-4 receivers have a 4 or 5 cavity helical filters already.

 

[rescuecomm]

Sorry, I overlooked that in your opening post. The only problem with the Micor setup was the frequency split being 2.49 mhz. Most amatuer handhelds wanted something rounded to 2.50 for front panel programming. The transmit frequency was chosen at 147.600 because there was a local repeater on 146.400/147.000. Turned out that 147.610 would have been better. Our target was to get something that would fit on a tree stand foot climber. There are plenty of tall pine trees to spot a portable repeater on and being less accessible to meth heads. Anything spotted on the ground and not monitored is fair game to those guys.

 

[kv6o]

The Codan/Daniels stuff is nice for portable repeaters, NIFC uses lots of them with lantern batteries.

I guess 2M bandplans vary, but I remember somewhere having a couple of 2.5MHz splits for portable setups - easier to accomplish. But at 7W, a 4 can full size setup should be enough...