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I thought I'd share my recent ammo can repeater build. The goals were: As small as possible Portable AC and battery power DMR and FM Good performance Parts list: 2 Motorola CDM1250 radios with control heads removed. Repeater Builder STM32 MMDVM paired with a Raspberry Pi 4. 100W Mean-Well switching power supply. Mobile duplexer 3D printed assembly that holds all of the parts together Fat 50 PA-108 Ammo Can 80mm Noctua fan Build notes: In order to fit size constraints all wiring and cables are purpose-built. I couldn't even use the standard SAE power connectors for the radios. I used tefzel mil-spec wire for all wiring. To optimize cooling for the TX radio there are 3 front exhaust holes for that radio compared to one exhaust hole for the RX radio and duplexer sections. There is a foam sheet top and bottom of the assembly between the assembly and the can to hold it all together tightly and provide some shock protection. The TX radio is set to 20W. At 20W the radio only draws around 5A, so the small power supply is more than sufficient. The cooling fan is quiet and runs continuously. Temperature rise is minimal even with a long stretch of continuous use. The whole thing uses about 800ma at 12V at idle. I started with pi-star on the raspberry pi but could not get it to work without an internet connection. Since I wanted to use this in the field with no internet, that was a deal breaker. Fortunately WPSD will boot up find and work without internet. So I'm using WPSD. I'm thinking I can build a custom Lithium battery pack with 21700 cells that will fit in the space on top to allow for 100% self contained field use. That will be next. Performance has been very good, better than expected in fact. Larry, N6TXX

Curious if anyone else has one of these & what they think of them. Measall KC901J is the particular model I'm looking at. A while ago I picked up a LibreVNA to help tune duplexers. Its pretty nice, but it uses a PC for the screen & software. Thats a minior drawback in some ways. So I thought I'd look around at some other equipment that's more portable & stand alone. Then seen these KC901 models from Measall.

Hey Guys: I have an MTR2000, which has worked flawlessly since I got it in the summer of 2020; a real workhorse! Lately, I have found the station non-responsive and upon inspection, I find the first LED (the left most LED) red. I have to power cycle the station to get it to come back to life (it's an AC powered station, btw). Today, I spun up my old XP box and used the RSS s/w to run a diagnostic check... everything seems to be OK (although I am not sure why the SCM RAM and ROM were not tested): I also looked at the Error Log: Interesting... only 3 lines? I left the PC connected and RSS running for an hour, when I returned, there are a couple of new entries: The lockups / station freezing are happening about once a day, sometimes once every 2 days. Any ideas? Thanks! Ramesh, VA3UV, WA3UV

Hello all, I have been looking for some older schematics for a Com3 service monitor. I have a earlier design with a serial of 1554 and a RF board from 1986 as etched in the board. The schematics on repeater builder which is the same ones across the internet are later that do not match up to what I have mainly for the power supply. Yes, I could remove the RF board and reverse engineer it but would rather not if I don't have to. The problem is while doing some maintenance, cleaning the noisy controls and replacing the internal battery I noticed while the unit is powered off there is 23 volts going to the battery. Ouch. When the unit is powered on the voltage goes to 13.6 volts. Voltage throughout the Com3 is at the regulated voltage thank goodness. Going by the schematics available this doesn't add up and appears virtually impossible to happen. Maybe someone has run into this or can see things differently or even have some schematics that match this unit. Thank you in advance for any information. Alan Bartkowiak N2ZVN

Greetings all, I have narrowed down my list of potential duplexers to buy for a 2m repeater that the local club is building to Sinclair Q2330E and TX RX 28-37-02A. Both have very similar specs in terms of insertion loss and isolation. The only noticeable difference is that the Sinclair has six cavities while the TXRX has 4 cavities but larger. Nevertheless, they still provide the same isolation with the same loss. I would appreciate some insight into choosing one over the other. Both items fit our budget, so price is not a factor to consider. Thank you, Sepehr N6IRN

I’ve got a MICOR PA laying around that I don’t need. TLE1693A. 47 watts out with around 1-3 in when I tested it a year or 2 ago. Not sure if that’s the rating, or if it’s supposed to be 75 watts etc. but it is putting out 47. $30 plus actual shipping cost to take it off my hands. (Shipping will probably be 25 -45 depending on location) Contact me directly at my email here. 73w0sky@... Thanks Skyler W0SKY

Does anyone know if an NXR 1800 repeater will tune itself when programming? Example, programming for a GMRS repeater 462.65+ offset and then later want to program it for a frequency of 440.950. Will the repeater auto align itself or does that have to be done manually with a service monitor still? Thanks. Chad Nelson WI9HF/WRPL979 Janesville Wisconsin 608-754-8671 Send from my spectrum iPhone 16.

An agency for whom I volunteer has been granted a repeater pair in the 460/465 MHz range. They want to put up a repeater. Of course, they don't have their use case figured out completely, but they want me to put together a budget. They are planning to order DMR mobiles and HT's, so a DMR repeater is desirable but could go with an FM repeater. They have unrealistically low budget expectations. But, who better knows low budget repeaters than the experts herein? Should I be looking for a used Motorola 8400? A bodged-together pair of mobiles and kit? Another brand? At this point I don't know if they want a fixed location or a transportable unit. I think they will decide that they want a transportable unit because they really don't have access to a location high enough to cover the service area. Any recommendations or offers of used equipment would be appreciated. In another organization, I am part owner and trustee of a 900MHz repeater originally built on an MSF5000 platform and then upgraded to a newer Motorola. I am also part owner of a DMR UHF repeater based on the Motorola 8400. I also own two Yaesu DR-1XDR repeaters that are in service. I am pretty sure the DR-1XDR will not reach 460/465 but I haven't researched that yet. 73 Kevin N5KRG