The post by Peter, G4ISJ, on the SOTAwatch site gave a brief overview of the new 'MTR' or 'Mountain Topper' rig and the fact that, as usual with Steven's kits, the sales had been brisk. I looked at the specifications and thought that it would be a fantastic kit and at $100, I thought it was very good value for money, if not a steal! I thought I had missed my chance to order a kit as Steven had made only 150 kits available, each with it's own serial number, Elecraft style.
I joined the ATS (Appalachian Trail Sprint) Yahoo group immediately with a view to learning more about the rig and to make sure that I would be informed of any further availability of MTR kits.
I was very pleased to see a post on the Yahoo group a day later stating that around 50 MTR kits remained available. With my 33rd birthday just around the corner, I thought the MTR would make a superb present. With my XYL's permission (!) I placed an order. I had a couple of days of wondering before Steven confirmed via email that my order had been successful.
My kit, serial number 131, arrived just before my birthday, I wanted to start building it straight away, but construction had to wait until after we had been away on a family holiday.
The MTR kit is almost fully based on surface mount components. I don't mind soldering SMD's as I work for an electronics company doing repairs on circuit boards.
I found the quality of the kit and instructions excellent, although I would say that the MTR is not a kit for beginners. I built the kit using a fine tipped, temperature controlled iron, soldering each component by hand, one at a time. I took my time building the kit over a couple of weeks.
Unfortunately the replacement processor chip had suffered a bit during it's Atlantic voyage and had bent pins, which took me a while to notice! I tried for ages to mount the processor chip, before I realised that some of the pins weren't actually touching the board! Viewed from above, all looked fine, but when viewed from the side, the problem was obvious. I put the processor chip flat on the desk, holding the body down with one finger whilst I pushed the pins down as firmly as I dared using the butt end of a pair of tweezers. This worked well, the pins now touched the pads on the board. The soldering of the processor then went smoothly.
Unfortunately the board suffered a little bit during my initial attempts to mount the processor, this can be seen if you look carefully at the photo - the solder resist on the right hand side of the processor has been scratched slightly, but these things happen!
The MTR was designed to fit inside an Altoids tin and I felt it would not be right to fit it in to anything else but an Altoids tin. I managed to find a tin (and a spare, which would be needed due to drilling mistakes!) of Altoids at my local supermarket, although at £1.25 each, they are not exactly QRP priced these days! ;-)
It took quite a lot of work to get all the holes drilled in the right position, the PCB is quite a 'cosy' fit into the tin, but I managed OK in the end. The connectors can't be fitted low enough down the sides of the tin and still allow the lid to close, this is due to allowing for clearance of the PCB. Notches had to be filed out of the lid with a 'rat tail' file to allow the lid to close. The tin is actually used up side down, as the photos will make clear.
Most builders are using their own graphics for the top of their MTR tins, but I used the one provided by Steven, KD1JV. I like to think that I have done a good job with MTR serial number 131 and I hope that KD1JV himself would be pleased with my efforts.
The specifications of the KD1JV Designs MTR from the build instructions:
Dual band, 20 M and 40 M typical, 30 M and 80 M possible.
MDS: ~0.2 uV
Small signal band width ~ 500 Hz
Audio output limited to ~ 800 mv p-p
Headphone output, 16 ohms min recommended.
Minimum current (no signal) ~35 ma
2.5 watts @ 9 volt supply typical
Spurs -50 dBc or better
I tried the MTR out from my local SOTA summit, Rombalds Moor (G/NP-028) a few weeks ago and I was very impressed with the performance. The receiver is excellent, very quiet indeed and very selective. The lack of volume control is not an issue whatsoever. I have yet to tweak the transmitter portion of the rig, but from 11v supply, my power meter was showing a healthy 4+ Watts on TX.
Overall, the MTR is an amazing rig!