My Mountain Topper Radio project

After doing some portable operations with the KX3, I felt that having something smaller and lighter would allow my pack to get smaller and smaller. The only problem is that there is nothing smaller than the KX3 that is comparable unless you get a CW only rig. I decided to get the MTR (Mountain Topper Radio) that was developed by Steve Weber (KD1JV). It’s a 2.5-5W QRP CW rig that gives you the options for two bands.

The problem is that the MTR kits are produced and sold in small quantities with high demand.  I’ve learned that Steve developed a version 2 of the MTR (3 bands) and had a pre-sale. Even though he gave out the wrong URL, people managed to figure out the correct URL and sold out within hours. I found out a tad too late and ended up having my money refunded.

I was a little bummed out. I was very excited that I might get this kit. I’ve never worked with surface mount devices and the CW only aspect of the rig would sort of force me to actually learn CW. After making my disappointment known, a local ham mentioned that he had an unbuilt kit from the orginal run that he might be willing to sell to me. Making fun of him didn’t help but I think the fact that I might learn CW might have compelled him to sell me his kit.

What did I just do?

Once I got my hands on the kit and took it home I inspected it (what ham doesn’t when they get a new toy?). That’s when I saw the components I’ll be dealing with. Very tiny resistors, capacitors and IC’s. The toroids were tiny and were not wounded.  Everything is so… small. I have built ham radio related kits before but they were all through hole meaning that the parts like the resistors and IC’s had legs and pins the fit into the holes. They were large enough to where I can easily work with them.

I am not prepared for surface mount work. My soldering iron is this $10 Radio Shack 35W fixed iron. I knew it was not ideal for SMT as I have tried and failed using that iron. I need to learn how to solder surface mount and I need the proper gear to do it with. I’ve learned over the years that working with the correct tools makes the job much easier.

New Tools In The Shack

I’ve learned the hard way many times over that having the proper tools can make things a lot easier. I feel that I have everything needed for the job except for a soldering iron. I looking at the sub $40 Chinese type irons but I stopped myself from purchasing one. I wanted an iron that can last me for many years so I ended up purchasing a Hakko 888D soldering iron. At around $100 I felt that it was worth the purchase.

The Build. Day One!

Soon as I got the iron in, I went straight to work. Following the assembly guide I started with the IC’s and the MCU. I felt that you are starting with the hardest part of the job by soldering small SMT IC chips with small leads and small gaps. I avoided installing the MCU and DDS chips until the other ICs were installed.  Once all the IC’s were installed, I used a jewelers loop and checked my connections. The MCU was crooked a bit and thought it was still good so I kept chugging along. I installed the resistors on the bottom of the board and called it a night.


My working area. You’ll see the board with solder, tweezers, assembly manual, solder, 10X  Jewelers loop, desk lamp with magnifying glass and my new soldering iron. When I purchased the soldering iron, I also purchased different sized and shaped tips.

The Build. Day Two

Next day I got back from work and installed everything else.  It wasn’t really bad as I thought. The soldering Iron was tight in some places but it appeared everything went quite well.


Here is a close up of my soldering. It could be better but I would say not too bad considering I’ve never done SMT work before.

Power On Time.

I didn’t want to wire up the power, headphones or anything else because I was going to design a case but in order to make sure it worked. I needed to wire it up.  Soon as I hooked up the battery… Nothing!  It did’t lite up, It didn’t beep. The only thing I notice was a slight noise in the headphones. Sounded like the noise of when you turn something on.

What Went Wrong?

As panic starts to set in, I was worried that I now have a nice new expensive brick  on my hands. All that time, energy and money spent on the kit and tools needed seemed be wasted. Out came the jewelers loop and soldering iron. I double checked every connection. Then I took out the multimeter and followed the troubleshooting guide in the manual and started checking voltages coming out of the regulators. Everything was checking out. The only thing I see is that the MCU was a little bit crooked.

I tried re-soldering the MCU but it proved to be very difficult. I used solder wick and suction tools that did not help, the chip would not move for me. For me the only choice was to remove the MCU. But how? After some internet searching I decided to use enameled wire and snake it under the chip where the leads meet the chip. I then touched the soldering iron to the leads and slowly pulled the chip off.


Using that method allowed to me to remove the chip, but in the process I damaged the MCU. The above images is not representative of my soldering work. It was more of a panic move and I just wanted to get the chip off without damaging the pads or board. The pads were in great shape and I’m just lucky nothing else happened.

Dealing With Steve Weber

Well it’s obvious the chip will need to be replaced. There are two options available. Beg steve for a new chip or purchase the MCU and flash it using a MSP Launchpad. I almost went the latter because Steve just released V2 and I am sure he was busy dealing with that and life in general but I decided to e-mail him anyways.

Dealing with Steve was a pleasure. I know these radios is not his full time job but he replied within a reasonable time and he was willing to send out a pre-programmed chip for my version of the MTR. Since I was having him sending me stuff, I purchased a case because the price he was asking was more than fair.

Attempt #2

Now that I have the new MCU, I promptly installed it. This time I quadruple check to make sure the chip was aligned properly before soldering. It went much better.


When I applied power I jumped for Joy as I saw the LED come to life and the sounds of CW in my headphone. I did some initial testing and then installed the last toroid.

It’s… ALIVE!!! ALIVE!!!  

Now that it turns on, it’s time to make the adjustments needed for proper operation. Thankfully I have Acquired the test gear I needed over the years from mostly local hams looking to clean their shack. I have a decent frequency counter, oscilloscope and a station monitor.

The manual found on the Yahoo Groups page provided step by step installation and tuning. It made things a lot easier.


First thing I did was adjusted the reference oscillator frequency to match exactly 10MHz. This was very easy. Just pushing a button until I see 10Mhz on the counter. There are reference points on the board to where you can easily measure things.


Adjusting the LO to find the center of the passband. This was a little tricky because I didn’t fully understand the manual and process. In the tuning mode the MCU sends out a tone and I adjusted it by watching the signal peaking on my scope while counting the steps between the peaks. I then went backwards only half of the steps. Hopefully it was done correctly. For me, this was the hardest part of tuning.


Here I am adjusting the receivers filters. With the station monitor I injected a signal into the MTR through the antenna port and adjust the band capacitors until the signal was at it’s loudest. I did the same thing on the other band. This was quite easy.

Last thing I did was hooked it up to a dummy load and checked for output wattage. Using a variable power supply and a DMM hooked in-line, I’ve sent out a tuning signal and adjusted the power supply until the DMM read 9Vdc with a TX load. I was seeing approx 2.5W which is within spec.

Time to get one the air

Now that it’s built and tested, It’s time to get on the air and see what I can (not) do.


Heh, it’s smaller than my paddle.  What’s great about CW is that you don’t have to call CQ over and over again hoping someone would come back to give you a signal report. Just call CQ a couple times and head over to the Reverse Beacon Network where you can see almost in real time where your signal is being heard. There are receivers all over the world scanning the bands for signals.


Here are my results using just a crappy 9V battery. I am pleased to see that not only are stations hearing my signal, but they are on the frequencies that the MTR is tuned to. While I was testing the worst thing happened… Someone replied. I tried very much to work the person. I know the call was a K2 something but that’s all I could make out.

Final Thoughts

This was my first actual kit that I built, It’s also the first time that I ever worked with tiny surface mount devices and even though I messed up the MCU, it was really fun to build. Soldering SMD seems to be a nightmare but after the first couple of parts, it felt real easy and it felt that I was working much quicker compared to through hole parts. This project is also a big kick in the ass to learn CW because I want to use this rig. I’m all about packing very lite when it comes to SOTA and even though I love the KX3, I feel it would be more of an adventure using the MTR. We’ll see.

Thanks for reading!

– Jeff




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