QRP Labs QCX-mini

QRP-Labs QCX-mini

Assembled QRP-Labs QCX-mini with dummy load and replacement op-amps.

The QCX-mini is a continuous wave (CW), think Morse Code, ham radio kit that transmits and receives on one band only at around 5 watts. I had been waiting for the release of the QCX-mini kits for a while and was able to order one as soon as it was released. I also bought the aluminum case and the 50-ohm dummy load.

The kit was pretty straight-forward to assemble, I am very proud of my soldering on this kit, it is the best I have ever done, but…

When I was done and went through the alignment process it didn’t work. I went off to the QCX forums to see what I could do. Turns out there is an issue with the pre-installed surface mount op-amps used in some of the early kits. The solution is to check the voltages of each op-amp, there are quite a few of them, and then replace the ones that aren’t working as designed. Also using an oscilloscope is recommended to collect more troubleshooting information.

I bought a 10 pack of op-amps directly from China on eBay, they arrived a lot faster than I expected.

I bought an inexpensive scope for Ali Express, the DSO FNIRSI-150 Digital Oscilloscope full assembled with P6020 BNC standard probe, along with an extra probe. I’ve turned it on but haven’t learned how to use it yet. I am hesitant to use the scope as some members of the forums have shorted out their radios breaking a lot of components in the process, the surface mount components are so small I can see myself doing that.

This also led me to buy a hot air rework station. After a lot of research I bought the Sparkfun Hot-Air Rework Station – 303D. I chose this unit because I trust Sparkfun and they stock replacement heating elements for it.

But I have never soldered surface mount components or used a hot-air rework station so I bought a handful of SMD kits to practice on, there will be blog posts in the future about those.

As of right now I have a non-working QCX-mini which I am pretty bummed about. QRP-Labs is in the process of making some design changes to the radio and my plan is to buy one of the new kits when they are available instead of trying to fix the one I have. Even though the radio doesn’t work I am not upset about it, I believe they are pushing limits and doing their best to create a great kit experience and a great radio for us.

I look forward to getting my hands on the next version of the QCX-mini and using it to make a lot of contacts with it.

QSL Cards

QSL Cards

QSL Cards

I really enjoy receiving QSL cards. During the COVID event I am only sending cards to US addresses, but look forward to sending them around the world in the future.

Here are some of the cards I have received in the last few months.

Shack Power

Powerwerx MEGAbox

Top of the Powerwerx MEGAbox

We have been having some power outages in our neighborhood recently so my plans for a portable power station have been moved up. I have done a lot of research and decided to spend the money now instead of spending more time trying to find something cheaper.


The battery I have chosen is a Bioenno Power Lithium Iron Phosphate 12V, 40Ah LFP Battery (PVC, BLF-1240A) and here is why:

  • 12V: All of my ham gear runs off of 12 volts and there are many other available tools that will also run off of the 12 volts. Using a 24V battery is tempting but requires more electronics to get the voltages I am looking for.
  • Charge Current: 6A, this is easily supplied by an external power source or by solar panel(s)
  • Max Discharge: 40A, my radios need around 21 amps to function well
  • Lithium Iron Phosphate (LiFePO4): Lead Acid sealed, gel, or old-school are heavier than I want to deal with and do not provide a weight to power ratio that is appealing to me. There are also a lot of other things that make LiFePO4
  • 40Ah: I want to be able to keep a radio running along with phones and tablets for a full day… but I also have to keep a budget in mind so 40Ah is what I bought. A 100Ah battery would be a lot better but is out of my price range.

A negative of the Bioenno batteries is that they are not to be used in series or parallel as they each contain their own Battery Management System (BMS) which is not designed to be used in a multi-battery configuration. The BMS in Bioenno batteries is very highly thought of and works remarkably well.


I chose the Powerwerx MEGAbox because I wanted one box that can hold the battery, charger, extra cables, and more. I also wanted USB-C and a light built into the box, when I looked at small and simpler boxes then included the cost of adding USB-C and a light it was almost as much as the MEGAbox. The light is kind of annoying with its seemingly endless number of modes, but it is a good light and is easily replaced if it gets too annoying.

Powerwerx MEGAbox

Inside of the Powerwerx MEGAbox with PWRGate and PWRCheck+

I am able to fit everything into the box and didn’t have to add any holes or make any major modifications to it. More details below.

Power Management

I needed a way to charge the batter via external power and solar, preferably with MPTT. Based on reviews and information from podcasts and such I chose the West Mountain Radio Epic PWRgate. The Epic PWRgate is rated up to 40 amps, instantly switch from external power to battery power, will charge Lead Acid, Lithium Ion, and LiFePO4 batteries, has advanced features available when plugged in to a computer via USB, has an optional temperature probe, and comes in a metal case that is very easy to mount.

Power Measurement

To measure the power coming from and into the battery I chose the West Mountain Radio PWRcheck+ for its easy-to-read screen and ability to store a lot of data that can be read back later on a computer. The PWRcheck+ is totally unnecessary, but I wanted a way to track the performance of the battery and figured it would be a good way to troubleshoot any issues that may come up.

For use with the solar panel, I got a Powerwerx Watt Meter – DC Inline Power Analyzer to have an easy way to see how much power is coming through the panel. It doesn’t have the features of the PWRcheck+ but it doesn’t cost as much either.

Solar Power

For solar I got the Bioenno Power 100 Watt Foldable Solar Panel (BSP-100-LITE). Its too big to take hiking but is a great size to carry in the back of the car and use for a field-day or to charge the battery on a sunny day when the power is out. I wanted enough wattage to give a decent amount of power to a battery but still be foldable and easy enough to move around. For the price I could have gotten 2 aluminum framed panels with twice the wattage, but they would not have been very portable. At some point I will probably buy those panels, but for now the foldable panel will do.

Shack Power

My mains power supply is a SamlexPower SEC-1235M with the Fan and Powerpole mods documented by Phil Salas – AD5X. I have also upped the voltage it outputs to 14.6 volts which the Bioenno battery prefers.

Modifications to the Box

I removed the top PowerPole connecter on the MEGAbox, took the connectors out and replaced them with Yellow and Gray connectors, Yellow for Solar input and Gray for power supply input, and they run to the Epic PWRgate which also has the battery and “load” plugged into it. I use Velcro to hold the battery in place along with the PWRgate and PWRcheck+. That keeps the outside of the box clean and offers a decent amount of water resistance.

In Use

Day-to-day the box sits under the ham shack desk plugged into the SamlexPower power supply keeping the battery topped off. About once I week I leave the power supply turned off and run on battery power until it gets down to around 11 volts, at that point I turn the power supply back on. It works great. I take it outside every now and then to plug in the solar panel to get used to using that setup and learn how it works in the field. The solar panel is ok, but not amazing.

W6NEL Shack

The Shack with the Powerwerx MEGAbox under the desk

I am very happy with my Battery Box solution; it has already been tested in an outage where it kept my son’s tablet charged until the power came back on. I look forward to using it in an upcoming field day to really test it.

Amazing Ham Radio Results

Here is a map of the contacts I have made so far, a couple were using RemoteHamRadio.com but the bulk were from my home using FT-8 over 20, 40, and 80 meters. I really blows me away that I have been able to reach so far with a bit of wire strung up in the trees.

Map of the world with ham radio contacts marked

W6NEL Ham Radio Contacts

The State of My Radio Shack

In ham radio the place where you keep the bulk of your radios is known as your shack. I currently have 2 radios and 2 antennas set up in my shack.

Icom IC-9700

The IC-9700 is an all mode, tri-band transceiver covering 2 meter (144MHz), 70cm (430/440MHz) as well as 23cm (1200MHz). In my area there is not much traffic on the 70cm or 23cm bands. There are plenty of repeaters on 70cm, but they are rarely used.

I have the radio connected to a Comet GP-95N which works with all of the bands the radio supports. I have the antenna at the top of 1 and a half fence rale toppers which has it up around 27 feet high. Due to local terrain, both natural and mand-made, I struggle to get signals from the West, but am able to hit repeaters 60+ miles away to the North East 30 miles away to the South.

I primarily use the radio to check into local nets and to ragchew with people on the 2-meter repeaters. The North Fulton Amateur Radio League NF4GA repeater on 145.47Mhz is where I hang out the most, but I also regularly scan all of the repeaters I have in memory and drop into conversations every now and then.

I hope to get an antenna(s) at some point so I can work satellites and do Earth-Moon-Earth (EME) with the 9700, but that is probably a couple of years away due to cost and limited space to put antennas.

Icom IC-7300

The IC-7300 is a High Frequency (HF) plus 50MHz radio that covers the 6 to 160 meter bands.

It is connected to an MFJ-2010 Off-Center Fed Dipole covering the 6, 10, 20, and 40-meter bands. With the space that I have available I don’t think this antenna can be beat. I have it running from a tree in the front yard to a tree in the back yard with one end around 25 feet high and the other over 40 feet high.

With atmospheric conditions being what they are, I have decided to contrate on 20- and 40-meter bands using the FT-8 digital mode. I have been able to reach California, Washington State, North Eastern Canada, Belize, Ecuador, London, Spain, Hungary, and others. I am really amazed at how well such and inexpensive antenna is working for me.

With an LDG IT-100 Autotuner between the radio and antenna I am able to use the 80-meter band, but even with the tuner the Standing Wave Ratio (SWR) is high enough to cause my transmissions to be very weak.

Other Bits and Pieces

I also have HamClock set-up on a Raspberry Pi with the official 7 inch touchscreen so I can keep track of UTC time, solar activity, satellite positions, and sun/moon position. It is really handy.

I also have a Raspberry Pi set up with HamPi, but have not put it to use yet. The IC-9700 can be worked remotely without a separate computer, but the IC-7300 requires a local computer that you VNC into to control the radio.


I don’t plan on adding much more to the shack, but I do plan on setting up remote control of both radios, I think it would be really cool to be able to use them while traveling or even from another location in the house.

My next project will be adding a radio to the car along with studying for the Extra exam, learning Morse Code (CW), and other digital modes.

Studying for the Amateur Extra Exam

I found myself floundering a bit after passing the General exam. I had been in “study” mode for a few weeks and not having anything to study left me feeling… odder than usual. So I decided to start studying for the Amateur Extra exam, why not?

So far I have read the ARRL Extra Class License Manual cover to cover. I found it much harder to read than the Technician or General manuals, not because the content is more complicated or detailed, but because the writing and editing are not up to the same quality as those other manuals. There are many errors and many passages that are written in ways that confused me.

Now I am on to reading and listening to the The Fast Track to Your Extra Class Ham Radio License by Michael and Kerry Burnette. You may recognize the title and authors from the book I used to study for the General exam, but this is for the Extra. I really enjoyed the General book, both on the Kindle and on Audible so decided to stick with them for the Extra.

This time I have also purchased The Fast Track to Mastering Extra Class Ham Radio Math  along with the recommended Texas Instruments TI-30XS. Statistically, memorizing all of the formulas and being able to do all of the calculations is not necessary to pass the test, but I have decided it is something I would like to learn. There was a time in my life that I really enjoyed math, let’s see if I can rekindle that flame.

The Fast Track Ham website https://fasttrackham.com/ is also a great help with a handful of videos to help explain some more of the math and practice exams for each chapter of the books. I really like the way the “by chapter” practice exams build upon the previous chapters. That works well for me.

And to round out my studies I am also using HamStudy.org website by SignalStuff to do even more practice exams. I really appreciate how HamStudy allows you to work through all of the exam pool and use flash cards to find your weaknesses and concentrate study time on them.

My plan is to take it slowly and learn the material well and hopefully take the test sometime in November. Wish me luck.

Amateur Radio Technician Exam

As you may have read in previous posts I studied and took the Amateur Radio Technician Exam recently, it was a great experience.

I bought a study guide and read it on a Kindle and the iOS Kindle app then took around 100 practice exams using an iOS app. All told I spent about 5 days studying after work and at lunch.

Using the National Association for Amateur Radio’s website I was able to find a local test which was on a Saturday morning at a local church around the corner from my house.

I showed up a bit early and met a great guy in the parking lot who would be helping with the testing who had a remarkable radio system setup in his car. He told me that he had talked with people in Russia from the unit in his car that is pretty cool. After awhile other began showing up.

There was only two of being tested that morning; we began around 9am after the retelling of a number of stories about our experiences in the military. Most of us had been in the Navy.

The technician exam went fast and after being told that I had passed I was offered the chance to take the general exam. That sounded like a great idea so I gave it a shot. Sadly I did not pass that one, I had not studied for it and did not know the terminology used in the test.

I recommend that if you are going to take the technician exam to spend some time also studying for the general exam, you may be able to get both of them on the same day.

So that was on Saturday, on Monday afternoon the examiner called me to let me know that I was in the FCC database and I could begin transmitting!

I am now known as Dave Kilo Mike Four Julliet Whiskey X-Ray (KM4JWX).