Category Archives: Articles

Using WSPR Data to Study Propagation 40 & 20 Meter Bands

Many thanks to Jim (KX4TD) who writes:

Hi Thomas,

I am a subscriber and ham radio operator circa 1974. Like you (and a lotta hams) I started as a SWL using a transistorized Lafayette Radio receiver.

Last evening, I listened to the April 2022 Wireless Flirt podcast from Ireland where you were interviewed about the comeback of SW radio. Well done Thomas! You are one articulate dude!

I currently have a uBitx that I use for base and portable operation. We share an interest in POTA and other QRP field operations.

My latest obsession is WSPR. Attached [linked below], please find some of my WSPR findings on 40 meters.

73,

Jim KX4TD

Click here to download PDF: “Using WSPR Data to Study Propagation on the 40-meter and 20-meter Bands”

Thank you so much for sharing this and for the kind words, Jim! It’s strange, but I’ve yet to dive into the world of WSPR. I actually have a QRPLabs QCX+ transceiver kit I purchased specifically to explore WSPR. I just need to find the time to build it now! 

Thanks again for sharing your amazing report!

Which to choose? The Venus SW-3B or the Penntek TR-35?

Many thanks to Pat (N0HR) who shared following question in a comment:

Thomas

I simply love your videos – both your impressions of the gear and the activations themselves. Great stuff.

I’m curious – now that you’ve played with both the SW-3B and the Penntek TR-35, which is the favorite? Seems like they’re both roughly in the same price range.

Thanks for your fantastic channel and website

73,
Pat N0HR

Thank you for the kind words, Pat, and great question! Several people have asked me variations of this very question recently.

I like both radios, so I’ll frame this in a way that might help others make a purchase decision.

Spoiler alert: You really can’t go wrong with either radio and I feel it’s more a question of operator preferences. Continue reading Which to choose? The Venus SW-3B or the Penntek TR-35?

A little off-grid radio and offline camping!

If you were hunting POTA contacts last week, you might have seen my callsign pop up in the spots quite a few times at New River State Park (K-2748).

Morning reading along with a proper brew in my C.R.A.Q. coffee mug!

Our family decided to take a little break from everything–including the internet–and simply enjoy the great outdoors and a little camping in our small travel trailer (caravan).

Our ferocious guard dog protecting the camp site from hostile invaders. Note that she’s actually awake and alert. A rarity indeed!

It was amazing fun.

In terms of radios, I limited myself to two. While we had room for more, I decided in advance I wanted to spend some proper bonding time with my Yaesu FT-817ND.

I’m so glad I did.

I also brought the Elecraft KX2 but primarily planned to use it when operating off-site. This way, I could keep the FT-817ND system hooked up and ready for action at our camp site.

In fact, the KX2 remained in my SOTA pack for the duration of the trip as a grab-and-go. I had an absolute blast with it activating the summit of Mount Jefferson.

Solar power

This camping trip gave me an excuse to use a station accessory I purchased last year: my Buddipole Powermini 2.

The Powermini 2 is a very compact and capable charge controller with an input for solar panels, a battery, two DC outputs, and even a USB power output. A genius little device.

I’ve been asked a number of times why I don’t do solar charging in the field during my activations. There are a few reasons, actually:

  • First of all, my activations tend to be short in duration–perhaps 45 to 75 minutes. I could easily operate for a few hours on one battery charge with most of my QRP radios. In other words, I rarely need to recharge in the field.
  • Often, my field activation sites are shaded by choice. Since I like to hang wires in trees, those same trees would block sunlight from ever hitting my panels.
  • Finally, unless I’m testing a new radio, I tend to take the least amount of accessories necessary to complete the activation. This is especially the case with SOTA activations. Since I’m unlikely to use solar panels, I leave them in the car or at the QTH. I do, however, keep them packed and at-the-ready should the need arise.

I paired the Powermini 2 with PowerFilm Solar folding panels I purchased many moons ago at Hamvention (I’m guessing in 2012 or so–?). These were blemished units and I snagged them for a brilliant price. Looking back, I wish I would have purchased a few more.

They’re only 5 watts each, but I run them in parallel to feed the charge controller with the equivalent of 10 watts.

QRP gear is so efficient, these modest panels actually do a respectable job keeping the battery topped off. At New River State Park it helped that our picnic table was in full sunlight most of the day.

Sure, we had shore power at the site, but where’s the fun in that?

QRM

During the week, the site had low levels of RFI/QRM. That all changed during the weekend when new campers moved in along with their leaky switching power supplies and noisy inverters.

On Saturday, I found it too frustrating to try making contacts from the campsite–the noise floor was a steady S7 with peaks around S9 simply washing over all but the strongest signals. I regretted not packing my Chameleon loop antenna.

Instead of fighting the QRM, I abandoned it. I drove to a large isolated picnic shelter at New River and set up the KX2 and CHA MPAS Lite antenna.

The site was noise-free and I had amazing fun.

Videos

I made quite a few activation videos, so I’ll eventually post them with abbreviated field reports.

Frankly, I am still catching up from having been offline so long.

Thank you

Massive thanks to my good friend Eric (WD8RIF) who took care of QRPer.com while I was gone. He’s been moderating comments and making sure scheduled posts published properly. In fact, my friend Robert Gulley (K4PKM) was holding down the fort over on the SWLing Post too. I’m so thankful to both of them.

Also, many thanks to all of the hunters who worked me on multiple bands and in multiple modes. A special shot out to NE4TN who was a life saver and spotted me on several occasions when the connection between the POTA site and Reverse Beacon Network were down. Many thanks, OM!

Of course, I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon and the Coffee Fund. While certainly not a requirement as my content will always be free, I really appreciate the support. Your support actually helps to make radio fun like this possible.

Here’s wishing everyone an amazing weekend!

Cheers & 72,

Thomas (K4SWL)

Antenna Challenge #2: K6ARK End-Fed Half-Wave paired with the Elecraft KX1

I mentioned in a previous post that my personal Activation Challenge for 2022 was “to build a new antenna each month and deploy it at least once that month during a field activation.”

In January, I built a doublet with a military fixture/winder.

For February, I decided to purchase and build a counterpoise-less end-fed half-wave kit from from Adam (K6ARK).  This kit is available on Amazon.com for a mere $19.95 (affiliate link).

The build itself is pretty straight-forward and not terribly complicated. With that said, you do need a fine soldering iron tip and a little dexterity to manipulate these super tiny components. Adam includes instructions for building an EFHW with a counterpoise, without a counterpoise, or a random wire antenna. The coil can be configured as a a 49:1 Unun, 9:1 Unun, or 1:1 Balun.

If you choose the EFHW route you will need to solder one surface-mount capacitor on the board. If you’ve never worked with surface mount components before, take your time and use a good magnifying glass.

Blue Ridge Parkway (K-3378 NC)

On Monday, February 21, 2022, on my way back from town, I hopped on the Blue Ridge Parkway and drove to one of my favorite roadside spots on a grassy hill surrounded by trees.

Since I configured the K6ARK kit as a counterpoise-less EFHW, I wasn’t entirely sure how stable the SWR would be in the field. For this reason, I was a wee bit nervous pairing it with my MTR-3B since that little radio lacks an SWR meter and really needs a good match.

I decided, instead, to pair the K6ARK antenna with my Elecraft KX1 which has a built-in ATU that can both monitor the SWR and find an impedance match if needed. Of course, I turned off the internal ATU for the activation, but if I needed it, I knew I could engage and use it. Continue reading Antenna Challenge #2: K6ARK End-Fed Half-Wave paired with the Elecraft KX1

Leo’s complete QCX-mini field kit and ZM-4 manual tuner kit

Many thanks to Leo (DL2COM) who recently reached out after watching my livestream with Josh at HRCC on the topic of QRP/CW portable. 

Leo shared some photos of a complete radio kit he built around the QCX-mini along with a ZM-4 ATU kit he also recently built. Leo has kindly agreed to share these on QRPer.com.

Leo notes:

Attached is a photo of my ultra light kit.

It consists of a QCX-Mini 20m version (self-built), K6ARK EFHW, Palm Radio Pico Paddle, Eremit 2Ah LiFePo battery, headphones and a few cables.

I usually also carry a small arborist kit and if there is still room also the 6m mast from Sotabeams, depending on what I think will work best.

I chose a hard case and went for the Peli 1060 Micro. It has room for everything I need and it could easily hold a bit of RG316 coax in addition (even more if I chose to shorten the 30m arborist line).

The main benefit for me is that I really don’t have to worry at all about what’s inside – compared to a soft pouch. So I can just shove it into my backpack or glove box and forget about it since this configuration is a lot more rugged and water proof – while being slightly heavier. Continue reading Leo’s complete QCX-mini field kit and ZM-4 manual tuner kit

Repairing Ruby: Dr. Vlado performs surgery on the Elecraft KX1

I might have mentioned in a previous post that I named my little Elecraft KX1 “Ruby.”

I name all of my field radios that are permanent; ones I never plan to sell or trade at any point in the future. Ruby is firmly in that keeper list.

Why do I anthropomorphize field radios? That’s perhaps a discussion for a different day but I reckon it’s because I feel they have a lot of character and are, quite literally, trusted companions. They go with me on travels, hikes, and all sorts of outings.

Ruby love

So Ruby is actually the second KX1 I’ve owned.

My first Elecraft KX1 also had a dedicated Pelican 1060 case. There’s even room to fit an external Whiterock paddle.

The first one I purchased in 2008 as a reward to myself for learning CW (see photo above). I enjoyed that KX1 until 2016 when I sold it to help fund the purchase of my KX2.

I immediately regretted selling it, although it helped that I sold it to an amazing person.

In October 2020, I purchased Ruby and wrote a post about how great it was to be reunited with this gem of a radio.

 

At the time, I had no idea what a great deal I had landed.

Ruby turned out to be a four band radio (it was advertised as three), included the built-in ATU, and the package came with a simple wire antenna, three different coaxial DC plugs, a Pelican 1060 waterproof case, earphones, and a set of KXPD1  paddles. All of this for $300 US shipped.

I took Ruby on a number of field activations and couldn’t have been happier

Intermittent issues surface

In the summer of 2021, I started noticing some odd behavior.

Sometimes, after turning on the power switch, the rig wouldn’t completely power up. Instead of the typical two clicks we KX1 owners are accustomed to hearing, I only heard one click and neither the display nor any of the functions worked.

This was an intermittent issue–the next day it might power up as it should.

I did a little troubleshooting: I completely disassembled it, visually inspected all of the solder joints, and removed/cleaned and reinserted the firmware chip. This had no effect at all.

So, I took Ruby to one of the best radio repair technicians in the world who also happens to be one of my best friends: Vlado (N3CZ). He actually does a lot of repair and even has a radio repair website.

Dr. Vlado

Vlado (N3CZ) draws a crowd during a joint park activation on the Blue Ridge Parkway a few years ago.

Vlado will be the first to tell you that the worst problems to diagnose are those that are intermittent; it takes much longer to trace the source of the problem.

A few days later, Vlado sent me a message notifying me that the patient (Ruby) was on the operating table and surgery was about to begin. (See why I call him “Dr. Vlado”–?)

Vlado checked the circuit board very carefully. He found a few solder joints that needed work including a couple on the chip holder. In fact, he completely desoldered the chip holder and soldered it back in properly. Keep in mind here that the KX1 was only ever available as a kit, so quality had everything to do with the skill of the original builder.

He re-assembled Ruby and she worked perfectly.

A second operation

I put Ruby back on the air for a few months, but then in December 2021, a variation of the same issue resurfaced. This time, the “two clicks” in startup took a couple seconds longer than it should. Then it simply stopped working altogether.

Vlado wanted Ruby back in surgery ASAP, so I dropped her off at his “Emergency Room.”

Since the problem was no longer intermittent, Vlado quickly sorted out the main issue: a faulty encoder.

I should note here that since the KX1 hasn’t been produced by Elecraft in many years, there’s always the fear that a replacement part might already be “unobtainium.”

I called Elecraft support and fortunately for KX1 owners everywhere, the encoder is one Elecraft uses in a few of their radios. They have a healthy inventory and the part costs less than $5.00. Woo hoo!

Admittedly, when I placed the order, I also order a few extra parts I thought could fail in the future and might be difficult to find: 3.5mm jacks, pots, and even the LED screen. If I was paying shipping anyway, why not add a few extras? The parts are all very reasonably priced.

The KX1 doesn’t seem to have a lot of unobtainium in it–I seem to recall though that the firmware chip can no longer be ordered from their website and neither can the pushbuttons.  I bet you could find other pushbuttons if needed, though.

I had the encoder shipped directly to Vlado and he completed Ruby’s operation in short order. Thank you, Vlado!

To the field!

I’m so happy to have Ruby back on the air! We’ve chased numerous parks and summits in the past week and I took her on an activation Monday, pairing her with my recently-built K6ARK EFHW antenna.

I’ll post an activation report and video in the coming weeks.

KX1 advice

Elecraft KX1s have become as rare as hen’s teeth lately. You’ve no doubt noticed this if you’ve been looking for one. I’m sure I could sell my KX1 package in a heartbeat for twice more than I paid a year and a half ago. It’s a little insane, really, but I get it.

If you’ve been looking for a used KX1, I would offer the following notes/advice:

  • Since these were only available as kits, you might ask the seller about the original builder and/or have them take photos of the soldering work inside prior to purchasing.
  • Assume issues might arise with time. With radios like this, I mentally set aside at least a couple hundred dollars for future replacement parts and/or repairs.
  • Keep in mind that as with any other radio that’s a bit long in the tooth, you may find that some components are simply no longer available. That’s the risk we take being custodians of these cool little rigs.
  • Actively looking for a KX1 at time of posting (Feb 2022)? Note that interest in particular radio models waxes and wanes over time. With a little patience, you’ll eventually find one. I’ve seen this happen with so many other radios over the years.
  • The KX1, as with most Elecraft radios, comes in a number of configurations and you need to be aware of this if purchasing. Some only have two bands, some have three, and some have four. I’m not certain if band modules are still available via Elecraft, so you might get stuck with the configuration you purchase.  Also, the internal ATU was an option; don’t assume the one you’re purchasing has the ATU.
  • KXPD1 paddles are very difficult to find these days. It’s a big bonus if your radio comes with them. Not everyone likes these paddles, but the version I have now seem to work really well, actually. N6ARA Tiny Paddles are a brilliant little replacement, but you might wish to make a 3D-printed holder to attach the the paddle point on the front of the radio to take a little strain off of the 3.5mm jack inside.

I should also add that Vlado is a brilliant repair technician and has worked on numerous Elecraft, Icom, Yaesu, Kenwood, and Ten-Tec models over the years–if it’s solid state, he can repair it. If you ever need his services he can be reached via his website HamRadio.repair.

Also, Dave (W8FGU) is an Elecraft employee that is devoted to their legacy radios like the KX1/KX1/K2, etc. He’s a great guy, brilliant resource, and I believe can also arrange repair, if needed.

Enough blogging: I think Ruby and I will chase a few summits now while I finish my morning cuppa’. 🙂

Rich builds a simple GX12 key/paddle adapter for the Discovery TX-500

Many thanks to Rich (KQ9L) who shares the following tutorial describing how to build a compact key/paddle GX12 connector for the lab599 Discovery TX-500:

This adapter is simple, compact, and eliminated the need for yet another wire extension.

How to build a Discovery TX-500 key adapter

I love my Lab599 Discovery TX-500 however I was frustrated with all the extra “wires” hanging from the connectors on the rig.

I took inspiration from Vlad Solovey (RA9QAT) who posted his design for a small and compact 3.5mm jack that allows you to connect your paddles directly into a GX12 connector. Continue reading Rich builds a simple GX12 key/paddle adapter for the Discovery TX-500

Portable Doublet-Building Party & my 2022 Activation Challenge!

This past weekend, my good friend Vlado (N3CZ) and his wife came over to the QTH for the afternoon. It’s been a while since our families got together, so it was fantastic to hang with them.

I’ve been trying to tempt Vlado to do more field activations–we’ve done a number together in the past and it has always been loads of fun. Thing is, both of us have pretty active family/work lives, so it’s challenging to make schedules work out.

Nonetheless, our 2022 goal is to do at least one activation per month as a team!

MK-911

If you recall, a couple months ago, I posted an activation report and video using my buddy Eric’s 40-10 meter doublet. I called it a “stolen” antenna because it had been on loan to me for so long, I think Eric forgot it even existed.

Exhibit A: The stolen antenna.

Eric’s doublet was build around a Hughes Aircraft MK-911 Dipole Fixture that was designed and manufactured for the US Military and appears to have been part of the PRC-74 manpack radio-set.

I had assumed Eric found this as a one-off at a military surplus sale. Turns out Eric (and a few readers) made me aware that it was available at Fair Radio Sales in Ohio for $10.

Image of the MK-911 from Fair Radio’s product catalog.

In fact, here’s a link to the MK-911.

I decided to buy two of them: one for me, and one for Vlado. The temptation was strong to purchase a few more just for the 30 feet of 72-ohm military-surplus twinlead, however I understand that there’s a limited inventory and wanted others to be able to purchase this gem.

I was also thinking this antenna fixture would pair beautifully with Vlado’s Yugoslavian RUP-15/PD-8 manpack or even his IC-703 Plus.

Doublet time!

While our wives were catching up, Vlado and I made our way to the storage shed and opened my antenna parts boxes.

I did a little digging and found what I was looking for: some wire I purchased at a thrift store many years ago.

This wire has a black jacket that’s quite slick. Guessing it might be 20 gauge and might even be teflon coated. It was ideal for antennas and eyeing it, I thought there might be enough for two doublets.

For a Norcal-inspired doublet–which covers 40-10–we would need two 22′ legs. I decided (prior to cutting) that I wanted our doublets to go as low as 60 meters (5,332 kHz) and cover everything above. 60 meters is such a useful band. Thing is, I hadn’t done research into suggested leg lengths in advance.

We decided to pick a longer non-resonant length and just give it a go. If it worked, great–if not, we’d cut them down to 22 feet and be happy with 40M and up.

We cut the legs to 31 feet, so there’d be a total of 62 feet of wire in each doublet. Many thanks to my daughter Geneva (K4TLI) for helping stretch, measure, and cut the antenna wire with us!

Assembling the antennas was incredibly simple as there are built-in binding posts attached to the twin lead on the winding fixture.

Vlado and I both decided to use the winder as the center-insulator of the antenna. This is actually how this military fixture was designed to be used. The negative, of course, is that the center insulator is relatively heavy. This isn’t a problem for me at all since I use super strong arborists throw lines to deploy my antennas.

From WD8RIF’s website.

Eric (WD8RIF), by the way,  actually detached the twin lead from the fixture and posts on his unit and built a new center-insulator from a discarded 35mm film canister (see photo above). He wanted to keep the weight down so he could support the center of the doublet on his fiberglass masts.

Testing QRV!

I had planned to hook up the doublets to my RigExpert antenna analyzer, then I realized it was essentially an unnecessary step.

The big question for me was, “Will my Elecraft KX2 find impedance matches on 60M and above?”

Vlado and I connected the doublet to the KX2 and tuned to 5,332 kHz. After confirming the frequency was clear, I pressed the ATU button. The KX2’s internal ATU churned for a couple of seconds and confirmed a 1.4:1 match.

Score!

We checked all of the bands above 60M and the matches were even better.

Standing in the middle of my driveway, I asked Vlado to load the POTA.app website and look for CW spots.

I couldn’t put the antenna away without chasing some parks!

We then proceeded to work about three stations on the air in CW with 5 watts. All of them gave us 599 reports!

Vlado chasing a POTA activator.

It was serious fun.

As I mentioned to Vlado, it might have been the first time I’ve ever used an HF “Handy Talky” with a doublet antenna!

In the end, we both walked away with two effective military-grade field doublets. A perfect antenna for our monthly “Team Baklava” activations.

2022 Activation Challenge

Last year, my personal challenge was to validate all of my park and summit activations with 5 watts or less.

Since I’m very much a QRPer and primarily a CW op these days, this turned out to be low-hanging fruit; lower than I would have guessed in this part of the solar cycle.

For 2022, I plan to continue the 2021 five watt challenge and add another layer…

This year, my challenge will be to build a new antenna each month and deploy it at least once during that month during a field activation. 

The MK-911 doublet will count as January’s antenna.

I’m going to allow myself to build these antennas from anything and everything. I might even cannibalize a few of my broken/worn-out antennas.

I do want to keep these projects quite simple and easy for anyone to build in one sitting. I’ve gotten so much positive feedback from the super-simple speaker wire antenna I built in the field last year no doubt because it was so easy to build and super cheap.

I already have enough ideas to take me through the summer months, but I plan on dusting off some of my antenna books for more ideas!

With that in mind, I welcome your input! If you have a suggestion, feel free to comment!

POTA Activation: In the Presence of a North Carolina Icon!

Dear QRPer readers:

As you likely know, my activation reports typically run a few weeks behind.  Although I’ve got several in the pipeline, I pushed the following report to the front of the line. 

You might brew a cuppa’ coffee or tea for this one. 

Here’s wishing you and yours very Happy Holidays and Merry Christmas!

73,

Thomas (K4SWL)


A Special Holiday Activation

As mentioned in my previous activation report, we’ve spent the past week on the Outer Banks of North Carolina; specifically, Hatteras Island.

It’s been amazing.

If you’re not familiar, the Outer Banks (OBX) is a 200-mile (320 km) long string of barrier islands off the coast of North Carolina and southeastern Virginia that separates the Pamlico Sound,  Albemarle Sound, and Currituck Sound from the Atlantic Ocean.

No trip to the Outer Banks would be complete without visiting North Carolina’s most iconic structure: the Cape Hatteras Light Station in Buxton, NC.

Cape Hatteras Lighthouse

On Thursday (December 16, 2021–last week) the weather was stunning, so my family took a few long walks on the beach, explored Hatteras Island, and spent the afternoon at the Cape Hatteras Light Station which is located within the Cape Hatteras National Seashore.

The Cape Hatteras lighthouse is a North Carolina icon and arguably one of the most recognizable lighthouses in North America due to its height, its age, and the black/white helical daymark paint scheme. Continue reading POTA Activation: In the Presence of a North Carolina Icon!

My Motto? Less theory, more practice!

I don’t often read comments in ham radio forums and discussion groups. 

Recently, however, I was trying to dig up information on a field antenna design and the search results lead me to two articles and discussions on two of the most popular ham radio sites on the internet. 

I read through the comments and (you might have guessed) was really disappointed with the number trolls who seemed to thrive in that fertile environment. It blows my mind that discussions like these seem completely unmoderated. I assume it’s a conscious decision since we seem to live in a society that rewards drama and division–I assume this leads to more site traffic and thus more revenue.

It’s a shame. It would be incredibly discouraging to a new ham who is reading the same article and comments looking for ideas. Gives one the impression the hobby is full of (I’ll keep my language clean here) schmucks.

But I digress…

What was perhaps equally discouraging were all of the comments from those who were trying to explain to the authors how the antenna design in their article simply wouldn’t work.  Even when the author posted positive results/data from having used the antenna. 

While not all of the naysayers were being rude–and sometimes in their roundabout way I’m sure they felt they were being helpful–I can’t help but feel sorry for them.

The naysayers, that is.

Why? These are people who are afraid to experiment. Continue reading My Motto? Less theory, more practice!