Tag Archives: QRP

The Elecraft KX1: Reunited and it feels so good.

The Elecraft KX1

A few weeks ago, I published a post about radios I’ve regretted selling or giving away.

Number one on that list was the Elecraft KX1.

Within a couple hours of posting that article, I had already purchased a KX1 I found on the QTH.com classifieds. It was, by any definition, an impulse purchase.

The seller, who lives about 2 hours from my QTH, described his KX1 as the full package: a complete 3 band (40/30/20M) KX1 with all of the items needed to get on the air (save batteries) in a Pelican 1060 Micro Case.

The KX1 I owned in the past was a four bander (80/40/30/20M) and I already double checked to make sure Elecraft still had a few of their 80/30 module kits available (they do!).  I do operate 80M in the field on occasion, but I really wanted the 80/30 module to get full use of the expanded HF receiver range which allows me to zero-beat broadcast stations and do a little SWLing while in the field.

The seller shipped the radio that same afternoon and I purchased it for $300 (plus shipping) based purely on his good word.

The KX1 package

I’ll admit, I was a bit nervous: I hadn’t asked all of the typical questions about dents/dings, if it smelled of cigarette smoke, and hadn’t even asked for photos. I just had a feeling it would all be good (but please, never follow my example here–I was drunk with excitement).

Here’s the photo I took after removing the Pelican case from the shipping box and opening it for the first time:

My jaw dropped.

The seller was right: everything I needed (and more!) was in the Pelican case with the KX1. Not only that, everything was labeled. An indication that the previous owner took pride in this little radio.

I don’t think the seller actually put this kit together. He bought it this way two years ago and I don’t think he ever even put it on the air based on his note to me. He sold the KX1 because he wasn’t using it.

I don’t know who the original owner was, but they did a fabulous job not only putting this field kit together, but also soldering/building the KX1. I hope the original owner reads this article sometime and steps forward.

You might note in the photo that there’s even a quick reference sheet, Morse Code reference sheet and QRP calling frequencies list attached to the Pelican’s lid inside. How clever!

I plan to replace the Morse Code sheet with a list of POTA and SOTA park/summit references and re-print the QRP calling frequencies sheet. But other than that, I’m leaving it all as-is. This might be the only time I’ve ever purchased a “package” transceiver and not modified it in some significant way.

Speaking of modifying: that 80/30 meter module? Glad I didn’t purchase one.

After putting the KX1 on a dummy load, I checked each band for output power. Band changes are made on the KX1 by pressing the “Band” button which cycles through the bands one-way. It started on 40 meters, then on to 30 meters, and 20 meters. All tested fine. Then I pressed the band button to return to 40 meters and the KX1 dived down to the 80 meter band!

Turns out, this is a four band KX1! Woo hoo! That saved me from having to purchase the $90 30/80M kit (although admittedly, I was looking forward to building it).


The only issue with the KX1 was that its paddles would only send “dit dah” from either side. I was able to fix this, though, by disassembling the paddles and fixing a short.

Although I’m currently in the process of testing the Icom IC-705, I’ve taken the KX1 along on a number of my park adventures and switched it out during band changes.

Indeed, my first two contacts were made using some nearly-depleted AA rechargeables on 30 meters: I worked a station in Iowa and one in Kansas with perhaps 1.5 watts of output power.

I’m super pleased to have the KX1 back in my field radio arsenal.

I name radios I plan to keep for the long-haul, so I dubbed this little KX1 “Ruby” after one of my favorite actresses, Barbara Stanwyck.

Look for Ruby and me on the air at a park or summit near you!

Parks On The Air 101: Some real-time, real-life videos of a typical POTA activation using the Icom IC-705

On Monday (October 19, 2020) I received an inquiry from Dale (KI5ARH) only an hour or so before packing up my radio gear to activate Lake Norman State Park (K-2740).

Dale is interested in using his recently acquired Icom IC-705 to get involved with Parks On The Air (POTA) and play radio in the field.

What’s in my field kit

Dale was curious about all of the components of the field kit I use with the IC-705, so I made this video:

Equipment links:

Since I had already set up my phone to record the video above, I decided to make a couple more.

I thought there might be some value in making real-time videos showing what it’s like operating CW and SSB during a POTA activation.  The videos have no edits and haven’t been trimmed.  It’s as if the viewer were there at the activation sitting next to me at the picnic table.

Operating CW with the IC-705

After setting up my station, I first started on the 40M band in CW. I meant to start the camera rolling during tune-up, but forgot to hit record. The video begins after I’d made a few CW contacts, but shows what it’s like changing bands and relying on the Reverse Beacon Network (RBN) to pick me up then the POTA website to auto spot me.

Note: to be automatically spotted by the RBN, you must schedule your activation via the POTA website in advance, or have been already spotted by yourself or someone else, so the system will know to look for you.

My video cut off abruptly due to a low battery message. I had to give my iPhone a quick power charge to make the next video.

Operating SSB with the IC-705

After operating CW for a while, I plugged in the hand mic that ships with the IC-705 for a little SSB action. My main goal with this video was to show how I call CQ and use the voice keyer memories in order to manage the field “work flow” process.  I also speak to how important it is to either self-spot or have a friend spot you to the POTA network while operating phone.

I spent so much time setting up and running the camera, I wasn’t actually on the air for very long, but I easily managed to achieve a valid activation and had a lot of fun in the process.

I’m not a pro “YouTuber” as I say in one of my videos. I much prefer blogging my experiences rather than “vlogging,” I suppose.

Still, I think I’ll do a few more “real-time” videos of POTA activations and speak to the various techniques I use to activate parks. Since these videos aren’t edited for time, they may not appeal to the seasoned POTA activator or QRPer–that’s okay, though. My goal is primarily to assist first-time POTA activators.

Have you been activating Parks or Summits lately?  Do you have any advice or suggestions I failed to mention? Or do you have suggestions for future topics? Please comment!

Have you ever regretted selling a radio? I have. More than once.

The Elecraft KX1

I’ve been a ham radio operator since 1997. In the first decade of my amateur radio life, I only owned three HF radios (Icom IC-735, Yaesu FT-817, and a Ten-Tec OMNI VI+).

As I got into writing, blogging, and evaluating/testing radios, that number increased. Quite often, radios are only in my shack for a short period of time as I alpha/beta test and/or review production run units.

I try not to get attached to radios because I know they’re often only temporarily in the shack.

Over the years, there have been a few radios I’ve sold for…let’s say “pragmatic” reasons. It’s very rare that I purchase a radio with the intention of keeping it only to find that I want to sell it shortly thereafter. More likely than not, I sell because the radio is redundant (how many field radios does one need–?) or because I’m raising money to make a larger purchase.

Here’s a short list of transceivers I regret selling/trading:

Elecraft KX1

I sold my Elecraft KX1 in 2016 in order to help purchase my Elecraft KX2. It was a solid decision. The KX2 has become my favorite field radio (here’s my review) and was SO much more versatile than the KX1. Still: I really miss the KX1. I loved how bare-bones it was, I loved the top-mounted controls and the fact I often operated it while simply holding it in my hands. The controls were super easy to use even with gloves on in the winter. Plus, it was “cute” in a boxy Elecraft sort of way. If I ever find a deal on another one, I might grab it!

Elecraft K2

I’ve owned both the Elecraft K2/10 and K2/100. Funny story: I acquired a K2/10 in 2008 or so and absolutely loved the radio. After I purchased my KX3 in 2013, however, it was rarely used and sat on my shelf as a “back-up” radio. Eventually, I decided to sell it and did so with ease. Within a week of selling it, a local ham posted on our club email list that he was selling a K2/100 in an SK sale. He wasn’t sure of all of the upgrades, but knew it was a K2/100. The price was very low, but there were no takers after a few days, so I bought it. I used the K2/100 for a few years and it served as a back-up 100 watt radio. I eventually sold it, though, to purchase a KXPA100 used. Now, of course, I do miss that radio. In truth, I’ll likely never purchase one again, because I own so many other transceivers–and the KXPA100 is truly a genius compliment to the KX2 and KX3–but I do have an affinity for that fine rig.

Index Labs QRP++

QRP+ ad from the Dec 1995 issue of QST. Source: WD8RIF

My buddy Eric (WD8RIF) is to blame for this radio. He owned an Index Labs QRP+ for years. He loved operating it in the field and at home. It was the first QRP radio I ever saw in action (at this particular field event). More than 10 years ago, I happened upon a great deal on a QRP++ and instantly bought it. It was SO much fun to operate—super simple, yet had pretty much every feature you’d want in a basic transceiver. I sold it because, frankly, performance was sub-par especially if you ever planned to use it in an RF-dense environment. The receiver front end would simply fall apart, for example, during contests or events like Field Day. Otherwise, it was a pretty sensitive radio. It was incredibly portable and had that awfully “cute” cube form factor. Another fear I had was availability of replacement parts. Index Labs was no longer in business and there were quite a few obsolete parts in the radio. Perhaps it’s a stretch to say I “regret” selling it because, in truth I don’t. But when I see them at hamfests, I’m still tempted to grab one if for no other reasons than nostalgia.

Yaesu FT-817

I purchased an ‘817 shortly after they were introduced in…what…2000? At the time, there wasn’t a radio like it on the market: it was the most compact full-featured HF/VHF/UHF radio in the amateur radio world. Back then, I was living in the UK and travelling all over Europe. I purchased the FT-817 with the idea that I could play radio while, say, working in Hagen, Munich, Chartres, Berlin, Torino, Pescara, or any of the other fabulous sites I regularly visited. I did pack the FT-817 on a number of occasions but since I’m a one-bag traveller, it was scrutinized to some degree at most airports—especially post-9/11. Also, my first production run model blew its finals within the first two years of ownership (a common problem that was addressed by Yaesu shortly after that production run).

I had the finals replaced by Burghardt Amateur Center but rarely used the FT-817 after that. Truth was, I found the radio’s front panel to be too compact and the embedded menus really frustrated me. But back then, I wasn’t as much of a field op as I am now and I could really appreciate a compact, affordable radio that also sports VHF/UHF operation—especially for SOTA activations. Plus, few transceivers have enjoyed a product life like the FT-817/818 which is now pushing 20 years on the market. While the 817/818 lacks a number of features I’ve grown to love (like memory keying) I do believe I may purchase an FT-818 next time they go on sale. In the end, I miss the rig.

How about you? Any regrets?

Please feel free to comment with any radios you regret selling, trading, or giving away over the years and tell us why you miss it! Inquiring minds want to know!

Operating the Icom IC-705 QRP transceiver in CW with full break-in QSK

Readers have been asking me about operating the new Icom IC-705 in CW; specifically if the T/R relay is noisy and how full break-in QSK sounds.

Here’s a quick video that should answer a few of those questions:

I made this video yesterday while testing the new mAT-705 ATU.

Please comment if you have other IC-705 questions.

642 Miles Per Watt with the new Icom IC-705 QRP transceiver

Thursday, I set out to test how long the Icom IC-705 could operate during a Parks On The Air (POTA) activation with one fully-charged Icom BP-272 Li-ion battery pack. This, following my listening endurance test.

I knew conditions were pretty terrible Thursday in terms of propagation, but that didn’t really matter. I intended to call “CQ POTA” in CW until the ‘705 finally shut down due to low voltage. In my head, I imagined this wouldn’t take much longer than 1.5 to 2 hours and during that time, despite propagation, surely I’d work 10 stations to validate the activation, right–?

Sandy Mush Game Lands (K-6949)

I picked Sandy Mush Game Lands as my test site. Since I’d been there before, I knew there were ample trees to hang the Vibroplex EFT-MTR end-fed antenna, and I knew I’d likely be the only one in the parking area as this site is secluded and this was not a designated hunting day.

The Vibroplex/End-Fedz EFT-MTR antenna

Setup at the site was pretty straight-forward. I quickly deployed the EFT-MTR antenna–using my arborist throw line–in a “V” shape hanging over a high tree branch.

I picked the EFT-MTR because it’s resonant on my three favorite POTA bands: 40, 30, and 20 meters. Note that the IC-705 does not have an internal ATU.

Although I have an mAT-705 external ATU on loan to test, I didn’t take it to this first activation–I wanted to keep the set up simple for testing battery endurance.

On the Air

I started calling CQ at 16:30 UTC on the 40 meter band and set the IC-705 to beacon mode call “CQ POTA K4SWL.” No replies for 10 minutes. At that point, I discovered the POTA spots website was down for a scheduled upgrade (I have impeccable timing!), so I posted my spot on the POTA Facebook page.

Then my buddy Mike (K8RAT) sent a text message stating that the Reverse Beacon Network (RBN) had spotted me, but with a very low signal report. Hmmm….why would that be?

Turns out, I still had the IC-705 power level set to “0” watts (this story might sound familiar). Doh!

Note to IC-705 owners: zero watts is not zero watts!

I turned up the power to 5 watts (the max the IC-705 will achieve on a 7.4V battery pack) and was greeted by an instant CW pile-up.

What a blast! I started on 40 meters in CW, but eventually worked both 40 and 20 meters in SSB and CW. I then lowered the antenna, removed the SMA cap on the EFT-MTR coil, and worked 30 meters CW for the remainder of my time.

I logged my first contact at 16:28, my last at 18:18 UTC. So 1 hour 50 minutes of near constant operating.

Remaining battery capacity after 1:50 of operating.

The IC-705 battery pack was still going strong and had about 40% capacity left, but I simply ran out of time as I needed to run an errand in town, so had to shut down the radio and pack up.

I must admit: the IC-705 is doing a much better job managing battery usage than I would have expected. I’m guessing I could have operated for 3 hours or so at 5 watts without needing to recharge the BP-272 1880 mAh Li-ion battery pack.

I do believe I’ll invest in the larger BP-307 battery pack which has a capacity of 3100 mAh. It’s a pricey battery, though, at $130 US.

How does the IC-705’s battery endurance compare with the Elecraft KX2? I’m not sure yet, but I’m guessing the KX2 will have even better longevity as its current drain is less than half that of the IC-705. The KX2 will operate at 10 watts output for about 1 hour 15 minutes with the internal battery pack, before decreasing to 5 watts output. I’ve never tried a battery endurance test with the KX2 at only 5 watts.

Of course, with an external 12 volt battery, the IC-705 will pump out a full 10 watts of power as well.

Five watts and a wire–wow!

The biggest surprise of the day?

I worked stations from Oregon, and Saskatchewan to the Azores…in single sideband!

Here’s a map of my contacts–red signal paths are SSB, CW in green (click to enlarge):

This was one activation where 5 watts SSB actually snagged more DX than CW. Great fun!

While I’d like to think it was a little IC-705 “mojo” on its first field outing, in truth it had everything to do with the EFT-MTR antenna and what must have been a moment of propagation stability.

This was also my maiden voyage with the CW Morse Single Lever paddle. CW Morse sent this paddle, along with their double lever paddle and a selection of straight keys, for me to evaluate. If you’ve been considering an affordable, portable single-lever paddle, this is a brilliant one. I really enjoyed using it and the action is very easy to adjust.

I’m already regretting the decision to send it to my buddy Eric (WD8RIF) for a proper evaluation. (Just kidding, Eric! (Maybe.)) He only uses a single lever paddle for his numerous field radio adventures.

Eric will give this single-lever paddle a proper workout and give us a full report.

I must admit, I had a lot of fun with the IC-705/EFT-MTR antenna combo.

Of course, I’ll be taking the IC-705 to the field a lot in the coming weeks.

IC-705 Questions?

Feel free to comment and ask any questions you may have about the IC-705. I’ll do my best to answer them.

A field antenna’s best friend: The amazing arborist throw line

At least 95% of the time I’m playing radio in the field, I use wire antennas and suspend them in trees.

Since I do a lot of park activations for the POTA program, trees are typically very easy to come by and most of the time the park office doesn’t care if I hang an antenna in their tree for a couple of hours.

For years, I’ve been using a heavy steel nut–a nut that would fit a very large bolt–as a weight and attach it to fishing line. I then simply throw the nut into a tree and pray the fishing line deploys properly. I have reasonably good aim, so–on a good day–I typically only need one or two throws/tries to get the fishing line over a branch. On bad days? Well… let’s just not talk about that.

There are some inherent weaknesses in the fishing line/monofilament system:

First of all, I’m lobbing a heavy metal object into the trees. If it ricochets–and it eventually will–it can come back down to earth and land where you might not want it to (for example, on your radio, on your car, or on your friend’s head).  Fortunately, I’ve never hit anything or anyone as I’m careful to clear the area first, but unfortunately, I once had the nut hit a tree and come back down near me. That was a little scary.

Secondly, fishing line isn’t exactly recyclable and you simply can’t use it over and over. I get at most three deployments with a section of fishing line before it gets too stretched and unworkable.

Finally, fishing line is incredibly prone to tangle, especially near the end of the spool.

A Better Solution? The Arborist’s Throw Line

The arborist throw line is no recent innovation. For years, I’ve read recommendations from other ham radio operators who swear by arborist throw lines but I only recently decided to take the plunge after one very frustrating park activation where my fishing line knotted and almost got permanently stuck in a gorgeous tree. I’m very much a “Leave No Trace” kind of guy, so I was incredibly relieved when I was finally able to work the fishing line out of the tree.

When I got home from that activation, I ordered a Weaver Throw Weight and Line and a Throw Line Storage Cube. (Note: these are Amazon affiliate links that support this site.)

Forester Throw Rope folding/collapsible Storage Cube

I once talked with an arborist about throw lines and he stressed the importance of getting not just the line, but also a throw line storage cube. The cube allows you to both deploy and take up the line without any tangles or knots.

All in, I spent about $50.00 US for both.

Preparing the throw line

My arborist buddy gave me an important tip: the throw line needs to be stretched.

As you can see in the photo above, the throw line is packed in a bundle that’s easy to unroll. After you unroll it for the first time, though, the line has a “memory” of all those bends from its life in the package.

You can remove much of the throw line memory by tying one end of the line to a tree and stretching the line to its full length. The line is 150 (or so) feet long, so you’ll need an open space to do this.

The arborist in this video shows how this is done (I’ve queued it to the point in the video where he shows how to do this):


You’ll need to attach the throw line to the throw weight, of course.

There are a number of knots arborists use, but I’m a fan of the slipped simple noose knot. Perhaps it’s because it’s easy to tie even with semi-rigid line, it holds quite well and, most importantly, it’s easy to untie.

Looks like arborists use it too because when searching for an instructional video, the first result was from an arborists’ channel:

Throwing up!

There are a few different ways to launch a throw line into a tree.

Take my advice here: practice at home before you hit the field! It could save you a lot of embarrassment, although, admittedly, my at-home practice sessions gave my wife and my daughters good reasons to chuckle.

I’ve only been using the throw line for a little over a week, so I’m still sorting out which method works best for me. One thing I discovered very quickly, though: no matter which launch method I use, I can send that throw weight into a tree at least 60% higher than I could before.

No doubt, the throw line and weight really put the laws of physics in your favor!

Here’s a great video highlighting different throw line launch techniques:

In practice

I took the throw line to the field today for the first time and I’m very pleased with how effectively it works.

I was able to place my antenna on a much higher branch than I could have otherwise. It took me three tries today, but it had more to do with my poor aim. As with any skill, this will, I think, improve with practice.

The storage cube folds down flat and keeps the line from tangling

Besides the improved antenna height, I love that the line can be used over and over again. Also, it’s strong enough that should it ever get caught in a tree, I can pull it out without the line breaking.

I can also reel in the line at least three or four times faster than I could with fishing line. Simply flake it into the storage cube one foot at a time.

When the line has been stored along with the throw weight, you can fold the storage cube down flat, then fold and secure it into a compact triangle.

Are there any negatives with the throw line system? Here are a few I’d note:

  • Bulk. Even when packed down, the line in the storage cube take up much more space than fishing line. Although it easily fits in even my smallest backpack (the GoRuck Bullet), I’m not sure I’d take it on a long hike.
  • This system requires a little practice and skill–you can’t pull it out of the package for the first time in the field and expect perfect line launches.
  • The throw line is more conspicuous than fishing line. If you’re trying to be a bit stealthy–as many of us are these days during the Covid-19 pandemic–the bright yellow throw line will attract more attention and questions from other hikers/campers, etc.
One happy activator!

Even though it’s bulky by my standards, I see the throw line becoming a permanent part of my field kit and I expect I’ll use it on most of my POTA activations.

Have you been using a throw line to hang field antennas? Or do you use a different system?  Please comment!

There’s magic in one watt and a wire

This past week, I hit the parks pretty hard while giving the lab599 Discovery TX-500 a good field evaluation. I managed to activate eight parks in the seven days I had the radio.

It was so much fun.

Today, I was going through my logs and was reminded of one park activation on the Blue Ridge Parkway in particular…

The activation was a bit impromptu (like most of my activations, if I’m being honest). My family packed a picnic, I grabbed the TX-500 from the workbench, and we headed to the parkway.

I set up the station on a picnic table and deployed my trusty EFT Trail-Friendly 40/20/10 meter end-fed antenna. I started calling “CQ POTA” on CW and within 15 minutes or so amassed the 10 contacts I needed to validate the activation. Signal reports were overall a little on the weaker side, but propagation that day wasn’t exactly stellar. I worked a few more CW stations, then switched to SSB.

I started my SSB run by trying to work a few “Park to Park” sites because my phone managed to load a list of POTA spots from my very dubious mobile phone connection. I heard a strong signal from a park and replied, “K4SWL, Park to Park, Park to Park!” No reply.

Typically, when you say “Park to Park” an activator makes your contact their high priority. So I was a bit shocked not to hear a reply. I tried again. Nothing.

Then I cycled through some of the radio settings and discovered I had left the radio set to one watt of output power. Earlier that day while testing the TX-500 in the shack, I checked output power levels by hooking it up to a watt meter and dummy load. I forgot to move it back up to 5 or 10 watts.

No wonder I was so weak on SSB! I increased power output to 10 watts (the TX-500 max output) and quickly confirmed that other park.

I worked a few more SSB stations, then packed up for the day.

When I got back home, I made a little map of my contacts.

On the map below, all of the green pins below were CW contacts and made with one watt of power. The red pins are SSB contacts with 10 watts. The yellow star is roughly my location:

I operate QRP (or, at least 12 watts and below) 95% of the time I’m on the air. On rare occasions, I’ll run up to 50 or possibly 100 watts. Besides the amazing portability QRP rigs offer, it’s so much fun to travel the airwaves on peanut power–whether I know it or not.

But I’m pretty sure I’m preaching to the choir here, right–?

I know this: there’s magic in one watt and a wire!

Adding CW mode to the EA3GCY DB4020 Dual-band 40 and 20M QRP Transceiver Kit (Part 2)

Many thanks to SWLing Post contributor, Frank (ON6UU), who shares the following guest post which expands upon his previous DB4020 article:

The EA3GCY DB4020 transceiver now has CW mode

by Frank Lagaet (ON6UU)

After telling you all about the DB4020 SSB build I’m here with the CW part of the kit,  let’s say this is part 2.  At a certain moment Javier let me know the CW interface kit was ready for shipment and some week later it was delivered to my QTH.

Again, a well packed kit arrived in a brown envelope, components and boards well packed in bubblewrap.  I found even a board I did not expect which can hold a push button,  a switch and the connector for your morse key.  Javier thinks of everything it seems!

Unpacking the bubblewrap gave me this result,  all components in 2 bags.  In the bigger bag another 2 bags with 2 printboards,  one for the CW interface,  one for the CW filter.  Great !!  Checking the material bill resulted in all components there,  another thumbs up.

I started, of course, immediately building it because I wanted CW in the transceiver as soon as possible.  I don’t do much in SSB mode anymore and I already started missing CW on the DB4020,  so I started my KX3 to listen to while I was populating the boards.  I never thought CW was going to have this impact on me! …. ..

I started building the CW interface,  again starting with all small items.  I soon saw that the 2 relays which need to be soldered in were ideal to protect all components when the board is upside down, so I soldered them in very quickly.  I then soldered in all other components ending with the elco’s.

Next phase was the CW filter.  This board is small and came together in a blink of an eye, no problems there, the long legs of the 3 and 4 pin headers went in last.

The following day, I made all wire connections and soldered a 13pin connector,  leaving one pin out since I want to have the option to choose the width of the CW signal I’m listening to.  By cutting the FL CW + pin and adding an additional switch, I have now 500Hz or 2400Hz.  Great option, for very little effort and simple.  Another thumbs up here.

Now it was simply a matter of inserting the sub boards in the main board and all should be working.  And it did!  Hurray!  The 500Hz filter works perfectly,  filtering away all above or below stations nearby my operating frequency.

This is the result of the soldering work,  2 small boards which need to be inserted in the main board:

The CW interface still needs the 13pin header of which I cut one pin and mounted a switch to have the 2400Hz width.

The IC you see in the middle of the CW interface is the KB2 keyer which gives you several functions like 4 memories and beacon mode.  The 4 potmeters are used to set the level on 40 and 20 meters,  to set the delay between TX and RX switchover and to set side tone monitor level.   The keyer also provides functions as keyer mode A or B,  straight key function and can be set for speeds between 1 and 50WPM.   WPM speed can be set in 2 different ways.  Handy!

Here a picture of the CW filter inserted on the main DB4020 board.

The CW interface is inserted at the side of the main board,  notice the 2 wires which go to the switch to allow switch-over between 500 and 2400Hz.

(Wiring still needs to be cleaned up in this picture.)

Finally, the result:  a good working multimode QRP transceiver with 2 bands.  It should be possible to make close to medium range with it as well as DX,  even with QRP power.

And while I was building I also made a new key for this radio,  it is made out of a relay and cost nearly nothing,  looks good doesn’t it ?  hihi.

Homebrew key

The key, when in practiced hands (fingers hi), can do 50 WPM without a problem. My friend HA3HK does without blinking an eye at 40WPM with this kind of key and tells me that he can go faster if needed.  Me? I’m going it a bit slower.

Battery pack

As this radio is only using little power (0.4A in RX,  1 to 2A in TX depending the power you set it) I thought,  let’s make a battery pack for the radio.

The first plan was installing it in the box.  I did not do that because the batterypack is also powerful enough to feed my KX2 and other QRP transceivers. Since I can use it with all of them, a loose battery works out better for me.

I started with an old laptop which had a broken screen and some other malfunctions,  but still had a good battery,  although I needed the battery connector of course.  A piece of wood to mount the connector on was my next goal.  And since I still have another laptop using the same batteries, I can charge the battery without problems.  Simple, but good and it weighs much less than a gel cell battery.

The battery provides me with 12.5V and some 5Ah.  Enough to last for hours on RX and for sure good enough to activate 2 SOTA sites in one day.   It doesn’t look great but works great– that is what matters and to test it was more then good.  Next will be getting the battery pack in a nice box.  Better to re-use stuff than throwing it away I’m thinking.

I need to do something about the cover of the OLED display,  there is still some work there to make it look nicer.

Some video can be seen on YouTube :

Finallym I’d like to thank you all for reading my articles about the DB4020. I had big fun soldering, tinkering with the box, making the key, and batteryholder/batterypack.  My Hungarian friend HA3HK told me it looks a bit like a spy radio. …. ..

I also include one more time the link where you’ll find this kit :


73 TU ee



Thank you so much, Frank. No doubt, you had a lot of fun putting this excellent little kit together.

Implementing a filter switch was a fantastic idea and, obviously, not terribly difficult to do.

Based on the videos, the DB4020 has a low noise floor and very good receiver characteristics. I’m impressed that the CW portion of the radios has so many features as well, such as a memory keyer and beacon mode.

I also love how you reused that 5Ah laptop battery! I think that could almost give you a full day of SOTA activations at those consumption levels!

Thanks again for sharing this with us, Frank! We look forward to your future articles!

Frank builds the EA3GCY DB4020 Dual-band 40 and 20M QRP SSB Transceiver Kit

The following article first appeared on our sister site, the SWLing Post:

Many thanks to SWLing Post contributor, Frank (ON6UU), who shares the following guest post:

Building EA3GCY’s DB4020 QRP Transceiver kit

by Frank Lagaet (ON6UU)

In May, I discovered via a newsletter that a new kit was available from Javier EA3GCY in Spain.  I was immediately sold as this was a kit from my favourite kit producer and it has 2 bands–it will also be able to do CW and there also will be a CW filter.

After building 2 MFT’s from Javier which work without problems, I needed to have the DB4020.  The MFT’s are for 20 and 40 mtrs and do DSB (double side band).  I did put them in a not-so-graceful box but they do what they are intended for which is QRP phone (SSB).   They came together without problems so I expected the same for the DB4020–I knew for sure when I saw the board:  all through-hole components (except for some capacitors which are factory soldered) and a lot of space on the board.   The board has been silk-screened with clear indications on where all components have to come and the manual has very clear instructions where each component has to be soldered with referral to a quadrant.  The manual provides a 252 quadrant page so it is a piece of cake to find where each piece goes.

What do you get?

Javier provides you with all components which need to be installed on the board and, of course, the kit board.  The components come in small marked plastic bags and all is well-wrapped up in bubble wrap.  The board is wrapped separately and that is put together with the component wrap which is then again wrapped up in bubble plastic.  All goes into an envelope.  Very well packed I must say.

Here’s a picture of the bags with components:

The silk-screened board:

I started with the resistors since that’s the easiest way. After that, I did the capacitors.  I like to solder in all flat components first, so next were the diodes and IC sockets followed by the elco’s.  The transistors were next together with all relays.  As you solder in the transistors one also has to mount the cooling heatsinks,  these cooling sinks are high and are ideal to protect the coils one has to make,  they also protect the polystyrene caps (which I always find vulnerable) when the board is upside down.

Many kit builders are afraid of winding the toroids in kits–don’t be!  It is easy.  Just take your time and follow the instructions given by Javier in the construction manual.  In this kit the builder has to wind 8 toroids:  6 are a single wire which goes through the toroid body,  1 is a toroid with 2 different windings, and 1 has a twisted pair which goes through the final toroid.  Be sure to measure the wire you need per toroid as instructed in the manual.  Javier gives some spare, so you can be sure.  You will also see that on next picture where the legs of the toroids have not been trimmed yet.  Once done I still had some centimetres of wire leftover.

Picture of the toroids ready to be soldered in:

Finally all other parts and pin headers went in,  jumpers were immediately put on where needed.

As I’m using a military-grade plastic box, I have to break-out some components like the display,  tuning encoder,  volume and rx control from the board.  I also have put an on/off switch on the box and already have the CW KEY connector ready installed. I also installed a loudspeaker in the box.  The SI5351 board and the Ardiuno Nano are the final components which go into the board after installing all wires.

Picture of the board:

I intend to attach a CW paddle to the box made out of a relay.  A HWEF tuner (from EA3GCY) which I was planning to incorporate in the box is I think a bit overkill. That HWEF tuner is already in a nice little box and would be a pity to dismantle,  also I’m running out of space in the box…  Maybe I can fit in a 9-1unun which would then give me good results on both bands…?

Maybe I will install a battery pack in the same box.

The box with board installed:

The box completed front side:

Mind you,  it still needs some additional switches for the CW part of the transceiver.

Frank (ON6UU)


Brilliant, Frank! I really appreciate the video as well–sounds like the kit produces smooth audio and should serve you well. No doubt, that military box enclosure will survive even the roughest field conditions!

Click here to check out the DB4020 kit at EA3GCY’s store.