Tag Archives: K6ARK EFHW Kit

Antennas, Guest Posts, How To, News, QRP

The Best Mountain Topper Antenna: How to build lightweight, in-line links

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Many thanks to Dick (K7ULM) who shares the following guest post:

The Best Mountain Topper Antenna

(And a modification that makes it a little better)

by Dick (K7ULM)

When I decided to pursue HF radio, I had already decided to learn Morse Code.  Since learning code on my own wasn’t working, I enrolled in CW Academy classes.   Nearly everyone that I met in the CW Academy classes, plus my Elmer, were all involved in QRP portable ops as well.  A common theme among them all was using efficient, lightweight, easy to deploy antennas.

New to ham radio, QRP, and antennas.  I started to research antennas that fit that set of criteria.  Of course, I stumbled onto K6ARK, Adam Kimmerly’s YouTube video on building an ultralight 40m EFHW.  I accumulated the parts and built an EFHW for 40m.  After tuning the antenna for the lowest SWR, I connected it to a KX3 and contacted hams in Long Island, NY and Atlanta, GA with 12watts using SSB.  I was hooked on QRP and Adam’s antenna design.

When the instructor in my CW Academy class asked what goals each of us had for ham radio, I realized that I had no real goals.  So, I told the group that I wanted to assemble a portable QRP kit that weighed under one pound, and I wanted to operate portable CW from my elk hunting camp in the fall.  The sub-one pound HF kit was inspired by SOTA guru and legend, Fred Mass, KT5X.   I ordered an MTR-3B (Mountain Topper 3b – a QRP CW transceiver), which arrived 2 days before I left for elk camp.  The sub one pound HF kit had become reality.

At elk camp, I was a little distressed that I couldn’t work 30m with the EFHW, but 20m and 40m were a great combination.  Three nights later I was laying on a cot in a canvas wall tent in elk camp scanning the bands and trying to decode signals as I found them.  I heard one signal calling CQ for a long time and decided to try to answer him with my very limited CW skills.  I was able to get the minimum information to make an official QSO.  Looking up the contact’s information on QRZ, I found that it was Lloyd, KH6LC in Keaau, HI, 3000+ miles from elk camp.  Hawaii worked on 5 watts.  I was totally hooked on QRP and CW.

The only problem with the 40m EFHW, is that it doesn’t tune up easily on 30m.  Adam’s 40m EFHW design is excellent, and I wanted to stay with his build design, so I concluded that I needed to put a 30m link in mine EFHW to cover 40m, 30m and 20m without the use of a tuner.   My first effort on building a 30m link worked well but it was heavy and rigid which made it hard to store.  Eventually I created a design for the link that met my goals.

How to build lightweight links

My goals for a link on a lightweight EFHW are that it needs to be lightweight and flexible for easy storage.  It should also be relatively clean in design to minimize the chance of hanging up in trees and bushes while deploying and retrieving the antenna.

The materials for the link design that are currently working the best for me are as follows:

  • Attwood 3/32” tactical cord.
  • Heat shrink tube.
  • Superglue.  Gel type is the least messy.

2mm bullet connectors, or a more solid connection, red knife disconnects from Aircraft Spruce and Specialties Co. https://www.aircraftspruce.com/catalog/elpages/knifedisc.php

The knife disconnects idea is from Charlie Brown of Red Summit RF.  They are worth looking into.  They are my current choice of connector although the bullet connectors are working OK.

The installation of this link is fairly simple.

The first step is to tune a 30m section of wire on your preferred transformer.  The narrow 30m band will normally be well below 1.5:1 across the entire band, which is awesome.  I have found that it is about 32’ 7” of wire for my deployment style and soil conditions.  Your mileage will vary.  You can cut this into an existing antenna but, plan on adding a piece of wire to the end of the antenna to retune it for 20m and 40m.  For an existing antenna, measure the overall length from the transformer to the end of the antenna prior to cutting in the link.  You will use this measurement to restore the overall length of the antenna for the 40m EFHW.

Step two is to cut two pieces of heat shrink tube that will fit over your selected antenna wire and the 3/32” cord.  Slide one piece of tube onto the newly tuned 30m wire and the other onto the wire that will be tuned for the final 40m EFHW.  I use 26ga Polysteath wire.

Step three, cut two pieces of shrink tube to cover the solder joint of the wire connectors and slide one piece of tubing on both wires.

Step four, solder the connectors onto the 30m and 40m wire sections.  When cool, slide the shrink tube onto the solder joint and shrink.

Step five, cut about 6.5” of cord and melt the ends of the cord.  Mark the center of the cord so you can center it on the connectors.  Center the cord on the connectors and slide the shrink tube over one end of the cord.  Leave the final location of the shrink tube exposed for glue.  Put a couple of drops of superglue on that area, slide the shrink tube into its final placement and shrink in place.

Step six, slide the shrink tube onto the other side of the cord and leave a little room to put glue on the cord as was done on the first end.  For strain relief on the connection, it is best to put some slack in the wire, so the full load of the antenna is placed on the cord and not on the connection.  The easiest way I have found to do this is to disconnect the connectors and overlap them by ¼” or so prior to shrinking the second shrink tube into place.  Once everything is ready, put a couple of drops of superglue on the cord, slide the tube into place and shrink.

When you reconnect the connectors, there should be a bit of slack in the wire that prevents any pull on the connectors while the antenna is deployed.  At this point restore the full original length of your antenna for add a new section of wire and tune for 40m and 20m as desired.

With K6ARK’s ingenious EFHW design and a 30m link, you can have a fantastic antenna matched to the MTR3B that is, tuned for resonance on 40m, 30m, and 20m, easy to deploy and weights under 2oz.  If you add one of Adam’s 3D printed paddles, a couple of 500mAHr LiPo batteries, and earphones your complete HF kit will be about 12oz.  Add a Carbon 6 mast and your total kit come in at a mere 23.7oz.  WINNING! 

For those operators who are fortunate enough to own an MTR4B, an 80m removable extension can be added to the 40m EFHW using a similar technique.  On the 40m EFHW, prior to installing the connector, a piece of the cordage can be folded back on itself to create a loop and slid through a piece of shrink tube.  This loop works as a good connection point for your guy lines while deploying the 40m antenna by itself and a place to tie on the 80m extension when needed.

For the 80m section, a single 5” length of cord will be connected to the wire to tie with superglue and shrink tube.  Solder the connector onto the 80m section before securing the cord.  The cord on the 80m extension is to tie the antenna sections together in a manner to provide strain relief for the couplers.  A cord loop can be put on the far end of the 80m section using this technique after it is tuned.

This is my vote for the best Mountain Topper portable easy to deploy antenna, or for any QRP radio without an ATU.  IMHO.

Accessories, Antennas, Articles, Morse Code, News, QRP, Reviews

A Few Field Radio Gift Ideas for Less Than $100!

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I received an email from a reader’s spouse asking about gift ideas for the holidays and beyond; ideas that could not only be used this month, but also tucked away for the future. They weren’t looking for the obvious things like a transceiver–they were looking for accessories that might enhance their significant others’ field radio fun.

Being the enabler I am, I was happy to oblige and, in fact, decided to turn my reply into a post (since it quickly turned into a very long email) with their permission. For obvious reasons, I’m keeping their ID secret! 🙂

Here’s a rather random sampling of things that came to mind. I tried to limit this to items that retail for less than $100 US. Note that some of these product links are affiliate links:

A quality LiFePO4 battery

Being a QRPer, I don’t need a large battery to enjoy hours of radio fun per charge. My favorite battery chemistry is LiFePO4 due to its weight, safety, shelf life, and recharge cycles (which is in the thousands as opposed to hundreds).

For me, a 3Ah battery is more than enough capacity to keep my QRP radios on the air for 3-5 activations per charge (depending on length of activation, etc.).

I’m a big fan of Bioenno batteries. Their customer support is excellent. You can purchase their 3Ah 12V battery for $64.99 US including the charger. If you already have a charger, the battery alone is $49.99. Click here to check it out.

If your significant other likes to push 100 watts, consider a larger capacity battery. I also have a 15Ah Bioenno battery for this purpose, though it exceeds the $100 gift price threshold). Click here to check it out.

A very affordable Li-Ion rechargeable battery


One of the most affordable rechargeable battery packs for the QRPer in your life is the TalentCell Rechargeable 12V 3000mAh Battery Pack. This pack typically costs around $30 US and is sometimes even less expensive.

This little pack is great because it will not only output 5V to recharge USB devices, but it also outputs 12 volts which is brilliant for QRP radios like the Elecraft KX series, TX-500, FT-817/818, Mountain Toppers, Penntek TR-35,  Venus SW-3B, and many others. I actually now pair this with my QCX-Mini. The battery comes with the charger and standard barrel connectors on the included DC cord which fits Elecraft and Penntek field radios among others.

This is a small battery, so can only be paired with efficient QRP radios.

While I don’t consider this a high-quality solution like a Bioenno battery, it is insanely useful and affordable. Click here to check it out.

Morse Code Keys!

I could easily write a series of articles about Morse Code keys. That’s not what you’re looking for, though, right? You want some quick suggestions. Here is a sampling of some of my sub $100 favorites listed in alphabetical order.

If your budget is flexible, you might also consider these paddles which are still less than $200:

Okay, so if you don’t mind pushing more than $200, I highly recommend any key made by the amazing Begali family. Their Simplex paddle was my first set of paddles and I still use them today. I plan to buy their Traveler next year. They’ve a massive selection of models and styles. Continue reading A Few Field Radio Gift Ideas for Less Than $100! →

Guest Posts, Hams, News, Portable, POTA, QRP

Rich packs the KX2 field kit for air travel and a POTA activation!

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Many thanks to Rich (KQ9L) for sharing the following field report:

Field Report and Lessons from Torrey Pines State Beach (K-3580)

by Rich (KQ9L)

As you can tell from my call sign, I am a W9er, but recently had the opportunity to travel to California and specifically to the San Diego area. I thought it would be fun to try to activate a park near my hotel. I consulted the POTA website and found one park which was within 5 miles of my hotel, perfect!

While planning for the trip, I carefully chose and packed my gear to minimize added weight and bulk of my carry-on luggage. Because on this requirement, I chose my Elecraft KX2 with built in battery, my KXPD3 paddles, a K6ARK end-fed half-wave and the telescoping fishing pole from the PackTenna portable mast system.

Everything fit perfectly into a Lowepro CS40 case and Tom Bihn HLT. I did not bring the tripod from the PackTenna system to cut down on weight and bulk.


The hardest part of traveling with this setup was the fishing pole as I could not fit it diagonally in my carry-on legal luggage and I ended up having it sticking out the top of my soft side Patagonia MLC carryon backpack / travel luggage.

I received a few odd looks from passengers and airline personal but to my relief I did not get hassled for the odd looking thing sticking out of my luggage. To minimize the space my luggage occupied in the overhead storage, I simply pulled the pole out of the luggage and stowed it in the bottom of the overhead bin. Easy! Everything made it safely to my destination and no the got destroyed.

This morning [October 15, 2022] I decided to go out early to activate Torrey Pines K-3580 which is just north of San Diego.

I ran into a problem which I guess I should’ve anticipated. Being from the central time zone and normally a 5 AM riser, I found myself ready to go by 3 AM Pacific time. I dillydallied for a few hours and watched a few of your YouTube videos to get me psyched up and ready for the activation.

I got out to the site right at sunrise and set up without much difficulty. I found the vegetation to be conducive to setting up the fishing pole by leaning it up against some of the shrubbery. Continue reading Rich packs the KX2 field kit for air travel and a POTA activation! →

Field Reports, News, People, Portable, POTA, QRP

POTA activation with WD8RIF at Beury Mountain WMA in West Virginia!

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Grist Mill at Babcock State Forest Headquarters

This year, instead of attending the 2022 Hamvention, my buddy Eric (WD8RIF) and I hatched another plan.

Eric and I–along with his son Miles (KD8KNC) and sometimes Mike (K8RAT)–attend Hamvention every year it’s held.  We’d planned to do the same this year especially with it being the first in-person Hamvention since 2019.

As Hamvention approached though, we both had a lot going on in our lives and decided to save a little money, a lot of travel time, and meet in West Virginia for several days of POTA activations and just hanging out. I explain a bit more about the decision in this previous post.

We camped three nights and performed activations together for four days. It was an absolute blast!

Setting up camp

On the afternoon of Thursday, May 19, 2022, we (Eric, Miles, Theo the dog, and I) met at Babcock State Park and set up our tents at the adjoining campsites we’d reserved.

Babcock would serve as our home base for the entire WV POTA expedition.

As a bonus, Babcock State Park (K-1798) is also a POTA entity, so we activated it in the late shift after dinner each evening.

As soon as the tents were deployed that afternoon, we all jumped into Mile’s Subaru with our radio gear and hit our first park!

Beury Mountain Wildlife Management Area (K-7036)

Beury Mountain WMA is so close to Babcock State Park, I have to assume they share a common boundary.

The drive to the site was very brief but as with many WMAs and Game Lands, the entry road isn’t paved and there are rough patches you might need to avoid. Of course, Mile’s Subaru was way over-engineered for this task! Continue reading POTA activation with WD8RIF at Beury Mountain WMA in West Virginia! →

Field Reports, Morse Code, News, QRP

POTA Field Report: Gazebo QRV & Gusty Winds with the Elecraft KX1 and K6ARK EFHW

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One of the things I love about our state and national parks is that no matter how often I visit, there’s almost always something new to discover.

This is especially the case as the seasons change from winter to spring.

On March 20, 2022, I carved out enough time in my afternoon to fit in a quick activation of Tuttle Educational State Forest. My main goal, in truth, was fitting in a nice hike–the weather was beautiful, although it was rather gusty.

I needed a little “radio therapy” that day as I had been spending time in the hospital with my mom who had a nasty case of pneumonia. This was a few weeks ago and she’s feeling much better now, thankfully, but those hospital weeks in March were pretty stressful for all of us.

Field activations are such an effective way for me to get in a little exercise, a little radio time, and clear my mind; again, proper “radio therapy.”

Tuttle Educational State Forest (K-4861)

For this trip, I packed the Elecraft KX1 field kit which included my K6ARK EFHW antenna since that was the last pairing I’d used int he field (click here to read that report). I did, however, transfer the KX1 to my new Pelican 1060 waterproof case.

I actually have a solid yellow Pelican 1060 case for the KX1, but after reading about Leo’s QCX-mini field kit built in a clear-topped Peli 1060, I realized how much I missed having a clear lid on the 1060. I checked Amazon and discovered that their blue one was on sale, so I grabbed one. This was a total impulse purchase, by the way.

And for the record: I’m accused of being a radio enabler on a daily basis, but in my defence I promise the enabling works both ways! I’ve bought so many things based on reader recommendations. 🙂 Continue reading POTA Field Report: Gazebo QRV & Gusty Winds with the Elecraft KX1 and K6ARK EFHW →

Antennas, Articles, Field Reports, Morse Code, News, QRP

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

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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 →

Antenna Tuners, Articles, Field Radio Kits, Grab And Go, Kits, News, Portable, QRP, QRP Radios

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

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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 →

Field Radio Kits, News, Portable, QRPers

Steve is QRV in the Swiss Alps

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Steve (MW0SAW) and I were recently exchanging emails and he has kindly allowed me to share a few photos and details of the QRP field kit he has taken on holiday:

I’m currently in Switzerland (ski holiday)–I did bring the Venus SW-3B. I was very surprised to get 2 USA stations last weekend with 4-5 watts in the ARRL CW contest.

Only a couple of Europeans today. But it’s all fun and I did have a lovely morning ski so can’t complain lol.

My gear:

Steve
HB9/MW0SAW

Wow, Steve! I would love to be in Switzerland right about now. I’ve got a bucket list item to journey there someday (in summer months) and activate at least 10 summits. Having lived in Grenoble, the Alps always feel a bit like home.

I love how compact your setup is and obviously the K6ARK EFHW is doing the trick if you’re making contacts State side with QRP and during a contest competing with the big guns!

Hmmm…I’m now thinking I might grab a second Maxpedition Fatty Pouch. I just checked and Maxpedition still has the “buy one, get one free” deal on their website.  The link above goes to Amazon (hence the affiliate link which my site auto-converts) because pricing is typically best there, but I believe you get an even better deal at present going directly to the source; especially if one could use two pouches!

Thanks again, Steve, for sharing your field kit photos and notes!