SOTA Activation Report: W4G/HC-003 Stone Mountain

SOTA Activation Report: W4G/HC-003 - Stone Mountain

Trip of 2012.11.10

  • Succeeded: Yes
  • First-activation: Yes

See my trip planning guide at: SOTA Guide - W4G/HC-003 - Stone Mountain

Commentary:

An easy activation, convenient to Atlanta. The hardest part was finding a parking place at the trailhead on a sunny Sunday afternoon.

There are plenty of places to support an antenna in the activation zone. There’s a fence on the south side, near the trail, protecting rare flora. It could be used to support a vertical. I found a dwarf tree, a little north of the summit, and bungee corded a 31’ fiberglass mast to it, for an EFHW for 20 meters.

It was a good opportunity to spread a little public awareness. Lots of interest from tourists about what I was doing. On the way up, a group of teens (or 20-somethings) asked if I was going camping. When I explained that I was going to set up a portable radio station and talk with people in Europe, there was lots murmuring of “cool.” There’s an opportunity to interest the young in ham radio here. Setting up a radio on top of a mountain sound more like an adventure and less like a bunch of old men sitting around and yakking. The young see themselves as adventurers and risk-takers, and we could do well to sell SOTA to high school and college kids.

16 contacts on 20 meters in just about 10 minutes. I made it to Kansas and to England on 5 watts with my KX3. My thanks to the chasers, who put up with me when I totally lost my train of thought as a parade of hikers marched past!


SOTA Activation Report: W4C/WM-020 Stratton Bald

SOTA Activation Report: W4C/WM-020 - Stratton Bald

Trip of 2012.10.06-2012.10.07

  • Succeeded: Yes
  • First-activation: Yes

See my trip planning guide at: SOTA Guide - W4C/WM-020 - Stratton Bald

Commentary:

I’m a recently minted General Class amateur radio license holder, with such poor radio reception at home that I decided to try portable operation from a better location. Participating in the SOTA program, my eldest son and I mounted an expedition to transmit atop Stratton Bald in North Carolina at 5360’.

We hit the trailhead at 11 on Saturday, October 6, 2012. With radio and camping equipment, our packs were 58 and 35 pounds. For us, that’s a lot. Combined with some wet leaves on wet roots, I took a tumble on the way in which left me with a minor abrasion and the ignomy of flailing on my back like an overturned turtle.

We were the first to arrive in the meadow at the summit, so we were able to claim the high ground. Visibility was about 50 yards, due to fog. We set up camp in a breeze I estimate at 10 MPH. It was chilly. After nightfall, the fog closed in and we had some heavy rain overnight, with a little lightning a mile or so away. Visibility fell to about 25 yards at dusk. It was typical weather for Stratton Bald.

The plan was to operate first with a vertical antenna and then with a W3EDP horizontal. We set up the vertical and staged the W3EDP, with one end about 20’ up the tallest tree we could find. Since we were traveling light, we left the feed line at home. We attached the antenna wire to a BNC-to-binding-post adapter on my Elecraft KX3, and we set up four 17’ radials near ground level (strung across the grass – generally not in direct contact with earth). The vertical component was 33’ of wire zip tied to a 31’ Jackite pole, with 2 ft’ running horizontal to the radio. We used 22 gauge stranded wire, with Teflon insulation. My radio’s antenna tuner only managed an SWR of 4-to-1, which surprised me.

Shortly before airtime at 1 PM, we found a contester (K6LA) using our primary frequency of 14.285, and at 1900+ contacts, he showing no signs of fading anytime soon. I made a brief contact with him – my first (lifetime) QSO. There was lots of noise on 14.345, our alternate frequency, so we called CQ on several nearby frequencies, with no response. At about 1:10 I decided we’d call CQ on my published frequency for 15 minutes, despite the noise and throw in the towel on the vertical, if we didn’t raise someone.

N1FJ responded from west Massachusetts within a couple of minutes and gave us our first spot at SOTAWatch, and a signal report of 57. NT1K also spotted us, as did N2YTF.

I think it is fair to say that I had a small pileup. At least, it seemed that way to me. The wind picked up about the time we went on the air, so I had a little trouble hearing. As I mentioned, I’m a very new ham, so I messed up a lot. Experienced hams rattle off their call signs quickly, and I think that experienced hams also hear and remember call signs quickly. I had to ask for lots of repeated identification in order to accurately record the call signs. Everyone was very patient and helpful.

One way I messed up is that I was just scribbling call signs, locations, and signal reports on scraps of paper. I neglected to accurately note the precise time for each QSO, and since I scribbled on multiple pieces of paper, I can’t reconstruct the exact sequence of whom I spoke with when! I started with a notepad and at some point I lost it in the folds of my jacket, so I started scribbling contacts on my cheat sheet of licensed frequencies. (Next time I operate sitting cross-legged with a radio in my lap, I want to use a kneeboard with pre-printed log forms – on waterproof paper.)

The fog turned to mist. The mist turned to rain and the wind picked up, so I had to shut down. Since we’d spent a full day in a thick fog, everything was getting damp, including our sleeping bags inside the tent. We were scheduled to return to the air at 4 PM with our other antenna, and planned to stay a second night. Since we’d been shivering in an open field, with damp clothes/sleeping bags/tent, and my stove had been difficult to light, and I was experiencing gastric distress, I decided it was time to get us off the mountain before we had an emergency It took us about 90 minutes to strike camp in the rain and to hit the trail.

By 4:30, we were half-way down the mountain, the weather warmed, and the sun came out! If we could have seen the future, we’d have stayed and held our second session and we’d have gotten to see the stars at night. (Since Stratton Bald is in a wilderness area, if you’re on top and the sky is clear, the stars are awe inspiring.) On the other hand, if we’d stayed and encountered more heavy rain with high winds, we’d have had a problem. I’d rather be in the valley, wishing I was on the mountain, than on the mountain, wishing I was in the valley. Plus, I’d promised Mom to bring our son home in good health!

We achieved a number of firsts:

  • First activation of Stratton Bald (summit ID = W4C/WM-020). My son is very excited that we’re the first to transmit from there.
  • My first QSO
  • First QSO with my new Elecraft KX3 transceiver
  • First portable operation
  • My first summit-to-summit activation
  • QSO with Canada
  • QSO with England
  • QSO with Germany

As best I can reconstruct it, here’s my list of SOTA QSOs:

Call Sign UTC Time Location RST My Sig Comments
N1FJ 1713 West Massachusetts 57 N1FJ followed up with a kind email, with helpful suggestions.
DK1AX 1715 Germany   Confirmed afterward via email. Klaus says, “I was in Germany - had about 700 Watts and a 3 element yagi. You had a good signal here in SW Germany… Good condx - but you must have also a good station.” I guess the KX3 did pretty well, and my half-wave vertical wasn’t such a bad idea after all. Plus 5360’ of terrain helped. ;-)
N1EU   Albany 57  
W0MNA   Leavenworth, Kansas 59 His signal was 59 too. I wonder if he had a beam or an exceptional antenna.
N2YTF        
NT1K   Massachussets 55  
VE2JCW   Montreal 55  
G4OBK     44 G4 Oscar Bravo Kilo was very patient. I had a tough time copying the ‘B’. Someone else was kind enough to interject and correct me when I read back ‘R’ instead of ‘B’ for the umpteenth time.
WA2UEM   New Jersey 56  
VA3SIE   Mont Sutton, Canada   I’d already called a sign off (QRT) due to the rain, but he called with a summit-to-summit activation, and I couldn’t let that pass. Mont Sutton is SOTA ref VE2/ES-009

All this on 8 AA lithium batteries and 6 watts. (Bad SWR caused KX3 to reduce power.)

There were more people to talk to, but the rain was a real problem. For the last 2-3 contacts, I was peering at my radio under the edge of a poncho I’d draped over it to try an keep it dry. The ink on my log was starting to smear and the pages were turning to mush, so I really had to quit.

The big observation from this trip – Ham radio is really much more fun when you make contact that when you call CQ and get no response. (Duh!)

The best part of the trip is that I’ve got a great Number One Son. He did a lot of work, carried a heavy pack, was an extra pair of hands with setting up the antenna, and hiked for hours in the rain without a complaint.

All errors in capturing contacts accurately are entirely my fault, and the result of my inexperience.

I am so grateful to the hams who returned my call and patiently worked with me as I shivered and stammered and mis-copied. THANK YOU!


SOTA Activation Report: W4G/HC-006, Flat Top Mountain

SOTA Activation Report: W4G/HC-006 - Flat Top Mountain

Trip of 2013.01.20

  • Succeeded: Yes
  • First-activation: No

See my trip planning guide at: SOTA Guide - W4G/HC-006 - SummitName

Commentary:

This was a ‘Plan-B’ summit. I had planned to first-activate Cowpen Mountain (W4G/HC-001), but found FS 64 gated at South Fork Jacks River.

FS 64 (and the last bit of GA-2) were good-quality dirt road, averaging about 20 MPH in my Toyota Corolla. I encountered no gates (closed or open) on GA-2 or FS 64 en route to Dyer Cemetery.

The 5 MPH dirt road from Dyer Cemetery on FS 64 up to very-near-the-summit of Flat Top was muddy and icy. I elected to drive part way up and park at a wide spot (actually, a less-narrow spot), due to ice and mud. After a dry spell, I see no reason my Corolla couldn’t drive to the top. Single lane, with long stretches between spots wide enough to pass a car. Plan to back up 1/4 mile or so if you encounter another vehicle. According to Forrest Service documents this road is closed for the winter, but its gate was open on January 20, 2013. There is a turn-around at the top.

The hike from the turn-around to the summit is easy to follow, and not strenuous. Hiking up the 5 MPH dirt road would be long but not unpleasant, if there is little auto traffic.

I set out early this morning to activate W4G/HC-001, Cowpen Mountain. As the sun rose, the sky was clear, the air was crisp but not unbearably cold, and the dirt road to the summit was in good shape with no traces of the snowfall earlier this week. A promising day!

Then I encountered the gate. Apparently, the Forest Service closes FS 64 between N34.84182 W84.59421 and N34.86438 W84.52028 from early January until March. Bummer. But wait! I had planned for such an occasion. My next thought was, “I’ll go to my plan-B summit, a bushwhack to Dyer Mountain (W4G/HC-009). Oh, wait, I haven’t driven to its access point yet. The gate blocks both summits. &@#$!!”

I drove back to the top of a hill, picked up cell coverage, and found Flat Top Mountain. It was close by. It wouldn’t be a first-activation, but it would allow me to salvage some points for the drive.

If you’re familiar with the area geography, you might have noticed something amiss at this point. After I got home, I realized that I had driven right past Dyer Mountain before I encountered the gate. Somehow, I got the coordinates of Dyer Mountain and the Cowpen Mountain trailhead reversed in my driving directions, so I only thought the gate blocked access to Dyer. Sigh. Could have had another first-activation and a bushwhack, had I not been so brain-addled.

I drove most of the way up the road to Flat Top. There were a few soft spots, but much of the road was frozen mud. I got about 3/4 of the way up before the road got too slippery. I didn’t want to get stuck. I managed to turn my car around in the single lane, without rolling it down the slope.

I hiked the rest of the way up. It is a nice summit. Good trees for antenna hanging, enough space to guy out a mast. In dry weather, the drive shouldn’t be too bad and there’s a turn-around at the top.

It was my 10th summit, and my first that was not a first-activation. In the meantime, the road had melted, so it was mud-city on the way down. It is a narrow, single lane road. I had just passed a rare turn-out and thought, “Gee. I’d hate to meet someone. You might have to back for half a mile,” when I saw a flash of sunlight. I backed up the few feet, and waited while an SUV came up the hill. Good timing.

Thank you chasers!

  • AC0A
  • KD6CUB
  • W0MNA
  • KE5AKL
  • NS7P
  • N7UN
  • KC3RT
  • KI8R
  • N4EX
  • W4MPS
  • W4CCH
  • K4PIC
  • KG3W
  • WA2USA

SOTA Trip Planning - Long Form

I have this idea of having a library of SOTA trip plans on the metaphorical shelf. When I think, “Hey! I could do a summit this weekend,” I’d like to reach up to the shelf, pull one out, and take off. I might even color code them green/yellow/red for easy/medium/hard, and store them on the shelf in last-activated order from left to right. So if I’m in the mood for a medium adventure, I’d pull out the left-most yellow, and get a medium summit that I haven’t done recently.

But I’m paperless to the extent possible. So I’ll do something electronic. And I’m analytically minded, so I’ll over-think it.

I have three types of info: Static, Public-dynamic, and Private-dynamic.

  • Static information includes checklists and reference material. Static information is tied to me at my current skill level. It changes very slowly, but it does sometimes change.
  • Public-dynamic information includes things like driving directions to the trailhead. This information is tied to the trip, and it is information that anyone making this trip from my neighborhood would need. I call it ‘dynamic’ because the info is different for this trip than it was for that trip.
  • Private-dynamic information is stuff that applies to the intersection of me and this trip. It is stuff that only I will need for this trip. Things like the crib notes I’ll use to go on-the-air on this summit, including my alert, my CQ call text (which I like to use to get me past the getting-started jitters).

I’ll store content:

  • Static content in Circus Ponies Notebook.
    • It does checklists the way I like.
    • If I publish it, I’ll do File/Export-as-website from Notebook.
  • Public-dynamic content in .mou (Markdown) files.
    • After my activation, I’ll paste this into a ‘SOTA Guide: xxx/yy-000, Summit_name, State_name’ story on my blog (or update my existing story, if it is a re-activation).
    • (In addition to publishing/updating the Public-dynamic content, I’ll also publish a ‘SOTA Activation Report: xxx/yy-000 - Summit Name, State_name’ activation report, which is my commentary. The activation report will include a link to the corresponding guide.
  • Private-dynamic content in Pages/Numbers (OS X office suite). This has to go into an office suite because I want a textual document which contains a dynamically calculated table. One of the pieces of my Private-dynamic content is a timeline, and I want to be able to update the on-the-air time and have it calculate when I have to get up in the morning and when I’ll get home afterward.

SOTA Trip Packet

(Numbers are collating guide.)

  • Dynamic Sections
    • Timeline [pvt-dyn] (1.1)
    • Drive Guide [Pub-dyn] (1.2)
      • Turn-by-turn Directions
      • Duration
      • Food:
        • McDonalds
        • Dinner
      • On the way home (scouting)
    • Trail Guide [Pub-dyn] (1.3)
      • Navigation instructions
      • GPS track or waypoints
      • Duration
    • Summit Guide [Pub-dyn] (1.4)
      • Hang antenna?
      • Guy a mast?
      • Cell coverage
    • OTA Notes [Pvt-dyn] (2.1)
      • Alert
      • SMS spot
      • The “call” script
    • Prior Trips [Special: Public, not-carried] (not printed)
      • Date I Last Attempted
      • Date I Last Activated
      • Did I First-activate?
      • Commentary
    • Plan-B Candidate List [Pub-dyn] (1.5)
  • Static Sections
    • Checklist: Concept Through Depart Car (3.1)
    • Checklist: At Site Through Return to Car (3.2)
    • Checklist: Afterward At Home (3.3)
    • Reference: Q-codes (3.4)
    • Reference: Frequency List (3.5)
    • Packing List (4.1, not carried)
    • Reference: Kit contents (4.2, not-carried)

Actions

  • print the static
  • pick a date
  • pick a summit
  • plan the drive [if new summit]
  • plan the hike [if new summit]
  • populate doc with picked. (Template if new, update old doc if old.)
  • print dyn-pub dyn-pvt, Google Map, log page

SOTA Planning - Dates to Avoid

  • Check http://www.arrl.org/contest-calendar
    • Check the dates listed on the page
    • Check also the Contest Corral link

The big weekends to avoid are:

  • Phone (SSB and other modes)
    • March
      • 1st full weekend in March (All Sat+Sun UTC) - ARRL DX (Phone)
      • Last weekend in March (All Sat+Sun UTC) - CQ WPX (Phone)
    • June
      • 4th full weekend in June (1800 Saturday to 2100 Sunday UTC) - Field Day
    • July
      • 2nd full weekend in July (1200 Saturday to 1200 Sunday UTC) - IARU Radio Sport
    • October
      • 4th or 5th weekend in October - CQWW - http://www.cqww.com/
    • November
      • 3rd full weekend in November (2100 Saturday to 0300 Monday UTC) - Sweepstakes
  • CW
    • February
      • 3rd full weekend in February (All Sat+Sun UTC) - ARRL DX (CW)
    • May
      • Last weekend in May (All Sat+Sun UTC) - CQ WPX (CW)
    • June
      • 4th full weekend in June (1800 Saturday to 2100 Sunday UTC) - Field Day
    • October
      • 4th or 5th weekend in October - CQWW - http://www.cqww.com/
    • November
      • 1st full weekend in November (2100 Saturday to 0300 Monday UTC) - Sweepstakes

CW and SSB all run on different weekends. Use the mode not in play for the contest that weekend or use the WARC bands.

KX3 USB Cable Not Detected On Mac OS X?

I hook up the USB cable for my KX3 to my Macbook only once in a while. Like many things electronica, it works flawlessly if you use it every day, but if you put it away for a month or two you/it forget how it works. Here’s some troubleshooting. This is not for connect-it-the-first-time. For that, see http://www.worldwidedx.com/elecraft-kx3/140013-elecraft-kx3-firmware-update-mac-os-x.html .

  • In the KX3 Utility, on the Port tab, be sure the leftmost control says “usbserial-A901…”.
    • If it says “Bluetooth”, you aren’t going to talk to your KX3.

Upcoming Antenna Testing

All testing with a 33-34 foot antenna wire.

Test One

On 20 meters, compare signal with the 20m matchbox versus the 6-40 balun versus no matcher (just KX3 ATU).

Test Two

On 40 meters, compare signal with the 20m matchbox versus the 6-40 balun versus no matcher (just KX3 ATU).

Test Three

One 20 meters, using the best from Test One, compare signal on the Jackite versus the 24’ carbon pole.

SOTA Antennas - 2013.01.12

My ‘Space’

I operate primarily on 20 meters.

I’ll generally give 40 meters a try, since it is supposed to reach a local geography which 20 doesn’t. (I haven’t actually found that to be the case, but it could be because I’m doing it wrong.) If there’s a big contest, I’ll look for an open frequency on 17 meters.

My first choice is 20, because it’s where I find daytime DX and it is so much quieter than 40.

Most hills I operate on have trees; most also have space (and dirt) to guy out an antenna.

I like EFHW because I don’t have to mess with radials. On the hill, simple is better. I also like EFHW because the low current at the feed point reduces ground loss which you’d get even with radials.

In the beginning…

At first, I carried a 31’ Jackite pole for an EFHW for 20 meters. I’ve got pre-cut rope and 3 stakes. If there’s a convenient tree stump, I use a bungee cord. If there is a convenient tree branch, I might simply lean the pole against it, if wind is calm. I use painter’s tape to stick my wire to the pole in about 4 spots. I can erect a 20 meter EFHW on a Jackite in about 5 minutes without assistance.

When I’m on site, I love my Jackite. Getting to the site, I hate it. It its collapsed form, it is taller than my pack. I’ve created a special holder, so it can hang down below my pack, and it still gets caught on overhead branches. I don’t mind the weight. I don’t mind the thick diameter. That length is just plain awful.

Slings and Arrows…

I tried using a slingshot to launch an antenna support into the trees.

The first time went great. Since then, I’ve had some successes and some failures. Some days I just can’t get off a good shot. When it works, it is OK, but it often takes longer than I’d like.

Using a 3/4” nut was awful. I kept hitting the upright of the slingshot when I tried to shoot it. I’m now using a 1 oz. “egg sinker,” and that seems to work pretty well. Since I’m using a heavy line, I’m also going to try a 2 oz weight.

One key to successful slingshooting is to put the spool of fishing line on the ground in front of where you stand, face up. That seems to give the weight time to clear the upright before the downward tug of the line affects the flight path. I still sometimes get a tangle of monofilament.

I used to send up fishing line and use that to pull up a stouter cord. Now, I just use 30 pound test monofilament. It is strong enough to support my wire. It is cheap enough that I don’t bother reusing it. I just cut it out of the tree when I’m finished, tie it in a knot, and trash it when I get home. Since my line gets shorter and shorter, someday I’ll shoot the weight and it will pull the end of the line off. I’ll cross that bridge when I come to it.

Carry a Big Stick

I’ve avoided the carbon fiber fishing poles from www.allfishingbuy.com because I did some testing with carbon fiber, and it looked like maybe it attenuated my signal a little. It is hard to tell when testing with RBN because so many variables are uncontrollable. (i.e. The data is full of statistical noise.)

Some people have been very happy with these poles, so I’m going to give them another try. I bought a nominal 24’ pole that collapses into 25”. (Warning: The nominal 24’ pole is actually about 23’!) 25” is good because I also carry a 24” foam pad (rolled up) as a sitting/operating mat, and I can roll it around the collapsed mast.

Instead of erecting a straight vertical EFHW, I’m going to shoot for a 33’ inverted L. The idea is to put a weight (and maybe some monofilament) on the far end of the antenna wire. I’ll use the pole to toss the weight/line over a suitable tree branch, and then I’ll bungee or guy the mast a few horizontal yards away.

I’d like to put the end of the antenna far enough away that the bottom of the antenna wire gets pulled about 6 feet up the mast. I’m using an EARCHI ‘matchbox’ transformer at the end of the wire, and I’ll zip tie that to the mast at the end of the wire. Then I’ll run about 8’ of coax to my radio.

I put 34’ of 24 gauge teflon insulated wire on a camping clothesline spool. I use that as my antenna.

We’ll see if I continue to get enough contacts. It doesn’t have to be the best antenna. It just has to be an adequate antenna that is fast and dependable to setup – even on a hill with dense tree cover, dense underbrush, snow cover, and ice frozen on the underbrush. (Been there. Done that.)

What About 40?

I’ve been using the 20m EARCHI matchbox to match the high impedance at the end of my EFHW. While this works well on 20 meters, when I use the same 33-34 foot wire on 40 meters, I get a quarter wave antenna, with no radials, and the matchbox which is designed to work about 3000 ohm impedance is getting handed about 50. I’ve made contacts, but my signal is weak.

I know from experience that using a 20m EFHW without a matchbox with my KX3 gets me a 4:1 SWR. This suggests that my KX3 tuner can almost tune an EFHW. So my plan is to use the EARCHI 6-40 matchbox, which is a 9:1 balun on both 20 and 40 meters. The 9:1 will get me past the 4:1 with an EFHW, and it won’t be too hard for the ATU to tune it in the other direction it on 40. So I’ll hook up the 33’ wire to the 6-40 balun without a counterpoise on 20 (it is an EFHW), and when I switch to 40 I’ll clamp a 30’ counterpoise to the shield connector of the feed line.

I could just use a non-resonant wire length with the 6-40 matchbox on all frequencies, and use a counterpoise always, but I like having the option of running the EFHW without a counterpoise if I’m running late when I arrive at the site. On occasions when I want to get the best possible signal, I’ll use the 20m matchbox on 20, and remove the matchbox entirely on 40 (and use a BNC to binding post adapter to connect the antenna and the counterpoise to the KX3).

EARCHI Matchboxes

EARCHI Matchboxes

I really like an EFHW for low power operation. Minimal counterpoise/radial requirements make for a convenient antenna for portable use, and I operate portably about 99%. Someday, when I get around to setting up an antenna at home, an end-fed antenna is probably what I’ll use because my lot makes radials a challenge.

You can build these transformers from parts if you’re handy that way. They aren’t terribly expensive, so I buy mine from EARCHI. They ship promptly and the completed product is neater that I’d cobble together.

20m EFHW

The 20m EARCHI matchbox is an L-C matching network designed to reduce the high impedance of a 33-34.5 foot wire (about a half wave on 20 meters) to 50 ohms. An EFHW antenna puts the feed point where your standing wave gives you high voltage, low current. A center feed puts your feed point where your standing wave gives you low voltage, high current. Your radio is designed for low voltage, high current.

If the impedance of an EHFW is about 4000 ohms, then this must be about an 80:1 UNUN.

This can work without an antenna tuner.

40m EFHW

I don’t use this one because I use a mostly vertical antenna, and I don’t have a 66’ fiberglass mast!

The 40m EARCHI matchbox is an L-C matching network designed to reduce the high impedance of a 66-67.5 foot wire (about a half wave on 40 meters) to 50 ohms. An EFHW antenna puts the feed point where your standing wave gives you high voltage, low current. A center feed puts your feed point where your standing wave gives you low voltage, high current. Your radio is designed for low voltage, high current.

If the impedance of an EHFW is about 4000 ohms, then this must be about an 80:1 UNUN.

This can work without an antenna tuner (and yes, I did use cut and paste)!

6-40 Matchbox

The 6-40 EARCHI matchbox is a 9:1 UNUN, which can handle 100 watts. Obviously, with a range from 6 to 40 meters, your wire won’t be a half wave, but it will still be end fend. That means you’ll still have relatively high voltage and low current. Since your radio is designed for low voltage, high current, an UNUN is still needed.

You have to use a tuner with this transformer because it can’t possibly match the impedance on each band. This isn’t a problem for me because my KX3 has a built-in ATU. Some people might have a problem with signal loss over a long feed line, with an antenna with a poor untuned SWR. Since I operate portably, my feed line is typically very short.

However, EARCHI recommends a minimum of 16’ of coax. (The shield is where your counterpoise comes from.) Since good coax can be heavy, I’m going to try using a short coax with 16’ or more of counterpoise, clamped to the shield connector of the coax, at the matchbox.

But…

Big difference – The 20 and 40 meter matchboxes should be used with a half-wave wire. (Honestly, I can’t figure out why you need both a 20 and a 40 – aren’t they both about an 80:1 UNUN?) But the 6-40 box cannot possibly be used on all those bands with a single wire and that wire be a half-wave everywhere.

When you use a half-wave, your feed point has very low current. This means you can get away with very little counterpoise – maybe just the metal case of your radio. When you do NOT use a half-wave, you’re going to have more current at the feed point, and you will need more counterpoise.

The EARCHI 6-40 box’s instructions say to use at least 16’ of coax as feed line. That shield wil become your counterpoise. If you don’t use a counterpoise with an end-fed non-half wave, you’re going to get RF in the shack (even if the shack is just your radio in your lap in the field). Somebody smarter than me said that when you use your coax and/or rig’s case as a counterpoise, you have an unpredictable counterpoise, and I’d rather use an explicit counterpoise with predictable behavior. I think it might be more accurate to say that the further your feed point current diverges from zero (i.e. the further away from a half-wave your antenna), the more important a predictable counterpoise becomes.

I think (and I could be wrong) that the 6-40 matchbox adds value for users whose built-in ATU cannot handle the higher-than-usual impedance of an end-fed non-half wave antenna. I think that means you should still choose a non-resonant length on all your bands with one of these boxes, just like you would do if you were feeding your radio’s ATU directly.

If/when I use the 6-40 matchbox, I’ll use a non-resonant antenna length, and I’ll use a single similar length ground-level counterpoise, AND… I’ll try it without the matchbox first. i.e. The matchbox will be just an “in case it won’t tune without” accessory.

I need to test this in the local park before I use it on a SOTA summit.