Category Archives: Antennas

Antennas, Field Reports, News, Portable, POTA, QRP, Videos

Breaking in the new Elecraft AX2 during a short POTA activation

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As I mentioned in my recent AX1 vs AX2 video and blog post, I purchased an Elecraft AX2 antenna and bi-pod in late January (note: two days before Elecraft announced their February ’23 sale price! Doh!).

I received the AX2 package a few days later and I was certainly eager to take it to the field.

My first opportunity came on Tuesday, February 14, 2023, when a short activation window opened up in the afternoon.

Zebulon B. Vance Birthplace (K-6856)

One of the first things I noticed after taking the AX2 out of the package is just how solid and compact it is. The AX1 is short, but the AX2 is a few inches shorter because the base is more compact.

Unlike the AX1, the AX2 is a mono band antenna, thus the coil only needs to accommodate one band. When you receive a new AX2, it’s configured for 20 meters out of the box, but the user can modify the coil to work anything from 20 to 6 meters.

“Resonant-ish”

Even though I mentioned this in my AX1 v AX2 article and video, I’d like to reiterate that the AX2 is nearly-resonant on 20 meters. It is not reliably resonant.

I’ve still been receiving a lot of messages from readers stating that their AX2 and AX1 are resonant on 20 meters, so they don’t pack any sort of matching device in their field kit. They simply hook the AX2 up to their little QRP radio and hop on the air.

While it’s true that these antennas may provide an acceptable SWR most of the time, you really can’t rely on a solid, reliable match as you could with an end-fed half-wave.

I’ll repeat what I mention in a previous post:

Small verticals like the AX1 and AX2, that use coils to electrically “lengthen” the antenna, have a higher Q than, say, a large aperture quarter or half wave antenna. In practical terms, this means that the window of resonance is narrow and more fickle than, for example, an end-fed half-wave.

A lot of factors can affect the SWR on higher-Q antennas like the AX1/AX2 including:

      • the type of terrain,
      • height off the ground,
      • length of counterpoise,
      • configuration of counterpoise,
      • and, most notably, the operator’s own body capacitance.

You may find that the AX2, for example, is natively resonant on 20 meters at one location, but isn’t at another location. This is quite normal. It’s also the reason why Elecraft states that both antennas are designed to be used with an ATU.

So there you go! If I hook up my AX1 or AX2 to a radio, I’ll always have some means of matching the impedance–either an external ATU, or a capacity hat. You can also tinker with the length of the telescoping whip and counterpoise to tweak the match.

The important part–especially if pairing these antennas with a radio that lacks both an internal ATU and SWR meter (say, the MTR-3B, G106, or TR-35)–is that you’ve some means to check the SWR before conducting a long activation session. Continue reading Breaking in the new Elecraft AX2 during a short POTA activation →

Antennas, Comparisons, Guest Posts, News, Portable, POTA, QRP, SOTA

How I found the best antenna for my SOTA/POTA activations

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How I found the best antenna for my SOTA/POTA activations

by Thomas (DM1TBE)

Intro

Until January this year I had a German “Klasse E” / CEPT-novice amateur radio license (equivalent to the US General Class), which limits the use of HF to the 10-,15-, 80- and 160-meter bands. When I started with SOTA I used homemade single band end-fed antennas most of the time. However, that is only feasible for the 10- and 15-meter bands.

Unfortunately, both bands are very moody and sometimes they have not worked at all. Unlike the UK for example, FM is uncommon for SOTA in my home association DM (i.e. Germany Low Mountains). You can be lucky and get your 4 QSOs, but I did not want to rely on pure luck.

Therefore, I bought an end-fed half-wave antenna for 10-, 15-, 20-, 40- and 80-meter bands, after some experiments with 10-80-meter end-fed half-wave antennas, from a small German company called ANjo.

Although I could not use the 20- and 40- meter bands at that time, the EFW80-10P (en: auto-translated) antenna gave me the possibility to use the 80-meter band. The antenna could also be tuned for 15. It has a mechanical length of 23.6 m / 77 ft and a coil for the 80-meter band. It is pretty lightweight with 0.4 kg / 14 oz and allows up to 30 watts PEP – more than enough for me. 80-meters is not the best band for daytime SOTA activations, but in 21 months doing SOTA activations, it worked 37 times and tipped the scales for an activation from time to time.

It was sometimes a bit tricky to raise the long wire into the air, but it always worked … better or worse …somehow … like here in the woods along a trail.

In January this year, I upgraded my license and a new world of HF-bands opened for me. Although I have learned a lot about propagation for the exam, I am in favour of a German saying: “The difference between theory and praxis is larger in the praxis than in the theory”. Continue reading How I found the best antenna for my SOTA/POTA activations →

Antennas, News, Portable, POTA

AX1, AX2, DS-1, HFJ-350M, MFJ-1899T: Compromised portable antenna strategies vary by location

31 Comments

Many thanks to Terry (N7TB) who sent the following question by email and has kindly agreed to allow me to share it here along with my response on QRPer:

Hi Thomas,

I cannot tell you how much I appreciate your POTA videos and all the suggestions you have made that I have adopted. I look forward to every activation you put on video. […]

[…]I have a question for you about using your AX1, and would really like your advice. I marvel at how quickly you can activate a park even with an AX1 antenna on 5 watts. I also have an AX1 antenna, counterpoise and KX2[…].

Anyway, I was out today activating K-0213, Maude Williamson State Park, about 20 minutes from my QTH in West Salem, OR. I operated 12W into a 33ft. EFHW antenna suspended vertically from a 31 ft. Jackite mast. All my activations are CW; I usually activate 20 meters.[…]

I was able to finally work 22 stations in an hour and a half, mostly in CA, UT, MT, and one in AZ. I did get a contact in KY, AZ NM, and MB, but it was a tough go for them to hear me. Most of my activations take me a bit over an hour to get 20 contacts.

As I thought about how much easier it seems that you are able to activate, I started to think about geography and population density differences between the East and West coasts. I used Google Earth and measured almost all points east of the Mississippi from Asheville and most were within 1200 miles. I would guess 2/3 of the US population live in this area. I drew the same range from my QTH and I get about half way into MT, barely into WY, most but not all UT, just touch the NW corner of AZ, and all of CA. In all but CA, I would guess the population total in this vast area is less than Illinois. That is my dilemma. I would love to be able to go out, setup my AX1 with my KX2 on even 10 watts, and make quick activations, but I would be surprised if I would get many contacts because the distances are so vast in the West and population density so low. I will actually try using the AX1 when the WX gets better and I can sit at a picnic table. So far, I have had little success with it, even deployed with the correct counterpoise. Do you have any thoughts on how to be successful with the AX1 from the West coast for POTA, or should I just concentrate on other antennas?

[…]Thanks again, Thomas, for the emails you have sent me with suggestions about equipment, and for all your great videos.

Very 73,

Terry

N7TB

Hi, Terry,

First of all, thank you so much for the kind words. I really appreciate that!

Regarding your message:

Keep in mind that the day you were operating was a very strange day in terms of propagation. There were times when we were having radio blackouts (especially in the western half of the US) and there were times propagation was amazing, yet very unstable. We were hit by so many heavy CMEs this weekend–one seemingly on top of another.

I think you do have a valid point, though, about the geography–one I try to mention when talking about compromised antennas like the AX1.

QSO Map from my latest AX1 activation.

I realize that I enjoy a lot of success with the AX1 because of where I live. I guarantee that the bulk of the US ham radio population is within easy reach of my AX1 antenna, no matter what band.

For you? There are no hams to your west (within easy reach), extremely few to your north (save WA and BC), and the best ham density is to your south in California.

In your shoes, here’s how/when I’d try using the AX1 (keeping in mind I’ve never operated POTA in the western states):

First, I would focus on using 40 meters when the band is healthy and/or for early morning, late afternoon/evening sessions. That should snag contacts across WA, OR, and CA with the AX1. Might be a stretch for southern CA, but I think you could make that work. The only caveat is that flaring has been wiping out daytime 40 meters a lot lately. You might check band conditions in advance.

I would also consider spending time on 17 meters, and possibly 15 meters with your AX1. This might throw your signal across to the midwest, Ohio Valley, and beyond. 17 and 15 meters isn’t typically as productive as 20 meters (at least, for me) but I routinely log west coast stations on 17 meters with the AX1. 15 meters is also getting a lot of attention in the POTA spots!

A wire antenna is almost always a better option than the AX1 if you have the time and space to put it up, but the AX1 is just so darn convenient.

Cheers,
Thomas
K4SWL

More suggestions?

The reason I asked Terry for permission to post his question and my reply here on the blog is because I suspect there are west-coasters (and those in similar geographic situations) who may be able to share some helpful strategies.

There are so many factors involved beyond what I mentioned in my reply. In fact, I imagine if the goal is to work parts further east, then adjusting the activation schedule for Central and Eastern time zones might also help (for example, not activating during dinner hours when I always see a bit of a lull in hunter activity).

If you have some experience, please feel free to comment!

Antennas, Field Reports, Morse Code, News, Portable, POTA, QRP, Stealth

Lunch Box POTA: Pairing the Elecraft AX1 with the Penntek TR-45L!

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As I mentioned in previous posts, I’ve been using the Elecraft AX1 in heavy rotation this year. I made a commitment to myself to do a string of activations with it in January and February and also pair it with a wide variety of radios beyond the Elecraft KX2 and KX3.  So far, I’ve paired the AX1 with the:

In truth, the AX1 can be paired with any radio when you use a tripod mount.

It’s a bit trickier when connecting the AX1 directly to a radio and using the Bipod as a support because 1.) the antenna connector on the radio mustn’t be too high off of the surface, 2.) there needs to be enough clearance on the back of the radio to accommodate the bipod legs and 3.) ideally, it’s nice to have a ground point on the radio, else you’ll need to clamp the counterpoise to the shield of the BNC connector.

In addition, if your radio doesn’t have a built-in ATU of some sort, then you’ll also need a capacity hat or external ATU to finish off the impedance match. (For more notes about the AX1 and AX2, check out this previous post.)

Of course, you don’t have to use Elecraft’s bipod to support the AX1 when directly connected to a radio–you can build or 3D print your own support–but the bipod is really convenient when it does work.

Objective: Lunch Box Radio

One radio I’ve been eager to pair with the AX1 is the Penntek TR-45L.

Why? Because I love the form-factor.

Something about having a lunch box-sized radio sitting on a table with a telescoping whip protruding out the back and, with that combo, the potential of making contacts all over the globe. Continue reading Lunch Box POTA: Pairing the Elecraft AX1 with the Penntek TR-45L! →

Antennas, Articles, Guest Posts, News, Portable, POTA, SOTA

Skip recommends the QRPguys DS-1 portable antenna kit!

29 Comments

Many thanks to Skip (K4EAK) who shares the following guest post:

The QRPguys DS-1 Portable Antenna Kit

by Skip (K4EAK)

There have been several videos and extended comments lately about the Elecraft AX1 and AX2 antennas, both of which function remarkably well for a small, highly compromised antenna.

For those interested in other, similar designs, especially those hams who find that building the equipment is half the fun, another option to consider is the QRPguys DS-1 antenna.

The DS-1 is similar in concept and design to the AX2. It consists of a base-loading coil, a 46.5-inch collapsible whip, and a plate to attach the antenna to a small tripod. One can also purchase an add-on 40-meter coil. The can be deployed in just a couple minutes and, when collapsed, the longest portion is only 6.5” long, easily fitting in the palm of one’s hand. QRPguys recommends a 16.5′ counterpoise; I use two such wires, usually spread out at a 180-degree angle. I’ve also used it with a clamp-on mount and a car window mount.

Building the antenna is simple and took me less than an hour. After installing a BNC connector into a brass plug and inserting the plug onto a length of PEX tubing, one simply runs the supplied 22AWG wire from inside the tubing, out and around making 22 turns, and then sealing it with a length of heat shrink tubing.

There are really only two aspects of assembly that are slightly more difficult. The first is that it’s necessary to drill and tap two holes for 4-40 screws, which obviously means that (1) one needs a 4-40 tap and (2) one needs to be careful tapping the threads to assure a clean cut. The second is that the heat shrink tubing, at least as supplied in my kit, was grossly oversized, which required some finesse in getting a final product that was at least reasonably aesthetic, to say nothing of accomplishing that without dry roasting my fingertips.

Field testing of the DS-1 shows that it works surprisingly well. The SWR is well below 2.0 across almost all of the 20-meter band and where it is higher than that (the upper end of the voice portion), the KX2 internal tuner can tune it easily. As one would expect, on 40 meters the antenna has a somewhat narrower range, although the KX2 tuner has handled it on all of the frequencies I’ve tested so far (all CW). And it appears to be efficient enough.

I have used it on numerous activations and consistently get to the requisite 10 contacts within 20 minutes or so after getting spotted. After that, the number of contacts depends on the time available, but for those occasions when I have only a 30-minute window for an activation, the antenna is a convenient and practical alternative.

I keep the antenna, the tabletop tripod, and the counterpoise wires in the water bottle pocket of my pack, ready for use whenever I have a few moments for a quick activation.

73 Skip K4EAK

Click here to check out the QRPguys DS-1 antenna

Antennas, Field Reports, Morse Code, News, Portable, POTA, QRP, QRP Radios

Pairing the Elecraft K2 with the AX1 at Tuttle for some QRP P2P DX!

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If you recall from my last field report, I’ve been pairing the Elecraft AX1 antenna with a number of radios. For me, it’s been a fun exercise because I always enjoy seeing what sort of results the AX1 might produce. So far, it has never disappointed.

On Thursday, February 2, 2023, I packed two radios in my car with the idea of fitting in two consecutive park activations.

At my first activation of the day–Lake James State Park–I paired the AX1 with my Mission RGO One transceiver. The activation was a blast! Not only did I stay busy working stations, but I also managed a little QRP DX thanks to a hunter from Italy.

K2 and AX1 Under Shelter

Little Guatemala Café

After grabbing a curried chicken salad wrap at Food Matters and a coffee at Little Guatemala roasters in Morganton, I hit my second and final park of the day: Tuttle Educational State Forest (K-4861). It was rainy, so the park was empty which allowed me to take over the very large picnic shelter at Tuttle.

Even though this particular shelter is in a bit of a dip in the land and has a large metal roof, I’ve had successful activations there in the past employing the AX1 antenna.

My hope was that history would repeat itself!

Setting Up

Attaching the AX1 antenna to the back of the Elecraft K2 was not complicated because the K2 has a BNC connector with nothing protruding to get in the way of the Bipod. Continue reading Pairing the Elecraft K2 with the AX1 at Tuttle for some QRP P2P DX! →

Accessories, Antennas, Articles, Digital Modes, Field Reports, Guest Posts, News, Portable, POTA, QRP

Elecraft AX1 Test Using American Radio Supply AM-801 Window Mount

11 Comments

Many thanks to Conrad (N2YCH) who shares the following field report:

AX1 Test using American Radio Supply AM-801 Window Mount: POTA Activation at Stuart B. McKinney Wildlife Refuge, K-0228

February 19, 2023

By: Conrad Trautmann (N2YCH)

If you’ve been reading the posts here on QRPer.com lately, you probably already know that the Elecraft AX1 has proven to be an excellent antenna for POTA activations for CW, SSB and Digital modes.

Personally, I used it for a New York City POTA rove I did at the end of 2022 and was able to activate four parks in one day all over Manhattan.

Recently, Alan, W2AEW contributed a story to QRPer.com detailing how he used a window bracket he constructed with an AX1 to do a CW park activation from his car. I’ve actually done a few digital activations from the car using the AX1, however, I used the tripod with the Elecraft tripod adapter and ran coax to it out the window and draped the counterpoise down the hood or trunk. This has worked well except for windy days where it would blow over. I was intrigued by the possibility of using the window mount and a number of the commenters to Alan’s post suggested sources for these types of mounts. I ended up ordering an AM-801 from American Radio Supply.

https://www.americanradiosupply.com/am-801-window-antenna-mount-bnc-connectors/

Since the AX1 depends on a counterpoise wire to operate properly, the first thing I did after receiving the AM-801 mount was to drill a hole in the base for a screw and a wing nut. The base is painted black, so I got my continuity meter out to double check that the screw was making a good ground, which it was. I had to bend the mount up slightly for the antenna to be vertical, since my Jeep windows don’t have much of an angle to them. I’m sure it would be just right for most cars.

My next step was to give it a try. Continue reading Elecraft AX1 Test Using American Radio Supply AM-801 Window Mount →

Antennas, News, Portable, QRP

Notes from new Elecraft AX1/AX2 owners

11 Comments

After posting my latest field reports using the Elecraft AX1 antenna, I’ve received a number of messages from new AX1 owners. All of the following have kindly allowed me to share them here with you.

AX1 Patio DXing

From Michael (K1ETA):

Thomas,

I am a subscriber and an avid follower. [L]ike you, I do a lot of portable ops with various antenna setups and radios. I was recently offered an AX1 and I was told it was basically a dummy load. Having seen your videos and proof of success I accepted it and I can’t say how much fun I have with it. Yesterday, I made 22 DX contacts throughout Europe in the ARRL World Wide CW contest from my patio in my back yard with 5 watts, the AX1 and my KX2.

I would never have tried that with the AX1 had I not seen your videos. You see it is even good enough for contests if you don’t try to compete with the big guns. Listen, search and call back the stations without pileups!

Many thank for all you do and for making me an AX1 believer.

72

Michael Kenney (K1ETA)

Pairing the AX2 and Emtech ZM-2

From Michael (N7CCD):

Hi Thomas,

I just finished your video comparing the AX1 and AX2 and thought you might appreciate a solution I came up with for making my travel more compact.

I purchased the AX2 during the February sale and found it pairs well with the ZM-2 ATU for my IC-705 (wow what a mouthful of acronyms. No wonder my wife and daughter call me a nerd…). I didn’t get the tripod adapter in the sale, but found the AX2 sits perfectly on the ZM-2 which acts as a very stable stand. There is some body capacitance when tuning, but not too much. I was even able to easily tune it on 17M. I need to try other higher bands sometime.

I set it up in our breakfast nook just for kicks and sent a few JS8 and FT8 transmissions to see where I was being heard (I’ll include a screenshot). Was able to successfully send an APRS text message, and I even made an SSB contact into a special event station in Nevada!

I found a hard sided case I can store the tuner and AX2 in, which also had enough room to put in a “speaker wire” antenna as an option. Why not?

I think this may replace the AlexLoop for air travel since it’s so compact and versatile.

Hope all is well on your side of the country!

Michael – N7CCD

P.S. +16 into Michigan!

AX1 DXing

From Kevin (KD8IE):

Hi Tom,

After video about the AX1 recently, I decided to order one and it came last week.

The weather’s been kind of chilly up here. As a matter of fact, it was 41 when I decided to go out and do an activation then at Cuyahoga Valley National Park.

Well, suffice to say I made contacts with the antenna a lot farther than I expected it would be. The bands were really long. First station I worked was in New Brunswick. The last two stations were Italy and Slovenia.

73,
KD8IE

Many thanks to all of you for sharing your experience and tips using the AX series antennas!

As a reminder, Elecraft has a February promotion on an AX1 and AX2 packages that includes free shipping. There are a few days of this promotion left at time of posting.

Accessories, Antennas, How To, Portable, POTA, QRP

Jim’s “WD-PT-PB” AX1/AX2 table/bench clamp mount

10 Comments


Many thanks to Jim (N9EET) who writes:

Thomas:

I look forward to all your videos and am enjoying how you use the Elecraft AX-1 in the field.

I have built the “WD-PT-PB” attachment for my AX-1 antenna.

That is, it is for Windy Day-Picnic Table-Park Bench use. It can be set up horizontally or vertically on the edge of a picnic table or at any angle on the back of a park bench and is a secure attachment for the AX-1 off the radio.

[I] bought the bolts straight and put them thru a random C clamp secured with a nut or wing nut and then bent one in my vise. Loosen the wing nut and angle the bolt any way I want and tighten the wing nut.

The pictures show it better than paragraphs of a description.

73,
Jim Long
Madison, WI
N9EET

That’s brilliant, Jim! I love how versatile the clamp is and that it even fits in your Maxpedition pouch! No doubt, it’ll help the AX1 (or AX2, or any similar antenna) survive the windiest of deployments.

Thank you for sharing.

Antennas, Field Reports, Morse Code, News, Portable, POTA, QRP

Postcard Field Report: Pairing the Mission RGO One with the Elecraft AX1 at Lake James for some QRP DX

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Welcome to my first Postcard Field Report!

If you’ve been following QRPer.com and my YouTube channel for long, you’ll notice that I typically post two field reports with videos per week when my free time allows. Each report takes about four hours to produce along with a video. I’ve currently got a small backlog of videos I need to post, so in order to squeeze them into my schedule, I’m going to use a slightly more abbreviated field report format: a “postcard” format!

My Postcard Field Reports will still be information-packed, just slightly more concise and distilled than my average field report. I’ll primarily post these for sites I visit frequently.

Speaking of which….

Lake James State Park (K-2739)

Thursday, February 2, 2023, was a rainy, dreary day so the perfect time to play a little POTA, right?  I made time in my morning to visit Lake James State Park (K-2739).

When I arrived at the Catawba River Access, the parking lot was empty. Not too surprising considering it was a Thursday morning on a chilly, rainy day.

Of course, I had the picnic shelter all to myself, so why not use it to stay dry? Continue reading Postcard Field Report: Pairing the Mission RGO One with the Elecraft AX1 at Lake James for some QRP DX →