Category Archives: How To

Antenna Tuners, Antennas, Homebrew, How To, News, Portable, QRP

BD4LB’s Simple Homemade L-Match for Field Operating

14 Comments

Many thanks to HUAQIANG Gu (BD4LB) who shares the following information about his homemade L-Match. Note that BD4LB doesn’t speak English, and I don’t speak Chinese, so the following was machine-translated via Google Translate:

Homemade L-Match for Field Operating

by HUAQIANG Gu (BD4LB)

L-MATCH has a simple structure and is easy to make.
It is mainly composed of a coil and an adjustable capacitor.

  1. The coil is made of copper wire with a diameter of 1.8mm, and the outer diameter of the coil is 50mm.
  2. The capacitance of the thin film adjustable capacitor is 0pF–200pF.
  3. When using, a balanced ground wire needs to be installed.
    (Different bands, multiple quarter-wave length wires, and together. I use a row of wires. For example: two balanced ground wires 10 meters and 5 meters long, respectively 40 meters band and 20 meters band balanced ground wire.)

After many outdoor communications, I adjusted the end-fed antenna. The length of the radiator was 10 meters, which was appropriate.

One end of it is hung from the top of a 6-meter-long fiberglass fishing rod. On the other end, connect the red binding post of L-match.

Balance the ground wire and connect it to the black binding post. Spread it out on the ground.

The L-match is placed on the ground and connected to the HS1B or KVE60C antenna analyzer using a one meter long 50-3 coaxial cable. (This reduces the length and weight of the coaxial cable.)
When using an inverted V antenna, the length of the coaxial cable needs to be at least 8 meters.

My outdoor communication is mainly on the top of a hill in the park, or on the beach by the sea.

On the beach, there is plenty of space. In addition to setting up end-fed antennas, you can also set up inverted V antennas.

On the top of the mountain in the park, the space is limited, and it is difficult to deploy the 20-meter-long antenna oscillator. Only 10-meter end-fed antennas can be used.

After fixing the fishing rod, installing the antenna radiator and balanced ground wire, first connect the antenna analyzer KVE60C.
Use copper alligator clips to clip on the coil and adjust the adjustable capacitance to minimize the standing wave ratio of 7.023 MHz.
(Change different coil taps, adjust the adjustable capacitor, and try several times.)

I carry a compass to adjust the transmitting direction of the end-fed antenna. I won’t get lost.

The actual communication effect is quite good.

In the 40-meter band, it is suitable for short-distance communication within 800 kilometers.

In the 20-meter band, it is suitable for communication within 1000-2000 kilometers.

Field Day, How To, News, POTA, Skills

Can a Field Day or contest contact count as a valid POTA contact?

18 Comments

Many thanks to @thogevoll who asked the following question following my field report and video from Field Day 2023:

Thomas, I’m still new to POTA and have not done an activation yet.

How does a Field Day contact from a park count as a POTA contact? Is it simply that you are operating from park? Do you have to send the park ID number? Or, is that actually not even required for POTA contacts?

These are great questions.

The short answer is, YES: almost any simplex contact you make as an activator counts as a POTA contact regardless of the exchange used.

I’ll try to break this down…

Contests, as a rule of thumb, have a defined exchange and the elements of that exchange must be logged with each contact. This often includes things like signal report, section, region, and/or serial number.

ARRL Field Day is no exception.

If you look at the Field Day video I posted, you’ll note N3CZ and I were logging our Field Day contacts on N3FJP’s Field Day version of ACLog. Two key components of the Field Day exchange are the section, and the category (1B, 2A, etc.). We were running 1B (one op, QRP, battery) NC (North Carolina).

Those elements must be logged in order to have a valid Field Day Contact.

POTA ≠ Contest

Parks On The Air, on the other hand, is not a contest. It’s simply an on-the-air activity that has no defined start and end time. You can activate or hunt a park any time of the day or night, any day of the year.

While there is a generally accepted convention for POTA exchanges (which varies based on country/region), there is no formal required exchange. The POTA activator guide is very clear about this.

True, we POTA activators in the US and Canada tend to exchange both the signal report and the state or province, but this isn’t done in most other countries in the world. It’s up to the activator if they send the park number.

Convention in voice modes is to send the park number, but it’s less common in CW unless a hunter asks for it or if you’re completing a Park-to-Park contact. That said, there’s nothing preventing you from sending the park number with each contact if you like.

For a POTA contact, you really only need to log the station/call, time, mode, and frequency. Those details are submitted with your logs that detail the park number, date, activator, etc. and then uploaded to the POTA database in an .ADI file.

Working contesters as an activator

If I happen to pick a crowded contest weekend to activate a park and don’t have a rig or antenna that can escape to the peace and quiet of the WARC bands (and, yes, POTA is very much allowed on the WARC bands) then I often hunt and work contest contacts. I especially do this if band conditions are rough and the contest activity is dense.

I prefer, of course, to run one frequency as a POTA activator in order to open the park to POTA hunters–that’s why I use the WARC bands on contest weekends–but in a pinch, I might work contesters in order to get the ten contacts needed to validate an activation.

Of course, I need to sort out the contest exchange and use that with each contact, but that’s not too difficult. Those random folks I log have no idea I’m activating a park.

I should also note that many contests (Field Day may be one of these) don’t allow self-spotting, so when Vlado and I worked as a Field Day station this year, we did not spot ourselves on the POTA network. We were actually making Field Day contacts first and foremost, with the side-benefit of activating a park at the same time.

In other words, we simply logged our Field Day contacts per FD requirements, then (with a bit of log tweaking) uploaded the log to both the ARRL and the POTA network.

In POTA, only the activator is required to submit their logs, not the hunter; they get credit via your uploaded activator logs.

POTA: Some QSO exceptions

To be clear (and redundant), any contact you make at a park–even when the other op isn’t a POTA participant–counts as a POTA contact, with a few side notes and exceptions:

  • Contacts via a land repeater are not allowed. I can’t hop on a local repeater and make/log valid POTA contacts. I can, however, hop on a local repeater and ask for someone to spot me or meet me on a simplex frequency for a contact.
  • Satellite repeaters are allowed. All satellite contacts are allowed.
  • Fully automated QSOs are prohibited. I can’t set up one of those fully-automated digital mode applications that will run unattended. As the POTA rules state: “Each contact must include direct action by both operators making the contact.“

I believe every POTA activator should read through both the POTA rules and Activator Guide prior to your first activation.

Summary

We’re entering the heaviest part of the contest season at present. If you arrive at a park on the weekend and discover that the bands are absolutely chock-full of contest stations–and you can’t find a free frequency to do your activation–feel free to work and log contest stations!

Otherwise, do what many of us do and either escape to the WARC bands or move closer to the band edges (being careful not to go too far) where you’ll typically find more free space.

Do you combine Field Day, contests, and special events with POTA? Feel free to comment with your approach!

Accessories, Guest Posts, How To, News, Portable, QRP

A Nifty Internal Battery Mod for the Elecraft KX1

3 Comments

A Nifty Internal Battery Mod for the Elecraft KX1

by Leo (DL2COM)

I was very happy to learn more about an interesting internal battery solution that came with my recently purchased Elecraft KX1. The original owner, Rolf DF2FK, built this KX1 himself and has a background in electrical engineering. He wanted an internal solution that is safe and delivers the full power output with this transceiver.

elecraft kx-1 internal lipo battery pack
KX1 with custom balanced 4S Lipo battery pack

Disclaimer: Working on custom battery solutions can be very dangerous, esp. with Lipo batteries (possible fire, explosion when handled improperly etc.). Please take safety precautions when attempting to build the following solutions and make sure you stick to the safety instructions of the batteries you work on. Everything happens at your own risk – just like always in Ham Radio 🙂

So he developed an idea around a 4S Lipo pack consisting of 4×3.7V Lipo cells each with a capacity of 820 mAh and each with an own battery management system (BMS). Of course all four are connected in series. The individual BMSs help a great deal in keeping the Lipo cells safe such as avoiding deep discharge, excess charge etc. Continue reading A Nifty Internal Battery Mod for the Elecraft KX1 →

Antennas, Field Reports, How To, News, Portable, POTA

The joy of a low-slung wire

24 Comments

(As is my usual, this article has a bunch of links – click on as many as you wish to receive the full experience)

by Vince (VE6LK)

In May of 2023 I embarked on a two week vacation to Hamilton Ontario that co-incidentally happened to include a side trip to Hamvention just outside of Dayton, Ohio.

For a guy living in Alberta, Canada, this would prove to be quite the trip and it created memories to last a lifetime. I also was told that I could play radio during the trip provided my wife would get to see some of the many waterfalls in the City of Hamilton, the area we’d call home for our two week trip.

At Niagara Falls

Yes, I did take a brief detour to Niagara Falls while on the trip as it is only an hour from Hamilton.

And thus the planning began. I started overlaying POTA entities that overlapped on waterfalls so we both could visit and enjoy in our own way. It also meant I had to figure out what radio gear and, most importantly antennas, to bring along.

I landed up mostly running with low-slung antennas. By this I mean something between 4 and 10′ off the ground and horizontal in orientation. But it’s what I discovered about this simple approach that made it appear like pure magic to me – I made great contacts at what I would consider to be beyond NVIS distances including one from OH to UT!

Continue reading The joy of a low-slung wire →

Accessories, Guest Posts, How To, Mobile, News

Scott builds a mobile desk for HF park-roving

8 Comments

Many thanks to Scott (KK4Z) who shares the following post from his blog KK4Z.com:

Necessity is the mother of invention

by Scott (KK4Z)

Plato’s Republic he said that *our need will be the real creator* or the proverb as we know it today *necessity is the mother of invention*.  Recently, my friend Thomas K4SWL acquired a Yaesu FT-891.  During his YouTube video, he expounded on how much fun he had with it. It did indeed look like fun. During this time I was pondering about doing more day activations instead of overnights.  With the cost of everything still climbing, the need to conserve becomes apparent.  I thought an FT-891 might really be a great radio for these day activations. Then reality set in.

I already have a number of projects I am working on and misc things like maybe having to replace my old 33′ push-up pole, it was not in the stars nor was there a twinkle in my wife’s eye when I mentioned it. In reality, the IC-7300 is a great radio and does everything I need to do especially in the field. I don’t need another radio, I have three 100 watt radios and three QRP radios. I still wanted an easy setup for these one-day activations. I want to drive to a park, set up in a few minutes, operate, tear-down in a couple of minutes, and head for home or another park. I also wanted to make my day activations park ranger friendly. To me, that means trying to be inconspicuous.

I have two projects planned. The first is a desk for my truck. I am making a desk to sit over the center console and front passenger seat big enough to hold my IC-7300, a laptop and a CW paddle. My plan is to secure the desk to the truck and the radio to the desk. I also wanted to make this as cheaply as possible. I used stuff I had on the property such as a half sheet of plywood and some construction lumber. The only things I had to buy were some screws and eye-bolts, about 14 dollars worth.


The plywood was cut to 24 x 38.5 inches. The length covers the center console and front seat while still allowing me to get to the heat/AC controls. I gave the corners a generous radius and I broke the edges with a router. On the underside, I used a 2 x 12 to make a spacer for the center console where the cup holder is and a leg for the other side over the passenger seat. The spacer is glued and screwed to the desktop but the leg is not attached. This is to make it easier to store. I made a socket for the leg using 2 x 2’s. It’s probably easier to look at a picture than me to try to explain. I added eye rings to the rear of the desk and use a bungee cord to secure the desk to the passenger seat. The only other thing I did, sprayed the top with polyurethane. Note. I am not a carpenter or cabinet maker. I use rough hand tools to get the job done and I am often making do with what’s on hand or what’s the cheapest way to do it.

Continue reading Scott builds a mobile desk for HF park-roving →

Field Reports, Hacks and Hints, How To, Morse Code, Portable, POTA

How to optimize low solar activity days for your activations

13 Comments

by Vince (VE6LK)

(As is Vince’s usual, this article is full of educational and fun links – click on as many as you wish)

Picture this ..  you are getting a bit twitchy due to lack of POTA activation and you have run out of Potaxxia. Further, You publicly stated a New Year’s eve goal to make at least 200 POTA CW activation contacts per month for 2023 (there may have been beer involved), and now you must stay accountable to your goal and you are currently behind plan. It’s too early in the season to be lawn mowing while listening to podcasts such as QSO Today, Ham Radio Workbench, ICQ Podcast, AP/DZ or Soldersmoke. Thus, chasing contacts is [always] a good use of your time.

Lastly, if you are like me, the the solar indices are still an art form being learned and the numbers for today aren’t all in the green zone.

One of many charts that help decode the magic behind propagation values – click through for source webpage

So you begin to wonder just how much effort it’s worth to load up your gear and try to activate. You think to yourself that there won’t be much action on bands other than 20m which has been noisy lately, so why bother as it’s at least a 45 minute trip to the nearest POTA entity.

With this background, on Saturday I placed myself in the city at the nearest-to-home spot I could park in the south part of Calgary adjacent to VE-5082, the Trans-Canada Trail. I was trying to make the best of what I perceived to be a rough conditions day and had no real plan except a convenient location requiring minimal effort for a minimal return. My expectations were, sadly, met in this regard.

The author in a suburban and *very* RF noisy place that he won’t return to.

I was at the edge of suburbia with large homes on my left overlooking the ravine and pathway on my right. To say it was RF noisy would be a colossal understatement. I made 18 painful contacts in an hour and I’m sure people called me but I didn’t hear them given the S7 noise floor on 20m. At least I made one DX contact to Denmark along the way. Overall feeling frustrated, I went back home.

Sunday morning rolls around and again I wonder “is it worth it”?

Continue reading How to optimize low solar activity days for your activations →

Hacks and Hints, How To, Kits, News, Skills

Video: Alan’s method for winding toroids

10 Comments

After posting my article about the K9DP BCI filter kit build, Alan (W2AEW) commented:

If you dislike winding toroids, the method I show in this video makes it a lot easier!

This is an excellent way to handle the toroid while winding. Check out his video below:

Click here to view on YouTube. 

Alan has a massive library of instructional videos on YouTube. If you haven’t already, subscribe to his channel!

Accessories, Articles, How To, Kits, New Products, News, QRP

Assembling a K9DP BCI Filter Kit (Photos)

6 Comments


If you own a Xiegu G106, X6100, or any other radio that is prone to overloading when in the presence of an AM broadcaster, you should consider building an in-line BCI filter!

As many of you know, I’ve been testing the Xiegu G106 over the past couple of months for a review that will be published in the May 2023 issue of The Spectrum Monitor magazine.

One criticism of the G106 is that its front-end overloads when there’s an AM broadcaster within a few miles of where you choose to operate. The Xiegu X6100 is identical in this regard.

One quick way to remedy this is to build or buy a BCI filter. We’ve mentioned in the past how you can homebrew them and I planned to do so. After checking my parts drawer, though, I realized I needed to buy a capacitor, toroids and at least one of the two BNC connectors needed if I wanted an in-line filter in a small project box.

I decided it would be much easier to simply buy a kit and, based on a tip from a reader here on QRPer.com, I purchased one from Dan (K9DP). Continue reading Assembling a K9DP BCI Filter Kit (Photos) →

Guest Posts, Hacks and Hints, How To, Morse Code, News, QRP

Bob pairs his ATS-20 with the Zachtek “Flea” CW transmitter

6 Comments

Many thanks to Bob (K7ZB) who shares the following guest post:

ATS-20 configured with Zachtek “Flea” CW transmitter

The ATS-20 in HF CW Transceiver Mode

by Bob Houf (K7ZB)

I picked up an ATS-20 last summer and played with it on SWBC and the ham bands but found the telescoping whip antenna to be marginal.

The unit I purchased from Amazon turned out to be solid: no problems have surfaced after 9 months of intermittent listening. By default, I have enjoyed it primarily listening to FM in my office.

When I used my long wire antenna, the performance on shortwave greatly improved – easy copy of DX and the value of the receiver began to impress me.

Recently I came across a Swedish ham who co-developed a line of radios covering a broad range of WSPR and associated designs built to a very high standard.

Already having a WSPR setup I was intrigued by a very low power CW transmitter that Zach co-developed with KB9RLW which puts out 300mW on 40, 30 and 20 meters at a price point that is less than the ATS-20, and – most interestingly – the design of the radio allows it to work in transceive mode with the receiver by providing a T/R switch when used with the proper SMA-BNC cable arrangement.

I bought a “Flea” and configured it with my ATS-20 then used an external antenna tuner to make sure the transmitter had close to a 1:1 SWR.  The “Flea” advertises that it is robust to high SWR and looking over the schematic that is evident, but for the sake of a trial I went with the ATU. Continue reading Bob pairs his ATS-20 with the Zachtek “Flea” CW transmitter →

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.