Tag Archives: Antennas

“What battery, antenna, and ATU should I pair with the Discovery TX-500?”

Many thanks to Vitor Morais who asked the following question in the comments section of my YouTube video:

Hi,

Greetings from UK.
I recently learned that POTA [is now in the] UK so I am really looking forward to it.

I also recently put an order for [the Discovery TX-500] so I am really excited as well.

I would like to create a very compact setup pouch for field use to pair with this radio; one that I could take to summits or parks and also travel abroad.

What battery and antenna would recommend?

Would you recommend an ATU?

Or would you compromise to fewer bands or pack a secondary antenna?

I love to know your opinion.
Thanks

Great questions, Vitor! In truth, these sorts of questions are easy to ask but quite complicated to answer due of the insane number of options and possibilities available. It’s impossible to cover them all so I’ll try to give you some suggestions based on what I tend to use in the field. Continue reading “What battery, antenna, and ATU should I pair with the Discovery TX-500?”

Phillip calls the white CHA MPAS Lite color a “Canadian-Winter Edition”

Many thanks to Phillip Novak (VE3OMI) who writes:

[…]A random note on the Chameleon MPAS lite that I purchased a month ago through DX Engineering; I was surprised to find that the matching unit I received was white – it’s always pictured as black on the Chameleon shop page.

Note the black matching unit to the right of the counterpoise winder.

I was a bit disappointed at first; the “stealthiness” of the black colour was something I was hoping for. It also had me wondering if perhaps I’d somehow gotten a test-unit.

[…]I was curious about the colour change and shot Chameleon a note.

Here’s what they came back with:

“Phillip, due to the black Delrin being much more in demand and causing supply chain issues, we opted to switch to the less commonly used white material. The two colors have the same specifications, and should perform identically, besides the color. The issue being more noticeable for some was anticipated, but could not be helped if we were to continue production. Hit it with some flat spray paint?”

I will add that I do like this antenna a lot and the build quality is excellent. I’ve also come around on the colour; I like to think of the white version as a Canadian-Winter Edition.

[A]ll the best,
-p
ve3omi

It does look like an antenna ready for deployment with the Arctic Forces! 🙂

Thank you for sharing this, Phillip. I had seen a few photos of the white matching unit but assumed it was a different size or configuration than the one I have. This explains it. 

I’m not sure if I’d have a preference for one or the other, frankly. If it was being used in a semi-permanent stealthy installation and in an area without snow, I’m sure painting it flat black or wrapping it with a dark color fabric/tape would help. 

Elecraft AX2 20M modifiable pocket antenna now shipping

AX2 illustration by Elecraft

Many thanks to Wayne (N6KR) at Elecraft who notes that the Elecraft AX2 20 meter pocket antenna is now shipping:

https://elecraft.com/collections/antennas/products/ax2-minature-20-meter-whip-antenna

Here’s the product description from Elecraft’s website:

The AX2 is small enough to take anywhere – just in time for lightweight field ops during the new solar cycle. Use it HT-style with a hand-held, like the KX2; on a picnic table with an AXB1 whip bipod; or with a tripod and AXT1 tripod adapter. The AX2’s rugged, nylon housing is water-resistant, with low wind resistance and our new anti-wobble design.

Illustration by Elecraft

Experimenters will love the AX2’s versatile design. A snap-off cover provides access to the high-Q inductor. Simply remove turns and re-solder one wire to cover your favorite band. Clip-off tabs are provided for band identification.

Elecraft also provides an AX1 and AX2 comparison chart on the AX2 product page:

COMPARISON CHART

The table below shows how the new AX2 20-meter mini-whip compares to our original AX1 multi-band whip. Both are designed for lightweight portable operation. The versatile AX1 covers multiple bands via a selector switch and can handle up to 30 W continuous TX power.

The ultra-compact AX2 has a new anti-tilt base design that minimizes BNC connector wobble – ideal for hand-held (HTstyle) use. While the AX2 covers 20 meters as shipped, it can be modified by the user to cover any single band from 17 through 6 meters. The base unit includes small tabs that can be clipped off to identify the target band.

NOTE: Both whips are intended to be used with an ATU to compensate for terrain, body capacitance, height, etc.

A reader recently asked if I’d be selling my AX1 after learning about the AX2, but that isn’t going to happen. The AX2 is a 20 meters and up antenna and I see it as being a brilliant SOTA companion since its lightweight, stable design should do well on windy summits.

For POTA and WWFF, however, I really rely on the 40 meter band for most of my contacts. The AX1 covers 40 meters brilliantly (and 20M and 17M) so I’ll still rely on it quite heavily.

Click here to check out the AX2 antenna on Elecraft’s website. The price is currently $79.99 US plus shipping.

Anatomy of a Field Radio Kit Part 2: Kit Types, Preparedness, and the Golden Rules

The following review was first published in the July 2021 issue of The Spectrum Monitor magazine. Read Anatomy of a Field Radio Kit Part 1 here.


Part 2: Anatomy of a field radio kit

Last month, I took us down the rabbit hole of field radio kits by discussing some of the most basic components of a field radio kit in Part 1.

This month, we’ll take a deeper dive into the types of radio kit you might choose to assemble based upon your activity goals.  And finally, we’ll look at my “golden rules” of field kits, which I hope you’ll find useful.

Types of field radio kits

I configure and outfit my radio kits based on the environment in which I plan to deploy and operate, and which determines in no small way just what I need to pack besides the basics.

I roughly divide my field kit types as follows…

The Field Day or “Picnic Table” Kit

This is probably the most popular type of field kit in the world of amateur radio. Picnic table kits are designed with portability in mind, but not designed with distance hiking in mind. This is a very popular type of kit for Field Day or park activations through POTA or WWFF.

These kits are typically packed in a backpack, a Pelican-type utility case, or a self-contained and field-ready box.

My picnic table kit is packed in a large Red Oxx C-Ruck rucksack. If I haven’t already made it clear, I’m a self-professed pack geek and I love this Red Oxx Pack because it has large zippered pockets on the outside, a rain flap with storage on top, and one large compartment on the inside.

Continue reading Anatomy of a Field Radio Kit Part 2: Kit Types, Preparedness, and the Golden Rules

Anatomy of a Field Radio Kit Part 1: Basic components and advantages of going QRP

The following review was first published in the June 2021 issue of The Spectrum Monitor magazine:


Part 1: Anatomy of a field radio kit

by Thomas (K4SWL)

Whether it’s the ARRL Field Day, Winter Field Day, a QRP contest, or, more likely, a Summits On The Air or Parks On The Air activation, I look for any and every excuse to hit the field with my radios.

Most of my on-air time is in the field. While I enjoy operating from the shack, I’ve discovered I especially enjoy operating in the great outdoors.

Besides being a fan of hiking, camping, and the great outdoors generally, I also am particularly fond of radio field gear. I like portable transceivers, portable antennas, battery packs, and all of the accessories that make field operation efficient and enjoyable.

I appreciate the emergency communications skills I’ve developed in the field, too. Should the need (or opportunity) arise, I now keep a complete field kit packed and ready to go at all times, and can even deploy all of it within just ten minutes. In my early days of ham radio operation, I might have easily spent thirty minutes setting the antenna, alone…especially on Field Day, with folks watching me struggle to untangle wires and cables, followed by the undoubtedly entertaining attempts I made to put a line into a tree to deploy the antenna. But after deploying a variety of antennas hundreds of times now, I find that––while I’m still not perfect––I finally have a bit of skill and the process of tossing up a line is becoming much swifter and smoother.

Confessions of a pack geek

The Red Oxx C-Ruck loaded and ready for the field!

If I’m being honest with myself, I admit: I also simply get a thrill out of kitting out my field packs, as well as organizing and tweaking them over time. Yes, (don’t judge me!) I actually like packing up my field gear.

I think my passion for organizing and packing gear goes back to a former career when I lived in the UK, Germany, and France, and was required to travel throughout Europe frequently. Originally inspired by travel guru Rick Steves, I’ve always appreciated the footloose feeling of having all of my travel gear in one lightweight pack. I don’t like checking in luggage, but love the freedom of grabbing my backpack and skipping the baggage claim carousels. And I also like knowing that, even though my gear is compact, it contains everything I need.

I’ve become something of a “less-is-more” traveller. Two years ago, for example, I traveled for one week using what Frontier Airlines classifies as a “personal carry-on.” My Tom Bihn Stowaway pack, which only measures 14.0″ (w) x 9.4″ (h) x 8.1″ (d), carried everything I needed for a conference, including my own presentation gear.

My Tom Bihn Stowaway personal carry on convertible pack with everything I needed for a one week trip including a conference.

Packing for that trip was great fun as it really challenged me to decide what was essential and what was not. My iPad doubled a computing and presentation device, for example, but I also packed a small flashlight and a mini first aid kit, which I felt were important. Of course, I also carried a small portable Shortwave/AM/FM radio and my Yaesu VX-3R handheld…also vital, as I can’t leave home without radios!

Getting started with a field kit

Putting together a field radio kit is so similar to packing for travel: you must first do an assessment of what you need, starting with the basics––then organize it, pack it, and test it.

In my world, this is a very deep topic. We’re going to break down this topic into two parts.

This article, Part 1, we’ll dive in:

  • first, going over the obvious components of a basic field radio kit;
  • second, discussing the benefits of going low-power (QRP) if that appeals

In Part 2, we will:

  • look at variations of kits based on activity, and finally
  • review what I consider the “golden rules” of a good field radio kit

The basics of a field radio kit

First, let’s go over the basics of your field kit, considering that that these primary components will dictate your bag, pack, or case size.

A transceiver

The lab599 Discovery TX-500

Since I’m a bit radio obsessed, I have a number of QRP transceivers I like to take to the field.  But if you have selected one transceiver you plan to dedicate to field work, or simply have only one transceiver, period, you can build a kit around it (and see my note below about “modular” kits). If budget allows, you might consider buying a radio specifically for field use, so it can always be packed and ready to go.

There are a number of transceivers on the market that are designed with field use in mind. Some are compact, power-stingy CW-only QRP transceivers that might only operate on three ham radio bands, while others are 100-watt general coverage transceivers that even have built-in antenna tuners––there’s a wide range of options.

Look for field-friendly, built-in options like:

  • CW and voice-memory keying;
  • SWR and power meter readings;
  • a battery voltage indicator;
  • low current consumption;
  • the ability to lower power to at least one watt;
  • an internal battery option; and
  • an internal antenna tuner option

And the more such options are already built into your field rig, obviously, the less separate accessories you’ll need to pack and keep track of in the field, which is a good thing.

The Elecraft KX2 has a built-in ATU, battery pack, and even attachable CW paddles!

Some of my favorite field-ready general-coverage transceivers currently in production are:

  • The Elecraft KX2 A full-featured, inclusive, and compact 80-10 meter transceiver that’s truly a “Swiss-army knife” of field operation (see November 2016 TSM review)
  • The Elecraft KX3 Benchmark performance, wide array of features, and compact design
  • The lab599 Discovery TX-500 Military-grade engineering, weatherproof, spectrum display, and benchmark current consumption for a general-coverage radio (see October 2020 TSM review)
  • Mission RGO One Top-notch performance, 50-watts out, and excellent audio (see November 2020 TSM review)
  • The Yaesu FT-817/818 Rugged chassis, 160-6 meters, VHF and UHF multi-mode, both BNC and PL-259 antenna inputs
  • The Xiegu X5105 Affordable, 160-6 meters, 5 watts output, built-in ATU, and built in rechargeable batttey
  • The Xiegu G90 Affordable, relatively compact rig with built-in ATU, color screen with spectrum/watefall, good audio, and 20 watts of output power (see August 2020 TSM review)
  • The Icom IC-705 Benchmark performance, a multitude of features, exchangeable battery packs, 160-6 meters, VHF and UHF multi-mode, D-Star, GPS, WiFi, Bluetooth (see February 2021 TSM review)
  • The Yaesu FT-891: Affordable relatively compact radio with detachable faceplate, 100 watts output, and excellent audio (see November 2017 TSM review)

And if you’re primarily a CW operator, you’ll have some incredibly compact radio options like the CW-only Mountain Topper MTR-3B or 4B, or the Elecraft KX1 (used).

An important side note for field contests: if you plan to use a field transceiver in an event like the ARRL Field Day and/or another popular radio contest, make sure you choose a transceiver that can handle tightly spaced signals in an RF-dense environment. This is not the time to pull out a lower-end radio with poor receiver specifications. Use Rob Sherwood’s receiver test data table as a guide.

An antenna––and a means to deploy/support it

The CHA LEFS sloper

This particular topic, alone, might warrant a three-part series of articles. So, to keep the scope of this article realistic, let’s just say that you should build or buy an antenna that can comfortably handle the wattage you’re pushing into it in all the modes that you operate, considering that some 100-watt SSB-rated antennas might melt or arc if you run 100 watts CW or FT8.

I would suggest you consider having at least one resonant antenna, like an end-fed half-wave (EFHW) that might cover 40 and 20 meters without the need of an antenna tuner to match the antenna impedance to your rig.

Some of my favorite portable antenna systems?

I’m a big fan of Chameleon Antenna for their ease of deployment and benchmark build quality. Their prices range from $145 for the Emcomm III random wire, to $550 for their MPAS 2.0 vertical antenna system. These prices are near the top of the market, but Chameleon antennas are all machined and produced in the US and the quality is second to none. These are antennas you might well pass along to the next generation, meaning, really heirloom-worthy kit!

Packtenna 9:1 UNUN Random Wire
The PackTenna 9:1 UNUN

PackTennas, likewise, are pricey for such a compact product, but they are also beautifully engineered, lightweight, and designed for heavy field use. PackTenna produces an EFHW, 9:1 UNUN random wire, and linked dipole models. They’re some of the most compact field antennas on the market that can still handle as much as 100 watts of power output.

My Wolf River Coils “TIA” vertical antenna

Wolf River Coils verticals are affordable, compact, and resonant––thus an ATU isn’t needed. It will take some time to learn how to adjust the coil during frequency changes, but they work amazingly well. I have the WRC Take It Along (TIA). Their antennas are designed to handle 100 watts SSB, 50 watts CW, or 20 watts digital.

The EFT Trail-Friendly

Vibroplex sells a number of compact field portable antennas and is the manufacturer of Par End Fedz offerings. I’m very fond of the EFT Trail-Friendly and the EFT-MTR.

The MFJ-1984LP EFHW packs a lot of performance for the price

MFJ Enterprises also has a few portable antennas in their catalog, and it’s very difficult to beat the price and performance of their antenna gear. I have their $50 EFHW antenna (the MFJ-1982LP) and love it.

The Elecraft AX1 attaches directly to the BNC port on the KX3 and KX2.

I’ve also had tremendous fun with the uber-compact Elecraft AX1 antenna. Unquestionably, it’s the most compact and quickest-to-deploy antenna I own. It’s designed to pair with the Elecraft KX2 and KX3 using the optional internal antenna tuner.

There are a number of other antenna manufacturers who cater to portable operators. For example––although I’ve not yet had the opportunity of testing their antennas––SOTAbeams is highly regarded among SOTA enthusiasts.

Short on cash? No worries; you can build your own! In fact, until 2016, I had never purchased a field antenna; I built all my own. EFHW antennas and random-wire antennas are no more than a carefully-wound coil, a female antenna connector, an enclosure or mounting plate, and some wire. Some of the most active field operators I know homebrew all of their antennas. It’s easy, affordable, and fun!

In fact, some antennas are no more than a bit of speaker wire matched with a good ATU.

A power source

A 3Ah Bioenno 12V LiFEPo4 powering my LD-11 transceiver

I’ll keep this point brief because we recently covered the topic of batteries in detail in our previous feature.

Make sure you choose a battery that is sized appropriately for your transceiver power output. I will say that I’m a huge fan of LiFePo4 rechargeable batteries for their voltage range, lightweight design, and longevity. Being primarily a QRPer, I typically use 3 to 4.5 amp hour batteries as they’ll carry me through as many as three or four activations without needing to be recharged. For longer field deployments, or when I’m powering my 100W KXPA100 amplifier, I’ll use my 15 aH Bioenno LiFePo4 pack.

I use my 15Ah Bioenno LiFePo4 pack for QRO transceivers

Again, check out our Portable Power Primer for a deep-dive into the world of portable power.

A key, mic, and/or computing device

It should go without saying that you need to pack these, but I have gone to the field with operators who forgot their key or mic and asked if I had a spare.

Keys are fairly universal, but keep in mind legacy transceivers often want a ¼” plug while newer rigs typically accept an ⅛” plug. Microphones, however, vary in port type and pin configuration based on the manufacturer and model. You could damage your mic or rig if you plug in a multi-pin mic that was designed for a different transceiver. Most mics that use a ⅛” plug are universal. Still, check before you plug it in if using an after-market or non-OEM mic.

Of course, choose a key, microphone, or boom headset that’s compact and rugged so that’ll be easy to pack and will stand the test of time.

I also always pack a set of inexpensive in-ear earphones. These can dramatically help with weak-signal interpretation.

Also, if you plan to operate a digital mode, you’ll likely need some sort of computing device. Even though I rarely operate digital modes in the field, I often pack my Microsoft Surface Go tablet in case I change my mind.

My Microsoft Surface Go tablet

In addition, I like logging directly to N3FJP’s Amateur Contact Log application directly in the field to save time submitting my logs later. Soon, I’ll be using the new HAMRS field log on my iPhone.

Speaking of logging…

A means of logging

I like compact notepads like Muji and Rite In The Rain for field use.

As simple as it is, it’s very important to take at least some paper and a pencil for logging your contacts. I like using small, pocket-sized Muji notebooks (affiliate link) for logging, and if the weather is even a little questionable, I’m a huge fan of getting my contacts down in Rite In The Rain mini notebooks (affiliate link) or notepads using a good old-fashioned pencil.

I like logging to paper and sometimes simultaneously logging to my Microsoft Surface Go. I have completed phone-only field activations where I only logged to my Surface Go tablet: in those cases, I snap a photo of my N3FJP call log, just in case something happens to my tablet between the field and the shack! Having endured enough technology failures, it gives me peace of mind to have at least one other backup.

Keep in mind that when you’re activating a park or summit, the folks calling you are relying on you to submit your logs to the appropriate programs so that they can get credit for working you. Many times, this might also help their awards for a state, county, or grid square. Always submit your logs after an activation even if you didn’t make enough contacts to validate the activation (POTA requires 10 contacts, SOTA requires 4 logged). It helps other folks out.

A pack or case

If you have a field radio kit, you’re going to need a means to organize and contain it for transport. There are at least three types of systems used for field kits.

A backpack or soft-sided case

My GoRuck BulletRuck is a brilliant SOTA pack

Since I enjoy the option of hiking with my radio gear, I love using backpacks. Although I’ll speak to this more next month in “Part 2,”, I choose quality packs that have at least one waterproof compartment and are comfortable to carry on long hikes. I also try to look for packs with Molle or some sort of external strapping so that I can attach portable antenna masts or even my hiking poles to the exterior of the pack.

A waterproof case or flight case

Ruggedized, weatherproof cases come in all sizes. This Pelican 1060 can house my entire KX1 radio kit.

Many field operators who want extra protection for their gear––especially when they don’t plan to hike or carry their gear long distances to the operating site––like hard-sided cases. I have built field radio kits in waterproof Pelican cases and appreciate knowing that I could drop my kit in a whitewater river, and it would likely survive the adventure unscathed. If you are one of these operators, look for quality watertight cases from brands like Pelican and Nanuk with interiors lined in pick foam padding that allows you to perfectly accommodate and safely protect your radio and accessories.

Portable ready-to-deploy cases

Although this option is almost outside the scope of this article, many emergency communications enthusiasts love having their gear loaded in rugged, portable––often rack-mounted and hard-sided––cases that they can simply open, hook to an antenna, and get right on the air. These systems are often the heaviest, least “portable,” and less suited for long distance hikes, but they’re often completely self-contained, with all of the components, including the power, hooked up and ready to go on a moment’s notice. While a system like this would be impractical for many Summits On The Air sites, it could be ideal for a park or island activation where you’re never that far from your vehicle.

Optional: Antenna cable

An ABR Industries RG-316 cable assembly

This doesn’t sound like an option, but it’s true.  I’ve often operated my Elecraft KX3, KX2, and KX1 without a feedline at all: I simply attached two wires to a BNC binding post, and connected that to the radio. It makes for a super-compact setup.

Even an 8-12 foot feedline can make it easier to configure your operating position in the field. If you want to keep the feedline as low-profile as possible,  especially if you’re operating QRP, consider investing in a quality RG-316 feedline terminated with the connector that fits your radio and antenna.

Optional: Antenna Tuner/Transmatch

A portable ATU with RF-sensing like the Elecraft T1 will give you an amazing amount of frequency agility. I’ve been known to use the T1 to tune my CHA Emcomm III random wire antenna on 160 meters..

Again, this topic could easily warrant a multi-part series of articles, but I’ll sum this one up in a nutshell: while I love (and even prefer) using resonant antennas that require no antenna tuner, I almost always carry a radio with a built-in ATU or an external portable ATU like the Elecraft T1 or ZM-2.

Why? Because an ATU will give you a certain amount of frequency agility or freedom. If I’m using an antenna that’s resonant on 40, 20, and 10 meters, but there’s a contest that day and the bands are incredibly crowded, I might use the ATU to find a match on 30 meters or 17 meters, thus finding a little refuge and space to operate. Also, sometimes antenna deployments aren’t ideal––due, for example, to site limitations such as dense vegetation that may alter the antenna deployment and thus its resonance. An ATU can at least keep your transceiver happy with the SWR when your resonant antenna might not be perfectly resonant.

But the main reason I carry it? A portable ATU gives you operational flexibility.

QRP or QRO?

I have operated QRO in the field with my KXPA100 amplifier on Field Day.

Its good to keep in mind that many of the station accessories listed above need to be matched to the output power of your transceiver and modes you use.

Many ham radio friendships have been placed in jeopardy over the question of either using QRP (low power) or QRO (high power) for field operations. This is a shame. Some operators have very strong opinions, but the truth is, there is no right or wrong answer.

In the spirit of full disclosure, I operate 97% of the time at QRP power levels––in my world, this means five watts or less. Personally, I enjoy the challenge of low-power operating.  But I also appreciate the portability QRP gear offers.

The wee Mountain Topper MTR-3B

Speaking pragmatically––and this fact really isn’t open to debate––QRP and lower-power transceivers and accessories tend to be more efficient, more compact, and lighter than their higher-power siblings.

Most of my QRP transceivers weigh anywhere from two to five times less than their 100-watt equivalents. If you’re operating mobile (from a vehicle or camper/caravan, for example), an eight to twelve pound difference might not be a big deal. But the moment you’re hiking several miles to a mountain summit, weight becomes an important factor.

QRP transceivers have modest power requirements: everything from battery, to antenna, and even to tuners, are smaller, lighter, and more compact.

When operating QRP, you don’t have to worry as much about RF coming back to the radio from, say, an end-fed antenna. If I’m pushing over 20 watts into an end-fed half wave or end-fed random wire, I’ll likely want an in-line RF choke to keep some of that energy from affecting my transceiver or giving me an RF “tingle” when I touch the radio chassis or my key. Too much RF coming back to the transceiver can also affect things like electronic CW keying. But at five watts? I don’t worry. This is almost a non-issue, unless your transceiver happens to be very RF-sensitive indeed.

And even though I’m predominantly a QRPer, I definitely do pack radios like the 50-watt Mission RGO One and occasionally my Elecraft KX3 and KXPA100 100-watt amplifier, especially for an event like Field Day where my club is operating at higher power. I simply size up my gear appropriately. Again, this is especially important with your antenna, feed line, ATU, and battery selections.

If you primarily activate parks and are never far from your vehicle, it’s quite easy to accommodate a 100 watt transceiver like an FT-891, for example. Of course, if you wish to operate low-power and save your battery, simply turn down the output power. If you plan to hike a lot with your gear, then get your mind around QRP!

Stay tuned for Part 2!

In Part 2 we’ll dig into some of the details, looking at different approaches to field radio kits and some guidance and suggestions based on my real-life experience (read: operating mistakes).

Click here to read Anatomy of a Field Radio Kit Part 2.


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Hike and Talk: Non-Resonant vs. Resonant Antennas and should you buy an ATU?

I had a topic on the mind as I made my way back to the trailhead after a SOTA activation recently.

I get a lot of questions from readers and subscribers about resonant vs. non-resonant antennas and whether or not an ATU is a good or bad thing.

If you know me, you’ll know that I tend to lean towards qualitative research; meaning, I like to base my opinions on first-hand observations rather than laboratory or textbook explanations. Part of the reason is I’m not an engineer, so specifications and performance stats don’t influence me–I don’t understand them half the time–rather, I base my opinions on trying or field testing.

The proof is in the pudding, right?

So with the topic of antennas and ATUs on the brain, I decided to turn on the action camera and do an unscripted video on the trail as I hiked back to my car.

This video is essentially stream of consciousness: I won’t blame you if you skip it.

With that said, if you manage to stay awake for the whole video (congratulations in advance) I’m curious what your thoughts are so please consider leaving a kind comment!

Thank you & 73,

Thomas (K4SWL)

Dan’s clever chalk line homebrew EFHW antenna

Many thanks to Dan (KQ8Q) who writes:

Hi Tom,

I discovered something you might have an interest in for your wire antenna deployment. Years ago when I was a building contractor, we used chalk line for floor layout. It has a very high tensile strength and is very light weight. After reflecting on this, I recently bought a 100’ spool of braided 1 millimeter chalk line and used it for a field deployment. I attached my “throw weight” to it and easily launched it about 60’ into a tree. You can see it in the attached photo holding my homebrew EFHW to my Jeep.

This link is what I used: Tajima PL-ITOL 100 ft .04″ Bold Braided Replacement Chalk Line New | eBay

Click here for full parts list (PDF)

The magnet wire was scavenged from a HUGE transformer from a neighbor’s discarded light fixture.

Lug Nut Throw Weight: left hand threaded from a 1966 Plymouth Fury

I did the new installation for him and he gave me the old one. I promptly disassembled it and collected miles of 14 and 20 gauge magnet wire 😊!

I haven’t added the capacitor to this antenna yet because it is sufficiently resonant and broadbanded on 40, 20, 15, and 10 Meters. I did some testing with the capacitors though on my previous build which was the PVC tube EFHW transformer. I believe I may have sent you a photo of that in a previous message. It too was resonant in the same places, but adding the capacitor smoothed and widened the acceptable SWR range.

The attached photos are my complete antenna assembly: matching transformer (49:1), 65.5’ speaker wire, 100’ braided 1MM chalk line, and throw weight (epoxy filled lug nut with short paracord pigtail).

Compact and lightweight.

Dan/ KQ8Q

I love this, Dan! I also like how self-contained and compact it is. What a professional job, too, with heat shrink, proper connection points and tie-offs.

Brilliant work!

Do you have an antenna or radio project you’d like to share on QRPer.com? Contact me!

G4USI has fun testing the matching ability of the Xiegu X5105 ATU

Many thanks to Stephen (G7VFY) who shares the following article posted on G4USI’s blog:

Xiegu ATU’s – just how good are they?

Preamble: Based on some social media comments, let me say at the outset that: a) I know that the ATU does not tune the antenna, but provides a good match to it; b) resonant antennas are more efficient; c) that you can tune a dummy load; d) just because you can tune something doesn’t make it an effective radiator. I do know these things. This post is intended as a bit of fun and to see just how much of a mis-match this ATU can handle to press objects into service as an antenna, even a very inefficient one. Please don’t take it too seriously!

Ask any Xiegu owner of the X5105, G90 or the XPA125B linear amp, and they will all tell you that they have great auto-tuners. Well, I own a X5105 and recently was lent a G90 for review for Practical Wireless. I decided to put the ATUs to the test using my X5105.

But what challenge to give it? Well, how about trying very, very long and very, very short antennas? What about metal gates, a cow shed roof, the framework of a polytunnel and a stock trailer?

Read on to find out how it really performs.

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I love G4USI’s philosophy with this fun experiment: see if it’ll match, then see if you can get spotted!

Xiegu ATUs certainly have a wide matching range–so do the Elecraft KX series ATUs. Indeed, having a super capable trans match means that you don’t necessarily need an extra inline transformer to make matching a non-resonant wire easier.

And I see why G4USI mentions that there’s a difference between a good SWR and efficiency. It’s an important note because, yes, dummy loads will yield perfect SWRs!

Many, many moons ago, I used to participate in a fun contest where the idea was to make as many contacts as possible from not-so-standard antennas. The rules of the contest really pushed the operator to metal objects that, in no way, resembled an antenna. They didn’t allow electric fences or even gutters, if I recall correctly.

One year, I remember loading two identical small trampolines and my in-law’s house. I think I ran them QRP with my Elecraft K2 and used a ZM-2 manual tuner to match them. I’m sure they weren’t efficient, but it worked! I made several contacts with other contest stations and it was amazing fun!

Have you ever had success with a non-traditional antenna? Please comment!

Mistakes and miscalculations might make us better field radio operators

I don’t know about you, but part of the fun of playing radio in the field are the inevitable frustrations.

It might not feel like it in the moment, but when I eventually overcome the challenges of a mistake, I feel like I’ve truly accomplished something.

That was my little epiphany this morning: making mistakes has perhaps made me a better radio operator. Less-than-efficient field deployments have honed my skills and had a major influence on the gear I pack.

If you’ve read some of my (rather rambling) field reports in the past, you’ll note that I rarely do field activations with the exact same gear combinations each time. I feel fortunate enough that I can pair different radios with different antennas and different accessories.  I get a small thrill out of not knowing exactly how well a combination will work, especially if I’m not activating a rare all-time new park or tough summit for that matter. In cases where getting to the site is a challenge in and of itself, I want to use a trusted combo of gear.

It’s that wee bit of mystery that attracts me to the field.

If I approached POTA more like a contest–where activation and contact numbers were my focus–I would have installed a mobile HF rig in my car a long time ago. I could rack up way more parks and contacts that way. It especially simplifies multi-site activation days since it effectively eliminates the time involved in setting up and later packing up gear.  Mobile operating is the most efficient way to hit number goals: drive up to a site, start calling CQ, work your stations, then move on.

K-6937 & K-4510

(Photo credit: K4TLI)

Yesterday, I did a last minute “two-fer” activation of Pisgah National Forest and Pisgah Game Land. I had not planned to do an activation that day–temps never rose above 29F (-2C) at the QTH day and it also snowed and flurried all day long. Winds were very gusty as well, so it effectively felt much colder on the skin.

I wanted to hike up to the ridge line behind my QTH and do the activation but I knew up there temps would be lower and (worse) winds much stronger. Cold doesn’t really bother me, but strong winds do. This was also the first weekend my ankle felt almost normal after twisting it badly last month. It’s healing and I hope will be in shape for a long hike from my QTH to a six point SOTA summit next weekend with my daughter (K4TLI).

All of those factors combined pointed toward simply staying at home, drinking coffee, and reading a book.

Hazel was ready for some field radio fun, though. (Photo credit: K4TLI)

But I really wanted some outdoor time. And I really wanted to make an activation with my Elecraft KX1, so I decided that instead of hiking up in elevation 800 feet, I’d drive down about 900-1,000 feet to a forest trailhead. That would get me on the air in a protected valley with less wind,  less snow, possibly warmer temps, and much less hiking which would be easier on my ankle.

The Last-Minute Antenna

When I use the KX1 in the field, I typically pack a very simple antenna: one length of radiator wire and one length of counterpoise wire–connected to a BNC binding post adapter, I let the built-in ATU sort out the match.

When I owned my first KX1, I had a magic length of radiator wire (the length of which I can no longer remember) that seemed to work amazingly well  on 40, 30, and 20 meters.

My new-to-me KX1 came with two lengths of wire: one 23′ and one about 20′. Although I made a fun and successful activation with this setup, the radiator was simply too short for the KX1 to find a decent match on 40M.

On the way out the door, I decided to cut a new radiator and counterpoise out of scrap wire I use for antenna experiments.

Being a bit stubborn and also in a hurry to beat sunset, I did no Internet research to sort out the ideal lengths for 40 meters.  I simply cut a 17′ length for the counterpoise and about 27.5′ for the radiator.

In the Field

After arriving on site, I deployed the antenna and tried finding a match on 40 meters with the KX1’s internal ATU.

No go.

I tried a few times hoping maybe the ATU would find something even semi-reasonable in terms of a match, but there simply wasn’t enough radiator to make it work. That was a shame because forty meters would have been the ideal band for yielding quick contacts this time of the afternoon.

I had options, but I wanted to make what I had work.

The activation took time and patience. The 30 meter band was now my best bet and it’s where I logged all ten contacts for a valid activation. I tried 20 meters where I had a 1:1 match, but the band was dead.

At one point, I switched out the KX1 with my KX2 that I also packed. I tried to find a 40 meter match with the superior KX2 ATU, but physics got in the way again. 🙂

40 meters was an option

Let’s be clear here: I could have easily cut 4′ off of the counterpoise and attached it to the radiator and I bet I would have gotten a match on 40M. Since the counterpoise was lying on the ground, its length was less crucial.

The EFT Trail-Friendly end fed antenna was also in my pack.

I also had a perfectly capable 40/20/10 en-fed antenna in my pack. Switching out the antenna would have only taken four minutes.

I bet I could have easily yielded 20 additional contacts on 40 meters because the band was in great shape. Almost without fail, 40 meters is my most productive band.

Working with limitations

Thing is, I’m starting to understand that I like working with self-imposed limitations.

Perhaps this is why I love QRP and low-power radio so much: I get a little thrill out of doing more with less.

Yesterday, even after I realized it would be a struggle to log my final three contacts on 30 meters, I persisted. One motivation was I’ve never completed a full activation using only 30 meters. With a little patience, I knew I could snag my ten contacts.

The only things making it a challenge were the facts that temps were dropping rapidly, winds were picking up, and the sun was setting. Hazel (the POTA dog) who so eagerly jumped in the car when she saw me put on my hiking boots earlier, was also starting to shiver.

Fortunately, after trying another short stint on 20 meters, I returned to 30 and worked two more stations in quick succession giving me a total of nine contacts.

It started to get darker, so I hunted and found an operator calling CQ  on 30 and simply made contact with him. He wasn’t a POTA station, just a general CQ call. He kindly gave me his details for the logs.

Lessons learned

I made a video of most of this activation and will upload it when I have a little bandwidth to do so. I’ll embed it in a shorter field report here on QRPer since I’ve described so much already.

Even though it was a challenge making ten contacts to accomplish a valid field activation with my time constraints, I’ll admit that I really enjoyed the challenge.

Next time I head to the field with the KX1, I’ll actually test the antenna prior to leaving the QTH.

In fact, I’m planning to make two radiators: one at an ideal length for 40 meters and above, and another–much longer–for 80 meters and above. Any advice and personal experience from KX1 owners would be much appreciated.

Perhaps most importantly, it’s only now dawned on me how much I enjoy making the most with self-imposed limitations or “trying to make lemonade with lemons.”

Do you feel the same? I’d love to hear your comments.

QRPGuys Tri-Band Vertical Antenna

On a tip from my buddy Eric (WD8RIF), I ordered a QRPGuys Tri-Band Vertical Antenna kit last week.

Not only will this antenna pair beautifully with my MTR-3B, KX1, and FT-817ND but I had completely forgotten I ordered it.

When I pulled the QRPGuys package from my post box, it was as if a little Christmas had arrived. I mean, is there a better feeling than getting a new kit in the mail–? I don’t think so.

Time to heat up the soldering iron!