All posts by Thomas Witherspoon

Accessories, News

25% Off: Spec-Ops Brand Backpack Sale This Weekend

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If you’ve been watching my videos and reading my field reports, you’ll no doubt have noticed that my favorite field radio backpack for SOTA and POTA is the Spec-Ops Brand T.H.E. Pack EDC.

This pack is made in the USA and is insanely rugged. Click here to see more details about this pack and click here to see how I kit out this pack for field radio use. This pack (and this T.H.E. pack series in general) even has antenna ports built in!

I just received a promotional flyer from Spec-Ops and this weekend they are offering a 25% discount on all of their backpacks plus free shipping on orders over $200.

This is an insanely good deal. This means you can buy the EDC pack like I have for $134.96 instead of $179.95.

You must use the coupon code BESTPACK at checkout to claim the discount.

If I didn’t already have their full size T.H.E. pack, I would buy one in this sale. Tempted to buy one of their Reckon Rucks!

Spec-Ops Brand hasn’t had a sale like this in years. If you’ve been considering one, now would be the time to bit the bullet.

Click here to check out Spec-Ops Backpacks.

Antenna Tuners, Antennas, Field Reports, How To, Kits, News, POTA, QRP

How to tune: Pairing the Emtech ZM-2 manual ATU with the Mountain Topper MTR-4B on the Blue Ridge Parkway

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You’ve no doubt heard me brag about the Emtech ZM-2 ATU in previous field reports. I think it’s an accessory every field operator should have.

The ZM-2 is a very capable manual transmatch/ATU and is also one of the more affordable tuners on the market. It’s available as both a kit and a fully-assembled unit. Both well under $100.

I do believe the “manual” part of the ZM-2 scares off some and it really shouldn’t. We are used to simply pressing a button these days and allowing our automatic ATUs to do all of the matching work for us.

Manual ATUs do require some amount of skill, but truth is, the learning curve is very modest and intuitive.

Manual ATUs require no power source in order to operate–you adjust the L and C values by hand–thus there’s never a worry about the ATU’s battery being depleted. They also are easy to manipulate outside the ham bands because they require no RF in order to read the SWR–you simply make adjustments to the L and C until you hear the noise peak.   This is why many shortwave broadcast listeners love the ZM-2 so much. It’ll match most any antenna you hook up to it!

I also argue that everyone should have a portable ATU even if you operate resonant antennas. Think of an ATU as a First Aid Kit for your antenna: if the deployment is less than ideal, or if you damage it in the field, an ATU can help you find an impedance match your radio can live with. ATUs have saved several of my activations.

Mountain Topper MTR-4B V2

I’ve also mentioned that I’ve had an MTR-4B on loan from a very kind and generous reader for most of the year. He was in no particular hurry for me to send it back to him, but I wrote him in early November and said, “I’m doing one more activation with this little rig, then I’m shipping it to its rightful owner!”

He had a request, and it was a good one:

I think it would be a good little twist to the usual YouTube if you paired a random wire with the ZM-2 and the MTR-4B…showing how to tune the ZM-2 with a Mountain Topper…

I really liked this idea, so I made plans to to hit the Blue Ridge Parkway nearby and give it a go.

The first time I tried this in the field, I paired the MTR-4B with one of my Sony amplified speakers because the MTR-4B 1.) has no internal speaker and 2.) has no volume control. During the video, however, I realized that there simply wasn’t enough audio amplification so that the viewer would be able to hear a noise peak as I manually tuned the ATU. I decided to scratch that video and just do the activation on my own. I really wanted to show how the tuning process worked in the video.

I went back to the field the next week–on November 10, 2022–with my Sony in-line digital recorder knowing it would be much easier to hear how the L/C changes affected the band noise. Continue reading How to tune: Pairing the Emtech ZM-2 manual ATU with the Mountain Topper MTR-4B on the Blue Ridge Parkway →

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

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

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

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

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

A quality LiFePO4 battery

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

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

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

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

A very affordable Li-Ion rechargeable battery


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

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

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

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

Morse Code Keys!

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

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

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

Funny, Guest Posts, Hams

Guest Post: Scott also names his radios

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

Naming Radios

by Scott (KK4Z)

Men in general, have a habit of naming things. All sorts of things, cars, body parts, you name it, we will cast our own nickname on it. I thought I would share some of the names I have given my radios. Typically, I don’t just throw a name on something. I am around it for a while, before I decide what I am going to call it. My poor dogs, when I first get them, I go through a plethora of names until I find one that fits. My latest dog, a boxer mix from the pound was named Hawkeye by them. I got him home. I had to get to know him.

He ended up being Andy but likes to be called pup-pup. Maybe his last owners called him that. He’s still very much a pup but is going to be a great dog.

I will start with my main radio which is an Icom IC-7610. It is my workhorse radio. It is probably the best radio I have ever owned. I have worked the world on it and it does everything I need it to do. I call it Zeus, the king of all my other radios. I believe there is not a radio out there that can do anything that Zeus cannot do. Any improvements over Zeus would be marginal.

Continue reading Guest Post: Scott also names his radios →

Antennas, Field Reports, Morse Code, New Products, News, Portable, QRP

Taking the new Chelegance MC-750 vertical on a POTA activation at Lake James State Park

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Back in September, I was contacted by Jesse Chen (BD7LLY) who has been a long-time reader of QRPer.com. Jesse is also the founder of Chelegance (a.k.a. JNCRadio): a company that has been producing ham radio gear and accessories since 2020.

Jesse reached out and asked if I would consider evaluating a couple of the field portable antennas he designs and produces in China.

In truth, I get a lot–and I do mean loads–of requests to evaluate products and I pass on 97% of them. I only have so much time and I simply don’t bother with gear I think is unnecessary or that could be cheaply made.

Before replying to Jesse, I did a little research on Chelegance and discovered that DX Engineering now distributes their products. I decided that if DX Engineering liked the quality well enough to add Chelegance products to their catalog, then it must be up to a decent standard. I’ve never purchased anything sub-quality from DX Engineering.

I also like the fact that Jesse is a real amateur radio operator.

After checking back in with Jesse, he decided to send me two of his portable HF antennas: the M-104 and the MC-750. In full disclosure, he sent these to me at no charge–i.e. free–with the idea I could do a proper evaluation and share my thoughts both with him and with my readers.

He knew that both of these antennas had the potential to compliment my style of portable operating. I also told Jesse not to rush ship them to me as I was quite busy. I received both antennas at the end of October.

The first antenna I wanted to try was the MC-750.

The Chelegance MC-750

When I received the parcel from Jesse, I was very impressed with the MC-750’s custom soft-sided case. The stitching and quality of it are much better than I would have expected. The interior is custom designed to hold all of the MC-750 antenna components. There’s enough extra space in it, in fact, that I can also carry a 40′ RG-316 feedline inside.

Product Photo by Chelegance

The antenna basically consists of the following components in the supplied padded bag:

  • A heavy stainless steel ground spike and matching unit
  • 40 meter coil
  • 50 cm antenna arm/extension
  • 5.2 meter telescoping whip
  • 4 yellow counterpoise wires with a wire winder board

The price for the antenna system is $250 via DX Engineering and 219€ via WIMO. Moonraker in the UK is also a Chelegance distributor, but doesn’t seem to have the MC-750 listed in their inventory at time of posting (Dec 5, 2022).

The only antenna I have that might compare with the MC-750 is the Chameleon CHA MPAS Lite which is one of my favorite portable HF antennas for its quick deployment, and overall quality. For reference, the CHA MPAS Lite retails for about $360.

I thought the best way to test the MC-750 would be to take it on a POTA activation. Continue reading Taking the new Chelegance MC-750 vertical on a POTA activation at Lake James State Park →

Antennas, Articles, How To, Mobile, News

Dave sorts out vehicle-mounted antenna SWR issues

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Photo by Katie Musial.

Many thanks to Dave (K1SWL) who writes:

Comments on vehicle-mounted antennas

by Dave Benson (K1SWL)

As with Rand’s recent post about his effective vehicle setup, I and others also use a small operating table inside the vehicle.  I’ve tried a number of approaches to antennas.  Without elaborating on those schemes, I’ll note that winter is now closing in here in NH. As a result, I’m now operating exclusively from my truck. My interest is now in minimizing setup and tear-down times.  Barry (WD4MSM)

also commented about the improvement in vehicle-mounted antennas with an added ground.  I’d like to quantify that.

I’d recently ordered a number of Hustler Mobile antenna components. They’re used as a stationary-portable setup using that company’s high-quality mag-mount. As I first evaluated the antenna, I was disappointed to find the minimum SWRs to be on the high side.

These results were related to the ‘floating’ coax shield, which serves as a counterpoise with the mag-mount setup.  Worse yet, these results were inconsistent. Touching the coax connector shell at the antenna analyzer caused the SWR to jump up, as did just changing the way I held the analyzer. Bad juju! It means RF inside the vehicle, with the potential for RF-‘hot’ symptoms at the rig..  Adding a 1:1 balun inline eliminated the stray RF at the rig, but didn’t do much for the SWR. It’s also just one more gadget to bring along.

A better fix was a custom bracket that bolted to the truck frame. I first confirmed that there was low-resistance continuity between a target location and the vehicle’s cigarette lighter shell.  This was something of a ‘comedy of errors’. I had a sheet-metal angle bracket on hand and went to work enlarging a hole in it. This had the usual outcome: a drill bit grabbed the workpiece and spun it. The bracket itself was buckled beyond redemption and my finger’s now healing well.  A length of 1-1/2 inch aluminum angle bracket was just the ticket.   Note that the mounting hole needs to be offset from the coax fitting mount. This avoids an interference between the mounting bolt and coax connector shell. Ask me how I know.  The bracket assembly uses a specialty coax fitting from DX Engineering. It’s their part number DXE-UHF-FDFB.

This bracket is bolted down on one of the corners of the Tacoma’s passenger seat assemblies.  It’s the closest location to the antenna I found without drilling holes and cutting the coax.  For this vehicle, it’s a 10mm bolt and was paint-coated for appearance reasons. I replaced it with a stainless-steel bolt from a hardware store. It’s important to include a split-lockwasher between the bolt and the bracket. This’ll keep the conductivity to the frame good over time. The bracket is deburred and its corners rounded to preclude injury to passengers.

In any event, it’s out of the way of the seat’s legroom space. A 3-foot coax cable assembly brings the coax nicely up behind the rig atop the operating surface.

So- how’d it work? It’s like the difference between night and day!  The broad SWR curves vanished – replaced by typical characteristics for monoband antennas. The sensitivity to handling the coax has vanished.  (A representative curve at right.) The curves are narrower, and that’s actually a good sign- it means that unwanted resistances have been reduced. 

With this fix in place, here are the SWR minima:

Frequency    SWR

14060        1.04:1

21060        1.05:1

28060        1.16:1

I took advantage of the CQ Worldwide CW Contest this past weekend. I was able to work 101 stations on 10M, 15M and 20M with this setup.  That was from a State Park 5 minutes away.  The attraction was a large and sunny parking lot, and solar gain was such that I needed to leave the truck door open several times.  This area is kept plowed out in winter, and I may try for the POTA ‘kilo’ award from there at the 1000-contact benchmark.  

We’ll see….   73, K1SWL

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

Cheap POTA thrills with my new-to-me TEN-TEC R4020 QRP CW transceiver!

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Last year, I made an impulse purchase.

You’re shocked, right–?

Right.

You see, I did something I’d never suggest others do: in a moment of boredom, I casually cruised the classifieds listings found on QTH.com.

One of the very first listings was for a TEN-TEC R4020 CW QRP transceiver. The price, if memory serves, was $120 (+/- $10) shipped.

Ten-Tec Model R4020 (Product Photo: Ten-Tec)

Without even thinking, I sent a message to the seller:

“I’ll buy it if it’s still available!“

He responded noting I was the first to reply to the ad, so it was mine if I wanted it.

I did, of course.

The R4020 arrived that same week, I opened the box, applied power to confirmed it powered up, then placed it on the top shelf in my shack.

At the time, I had a mountain of review and evaluations in process along with several articles in the pipeline for TSM and one for RadCom, and simply didn’t have time to properly explore the R4020. I thought it might be fun saving it as a little reward for meeting my deadlines.

Then, frankly, I just forgot about the R4020. This spring was a very busy time for me family-wise, then I spent the summer in Canada, and most of this fall has been all about catching up after having spent the summer in Canada. Funny how that works!

Fast-forward to November 11th, 2022 when I was packing a field radio kit to take on an overnight trip and I noticed the R4020 on the top shelf! My reward, finally–!

I quickly packed the R4020 in my Spec-Ops Order Pouch along with a 3Ah Bioenno LiFePo4 battery and a power cable.

South Mountains State Park (K-2753)

On Saturday, November 12, 2022, I jumped in the car and headed to South Mountains State Park with the R4020.

This past year, I’ve mostly set up at South Mountain’s Clear Creek Access on the west side of the park, but this time I decided to make my way to the equestrian picnic area near the main entrance and ranger station.

Continue reading Cheap POTA thrills with my new-to-me TEN-TEC R4020 QRP CW transceiver! →

Kits, New Products, News

Now Shipping: The Halibut Electronics Common Mode Current Choke Test Rig

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I’ve just learned that my buddy Mark (N6MTS) at Halibut Electronics has just kitted up a new batch of his CMCC Test Rigs and is now accepting orders. I know that some of the experimenters in our community might appreciate this brilliant bit of gear that Mark originally designed as a piece of test gear for his own workbench.

I asked Mark to shed a little light on this kit and exactly what it does:

A Common Mode Current Choke, aka a 1:1 Current Balun, is a common (pardon the pun) device in a ham shack. They can be used: at the Antenna feed point to prevent dangerous unbalanced return currents on the outside of the feedline, at the Radio’s antenna port to minimize RF noise picked up on the feedline, on DC or AC power cables and other interconnect cables to minimize RF pick-up in the shack, etc.

Most RF test equipment, such as a (Nano)VNA, measures the Differential Mode of a system, that is, the balanced currents that flow on the INSIDE of a coax cable. This is great for measuring things like: the frequency response of a filter, the complex impedance (or SWR) of an antenna, or the loss of a length of coax.

It cannot measure the Common Mode of a system, that is, the unbalanced current that flows on the OUTSIDE of a coax cable. This means it cannot (directly) measure a Common Mode Current Choke.

The Halibut Electronics Common Mode Current Choke Test Rig converts the Differential Mode signal generated by the VNA into a Common Mode signal, and places it on the outside of the shield of a coax system. This allows the VNA to directly measure how effective the choke is at choking common mode RF currents. Once you can directly measure a device, you can measure the real world effect of changes you make, and optimize the device for your specific use case. As opposed to relying on calculations and predictions of ideal conditions in free space.

The Common Mode Current Choke Test Rig is a kit that requires some assembly, using a soldering iron and Philips head screw driver.

Click here to purchase a Halibut Electronics CMCC Test Rig kit.

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

Mountain Topper MTR-3B: A quick POTA activation before leaving camp!

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View from Yonah Mountain the previous day.

As I mentioned in previous field reports, the W4G SOTA Campout was amazing fun this year.  I enjoyed hanging with Joshua (KO4AWH) as we activated a total of three summits and a few parks–plus it was great meeting so many fellow SOTA activators at the Saturday evening potluck!

On Sunday morning, October 16, 2022, it was time to pack up the campsite and hit the road.

Although I was a little pressed for time, I decided to fit in one more activation as Joshua packed up his tent and before we took down the 40 meter Tufteln end-fed half-wave.

Chattahoochee-Oconee National Forest (K-4473)

Fortunately, our campsite was within Chattahoochee-Oconee National Forest and since all I needed to do was to connect my rig to our campsite antenna, setup took all of two minutes.

I pulled out the Mountain MTR-3B for this activation. It had been quite some time since I used this wee radio because I had only recently finished a review of the MTR-4B V2 (look for that review on QRPer.com very soon).

The MTR-3B is now permanently at-the-ready inside my MTR-3B ultra portable field kit, but since there was already an antenna and key in place, I only needed the radio, power cord, logging items, and battery.

Continue reading Mountain Topper MTR-3B: A quick POTA activation before leaving camp! →

News

HRWB 2002 Holiday Shopping Show

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The Ham Radio Workbench podcast has just published their 2022 Holiday Shopping Show episode. I had the honor of being a guest in this episode and…well…it was essentially a license to release my inner enabler which–in the best of times–I have a difficult time containing.

Seriously, though, it’s always so much fun to hang with George, Vince, Mike, Rod, and Mark–they’re great guys.

I would suggest freezing your credit card in a block of ice before listening to this episode.

You’ve been warned!

If you’d like to see “how the sausage is made” check out this unedited video of the entire episode including before/after the podcast recording:

Click here to view on YouTube.

Or, if you’d rather hear the podcast–which is trimmed and formatted–you can listen via the embedded player below, or on the Ham Radio Workbench podcast website.

Click here to check out the Ham Radio Workbench website.