All posts by Thomas Witherspoon

Antennas, Guest Posts, How To, News, Portable, POTA, QRP, SOTA

Build a Linked End-Fed Half-Wave Antenna with Bluetooth-Remote Band Switching!

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A Remote Control Antenna Link

by Dave (KO4YLZ)

Like so many other SOTA activators, I’m constantly tweaking my gear to optimize it for all the variables we encounter in the mountains. One of my main antennas is, of course, an EFHW. Paired with my KX2, I generally get sub-1.6:1 SWR on 40, 20, 15, and 10. However, 30m has an unacceptably high SWR. I considered switching to a multi-link EFHW, but hopping up to change links to chase an inadvertent S2S on another band is inconvenient, especially when the link for low bands is generally well beyond my reach and requires lowering the antenna.

To fully optimize my EFHW I decided I needed to come up with a way to add a “remote” link for 30m. After a couple of design iterations, I came up with the light-weight and compact remote antenna link shown/described below. The version described here is not my final one. While this “pill bottle” version is still quite small, I’d like to reduce the size even further.

Let’s start with the end…

Here’s the final product. It weighs under 1 oz. and is ~2.5” long. I have included a complete parts list at the end of the article.

My design considerations were:

  • Small and light
  • Range of at least 75 ft.
  • Reasonable battery life
  • Waterproof
  • Durable
  • Able to withstand the current at the 30m position on the antenna
  • Doesn’t adversely impact antenna performance on other bands
  • Easy to connect and disconnect from the antenna

Executive Summary

For those in a hurry, here’s a summary description of the remote antenna link. It consists of a very, very small remote control Bluetooth relay powered by two CR2032 batteries (user supplied). A set of contacts (either normally open or closed) lead from the relay to male and female 2mm bullet banana connectors in the cap of the pill bottle. Two matching bullet banana connectors at the antenna plug into the remote control link.

To operate, you simply open the bottle, switch on the batteries, re-install the cap, extend the antenna, and plug the bullet banana connectors at the antenna into the opposite pair embedded in the cap of the pill bottle. When you are ready to operate, you just push the remote button. When the remote button is pushed, the relay opens or closes thereby making or breaking the link and physically shortening or lengthening the antenna. Below is a picture of both sides of the mini-relay (antenna wire not shown)

The relay can run on 3.5-12 volts and can handle 1A. The included 1-button transmitter sends a signal (455mHz) to the relay and either opens or closes a set of contacts depending on how the user programs the relay.

Wiring It Up

I won’t bore you with a detailed written explanation…it’s a pretty simple build. Below are a simple wiring diagram and a series of photos with build details [click images to enlarge].

Making It work

The relay has three operating modes: latched, momentary, and toggle. Because I wanted the 30m link to be normally connected when the relay is in standby waiting for a signal from the remote control and open and stay open when I pressed the remote button, I had to reprogram the relay. Programming is accomplished by turning the unit on, then putting a 22ga wire jumper between the two “programming dots” and then pressing the remote button until the LED on the relay board flashes the number of times specified in the instructions for the operating mode you want.  The instructions are not very clear, so I recommend connecting the unit to your VOM in continuity mode to figure out the button/LED flashing sequence that corresponds to how you want the relay to behave.

Testing

The unit is rated for 1A so, to be sure I wasn’t going to blow it up when I transmitted with 10 watts, I used ChatGPT to produce a very nice graph showing the current at the 30m position on the antenna for each band when transmitting with 10W. Here’s the graph. Luckily, the maximum current at the 30m position (~43’) is .6A at 7.062 MHz.

I tested the unit on my KX2 by setting my operating frequency and then putting the KX2 tuner in bypass mode and pressing the button on the remote control; Ding…the SWR jumped immediately to the expected pre-determined (and acceptable) SWR value for the 30m band!

The unit draws 7mA when in standby and 32mA when the relay is energized. Assuming 40 minutes of operating off of the 30m band (relay not energized) and 20 minutes on the 30m band (relay energized), I calculated that approximately 17mA would be drawn from the two CR2032 batteries. Given that a CR2032 battery has a capacity of 220mAh, they should provide about 12 hours of operation.

Any questions, please comment.
Dave – KO4YLZ

Parts List

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Accessories, News

ABR Industries 20% Off Site-Wide Sale (May 21 – June 2)

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Just a quick note: ABR Industries—known for their high-quality, US-made coaxial cable assemblies—is running a 20% off site-wide sale now through Monday, June 2nd.

Here are links to some of my favorite ABR cable assemblies:

We’re proud to be an affiliate of ABR, so any purchase you make using our links also supports QRPer.com. Thanks as always for your support!

Events, FDIM, News, QRP

Mike’s 2025 Four Days In May (FDIM) Photo Gallery

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It’s hard to believe that Four Days in May (FDIM) 2025 has already come and gone—and even harder to believe that attendance was even larger than last year!

What an amazing event.

As always, FDIM is my favorite part of the Dayton Hamvention weekend. If you’re a QRPer and haven’t made it to FDIM yet, I can’t recommend it enough—this gathering is pure QRP energy from start to finish.

I truly enjoyed meeting so many QRPer readers and supporters in person. Thank you for stopping by and sharing your stories—it was an absolute highlight for me!

Once again, I was so busy chatting and connecting that I barely had time to snap any photos. Thankfully, my friend Mike (VE3MKX) came to the rescue with another fantastic gallery.

Thank you, Mike!

Photo Gallery

Click to view the entire photo album–> Continue reading Mike’s 2025 Four Days In May (FDIM) Photo Gallery →

Hamvention, News, QRP Radios

Hamvention 2025 Day 2: I Couldn’t Help Myself…

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Good morning, QRPers!

Day two of Hamvention 2025 was absolutely amazing—and the weather couldn’t have been more ideal. I wish I had time this morning to write a proper recap, but I’m grabbing a quick breakfast and heading back to the Greene County Fairgrounds for day three.

That said, I wanted to drop a quick note and share a photo of a little surprise from the Flea Market…

Even though I told myself I wouldn’t buy another radio at Hamvention, I spotted one I simply couldn’t pass up:

I already own a TR-35 (a rig I absolutely love), so I let that one go. But I didn’t have an MTR-4B in my collection… and that red chassis in the early morning sunlight? Irresistible. The asking price was $200—very fair, in my opinion—so I snagged it.

Later that day, I showed it off to my good friend Joshua (N5FY), and wouldn’t you know it—he gifted me one of his MTR-4B protective covers!

As soon as I got back to the hotel room that evening, I installed it.

She’s ready for the field.

 

I’ve actually wrote a review of an MTR-4B I borrowed from a reader. You can check out that review with links to field report here. I’m looking forward to taking this little red machine out to a summit soon!

More to come after Hamvention wraps up.

Thanks again to everyone who’s stopped by to say hello—it’s truly been the highlight of my weekend!

— Thomas (K4SWL)

FDIM, Hamvention, News, QRP

Day One at Hamvention 2025: Friends, Fun, and One Cancelled Reservation

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Good Morning, QRPers!

Day one of Hamvention 2025 (Friday, May 16) kicked off bright and early!

I started the day with a quick walk-through of the Hamvention Flea Market before the gates opened. I also shared an impromptu video with Patreon supporters—it was a peaceful moment before the weekend’s whirlwind began.

I spent most of Friday at the Ham Radio Workbench Podcast table, which served as a kind of home base. I had the pleasure of chatting with so many HRWB listeners, QRPer readers, and YouTube subscribers.

My dear friend Mike (VA3MW) shows off the new Flex Aurora.

Thank you for taking the time to introduce yourselves—it was a true joy to reconnect with many of you in person! Your kindness and encouragement fuel me through the wonderful chaos that is Hamvention.

First Stop: The Yaesu FTX-1 Field and Optima

As soon as the indoor exhibits opened, I made a beeline to the Yaesu booth to check out their new FTX-1 Field and FTX-1 Optima. They had multiple units on display, ready for hands-on testing.

In person, the rigs look fantastic—the displays are crisp, the fit and finish are excellent, and I really appreciate the modular design with snap-on battery and ATU options.

That said… my first reaction was: “This is bigger than I expected.” I wasn’t alone—I overheard several others expressing the same surprise.

I think that’s partly due to some early promotional material. One Yaesu rep video seemed to suggest the FTX-1 would be just a bit larger than the faceplate of an FTM-500D.

In reality, it has a much larger footprint. Even with just the battery attached, it has noticeable bulk—and with the optional ATU in place, it grows even more.

The Optima version, with its 100-watt amplifier and internal ATU, is larger still—definitely a full-size 100-watt rig. I’d say it’s bigger in every dimension than the FT-891.

I also recorded a quick video with my iPhone while checking out the FTX-1 at the Yaesu booth and shared it on YouTube yesterday, if you’d like a closer look.

Why I Cancelled My FTX-1 Reservation

After spending some time with the FTX-1, I walked over to DX Engineering and cancelled my reservation.

To be clear: I think Yaesu has done a great job with this rig. It’s incredibly feature-rich, well-built, and will no doubt be the perfect radio for a lot of operators. I’m willing to bet Yaesu will sell a ton of these—and rightfully so.

But for my specific needs—especially as someone who values small, minimalist radios for portable field use—the FTX-1 simply isn’t the right fit. Even the head unit of the FTX-1 Field is larger than I prefer. I could tell that, as much as I might enjoy the radio at home, I’d likely leave it behind more often than take it to the field.

So this was a personal decision, and canceling also frees up over $2,000 in funds for other gear that better aligns with my style of operating.

One thing I heard repeatedly throughout the day–a number of folks who had pre-ordered the FTX-1 Field through Ham Radio Outlet were frustrated. Several told me they were surprised—and disappointed—that HRO had a batch of FTX-1 Field units for sale at Hamvention, even though some customers placed reservations months ago.

These folks followed HRO’s instructions last year to reserve early and expected to be first to receive units in-hand.

Update: Two readers have noted that their FTX-1s reserved via HRO actually shipped on Friday, so perhaps all or some of the reserved orders actually shipped day of Hamvention.

Wrapping Up Day One

Mike (VA3MW) snapped this photo of us at the HRWB table.

Hamvention day one was absolutely amazing—but I’ll admit I was wiped out by the end of it (and I know I wasn’t alone!). I did make it to Club Night at Four Days In May (FDIM), but we headed back to the hotel early—just in time to avoid the intense storm that rolled through Dayton around 8:30–9:00 p.m.

I’m wrapping up this post over breakfast, then heading back to the Greene County Fairgrounds for day two. I can’t wait to see what’s ahead!

Once again, thank you to everyone who stopped by to say hello. Your encouragement and kindness truly mean the world to me.

— Thomas (K4SWL)

FDIM, Hamvention, News, QRP, Travel

Trip Report: Road to Hamvention 2025 and Four Days in May

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I’ve got a few quiet moments this morning as I sit in the dining room of our hotel in downtown Dayton, Ohio. It’s peaceful here—no one else is around, and no one has turned on the TV. Bliss…

Of course, that’ll change in a couple of hours when we pull into the parking lot at the Greene County Fairgrounds for Hamvention 2025!

So far, the trip and Four Days in May have been amazing.

I left Swannanoa bright and early Tuesday morning in the rain, but it cleared up as I crossed into Tennessee. The theme of the day was passing through thunder showers as I made my way north.

The plan was to activate Camp Creek State Park (US-5584) in West Virginia, grab lunch, then head to the QTH of Eric (WD8RIF).

I rolled into Camp Creek around 11:15 in light rain. Eric had confirmed there was at least one picnic shelter in the park, so I figured I’d activate from there to avoid scrambling if a downpour started.

I grabbed my end-fed half-wave and throw line from the back of the car—but then heard a very distant rumble of thunder. It was barely audible, but I decided to play it safe and set up under the metal shelter roof using my AX1 vertical instead. If I could wrap up the activation in 10–20 minutes, I could be packed up before any storms moved in.

It only took two minutes to set up the KX2 and AX1. I started scanning 20 meters for an open frequency, but could only hear one ragchew in progress—the band was otherwise dead.

I called QRL on 14,033.5 kHz, hoping for the best, when a loud clap of thunder hit.

Ugh.

I don’t mix radio and thunderstorms, so I packed up quickly, tucked in my tail, and hit the road. Camp Creek will have to wait for another day.

For lunch, I stopped at Tamarack in Beckley, WV. While the dining area might look like your typical folk art center café, the food is exceptional—the staff are in training for the famous Greenbrier Resort. I had a trout filet with green beans and mushrooms, kale, and sweet potato fries. It was incredible.

After a relaxed lunch, I hit the road again. A couple of hours later, I crossed the Ohio River and rolled into Ohio.

I arrived at Eric’s QTH around 4:30 and was warmly greeted by my canine buddy Theo—“The Great Warg” himself. You might remember him from some of Eric’s previous POTA adventures.

The Great Warg with WD8RIF circa May 2022.

Eric and I packed the car and headed into uptown Athens, Ohio for a quick bite.

On Wednesday morning, we hit the road early and activated Lake Alma State Park (US-1967), then headed to Great Seal State Park (US-1954) for a second activation.

Lake Alma State Park (US-1967)

While conditions were a bit unstable, we didn’t have to work too hard to complete both activations. (Full field reports and activation videos are coming soon.)

Great Seal State Park (US-1954)

Afterward, we drove another 90 minutes to Dayton and made a few stops at Wright-Patterson Air Force Base, including the clothing store—where I stocked up on my usual Rite in the Rain pads—and the Commissary, where Eric picked up his annual supply of Nutella!

We checked into our hotel and later grabbed dinner at Carillon Brewing Co., one of my favorite spots in Dayton.

Yesterday, we left the hotel around 7:00 AM to attend Four Days in May at the Holiday Inn Fairborn.

I wish I had more time to describe what an incredible event it was—truly a highlight of the year!

L to R: Vlado (N3CZ), Thomas (K4SWL), and Phil (W9IXX)

We wrapped up the day at a jam-packed Vendor Night. And I do mean jam-packed—it was shoulder-to-shoulder.

A huge thank you to the many readers and subscribers who introduced themselves. I truly appreciate it!

I’ll cap off this report now because it’s time to hit the road again. More to come!

News

On the Move! Heading to Four Days in May and Hamvention 2025

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Just a quick update: I’m heading out today for Four Days in May (FDIM) and Hamvention—both taking place this week—and will be on the road and fully immersed in the events for the next several days.

While I’m away, things may be a bit quiet here on QRPer.com.

My inbox is likely to pile up, and my posting may be limited while I soak in the energy, fun, and (let’s be honest) chaos of the world’s largest ham radio gathering and one of the best QRP conventions of the year!

Thanks for your understanding—and if you’re also attending Hamvention or FDIM, I hope to see you there!

72,

Thomas (K4SWL)

Field Reports, News, Pedestrian Mobile, Portable, POTA, QRP, Videos

Elecraft KH1 to the Rescue: Squeezing in a 20-Minute POTA Activation

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I feel incredibly fortunate to live in an area where a POTA park—the Blue Ridge Parkway—quite literally runs through town. As convenient as that is, I’ve still struggled to squeeze in activations over the past few months. We’ve had so much going on that even impromptu POTA time has felt out of reach.

Fortunately, I have a secret weapon for making the most of even the shortest activation window:

The KH1!

Left: My accessories pouch with contains a throw line, antenna adaptors, audio recorder, cables, spare key, and extras. Right: My Elecraft KH1 in a Pelican M40 case.

My Elecraft KH1 goes with me everywhere—it’s my proper EDC radio. And on Thursday, April 3, 2025, it came in very handy.

I dropped my daughter off at a physical therapist’s office, which just so happened to be right next to the Blue Ridge Parkway. Instead of waiting in the office for 45 minutes trying to catch up on email, I opted for some POTA radio therapy instead!

I left the parking lot and drove to a nearby gravel pull-off along the Parkway—just about four minutes from the PT office.

I hadn’t originally intended to film an activation, but I happened to have my camera, digital audio recorder, and a new magnetic clip-on camera mount with me.

I purchased this mount specifically to record pedestrian mobile activations. The first time I tried it, the results weren’t great: I mounted it at chest level, but my arms dominated the screen, making it tough to see both the radio and the logbook.

That Thursday, though, I had everything I needed—and I figured it was worth another try, this time clipping the camera mount higher and on my right shoulder.

With the clock ticking, I deployed the KH1 and hit the air!

Gear

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Radio and Antenna System

Camera and Audio Gear

On The Air

If you’ve done any POTA or SOTA activations in the past six weeks, you’ve probably noticed conditions have been rough—at times, downright miserable.

Luckily, I picked a day with reasonably good propagation. Continue reading Elecraft KH1 to the Rescue: Squeezing in a 20-Minute POTA Activation →

Hamvention, News, QRO, QRP

Tariffs May Impact Radio Prices — What That Means for U.S. Buyers (and Hamvention Shoppers!)

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Please note: I hesitated to bring up this topic because of the inherent political weight it carries here in the United States (and this really only applies to those of us in the U.S.). So please—no political comments. Our moderators will remove them. 

That said, I feel it’s important to share this, especially for anyone attending Hamvention 2025 or planning a radio or gear purchase in the near future.

Many of you know I have a number of contacts in the amateur radio world, including manufacturers and retailers. While I won’t share names or specific companies, I can tell you there are two common concerns among all of them right now: tariffs and uncertainty.

As of this posting, most amateur radio goods imported into the U.S. from China and Japan are subject to tariffs. These tariffs can increase the price of an item by 24% or more—in some cases, more than doubling the cost, depending on the item and country of origin. One manufacturer mentioned to me, “What impacts us most as hams is stuff [components and final products] generally comes from Japan 24% or China 145%.”

Even U.S.-based manufacturers are feeling the impact. Many rely on components from China simply because there’s no equivalent supply chain available in the States. Another manufacturer told me he recently paid $1,800 for components and was then charged a $2,700 tariff on top of that. When profit margins are already thin, those added costs inevitably get passed on to the customer.

Retailers are seeing this too. Unless something changes, certain products may not be imported at all because tariffs make them unaffordable. According to two different sources in the world of amateur radio retail, this could even affect the availability of the new FTX-1 in the U.S. It’s already a premium-priced radio—would customers be willing to pay 24%+ more than MSRP? Retailers are betting not.

The Uncertainty Factor

Some manufacturers tried to plan ahead by stockpiling components before tariffs took effect. Others are using options like bonded warehouses to hold inventory in hopes that tariffs will be rolled back soon. But many smaller, mom-and-pop manufacturers don’t have the capacity or resources to do this, so they’re forced to deal with tariffs in real time.

The Takeaway

If you’re based in the U.S. and considering a large purchase like a new radio, now might be the time. Tariffs do not affect inventory that’s already Stateside. So if you’re shopping Hamvention next week and buying direct from a vendor and walking away with the product in-hand, you’re likely getting a better deal than you would a few weeks or months down the road if tariffs persist.

Of course, this could all change overnight if tariffs are lifted or reduced—it may become a non-issue. But as things stand today, we’re on the cusp of seeing the real impact of tariffs on amateur radio gear here in the US. Once existing inventory is depleted, expect increased costs to be passed on to the consumer.

Please remember: I consider QRPer a safe haven from political discussions. There are much better places online to explore and debate the politics of this issue—QRPer simply isn’t one of them. Our community has always been welcoming, civil, and focused on what we love: field radio. Thank you in advance for helping keep it that way!

Field Reports, Guest Posts, News, Portable, POTA, QRP, Travel

Activating on the Road:  The Last Park

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by Brian (K3ES)

In case you haven’t seen previous Field Reports in this series, let me set the stage.  In September and October of 2024, my wife, Becky, and I set out with our dog, Molly, for a great cross-country driving adventure.

We left from our home in northwest Pennsylvania on September 18, driving west to spend some time with my parents at their home in California’s Bay Area.  We returned home on October 31, after driving through most of the states of the American West.  One of the goals for this trip was to activate Parks on the Air (POTA) entities in as many new states as possible along the way (it turns out that with good planning and good weather, it is possible to activate a LOT of states).  An overview of our trip can be found in the following Field Report (linked) on QRPer.com:  Six Weeks and 7300 Miles:  Activating on the Road.

On the westward leg of our trip, we zipped through Ohio and Indiana in a single marathon day of driving, without stopping to activate a park.  There was no intent to diminish these fine states of our union, but I had previously activated parks there.

On the return leg of the trip, our priorities and our perspectives had changed a bit, so we made up for our previous inattention by activating new parks in both states on the way home.  The change in priority came with the realization that we had succeeded in activating every state that I had planned to complete.  I have now activated every lower 48 state west of the Mississippi River, save Arkansas and Louisiana (we intentionally left them for a future trip through the southern states).  The change in perspective came from the realization that activating a park made for a nice break during a day of driving.

We planned for a modest 3-1/2 hour drive on our final day of the trip, so that we could arrive home before dark.

We spent the night near Mansfield, OH, and took our time getting breakfast and checking out in the morning.  We had also looked over our maps and found an Ohio park to activate during the drive:  Lake Milton State Park, US-3515.

Lake Milton State Park

Seen from the park, this bridge carries Interstate 76 across Lake Milton

As I-76 runs east-to-west across northern Ohio, it crosses over the middle of Lake Milton.  For radio amateurs familiar with other attractions along the I-76 corridor, Lake Milton is about 20 miles east of the DX Engineering store.

Lake Milton State Park incorporates the lake itself, as well as selected land around the lake-shore.    We decided to head for one of the park’s picnic areas, located on the eastern shore of the lake near the I-76 bridge.  We found a parking lot, a large grassy area running down to the lake, picnic shelters, and comfort facilities.  As Becky took Molly for a walk around the grounds, I set up to operate from a table in a picnic shelter.

A view of the picnic area beside Lake Milton shows me activating from the shelter at left.  I threw a line over a branch on the tree to the right, and used it to hold my antenna as a sloper.
The gull in this picture was riding the wind, but going nowhere fast.
Standing straight out from its flagpole, this flag spoke eloquently of the wind.

It was a nice afternoon at the park.  The weather was warm and sunny, but a stiff breeze was blowing across the lake.  An American flag stood straight out from flagpole, and soaring gulls hung near-motionless in the sky.  Both provided evidence of the wind’s power.  The warmth of the day and the winds cooling effect were in perfect balance to produce a comfortable environment for activating, even though the breeze provided a bit of audio spectrum QRN.

The Activation

Caught from behind, while focused on incoming code…

I tossed a throw-line over a branch on one of the large trees near the shelter, and quickly hoisted up my Tufteln 35 ft end-fed random wire (EFRW) antenna.  With the antenna set up, I connected the rest of the station.  Moments later, my log was ready, and I was on the air.

I was able to spend an hour on the air, and with the EFRW and the KX2’s amazing internal tuner, I was able to rapidly transition between HF bands.  Operating CW mode at 5 watts, I was successful in making contacts on the 40, 30, 20, 17, 15, and 10m Amateur bands.  In total, I logged 30 contacts, including 3 DX stations from Europe, a thoroughly satisfying activation experience.

This map shows the contacts made from Lake Milton.  It was gratifying to get some DX during the last activation of our trip.

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Conclusion

Becky takes amazing pictures.  Here, another view of Lake Milton.

Packing up the station went quickly, and we were back in the truck and ready for the final leg of our trip.  In about 2 hours of driving, we were pulling into our own driveway for the first time in a month and a half.  It is difficult to fully describe the feeling.  It was really nice to be back home.  The prospects of sleeping in my own bed and relaxing in my own chair were really welcome.

But, at the same time, this adventure was over, and we would soon be back to our old routines.  After 6 weeks together, Becky, Molly and I would again be headed in the different directions occasioned by our day-to-day activities.  So, there was gladness of a return to the familiar, combined with the bittersweet feeling of the end of our travel adventure.

As I think about our trip from the distance of almost 6 months, and a long, cold winter, I realize that I am ready to start thinking seriously about our next driving (and radio) adventure!

Home.  After 6 weeks and 7300 miles, it was nice to get back…

Best 73 de Brian, Becky es Molly