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A review of the LnR Precision Mountain Topper MTR-4B ultra-portable QRP transceiver

December 11, 2022 Thomas Witherspoon 15 Comments

The following article originally appeared in the November 2022 issue of The Spectrum Monitor magazine:

A Review of the LnR Precision Mountain Topper MTR-4B V2

by Thomas (K4SWL)

I confess, there is something that I’ve come to believe is almost a rite of passage in the SOTA (Summits On The Air) community. And, no, I’m not talking about activating an All Time New One (ATNO) summit, or completing a particularly challenging activation on a snow-capped peak.

I’m talking about owning one of the iterations of the amazing “Mountain Topper” pocket-sized QRP CW transceivers designed by Steve Weber (KD1JV).

This little radio first caught my attention at a Four Days In May (FDIM) QRP conference over a decade ago: a ham friend in the SOTA community proudly showed me a very early version of the Mountain Topper that he built from a kit. The first thing that struck me was how impossibly small and extraordinarily lightweight it was. But when he showed me the 9-volt battery he used to power it––a power supply not only small, but convenient––I was mesmerized.

Over the years, the Mountain Topper has evolved. There have been many models, ranging from two bands to five. To my knowledge, they’re no longer offered in kit form, but LnR Precision manufactures and tests these in North Carolina, and they’re better than ever in terms of features and performance.

At present, the MTR-4B V2––the second version of the four-band Mountain Topper––is the only model in production, and if you’re hoping to acquire one, due to supply chain issues (at time of publishing) there’s a rather long wait time. They retail new for $350 US, and frankly, the used ones I’ve seen posted in ham radio classifieds ads have been equal to, or even over, the listed price for a new rig. Obviously, demand for these radios is much higher than supply.

So, how could it be that this minuscule QRP radio performs well enough to produce some serious DX from a remote summit…so well, in fact, that people are willing to wait in line for one?

Magic or method?

As any CW operator will tell you, the magic is in the mode. CW is such an efficacious mode that it cuts through the ether like a knife, even when conditions are less than favorable.

Obviously, pint-size radios like the Mountain Topper are QRP––low power––so designing them around such a simple mode is a very smart choice. CW transceivers are much less complex than a similar SSB transceiver, thus have less components, less mass, and are in general more affordable (when compared to those with similar receiver performance).

My comprehensive MTR-4B field kit (the MTR-4B is in the mesh pocket).

In addition, the Mountain Topper is designed with the field activator in mind: specifically, SOTA activators, but of course, POTA (Parks On The Air), WWFF (World Wide Flora and Fauna), IOTA (Islands On The Air), or any other popular “-OTA” field activity. As a field activator in one of these programs, you are the DX. This means chasers and hunters are actively seeking your signal, and thus you are not competing with blowtorch stations to punch through a pileup.

I can also assure you that standing on a tall summit also gives you a brilliant starting point for your QRP signal. Some of the best DX I’ve ever worked has been from a summit.

So, for the average CW SOTA activator, QRP is preferred because QRO simply isn’t necessary––indeed, in my opinion it’s a bit of an overkill. At least that’s been my experience now with my few hundred SOTA, POTA, NPOTA, SOTA, and even one Lighthouse On The Air activations.

So this brings us back to the wee Mountain Topper series and the model being reviewed here in the pages of TSM: The Mountain Topper MTR-4B. Continue reading A review of the LnR Precision Mountain Topper MTR-4B ultra-portable QRP transceiver →

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

December 9, 2022 Thomas Witherspoon 21 Comments

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, News, Portable, POTA, QRP, QRP Radios, Videos

Taking the Mountain Topper MTR-4B on a quickie activation at South Mountains State Park!

September 30, 2022 Thomas Witherspoon 2 Comments

The entire time I was in Canada this summer–about two months–I used two field transceivers: the Elecraft KX2 and the Discovery TX-500.

I did sneak in two extra radios under the floor of my trunk/boot space, but they both were limited to three watts and conditions were so rough during many of my activations, I wanted the option of a QRP “Full Gallon” (5 watts). Thus, I stuck with the TX-500 and KX2 (which are both actually capable of 10 watts output).

When I got back to the States, I was eager to do a POTA activations with my other radios–many of you know I like to rotate them–but there was one, in particular, I was eager to put back on the air…

The Mountain Topper MTR-4B.

This MTR-4B V2 is on loan to me from a very generous reader/subscriber. In fact, get this: he ordered the MTR-4B early this year and had it drop-shipped to me directly from LnR Precision. He knew I’d be in Canada for the summer, so has been incredibly flexible with the loan period (basically leaving it open ended).

My review of the MTR-4B will be published in the November or December (2022) issue of The Spectrum Monitor magazine. Then I’ll be sending the MTR-4B to its rightful owner!

In the meantime, I built an ultra- compact field radio kit around the MTR-4B and in my Tom Bihn HLT2 EDC pouch.

This kit is nearly identical to the one I made for my MTR-3B (just a different color, really).

It contains the radio, a battery, an antenna (although I used a different one during this activation), fused power cord, paddles, earphones, RF choke, RG-316, logbook, pencil, and even a full throw line and weight. I’ve listed all of the components with links below.

It’s hard to believe it all fits in such a compact kit and it works so well. It’s nice to know that with the kit it in my backpack, I’ve got everything I need to play SOTA or POTA at the drop of a hat.

South Mountains State Park (K-2753)

On August 8, 2022, I drove to my hometown to check in on my parents. I didn’t have a lot of time, but I wanted to fit in a quick activation with the MTR-4B along the way.

One of the easiest parks for me to hit en route is the South Mountains State Park Clear Creek Access–it’s maybe a 10-15 minute detour off of Interstate 40.

The weather was amazing that day, although I’ll admit I had to get used to the heat and humidity after spending so much time in Canada this summer!

This access point of South Mountains only has one picnic table. I’m always prepared with a folding chair if that table is occupied, but so far it’s always been available. I’m sure the reason is because this particular South Mountains access point is way less popular than the main entrances. Most of the visitors here come to fish at the reservoir.

Setting up

The great thing about having your whole station in a pouch is that setup is quick and easy.

Continue reading Taking the Mountain Topper MTR-4B on a quickie activation at South Mountains State Park! →

Announcements, New Products, News, QRP Radios

The new Mountain Topper MTR-4B V2 by LnR Precision

December 8, 2020 Thomas Witherspoon 7 Comments

I’ve just noticed that LnR Precision has announced their new Mountain Topper MTR-4B V2.

They’ve released a few details with the promise of photos soon. Looks like the MTR-4B will of course sport four bands (80, 40, 30, and 20 meters) but adds two valuable tools its predecessors lacked: an SWR and RF power meter.

A full 5 watts output power is attained with a 12V supply, but the voltage operating range is 5.5 to 13volts. The MTR-3B’s (photo above) has an upper operating range of 12V.

I look forward to checking out the MTR-4B and we’ll post photos as soon as they are available.

Here are the details from the LnR Precision Website:

MTR-4B V2

Photos COMING SOON

“The Mountain Topper”

The LnR Precision MTR transceivers are designed to be efficient portable CW rigs. Whether climbing a mountain and operating SOTA or just out for an afternoon in the park, the MTR’s small size, light weight and meager battery requirements makes it a great choice for these activities.

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