Tag Archives: MTR-4B

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

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

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

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

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

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!

Matt’s “Ultra-Lyte” Hydration Vest QRP Field Kit

Many thanks to Matt (W7MDN) who writes:

When I was first getting into Ham radio a couple years ago, I ran across a slide presentation done by Fred KT5X on “Ultra-lyte” QRP. In it, Fred has pictures of a trail running hydration vest that contains a complete SOTA station, water, snacks and a jacket. I was sold on the idea, and made it my goal to start making my own ultralight setup.

Click here to download KT5X’s original presentation (PDF).

As time went on, I really got into the ultralight approach to SOTA, taking every opportunity to reduce weight and shrink my pack down. I enjoy some trail running, mountain biking and combining SOTA/POTA with either is the ultimate combo of adventure and ham radio. Continue reading Matt’s “Ultra-Lyte” Hydration Vest QRP Field Kit

MJ’s Mountain Topper MTR-4B brag photo!

Many thanks to Mike “MJ” ( WO9B) who writes:

Hi Thomas,

I’m not normally enthusiastic about an equipment review, but as for the MTR gear…welcome to the 4B-V2 club. For no good reason I have to pass along a brag photo of my setup.

After growing tired of chasing a key around the picnic table, a removable epoxy bracket was added to mount the venerable Begali Adventure paddle. The battery is a small LifePO4 1.1 Ah battery which provides about 5 hours of Field Day operating.

Naturally, I use a Spark Plug for my antenna. The last two Field Days have been with this setup. It is an outstanding piece of gear. It took me one email exchange with Steve, WG0AT, to overcome the lack of a volume control. Not a moment of buyer’s remorse.

See you on the air….

MJ, WO9B

Thank you for sharing this, MJ! I love brag photos.

What a nice combo, too: the Begali Adventure and the MTR-4B! 

Readers: MJ is owner of www.sparkpluggear.com. I’ve heard many good things about his Spark Plug EFHW. I need to grab one and give it a go soon!

And yes, MJ, I’ll see you on the air!

My first POTA activation with the Mountain Topper MTR-4B V2

As you might have noticed from past field reports, I’m a big fan of the LnR Precision Mountain Topper MTR-3B. It’s a wee CW-only transceiver that is almost perfectly designed for summit and park activating. It’s so lightweight and compact, you barely notice it in your backpack.

Thing is, the MTR-3B is no longer produced and I’m not sure if it ever will be again, but Steve Weber (KD1JB) hasn’t stopped making iterative improvements to the Mountain Topper design and LnR hasn’t stopped producing them.

In late 2020, LnR introduced the new MTR-4B which replaced the MTR-3B and added a few extra features that many of us had been asking for including:

  • Easy access to sidetone volume control (with a dielectric screwdriver)
  • A built-in SWR meter
  • A wider voltage range and higher output power (up to 5 watts)
  • And the 80 meter band in addition to 40, 30, and 20 meters

The MTR-4B also has an attractive red gloss chassis.

And the right and left sides of the chassis even protrude a bit to better protect the front panel buttons and switches when the unit is flipped over on its face. Nice touch!

Generosity

One of the great things about being me is I am often at the receiving end of incredibly generous people who like supporting what I do.

QRPer.com is a pure labor of love and I’d do what I do without any compensation, but it’s an honor when anyone goes out of their way to thank or support me.

Seriously: the kindness I feel here restores my faith in humanity.

In January, a reader (who wishes to remain anonymous) approached me with a deal I simply couldn’t refuse. He is a very seasoned and accomplished field operator but has only recently been upping his CW game. I believe as a reward to himself for starting CW activations later this year, he told me he wished to order a new MTR-4B.

What he proposed was to purchase the radio from LnR and have it drop-shipped to me. He wanted me to have the opportunity to review this little radio and log field time with it as well. He told me I could use it for months before shipping it to him and not to worry about it getting scratched or showing other signs of field use.

Wow.

I loved this idea because, as a reviewer, it isn’t financially viable to buy each and every radio I would like to review. I do like asking manufacturers for loaner radios, but LnR is a small manufacturer and make these units to order. I know them quite well and they simply don’t have extra loaner units lying around the shop–much like new automobiles these day, each one produced is already spoken for.

I accepted his offer with gratitude. I looked forward to getting my hands on the MTR-4B!

But that wasn’t all: this kind reader has actually been sending me coffee fund contributions that will add up to half the price of a new MTR-4B should I decide to purchase and add one to my own field radio arsenal! I tried, but I couldn’t talk him out of it.

So there you go. I’m so incredibly grateful.

Delivery

As LnR Precision states on their website, there’s roughly a 6-8 week lead time on the MTR-4B. I took delivery of this unit in early March.

As with all LnR Precision products, it was packed amazingly well.

I wasn’t sure what to expect in terms of size, but the MTR-3B is only slightly bulkier than the MTR-3B (indeed, in my activation video below, I compare the two).

I love the hotrod red paint job!

This unit arrived during what turned out to be a crazy time for me–one where there was nearly a four week period with no field activations. That’s how crazy!

I did play with the MTR-4B in the shack, however, during that time and logged numerous POTA, WWFF, and SOTA activators. I even had a couple of 80 meter rag chews.

Many field ops were surprised that the MTR-4B didn’t use the forth band position for 17 or 15 meters and I tend to agree. In the field, efficient 80 meter antennas are a bit bulky for the likes of a summit activator. Then again, when in the shack or for extended camping trips? I find 80 meters a brilliant band for evening rag chews and late night DXing.

Not sure how much I’ll use 80M in the field, but I do appreciate this additional band!

Of course, the MTR-4B is built for playing radio outdoors and that’s exactly what I had in store for it on April 13, 2022. Continue reading My first POTA activation with the Mountain Topper MTR-4B V2

Guest Post: Field Day – 200 QSOs with a Flashlight Battery

The PowerFilm LightSaver (Image: PowerFilm Solar)

Many thanks to Jim Cluett (W1PID) who has kindly allowed me to share this recent post from his website:


Field Day – 200 QSOs with a Flashlight Battery

June 2021

by Jim Cluett (W1PID)

Field Day was an experiment this year. I operated for nine hours using a 5V 18650 battery and made 200 QSOs before calling it quits.

I operated on the deck with an MTR 4-B designed by KD1JV. The antenna was an 88 foot doublet up about 45 feet. I used the ZM-2 tuner. For power I used the PowerFilm LightSaver. This is a 5 watt roll-up solar panel that charges a 3.7V 18650 battery rated at 3.2 Ahr. The battery inside the Powerfilm product is commonly used in flashlights. The combination of the rig and the power supply is crucial.

The MTR rigs will operate from 6 to 12 volts. The Powerfilm puts out 5V to a USB socket. The secret ingredient required to bring the USB voltage up to the operating voltage of the rig is a Baofeng USB charging dongle. This device takes a 5V input and outputs 10.3 volts… perfect for the MTR transceiver. With this voltage the MTR puts out a little less than 3 watts.

The PowerFilm LightSaver is designed to charge cell phones for hikers and campers. It weighs only about 5 oz. and rolls up into a tiny package. Any USB 5V cell phone charging battery could be used with the Baofeng dongle.

This year my whole station operated on 5V. I used a Samsung tablet for logging.

In New Hampshire it was cloudy for most of Field Day, but fortunately the amorphous solar panel provides some charging even when it’s cloudy. I’m guessing that after 9 hours of operating the battery was down to about half capacity. The beauty of this system is that one could operate indefinitely with moderate sunshine.

I’ve been experimenting with this setup during hikes and bike rides for the last couple of months with a view to using it for Field Day. This year’s emergency exercise proves that it is viable for an extended grid-down power outage.

Click here to check out Jim’s website!


What a brilliant challenge and test for Field Day, Jim! Thank you for allowing me to share it here on QRPer. Also, a hat tip to Eric (WD8RIF) for bringing this article to my attention!

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

The venerable Mountain Topper MTR-3B

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.

Features:

  • Four bands – 80M, 40M, 30M and 20M
  • Very low receiver noise floor
  • Low current for maximum battery life
  • Wide operating voltage range – 5.5V to 13V
  • Full 5W “QRP” gallon with 12.0 Volt supply
  • 2 line, back lighted LCD display
  • SWR – RF Power display
  • Built in Real Time Clock
  • Internal Iambic B mode keyer, 5 to 31 WPM in 1 WMP increments.
  • Three Morse message memories with beacon mode.
  • Specifications: coming soon