Category Archives: Portable

Field Reports, Hams, Hamvention, Morse Code, News, Portable, POTA, QRP, QRPers, Videos

QRP POTA with Friends: Two Park Activations with VE6LK, NJ7V, WD8RIF, and KD8KNC!

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Sunday, May 21, 2023, was the final day of Hamvention.

I traveled to Hamvention with my buddies Eric (WD8RIF) and his son Miles (KD8KNC). We decided in advance that instead of attending Hamvention that Sunday (after having spent all day Friday and Saturday there) we’d opt for a relaxing day playing POTA near Dayton/Xenia.

We weren’t, in fact, the only ones who skipped Hamvention that Sunday–our friends Vince (VE6LK or AI7LK State-side) and Charlie (NJ7V) did as well, so we decided to play POTA together!

Both Charlie and Vince were leaving the Dayton area that afternoon, so they needed to finish up their activations by noon at the latest. We decided we could fit in two activations that morning before Charlie and Vince headed back, then Eric, Miles, and I would hit a third park in the afternoon. Actually, Miles never planned to hop on the air, but he was both our ride and valuable POTA support!

Vince and Charlie in the rear view mirror!

Charlie and Vince met us at our hotel around 9:00 AM and we drove to the first of two parks we’d activate together.

Cowan Lake State Park (K-1943)

Charlie (NJ7V) and Vince (VE6LK/AI7LK) ready to deploy their gear.

The weather was beautiful that day, but the space weather, much less so. We knew in advance that it would be a struggle based on the propagation forecast and numerous reports from other activators.

Vince set up his Elecraft KX3-based station in the trunk/boot of his rental car.

He deployed his “low-slung” wire antenna (read more about that here) and hit the air.

Vince’s low-slung antenna

Eric described the POTA station he deployed in his field report on WD8RIF.com:

Eric found a shady, level spot near the parking lot, strapped his 31′ Jackite telescoping fiberglass pole to his folding camp-chair, deployed his 28½’ wire vertical on the pole, set up his Elecraft KX3 on the camp-chair’s flip-up table, and was on the air at 1412 UTC. Eric began his operation with a lovely touch-paddle which he had unexpectedly been given as a gift from the builder, Brian Manley, K3ES. 

Eric’s station

Note that Eric carefully documents each and every one of his field activations and field contests on his website. His field reports date back to Field Day in 1995!

I found a spot to set up next to the lake under the shade of a large tree. I deployed my Tufteln no-transformer 28.5 foot end-fed random wire.  This antenna is simply two lengths of 28.5′ wire: one wire for the radiator and one for the counterpoise. The KX2’s internal ATU does all of the heavy lifting. Continue reading QRP POTA with Friends: Two Park Activations with VE6LK, NJ7V, WD8RIF, and KD8KNC! →

Articles, Morse Code, News, Portable, POTA, QRP, QRP Radios, Reviews, SOTA

An in-depth review of the Xiegu G106 QRP HF transceiver

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Note that the following review first appeared in the May 2023 issue of TheSpectrum Monitor magazine.

Update: Also, please note that the G106 is on sale at Radioddity at time of posting. With our affiliate link pricing is only $264 US (see note at end of review). Please read this review prior to making a purchase decision!

An in-depth review of the Xiegu G106 QRP HF transceiver

by Thomas (K4SWL)

Last year––in May of 2022, that is––Xiegu announced a new compact field radio that would be added to their line of transceivers: the Xiegu G106.

Xiegu has really made a name for themselves over the past few years with several transceiver offerings, many of which have become very popular. Among these:

  • The Xiegu G90 is a 20-watt transceiver with an excellent built-in ATU. The G90 has become a very popular field radio over the past few years.
  • The Xiegu X5101 is a five-watt shack-in-a-box HF transceiver covering 160-6 meters. The X5105 has become a go-to QRP portable due to its fine built-in ATU and built-in rechargeable battery pack.
  • The Xiegu X6100 is much like the X5105, in that it’s also a shack-in-a-box QRP transceiver, but it leverages SDR technology to provide a beautiful color spectrum display and a host of features not found on its predecessors. Many have adopted the X6100 because its operating system is Linux-based and many enthusiasts have created their own X6100 interface that promised direct digital mode operation.

Because we’re seeing more products like these from Xiegu, the up-and-coming Xiegu G106 stirred interest.

Moreover, Xiegu has become a low-cost leader among HF transceiver manufacturers. In each of the reviews I’ve published about Xiegu radios, my summary statement is that each unit offers a lot of performance for the price. Xiegu transceivers don’t have the most robust receiver front-ends, and the audio is unrefined, but their rigs get the job done and have some serious “fun factor.”

So when I first learned about the new Xiegu G106, I was curious where it would fit into their product line.

Introducing the Xiegu G106

As I was capping off my summer in Canada back in August of 2022, Xiegu retailer Radioddity started shipping the G106. Radioddity had me on the list to send a loaner G106 for review, but  upon my return I found myself so busy that I didn’t immediately request it.

I did watch, however, K8MRD’s initial and updated review of the G106 on YouTube. While it was less than stellar––understatement alert––more relevant to me was that Mike shipped his second evaluation unit to me on behalf of Radioddity.

I connected that G106 to a dummy load, checked the transmitted signal on my SDRplay RSPdx spectrum display, and it simply didn’t look very clean. In fact, it looked worse than it did when Mike checked it only a couple of weeks prior.

I shared my results with Radioddity and told them I didn’t feel comfortable putting the G106 on the air; they asked that the unit be returned and checked out.

Fast-forward to January 2023, when I was once again contacted by Radioddity to see if I would like to field test an updated G106? I answered that I was happy to do so, because I was curious whether the G106 experience had improved.

In the spirit of full disclosure, keep in mind that Radioddity is a Xiegu retailer/distributor––the company is not the manufacturer, nor is it owned by Xiegu. They sent this G106 to me on an extended loan for an honest evaluation.

So where does the G106 fit into the Xiegu product line?  It’s being marketed as a low-cost, entry level, multi-mode QRP HF transceiver that leverages 16-bit CODEC sampling to provide the user with a lot of radio for the price. It’s basic, and meant to be so, in that  it’s only a transceiver; there is no built-in ATU or battery. The G106 is marketed as a bare-bones portable HF transceiver.

I feel like it hits this mark.

The G106 doesn’t have a lot of features or controls one might expect in other Xiegu radios, but it has more features than any other modern HF radio I know of in its price class (see features list below). Indeed, I can’t think of any other 80-10 meter general coverage QRP transceiver that retails for $320 or less. The G106 has this market niche to itself for the moment.

Overview

When I first received the G106, I was a little surprised:  it was even more compact than I had imagined.

The sides of the G106 are rounded and the chassis extends beyond the encoder and front controls of the radio, thus the interior is quite well protected in the event the radio is dropped. This is one of the few QRP field radios on the market that doesn’t need an aftermarket cage. I’ve been transporting the G106 in an old hard shell headphone case a friend gave me. The case isn’t large, but it easily holds the G106 and a power cord with a bit of room to spare.

 

The G106 sports a small monochrome backlit display that’s very easy to read in the shack or in the field with full sunlight.

Besides the weighted encoder (which has soft detents), the volume control, and microphone port, there are also four multi-function buttons located under the small display on the front panel. On top of the radio, there is a power/backlight button, mode/pre-amp button, and two band buttons that also can be pressed and held to change the frequency cursor position. The internal speaker is also mounted on the bottom of the top cover, just behind the top panel buttons.

On the back of the G106, you’ll find a BNC antenna port, ground/earth lug, key port, COM port, 8 pin ACC port, and a DC input port.

The most conspicuous omission is a headphone or external speaker port. I would have expected this in a QRP field radio because operators often prefer using headphones in the field rather than a speaker. I know that some G106 owners have built their own RJ9 audio plug to port out the audio to headphones. There is a headphone port on the supplied speaker mic, but CW-only operators might prefer a more direct way to connect earphones in order to keep the bulk of their field kit to a minimum.

What is surprising is that the G106 has a very basic spectrum display that is actually quite useful!

Ergonomics

The ergonomics of the G106 are overall pretty good…but a bit quirky. To be honest, giving the user access to numerous functions and features on a radio this small is always going to affect ergonomics; there’s only so much control-surface real estate. Continue reading An in-depth review of the Xiegu G106 QRP HF transceiver →

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

Tu-Endie-Wei State Park: Low-impact QRP fun and one speedy P2P confirmation!

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On Wednesday, May 17, 2023, I did something I hadn’t done since 2019: I woke up, hopped in the car, and started my journey to the Four Days In May and the Dayton Hamvention!

It’s about a seven hour drive from my QTH directly to Dayton, but in the 12+ times I’ve attended Hamvention, I’ve never actually driven there directly. Instead, I drive to Athens, Ohio, spend the evening with my buddy Eric (WD8RIF) and his family, pack one car, then carpool to Dayton.

Heading to Athens, I like to time my drive so that I pass through Beckley, West Virginia around noon and enjoy a fine lunch at Tamarack Marketplace. It’s always a nice reward after spending a little over four hours in the car.

This year, I enjoyed local almond-crusted rainbow trout, braised kale, and dill pickle soup. I know…dill pickle soup sounds a bit strange, but trust me: it was exquisite. The food at Tamarack is always top-shelf because the chefs behind the scenes are training for positions at the famous Greenbriar Resort.

Park en route

Of course, another way to break up the trip and add a little fun is to activate a park. I decided I wanted to activate a new-to-me park not too far off my route, so I consulted the regional POTA expert: WD8RIF.

Eric is an avid park activator and has hit pretty much every park within a three hour drive of his QTH. He made a few suggestions, and I opted for Tu-Endie-Wei State Park in Point Pleasant, West Virginia.

Tu-Endie-Wei State Park (K-1823)

Tu-Endie-Wei is a small, four acre state park, situated at the confluence of the Kanawha and Ohio rivers in Point Pleasant, WV. Indeed, the name “Tu-Endie-Wei” is a Wyandotte word meaning “point between two waters.” Continue reading Tu-Endie-Wei State Park: Low-impact QRP fun and one speedy P2P confirmation! →

Antennas, Field Reports, Guest Posts, Portable, POTA, QRP, SOTA

Quick test of my new SOTAbeams Band Hopper III antenna at a POTA/SOTA location

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by Thomas (DM1TBE)

Since I have seen the Band Hopper III antenna at the website of SOTAbeams, I have been thinking about it. Most of the time I have used end-fed half-wave (EFHW) antennas when operating portable – vertical attached to a fiberglass mast or in a sloper configuration with a tree.  Those EFHW antennas seemed to cause way less troubles than a dipole with its centerpiece and coax at the thin end of the fiberglass mast.  However, there was this “other” dipole from SOTAbeams. So I thought I could give it a try and ordered it.

Two days later -including customs procedure- the antenna arrived. The antenna is a linked dipole for the 20-, 30- and 40-meter band and weights less than 500 g / 18 oz. That includes the coax and guying material. I already had the Tactical Mini ultra, a 6 m / 19.6 ft fiberglass mast that is a perfect fit for the Band Hopper antenna.

The weather was fine, my manager at work was on vacation, so there was no reason for not leaving the home office early and go for a quick activation. I went to the SOTA location for Kaltes Feld (DM/BW-659), which is also POTA (DA-0410). I have been there a couple of times this year, but offering chaser points for both programs promised more QSOs, especially when conditions are difficult. The other advantage of this place is that you can drink cold beer if the antenna fails to work. 😉

You may, or more likely may not, remember this image from an activation report in March this year.

The place looks much more inviting now with kids playing, people enjoying barbecue and a cold beer, and operating a radio is much more pleasant.

Although I have been here a couple of times, I have never visited the ruins of Castle Granegg, just a mile away. While the SOTA activation zone is surrounded by trees, the walk to the castle satisfies with a nice viewpoint on the way. Continue reading Quick test of my new SOTAbeams Band Hopper III antenna at a POTA/SOTA location →

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

A Rock Leads Teri on an Unexpected POTA Activation!

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Many thanks to Teri (KO4WFP) for the following guest post:

A Rock Leads to an Unexpected POTA Activation

by Teri (KO4WFP)

Sticks and stones may break my bones, but a rock can change the trajectory of one’s week.

Monday, while driving to the barn, a rock landed on my windshield leaving a chip in the glass. The soonest and closest appointment was in Bluffton, South Carolina. But having to work the appointment into my week, nixed my planned POTA activation for Wednesday at Wormsloe K-3725. However, I thought to check for any parks near Bluffton and yes, Victoria Bluff Heritage Preserve, K-9197, was within 15 minutes of my appointment. I could fit in an early activation before the appointment and put the AX1 to use for the first time. (Score!)

The drive Tuesday morning from Savannah, Georgia to Bluffton, South Carolina was scenic – lush, green foliage along the road interspersed with salt marsh and freshwater views.

The Victoria Bluff Heritage Preserve is 977 acres and has four miles of easy hiking trails. The warning on the SC Trails website about protective clothing & insect repellent for the large number of ticks that flourish in the preserve’s forest encouraged me to set-up in the parking lot. There were no picnic tables (my usual set-up) present so I planned on operating out of my car, a first for me.

However, how was I to mount the AX1 while sitting in my car since I had no tripod? I was still puzzling over this the morning of the activation when I remembered the Joby Gorillapod stand I purchased last year. Would the tripod mount for the AX1 work with it? Yes! It did. Continue reading A Rock Leads Teri on an Unexpected POTA Activation! →

Field Reports, Guest Posts, Hams, News, Portable, POTA

Mark finds an opportunity to introduce students to the world of POTA and Ham Radio!

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Many thanks to Mark (W8EWH) who shares the following field report:

Right Place – Right Time

by Mark (W8EWH)

This is the story of how I was able to introduce about 40 elementary school kids to Ham Radio and more specifically, POTA.  All by just being at the right place at the right time.

I was activating K-1518 (Maybury State Park) on the morning of May 16th while my wife was at the dentist. As I pulled into the parking lot, I saw a yellow school bus (Holy Redeemer), but no kids.  I figured they must be on a hike or already at one of the many shelters.  So, I parked, grabbed my gear, and walked to the spot where I wanted to activate.  This is a spot I’ve used before – a picnic table under several tall, mature trees with great branches for hoisting a wire antenna.  The location is on the top of a rise at the far end of an open field surrounded by forest. Turns out the shelter at the near end is where the students were, busy with whatever the teachers had them doing.  My activation spot seemed available, so I walked back to it staying well clear of the class.

Set up was straight forward (KX3 and EFHW) and I was quickly on the air on 40M.  Band conditions were good, and I quickly had my 10 contacts to make the activation.  After about 20 contacts there was a break in the action, so I switched to 20M and decided to speak to one of the teachers which, while I was activating, had brought a group of about a dozen students to my end of the field for some sort of activity.  I waived to her and introduced myself, first asking if I was in their way.  She said no, and asked if she was in my way.  Of course not.  I explained what I was doing and offered a demonstration if she wanted to bring some or all the kids over.  She enthusiastically agreed to this.

So about 10 minutes later, the teachers brought the class over to me.  I had them stand behind me in a way that kept them from getting tangled in the antenna and coax.  I introduced myself and explained that I was an amateur radio operator using a portable radio and antenna to contact other people like me as part of an activity called Parks on the Air.

In this case I said, I’m set up here in this state park which makes me the “activator”, and everyone else the “hunters”.  They thought that was funny.  I then told them about the contacts I’d already made to various states around Michigan, and this seemed to get their attention.  I then explained that I was not speaking with them, but instead using Morse Code.  They all seemed to have heard of this before.  OK I said, I’m going to unplug my earbuds, turn up the speaker, and let’s see if we can make a couple contacts.

Before I started calling CQ POTA, I explained what I was going to be sending in morse code.  That I was letting anyone listening know that I was operating from a park, so please call me, and here is my call sign – my amateur radio name.  I also warned them that just like when you go fishing, you don’t catch a fish with every cast.  You must be patient.  They understood.  I was nervous – I’ve never had an audience like this before.  But then I thought, they won’t know if I make a mistake!

It took about 5 or 6 CQ’s before I got bite.  Yes, I was starting to get a little worried!  But then we had a catch and after I finished the back and forth of the contact I said – that was Georgia – and was greeted with a cheer.  Another I said?  Yes!  I sent another CQ and right away another bite.  The kids listened to the back and forth and then I said – Kansas!  Another cheer.

I this point I answered a couple of questions (including one about how I was it that I could understand the noises they were hearing) and then the teachers called an end to the demo so that they could start a nature hike.

I finished up the activation with a handful of additional contacts on 20, 30, and 17 meters, then called it a day.  See Figure 1.  My wife was on her way home from the dentist and she would stop by so we could go for a hike before going home.

I’m so glad I had the opportunity to conduct this demonstration.  I’ll never forget it.  I hope a least a couple of the kids will remember this and become hams in the future.  I only wish I had a handout or two that I could have given the teachers so if they wanted to explore amateur radio with the class later, they’d have some background info and links.  I’ll be ready next time.

Figure 1.  QSO Map for POTA activation of K-1518, via HAMRS..  The contact in Idaho was my one and only on 15M.

Mark Yergin

W8EWH

Accessories, Antenna Tuners, Field Reports, News, Portable, POTA, QRP, Reviews, Videos

POTA QRP: Testing the new JNCRadio CS-818 ATU with my upgraded Yaesu FT-818ND

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I love testing new stuff in the field and on Tuesday, May 2, 2023 I had a great opportunity to test a number of new items.

FT-818ND Upgrades

I mentioned in a previous post that I purchased a new Yaesu FT-818ND from DX Engineering on December 28, 2022. It smacked of an impulse purchase only in that I had not planned to purchase the radio that very day.

Thing is, Yaesu announced they were discontinuing the FT-818 and I always planned to purchase one to replace out one of my two FT-817NDs. I didn’t want to miss the opportunity to buy a new one under warranty, so I bit the bullet on short notice.

Within a few days of purchasing the FT-818ND, I also purchased another 500 kHz CW filter, a WINDCAMP 3000mAh LIPO battery and a WINDCAMP Anderson PowerPole Adapter.

I planned to make the FT-818ND my primary HF radio and use the other FT-817(s) for full duplex satellite work (and HF too, of course, especially since one is now in a TPA-817 pack frame).

I had all of the upgrades in hand by mid-February, but that Yaesu FT-818ND sat in its box under my radio bench until late April. I was so busy evaluating other gear and keeping up with my busy family life,  it had almost slipped my mind. Well, that and I received the incorrect narrow Collins filter from a seller on eBay; instead of sourcing a replacement, I decided to steal an original 500 Hz filter from one of my other radios while waiting on a replacement.

Those narrow Collins filters? They’ve become pure unobtainium over the past couple of months. At one point, eBay was chock full of them. No longer…

It had actually been a very long time since I pulled out a brand new (non-loaner) radio from the box. It’s funny because I remember opening my first FT-817 back in…what…2001? The box and packaging were identical some twenty one years later!

I unboxed then immediately opened the chassis of the FT-818ND to add the Collins filter, attach my Portable Zero side rails (stolen from my FT-817), add the Windcamp battery pack, and add the Windcamp Anderson PP adapter.

JNCRadio CS-818 ATU

Around the same time, Jesse, with Chelegance, also sent me his latest ATU: the CS-818 which is specifically designed to work with the FT-817 and FT-818 series radios. To be clear, Jesse sent the MC-818 at no cost to me to evaluate.

The CS-818 actually works with any radio, but it ships with the command cable for the FT-817/818 for full integration.

The CS-818 can handle up to 30 watts of power, so it’ll pair nicely with any QRP radio. If using it with a QRO radio, you’d have to be very careful not to push more than 30 watts.

NOTE: Due to the frame rate of my camera and the refresh rate of the OLED display, only a portion of the display shows up in my shots.

In truth, ATUs don’t get me terribly excited. I’m quite content with my Elecraft T1 and Emtech ZM-2; these two portable ATUs match anything and everything I use in the field. Continue reading POTA QRP: Testing the new JNCRadio CS-818 ATU with my upgraded Yaesu FT-818ND →

Field Reports, Guest Posts, Portable, POTA, QRP, SOTA

My One Day Mini-DXpedition to Switzerland

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View from the Swiss Radegg castle over the valley towards Germany

My wife and kids were with her parents for some days, the weather forecast 25° C / 77° F and the following Monday was a public holiday in Germany – perfect condition for an activation day trip during the weekend. With France and the Czech Republic already visited this year, there were two other neighbor countries waiting to be visited: Switzerland and Austria (the one without kangaroos).  Austria is on my schedule for the Ham Radio fair in Friedrichshafen, so it became Switzerland.

The area northwest of the Swiss town Schaffhausen was perfect.

The region has been inhabited for more than 10,000 years.  Schaffhausen started as an independent city-state around 1000 AD and became a Canton later. A canton is a type of administrative division similar to a state, but in European dimensions. The Swiss Confederation, as a whole, is smaller in size compared to West Virginia and has a slightly smaller population than New Jersey. Anyways, in 1330, the town lost all its lands and its independence, but regained its independence back in 1418. Schaffhausen joined the Swiss Confederation as the twelfth member in 1501. In 1944, Schaffhausen experienced a bombing raid by aircrafts from the US Air Forces, which misidentified the town in the neutral Switzerland as their target Ludwigshafen in Nazi-Germany.

The region is not too far from my home, it has a SOTA summit, which is in a POTA and WWFF area, is history-rich and has a second, although German, SOTA summit not too far away.

OpenTopoMap, OpenStreetMap CC-BY-SA, STRM

I started early on that Sunday morning at 8 a.m. The autobahn was nearly empty and just like an invitation to drive a bit faster. Since Corona, I haven’t been using my car very often, so I still had winter tires on, which are limited to 160 kmh / 100 mph.

Since 2008, Switzerland is in the European Schengen Area, so there are no regular border checks. Even before, it was a so-called “Green Border”, i.e. you could often pass it without checks. Without this old, unused border station, you would barely notice that you have crossed the line.

Some minutes later I approached the area, where the first summit is located.

The Wannenberg / Wannebärg (HB/SH-002) is a wooded mountain with an elevation of 661 m / 2168 ft. The peak is rather flat and also wooded. The way from the parking place at the foot of the mountain to the top is rather short and easy, with 2.1 km / 1.3 mi and an ascent of 140 m / 460 ft. Continue reading My One Day Mini-DXpedition to Switzerland →

Field Radio Kits, News, Portable

Will the Yaesu FT-891 fit in the CP Gear Tactical Aircrew/Pubs bag?

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Many thanks to Rick (K3RTK) who writes:

Thomas,

I watch your videos often and enjoy them thoroughly! Quick question : I really like CP Gear Pack Aircrew Bag that you reviewed on one of your recent videos. I was wondering if the Yeasu FT-891 would fit in the padded compartment where you are storing the 817. I know you now have a FT-891, but for reference, the 891 is about 2 inches deeper, 1/2 in taller and almost an inch wider. Thanks in advance!

Rick K3RTK

You’re not the only person to ask this question, Rick! Several people have contacted me to find out if the FT-891 will fit the CP Geat Tactical Aircrew/Pubs bag. 

The answer is yes. See the photos below:


In fact, the Aircrew bag fits the ‘891 with a wee bit of room in the padded pocket to spare.

Keep in mind that the FT-817 or FT-818, when outfitted with the Armoloq TPA-817 Pack Frame (see photo below), is actually a bit bulkier than the FT-891 without a pack frame or side rails:

I think the Aircrew bag would make for a very handy FT-891 field pack!  Thank you for your question!

Articles, Field Reports, Guest Posts, Morse Code, News, Portable, QRP, QRP Radios, QRPp

Guest Post: Lake Thunderbird (K-2792) with a homebrew transmitter!

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Activating (sort of) Lake Thunderbird (K-2792) with a homebrew transmitter

Sam Duwe WN5C

When I dove into radio a couple years ago a few sub-hobbies caught my attention: QRP, portable ops, CW, and homebrew. Of course, these all fit nicely together, but in my mind there was a huge leap between soldering an unun and a building a radio. But why not try? What’s the worst that could happen by melting solder and then sitting at a picnic table? This is how I built a simple transmitter and kind of activated a park.

The Michigan Mighty Mite

Nearly everyone has heard about the Michigan Mighty Mite (MMM), a QRPp transmitter popularized by the Solder Smoke blog. There are countless YouTube videos and posts across the internet. It’s very simple: a single transistor, a variable cap, a coil, a crystal and some resistors and a cap. Supposedly one can get up to half a watt of output (I couldn’t). But with a small purchase from Mouser one can oscillate. That seemed pretty cool.

I hadn’t touched an iron until I started playing radio. But I’ve been drawn to homebrew projects. I built a regenerative receiver last year which was very rewarding. I’ve also put together kits (a QCX mini and a TR-35). But my dream has always been to construct a transmitter/receiver combo, or a transceiver. I thought a good place to start was the MMM.

I built the transmitter based on the common schematic for the 40-meter band. The MMM is crystal controlled but I opted to solder in a socket and buy a handful of crystals, so I have the luxury of operating on 7056, 7040, and 7030 kHz. I made a few other improvements, too. The first was to build a low pass filter to attenuate harmonics. Second, although I haven’t finished it yet, the switch on the right will be to choose between multiple crystals. And third, I added a BNC jack to connect a receiver, with a transmit switch. When not in use the transmitter will dump into a dummy load. This receiver switching idea was lifted from the design of the MMM that QRP Guys produces.

When I tested the transmitter at home the best I could get with my charged Bioenno 3 Ah battery was about 300 mW output. The filter is reducing things somewhat, but maybe I need to look into a different transistor or rewind the coil. But I was able to get a 339 signal report from Illinois (no sked) in the midst of distance lightning crashes, so I had a little confidence going forwards. School is out for me this summer, so I decided to head to the park. Continue reading Guest Post: Lake Thunderbird (K-2792) with a homebrew transmitter! →