Tag Archives: QRP

QRP operation from Boston Harbor Islands

The ARRL organized a National Parks on the Air program (NPOTA) in 2016 that made operating portably extra fun. But you don’t need a special event year like this to have a reason to get out and make QSOs. There are other programs that operate continuously that are good draws for these far away places. I made several trips to Boston Harbor Islands in 2016 to celebrate NPOTA, and help operators put some QSOs in the log for other awards programs as well. Here are a couple of programs that will continue long after NPOTA is over:

The British program Islands on the Air (www.rsgbiota.org) gives participants an opportunity to collect islands much like the ARRL’s DXCC program collects countries (entities). As it turns out, because there is no commercial power (mains) available to the public, the Boston Harbor Islands are somewhat rare (being claimed by only 30.2% of IOTA participants). It is a lot harder to get on the air and be heard when it is only battery and solar power driving things. That makes the challenge even more fun. And, when you are heard, you’ve often got a pileup!

The US Islands Awards Program (www.usislands.org) is similar to the IOTA program, except it accepts islands anywhere in the United States. (The IOTA program only counts islands that are true “sea” islands.) Lovells Island in Boston Harbor has the designation MA042S, and I was lucky enough to be the first to activate it for this program.

These mini-DXpeditions to Boston Harbor Islands begin at home, sorting, selecting, and packing the items needed for a successful activation. For day trips to Georges Island, the largest of the group, and the main destination for the Boston-to-island ferry service, I concentrate on packing just the bare essentials of radio, antenna, coax, rope, and so on.

Cart full of gear
Maybe a little more than a 100 pound DXpedition this time. Lovells Island offers campgrounds but no water. You must bring your own. At about 8 pounds per gallon, things get heavy in a hurry.

Georges Island is about an hour long ferry ride from Long Warf in Boston, and it has been built up quite a bit just in the last ten years. It how has a snack bar, a new play area for young children, and hosts many festivals and events during the summer. The boats that once carried only a handful of passengers ten years ago are now often full of families and groups.  Everyone is friendly, and more than once I’ve had help from my fellow voyagers with my gear.

Once off the boat on Georges, I hike quickly to a picnic table near a tree. No trees on this island are very tall, so there are no prospects for running wire dipoles or other wire antennas. Instead, I build a vertical antenna from a mini-Buddipole (www.buddipole.com) kit. I will often lash the shock-cord mast to one of these short trees to hold it up. The wires from my home-brew four-wire radial kit also serve as guys for the setup. Assembly is usually quick (under ten minutes) and a quick check with an antenna analyzer confirms the antenna is resonant.

NE1RD in front of sign
Georges Island and Lovells Island are about seven miles out to sea in Boston Harbor. They offer a great day trip, or camping (on Lovells).

In previous years, daytime operations were typically on 20m, 17m, or 15m. Because of changing propagation conditions, in 2016 I only operated almost exclusively on 20m. Selecting an operating frequency can be a challenge when operating QRP. I’ve often been “pushed off” my calling frequency by another operator that likely couldn’t hear me. Oddly enough, I’ve had good luck operating near the top of the 20m band, well into the General segment, which has the additional benefit of increasing the number of people who can call you.

Day trips with only a couple of hours of operation need only a battery, but I find that I bring a solar panel out of habit. With the panel connected, I usually leave with my battery fully charged. Running without the panel would also work, but I’m unwilling to take a chance that my day would be cut short because of power problems.

Tents
The operation on Lovells Island includes a pop-up enclosure that fits over a picnic table, and a tent for sleeping. Two 20-Watt and one 13-Watt solar panels are visible in the foreground among the rocks.

Camping trips are more involved. Lovells Island is the only place that both counts for the IOTA program and provides campsites. You need to plan ahead as campsites are allocated on a first-come-first-served basis, and reservations begin in January. I am rarely able to reserve all the dates I would like, and choosing dates seven months in advance means you’ll never know what kind of weather you’ll encounter. A severe thunderstorm over one of these islands is magnificent and terrifying!

Getting to Lovells is also more difficult. The ferry shuttles between Georges Island, a few other large islands, and Boston Harbor’s Long Warf. Connections to Lovells Island are made from Georges, and only occur three times per day. Once that last boat has left, you are stuck on Lovells until the next morning. You better have everything you need! That includes food, water, first aid supplies, power for your phone and radio, and anything else needed for a successful camping trip.

Solar panels
NE1RD Power and Light. Multiday QRP operations depend on a good power source. Two 20-Watt panels are connected in series to the GoalZero Sherpa 50 battery. The small 13-Watt panel on the rocks is recharging my phone.

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Lovells Island is covered in trees, many of them tall enough to easily support a wire antenna. That sounds convenient, but how long did it take you to hang your last wire antenna at home? Was it a several hour operation with a couple of friends? Given the short time available during one of these trips, I bring a backup antenna in case the wire antenna cannot be hung successfully (or hung high enough). My tool of choice is a throw weight and line like those used by arborists. Though the lead filled leather bag is heavy, it is compact and effective for getting a rope through a tree. An end-fed half-wave (EFHW) antenna is a good choice for this duty since it only requires one line high in a tree. The remainder of the wire that isn’t hung vertically can slope down to the ground and be tied off.

I’ve had good luck with two EFHW antenna models.  PAR EndFedZ antennas (www.lnrprecision.com) offer a trail-friendly antenna good for 10-20-40m that easily handles QRP power. This packs small and is light.

Intrigued by an advertisement on the ARRL website, I ordered and tried the MyAntennas (www.myantennas.com) EFHW-8010, a multiband antenna good from 80m through 10m that can also handle high power. On my last camping trip, I was very lucky to get my first throw through the tree in a good spot, and this EFHW antenna was up and running in about thirty minutes. It performed very well and will be in my pack on future trips.

Camping on Lovells is primitive. The park service offers chemical toilets, and cleared areas with picnic tables, but nothing else. You must bring your own water. Budget at least a gallon a day, and more if it’s hot. Suddenly, a three-day camping trip can get bulky and heavy! I’ve tried several “beach carts” and may have finally found one that is robust enough to handle the weight of all my gear, and the rough terrain of the island. Remember to bring everything you need to pack out your trash, too. Good campers leave nothing but footprints.

Ocean view
Boston to the left and Logan Airport to the right on the horizon. You can’t beat the view from Lovells Island.

Prior to each trip, I will array everything to be taken on the floor, and I’ll perform an inventory, thinking through each step and each thing that must be accomplished. Forgotten rope or even a forgotten connector might ruin an operation. Once everything is counted, the cart and my large backpack are filled.

Operating begins after camp is assembled, and I’ve had a short rest. These trips often happen in July or August, and it can be hot and sticky on these islands. Beware dehydration and overheating. When operating in a remote area, help may not be just a phone call away. It is important to take care of yourself first.

In three trips out to the islands in 2016, including two camping trips, I made 343 QSOs to 18 DXCC entities and 42 states. I’m going to work on completing my Worked All States award from these islands next year! That said, it isn’t just my awards program that keeps me going. I know that I’ve made it possible for other hams to work these islands for the IOTA program, the US Islands program, and even Worked All States. It is gratifying to hear, “Thanks for the new one!” several times during each trip.

NE1RD operating
Nighttime is a great time to operate. The pop-up enclosure over the picnic table protects me from pests, even with the lights on.

I’m already planning next year’s trips. I operate as NE1RD/1 and have a fine QSL card that I would love to send to anyone I work. While Boston Harbor Islands are not exactly exotic, they are beautiful, and the act of planning and executing these excursions has made me a better DXpeditioner, and I believe a better operator.

A Block Diagram for the LNR Precision MTR3b

When I was a young child, there was nothing more dangerous in the house than me and a screwdriver. I took everything apart. Nothing was safe. I wanted—no needed—to see the insides of things, and see how they worked. At some point, learning how to put things back together was the only thing that kept me from a seriously sore backside. Still, every bit of it was worth it, and I have retained that kind of curiosity throughout my life and my career. 

Things are a little easier today. You can understand a lot from just looking at the drawings for a device. One of the things I enjoy doing is looking over radio schematics and trying to understand how they work, and the choices that the designers made. In this article, I’d like to do that for the three-band Mountain Toper MTR3b, a radio designed by Steve Weber (KD1JV) and sold by LNR Precision.

The MTR3b is a CW-only, 3-band (20/30/40) radio that can fit in the palm of your hand. The photograph of the radio with an accompanying 9-volt battery gives you some idea of its size, though you don’t truly grasp the compactness of the unit until you hold it in your hand. The 9-volt battery is not just a prop for the photograph. The radio can be powered by a single such battery, though it works better with something a little larger. I use a compact 11.1-volt LiPO battery packs made popular by drone users.

I’m not going to provide a detailed review of the user interface (just 3 slide switches, four buttons, and a single 7-segment LED), or go through its on-air performance. There have been several excellent reviews for this radio in QST and other places. Instead, I’d like to take it apart for you. Well, not exactly disassemble it as much as analyze the schematic and see how Steve Weber made it work.

I was lucky enough to have a fellow named Mr. Davis for my high school physics instructor. He said many wise things (that I only understood long after high school, alas), but one that stuck immediately was his adage, “If you can’t draw the picture, you don’t understand the problem.” How very true! So, I often made models and block diagrams of things to better understand them. These models don’t need to be exact. In the words of George Box, “All models are wrong, but some are useful.” A block diagram of the insides of a transceiver can be useful. Here’s the diagram for the MTR3b I sketched on my iPad Pro tablet a few evenings ago.

Let’s walk through it. The antenna is on the far left. The antenna connects to the radio and is presented to a low-pass filter (LPF). As it turns out, each band requires its own special LPF so there are slide switches on the front of the radio to switch-in the correct filter. Switch position 1 is for 20m, switch position 2 is for 30m, and switch position 3 is for 40m. The way the radio is designed, as we will see, it is important that all three switches be in the same relative position for the radio to operate properly. 

The next thing in line as we walk towards the receiver is a transmit-receive (T/R) switch. When we transmit, the signal path is cut off from the receiver and the transmitted signal only goes to the antenna. When we are receiving, the signal path is routed to the receiver, pictured along the top of the diagram.

After we pass the T/R we have a band-pass filter (BPF), also selected by one of the slide switches, that rejects out-of-band signals. This is the lead-in to the first mixer that generates the intermediate frequency.

We should take a quick detour for a moment and review what a “mixer” does. A mixer is an electronic device that takes two signals in and yields four signals out. It sounds complicated, but it really isn’t. Say we have two signals of frequency A and B. The mixer will output those same frequencies A and B (not very interesting), and two other signals: A-B and A+B. These signals are interesting. 

Superheterodyne receivers like this one mix the received signal with one from the radio (tied to the main tuning system) to produce an intermediate frequency that can then be further processed. By turning the original signal received from the antenna into this intermediate frequency, we can have a system common to all three bands 20m/30m/40m in the rest of the receiver. This common system works because it only has to deal with signals at this selected intermediate frequency. The intermediate frequency selected by Steve Weber for this design is about 4.1 MHz.

After we mix the signal with the first mixer (illustrated as a circle with an X in it), we pass the resulting signals through a crystal filter that allows only the 4.1 MHz-related frequencies through it. This is the A-B output from the mixer. The other products are discarded. Once through the crystal filter, we now have a nice signal from our selected frequency, but it is in the 4.1 MHz range. We need a subsequent step to bring it down to the audio frequency range.

The product detector that produces the audio frequency range signal from the 4.1 MHz intermediate frequency is obtained by passing the signal through a second mixer. When we’re through here, we have something our ears can hear. All that is left is to bring that audio signal through a few amplification stages, and send it to the headphones. This radio is so simple that it doesn’t even have a volume control! 

Just before the headphones is a multiplexor that allows audio to be selected from either the receiver (as we’ve just done above), or from the sidetone generated when we send Morse code. The CPU generates the sidetone signal and controls the multiplexor. This is the whole receiver.

The transmitter is even more simple. The Texas Instruments extremely-low-power CPU watches the paddles, slide switches, and push buttons, and controls the 7-segment LED display. When dot or dash paddles are pressed, it signals to the DDS (Direct Digital Synthesis) frequency generator to output a signal. (The DDS is also used to select the receive frequency.) The output signal is sent through a few amplification stages, the T/R switch is changed to transmit, and the amplified signal is sent to the antenna.

I was able to get all this just by perusing the schematic included at the rear of the MTR3b manual. You can download the manual for free from the LNR precision website and follow along from the block diagram I’ve provided.

Every time I do this for a radio I feel like I’ve learned something new. It is also gratifying to use a radio that you understand, and know how it works under the hood. 

http://www.lnrprecision.com

Scott, NE1RD

Project Night 2018

Every January Meeting we hold Project Night, where members bring in and share recent homebrew projects that they have built. This year’s Project Night was full of interesting projects built by our members.

Member Projects
Scott NE1RD Kits
Scott NE1RD Kits

Our Programs Chairperson, Scott, NE1RD led it off by showing us some kits he had built, including the K1EL PaddleStick Keyer that we will be building for the February Tech Night.

Bob KB1TEK - QRP Kits
Bob KB1TEK – QRP Kits

Bob, KB1TEK brought some QRP kits that he had built.

Dave K1DHP - VLF Detector
Dave K1DHP – VLF Detector

Dave, K1DHP showed us the VLF Detector that he built.

Hamilton, K1HMS – Antenna Switches

Hamilton, K1HMS brought Antenna Switches that he had built.

Dave K1DLM - Heakthkit
Dave K1DLM – Heakthkit

Dave, K1DLM showed us a Heathkit that he plans to build.

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Dennis, K1LGQ had another explosive presentation when he showed us a KX2 stand that he built.

Dennis shows plans for his KX2 Stand
Dennis hows plans for his KX2 Stand

 

Fred AB1OC - Low-Band Match
Fred AB1OC – Low-Band Match

Fred, AB1OC brought an 80m band matching system that he will install in order to make our 80m delta loop be resonant across the band.  He has programmed our MicroHam system to automatically have the box switch the matching system as we tune through the 80m band.  I’m looking forward to using this to get the last 20 80m contacts for my 5 Band DXCC!

Anita AB1QB - CW Pi
Anita AB1QB – CW Pi

I (AB1QB) demonstrated a Raspberry Pi project that I built over the holidays.  It is called a Morse Code Virtual Radio.  When you hook up a monitor and a straight key to the Raspberry Pi, it will decode what you key in.  This was a big hit with the kids who visited us for ARRL Kids Day.

Mike, AB1YK - Panadapter
Mike, AB1YK – Panadapter

Finally, Mike, AB1YK brought in a number of projects that he has done including a Panadapter and a CW Generator.

Overall it was great to see all of the projects that our members have been working on. The gallery above contains more pictures from Project Night.

Anita, AB1QB

Radio Amateurs Developing Skills Worldwide