Category Archives: How To

Jim’s Elecraft KX2 leg mount

Many thanks to Jim (WU3K) who writes:

Hi Thomas,

I recently came up with a new way (for me) to hold the KX2 when I am out in the field.

The set-up utilizes the Side KX KX2 mount and the RAM Body Mount for Legs.

This set up does a pretty good job for me.

73,

Jim
WU3K

This is absolutely genius, Jim! Besides the leg mount looking like a excellent solution, the Side KX mount could then be used for other mounting locations either at home or mobile!

Thank you for sharing!

Rich’s easy-to-build and incredibly affordable Field Clip Board V 1.0

Many thanks to Rich (KQ9L) who writes:

Hello Thomas,

I’ve attached couple pictures of V1.0 of my field clip board. I’ve been searching for the perfect clipboard to use in the field. The main requirements of the design include: lightweight, low cost and the flexibility to allow a comfortable operating position while securely holding a radio.

What I came up with is a based on an inexpensive fiber board clip board:

I chose to set it up somewhat unconventionally and designed it to use the clipboard “upside down”.  Setting it up this way provided ample space at the top to mount the radio while still providing room to attach a metal pad mounting point for paddles.

The radio is held securely in place with craft 3mm elastic bands. The bands were made with metal “toggles” so I can easily add more holes to the clipboard to accommodate varying rigs.

The metal pad is just a stick-on metal plate purchased from Amazon. I plan to add a leg strap in the future and will do so once I’m sure no other major modifications need to me made.

I’m pretty happy with the way the clipboard came out and would appreciate any comments or suggestions!

Rich
KQ9L

This is brilliant, Rich! I love both how affordable this board is and how easy it is to build. Having the clip at the bottom of the board is a fantastic way to secure your logging notebook as well. 

Thank you for sharing!

Charles’ simple solution to protect the MC-750 ground spike tip

Many thanks to Charles (KW6G) who writes:

Thomas:

I purchased an MC-750 from DXE last week…It arrived Monday….Great antenna; very nice workmanship….I have not yet deployed it, but that will be in the near future….

After reading your emails/posts and viewing the videos, I got to thinking…The real oversight in this antenna design is the fact that the manufacturer has provided no protection for the tip of the ground spike….I can see where it would not be long until it worked its way through one of the ends of the carrying pouch…

So with this in mind, I went off to the hardware store where I found a 3/8″ ID X 1 inch long nylon spacer which fit over the end of the spike perfectly — problem solved for all of 58 cents…

Here are a couple photos:

73’s de Charles, KW6G

What a great, affordable solution! Thank you for sharing this, Charles!

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

Dave sorts out vehicle-mounted antenna SWR issues

Photo by Katie Musial.

Many thanks to Dave (K1SWL) who writes:


Comments on vehicle-mounted antennas

by Dave Benson (K1SWL)

As with Rand’s recent post about his effective vehicle setup, I and others also use a small operating table inside the vehicle.  I’ve tried a number of approaches to antennas.  Without elaborating on those schemes, I’ll note that winter is now closing in here in NH. As a result, I’m now operating exclusively from my truck. My interest is now in minimizing setup and tear-down times.  Barry (WD4MSM)

also commented about the improvement in vehicle-mounted antennas with an added ground.  I’d like to quantify that.

I’d recently ordered a number of Hustler Mobile antenna components. They’re used as a stationary-portable setup using that company’s high-quality mag-mount. As I first evaluated the antenna, I was disappointed to find the minimum SWRs to be on the high side.

These results were related to the ‘floating’ coax shield, which serves as a counterpoise with the mag-mount setup.  Worse yet, these results were inconsistent. Touching the coax connector shell at the antenna analyzer caused the SWR to jump up, as did just changing the way I held the analyzer. Bad juju! It means RF inside the vehicle, with the potential for RF-‘hot’ symptoms at the rig..  Adding a 1:1 balun inline eliminated the stray RF at the rig, but didn’t do much for the SWR. It’s also just one more gadget to bring along.

A better fix was a custom bracket that bolted to the truck frame. I first confirmed that there was low-resistance continuity between a target location and the vehicle’s cigarette lighter shell.  This was something of a ‘comedy of errors’. I had a sheet-metal angle bracket on hand and went to work enlarging a hole in it. This had the usual outcome: a drill bit grabbed the workpiece and spun it. The bracket itself was buckled beyond redemption and my finger’s now healing well.  A length of 1-1/2 inch aluminum angle bracket was just the ticket.   Note that the mounting hole needs to be offset from the coax fitting mount. This avoids an interference between the mounting bolt and coax connector shell. Ask me how I know.  The bracket assembly uses a specialty coax fitting from DX Engineering. It’s their part number DXE-UHF-FDFB.

This bracket is bolted down on one of the corners of the Tacoma’s passenger seat assemblies.  It’s the closest location to the antenna I found without drilling holes and cutting the coax.  For this vehicle, it’s a 10mm bolt and was paint-coated for appearance reasons. I replaced it with a stainless-steel bolt from a hardware store. It’s important to include a split-lockwasher between the bolt and the bracket. This’ll keep the conductivity to the frame good over time. The bracket is deburred and its corners rounded to preclude injury to passengers.

In any event, it’s out of the way of the seat’s legroom space. A 3-foot coax cable assembly brings the coax nicely up behind the rig atop the operating surface.

So- how’d it work? It’s like the difference between night and day!  The broad SWR curves vanished – replaced by typical characteristics for monoband antennas. The sensitivity to handling the coax has vanished.  (A representative curve at right.) The curves are narrower, and that’s actually a good sign- it means that unwanted resistances have been reduced. 

With this fix in place, here are the SWR minima:

Frequency    SWR

14060        1.04:1

21060        1.05:1

28060        1.16:1

I took advantage of the CQ Worldwide CW Contest this past weekend. I was able to work 101 stations on 10M, 15M and 20M with this setup.  That was from a State Park 5 minutes away.  The attraction was a large and sunny parking lot, and solar gain was such that I needed to leave the truck door open several times.  This area is kept plowed out in winter, and I may try for the POTA ‘kilo’ award from there at the 1000-contact benchmark.  

We’ll see….   73, K1SWL

Mike turns a trailer wiring harness into ready-made ground radials

Many thanks to Mike (KE8PTX) who shares the following tip:

[Recently, I walked into a] big box store and this caught my eye:

When separated, they have very little memory.

So now we have four 25 foot radials. Bonus was all were different colors. Easy to untangle.

Performance, so far, is good. Total price with clip: 12 bucks.

That’s a brilliant tip, Mike! Thank you for sharing. Like you, I’m always on the look out for products that could serve double duty in the world of amateur radio. While one can find less expensive sources of wire, for 100% copper wire pre-cut to a standard radial lengths, this is a pretty good deal!

I did some searching and pricing varies between various suppliers. 

 

Sample Retailers:

Thanks for the tip!

Rand’s “Shotgun!” Mobile QRP Station

Many thanks to Rand (W7UDT) who shares the following guest post:


 ‘Shotgun!’ My Mobile QRP Station…

by Rand (W7UDT)

I’ll confess, at our overly stylish home, sadly, I don’t have a shack… my XYL has “concerns.”  So, in an attempt to keep my operating license and man card active, I happily practice portable QRP field operations at my QTH and afield.

This time of year however, with winter bearing down on us, I choose to deploy via my ‘Shotgun!’ mobile QRP station.  Simply, a quarter inch sheet of birch plywood, cut and finished nicely to fit suspended from the grab bar and headrest of my Jeep Wrangler’s passenger seat.  Ergo, ‘Shotgun!’

Grab, hang, stow and go!

It’s not a new idea, but I must say, it has become a very good solution to the chilly problem of posterior frostbite and hypothermia.

I’ll elaborate…

Continue reading Rand’s “Shotgun!” Mobile QRP Station

Field Report: How I evaluate a new POTA site plus serious QRP fun with my new-to-me Elecraft KX1

On Friday, October 7, 2022, I had a couple of errands to run in/around Morganton, NC. Of course, I always have POTA in mind so squeezed in an activation at nearby Tuttle Educational State Forest that morning.  That activation took longer than expected due to swapping out antennas and radios, but it was a success and quite fun.

After Tuttle, I knew I could fit in one more activation if I made it quick, so I set my sights on Table Rock Fish Hatchery (K-8012), but first I had a couple of errands to run in Morganton!

I visited my friend Hamilton at his ceramics studio, popped by another store to pick up a couple of items, then (on Hamilton’s advice) grabbed lunch at the The Grind Café.

I must say that Hamilton was spot-on. My wrap was delicious!

Just what I needed to fuel another POTA activation, right? Right!

After lunch, I drove to Table Rock Fish Hatchery. The weather was ideal and the leaves were beginning to show color.

At our home in the mountains, we were almost at peak leaf color, but the fish hatchery site is much lower in elevation. The weather was simply ideal.

On days like this, driving to a site is half the fun. Continue reading Field Report: How I evaluate a new POTA site plus serious QRP fun with my new-to-me Elecraft KX1

How Joe keeps his Icom IC-705 cool during long FT8 sessions

Many thanks to Joe (KD2QBK) who writes:

Hi Thomas:

I’ve recently discovered QRP FT8, which I’ve been working with my Icom IC-705. I run with an end-fed sloper that runs out of my 2nd floor shack window using a 49:1 unun and a length of RG-58. I’m also using an Emtech ZM-2 tuner between the antenna and the radio when needed.

The set up works really nicely, except for the way FT8 heats up and overtaxes the radio after a while. Searching around a bit, I’ve found just the right solution for that issue. The AC Infinity MULTIFAN S1 USB-powered table fan.

https://amzn.to/3DvqemJ (affiliate link)

It’s basically just a 3-inch square fan like you’d find in a computer or some other electronic devices, with rubber “feet” attached. It can stand upright or lay flat depending on your need. it’s stated purpose is to cool or ventilate routers, game consoles, audio equipment, etc.

The AC Infinity MULTIFAN S1 includes a speed control switch and an inline USB socket to daisy-chain other devices. One caveat with the inline socket: because it’s placed in the line between the fan and the speed control switch, the switch must be set to high speed else the socket won’t have adequate power for the attached device.

All I do is plug the fan into a USB socket and place it at the rear of the radio, sans battery, to keep it cool. I have it set up to blow onto the radio. Obviously I need to power the radio with an external source when the battery isn’t attached. I’ve not tried to use the fan with the battery attached, but I don’t think it would help much. The ventilation slots next to the battery compartment don’t seem wide enough to let much air in. Continue reading How Joe keeps his Icom IC-705 cool during long FT8 sessions

Radio Field Craft: Rand explores the handy Prusik Knot

Many thanks to Rand (W7UDT) who shares the following guest post:


The Prusik Knot… strain relief for Wire Antennas and Coax.

By W7UDT, Randall ‘Rand’ Tom

The Prusik knot is a simple, yet effective means to provide needed strain relief to wire antennas and coax, while deployed. It’s comprised of a simple loop or length of suitable cordage (of smaller diameter than the shank, Coax or Wire, it secures).

The link below, is from our friends at Animated Knots…. It’s a brief video tutorial on how best to tie the Prusik knot. Having the Prusik in your ‘bag of tricks,’ will help make your next field deployment be a successful one.

https://www.animatedknots.com/Prusik-knot

As seen in the instructional video, the knot is comprised of a simple loop of cordage, sufficient in length for the task, which is fine, but, I would recommend NOT making a loop. Rather, keeping tag ends for easier anchoring. These tag ends should be at least 12” in length. This is called an open-ended Prusik. Either way, both have utility.

To do this, fold a 24” of cordage in half, to make a ‘bite.’ Lay the bite over the shank of the coax or wire, and feed the tag ends inside the bite loop. This forms a larks-head knot. Wrap two additional turns around and through, then dress and test the knot to form the Prusik. Simple. Anchor (tie) the tag ends at a point where strain relief is best positioned. Then adjust (slide) it to load.

After deployment, I would also recommend leaving the Prusik attached. It comes in handy, when coiling your feed lines or elements later for proper storage.

The Prusik allows it to slide along the wire or coax while free of tension, yet it holds fast under load. Much like a monkey’s fist hanging onto a vine. The tag ends, can then be affixed to suitable anchor where needed. The key here, is using a smaller diameter cordage, than the wire or coax itself.

The Prusik, along with similar ‘Friction Hitches’, can be used in any number of applications in Ham Radio. e.g. Anchoring coax, joining linked antenna elements, power cords, and adjustable guying. The list is long, wherever strain relief is needed.

I would encourage you to tie it, try it, test it, and judge for yourselves. As well, I would encourage you to check out other useful climbing friction hitches… YouTube is a great place to start. I hope you find this useful afield, and to hear you ‘On the Air!’

73! de W7UDT (dit dit)

W7UDT, ‘Rand’, lives and operates near Boise Idaho, with his lovely wife Stacy. Portable QRP operations, along with his Jeep and Harley are his ‘vices.’ Your comments and questions are welcomed. My email is [email protected].