I’ve had a lot of fun with my Elecraft AX1 antenna since I bought it six or seven years ago. I’ve activated several parks with it, and it has yet to let me down. Running five watts into a 45-inch whip shouldn’t really work, but somehow it does. While I don’t always use it as my primary antenna, I always take it along on outings as a backup.
I have used my AX1 in a variety of settings, e.g., picnic table portable, with a car window mount, clamped to the handlebars of my bike, etc. While perusing the Temu website, I stumbled upon a tactical-style MOLLE pouch capable of holding the AX1 and all the accessories I typically use for those configurations. The cost was a mere $8.00 (USD) for a pair of them. (The original offering is no longer available, but a search for “molle pouch” on Temu or AliExpress should find this pouch or something similar.)
AX1 Kit (front). I have two of these pouches, so I used a nylon zip tie label to tell them apart. AX1 Kit (Rear). The pouch is MOLLE-compatible.
It measures 6.3 in. (16cm) x 4.33 in. (11cm) x 2.1 in. (5.5cm). For as inexpensive as they are, the quality is pretty good. The material is durable, and the zipper works smoothly. Each pouch came with an American flag velcro patch. At these low prices, you often get what you pay for. This time, though, I think it was a pretty good deal.
Everything fits comfortably in the little pouch, but there isn’t much room to spare.
This is what I carry in my AX1 kit. Not shown is a 3-foot RG-316 coax cable. (See text for list)
I normally carry my AX1 pouch in my backpack. When I have too much other stuff in my pack, I can use the MOLLE straps to attach the pouch to the outside of the pack.
It’s nice having all of this stuff in one place. Now my little AX1 is always ready to go, however I plan to use it.
While still on my extended stay at my daughter’s house in central Pennsylvania, I wanted to do some casual operating. So, I set up in the backyard to make a few contacts.
Today, I decided to give my Gabil GRA-7350TC vertical some air time. It’s been a while since I’ve used it. I set it up using the Gabil GRA-ULT01 MK3 tripod. I had forgotten how well engineered the Gabil stuff is. Anyway, I used four 15-foot speaker wire radials spread out on the ground. For the coax, I used 20 feet of RG-174.
My Gabil GRA-7350TC vertical on the Gabil GRA-ULT01 MK3 tripod
I started out on 40M. Using an antenna analyzer, I got the SWR down as far as I could and let the KX3’s tuner do the rest. Taking a quick dial spin down the band, I didn’t hear much at all. Eventually, I came across WA2NYY activating a park in New York and called him. Despite the horrendous band conditions, he heard my 5-watt signal on the first call. Next, I heard an activator in North Carolina, but I had a rough copy. We still managed to complete the contact.
My KX3 and 6Ah LiFePO4 battery
I then moved up to 20M and found the same crappy conditions. Eventually, I found and worked two more POTA activators.
I checked the POTA spotting page and saw that there were a couple of European activators on 15M. I tuned up the antenna and did a quick check. Nothing but dead silence across the band.
It was at that point that I checked the band conditions online and saw that there was a severe geomagnetic storm in progress. It showed poor conditions on all the HF bands. That certainly explained the lousy band conditions.
Yikes! This explains the lousy band conditions today.
Not being a glutton for punishment, I shut down for the day. Still, I was thankful for the four contacts I made with five watts of CW into an eight-foot base-loaded whip during a severe geomagnetic storm.
I’m currently out in the Harrisburg, Pennsylvania area for a week of house and puppy sitting for my daughter. My companion for the week is a five-year-old German Shepherd named Belle, who was adopted by my daughter and her family nine months ago. She’s a sweet dog, but she sometimes has some separation anxiety. So, I’m making sure my ham radio activities are short and close to home.
The first two days of my puppy sitting duty coincided with this year’s Field Day, so I did a little “backyard-portable” operating as category 1B. In my nearly 50 years of ham radio, this was my first-ever Field Day using my own callsign.
My plan was simply to set up an antenna in the backyard and make a few contacts each day. The weatherman was calling for dangerously hot temperatures over the weekend, but there’s a section of the yard that has some shade for most of the day.
Yours truly operating backyard-portable (Photo by my (far) better half)
My (far) better half came out for the weekend. While I was surveying the backyard trying to determine what antenna to use, she suggested strapping “that fishing pole antenna” (aka Jackite pole) to my grandson’s basketball pole. Great idea! So, I strapped my 31-foot Jackite pole to the pole and used a 29-foot wire and my weather-resistant 9:1 UnUn. I ran 18-feet of RG-8x over to the two chairs that served as my makeshift operating position. My rig was an Elecraft KX3 (5 watts, CW) powered by a 6 Ah LiFePO4 battery.
My Jackite pole strapped to my grandson’s basketball pole. (Photo by my (far) better half)
I started off logging contacts in HAMRS on my cell phone. That lasted for about two contacts before I switched to paper logging. I wanted to keep things simple and forgo using my laptop, so paper logging was just easier for me than using my cell phone.
My minimalist setup. I opted to keep things simple this year.
With temperatures in the high 90s (F), I only stayed out there for two brief sessions on Saturday. When a strong thunderstorm blew through, I called it a day.
My Field Day Security Officer
After breakfast Sunday morning, I went back out to make a few more contacts before the weather heated up again. When I called it quits, I had 62 CW contacts in the log, including one DX station (France).
My three hour effort didn’t break any records, but it was fun. I just wish the weather had been cooler, and I could have done without the thunderstorm.
Today I did something I don’t think I have done before: a single-band activation. Normally, I spend time on several bands. Today, however, I wanted to see how my 17-ft whip would perform mounted directly to the antenna mount on my truck (sans loading coil).
I drove down to Ridley Creek State Park (US-1414, KFF-1414) this morning and set up in one of the picnic areas. After mounting the antenna, I broke out my antenna analyzer. Since the fully extended whip is approximately a quarter-wave on 20M, I wasn’t surprised by the SWR readings. With 15 feet of RG-8X coax attached, the SWR was a flat 1.45 across the band. So I fired up my Penntek TR-35 (5 watts, CW) and hung out on 20M for the next hour.
My 17-foot whip mounted on my truck at Ridley Creek State Park (US-1414, KFF-1414)
When I checked the band conditions, I saw the geomagnetic field was “unsettled.” Solar wackiness notwithstanding, I logged my first 10 contacts in about 12 minutes. European signals weren’t very strong this morning, but I still managed three DX contacts: two from Italy and one from France. An hour’s effort produced 26 contacts, including four park-to-park contacts.
I’m planning to dust off a 25 year old 20M QRP rig and use it for a future activation. This antenna configuration might come into play for that. Stay tuned…
I went back to Marsh Creek State Park (US-1380, KFF-1380) for a quick activation this morning, and things got off to an interesting start. After setting up my trusty Penntek TR-35 (5 watts, CW) and 12-foot loaded whip, things just didn’t seem right. My SWR on 40M was high, and even my Elecraft T1 antenna tuner couldn’t get it lower than 3:1.
I started checking cables and connections, but everything looked OK. Heck, it’s not a very complicated antenna, so there isn’t much that can go wrong. When I got out of the truck to change to another antenna, I noticed my 12-foot whip looked a little shorter than usual. I took the whip off and immediately found the problem. In my haste to get set up this morning, I neglected to extend the top section of the telescoping whip. Doh! Once I pulled the top section out and re-installed the whip, all was right with the world again.
Using a notepad as an impromptu sun shield for my Penntek TR-35
Despite getting off to a slow start, my results weren’t too bad (by my standards). I finished with 36 contacts, including one known park-to-park contact. I had one DX contact with IW2NXI.
I finished my activation just in the nick of time. An hour after I got home, there was a major geomagnetic storm in progress. Timing is everything.
Back in December, Becky Schoenfeld W1BXY, Editorial Director for ARRL’s On the Air magazine, asked me if I would be interested in writing a detailed set of step-by-step instructions for my Drive-on Portable Antenna Support. Naturally, I said I would.
I submitted my manuscript, along with an all-new set of pictures. The article was published in the current issue (May/June 2024) of On the Air (pages 20-22).
If you’re interested, have a look. ARRL members have access On the Air as part of their membership.
I’ve been toying with buying a 17-foot telescopic whip for some time now. I didn’t really have a pressing need for it, since my 12-foot whip has been doing a great job for me. As a result, I kept talking myself out of buying it—until now. When I heard the news that MFJ was shutting down production, I figured I might as well buy one while they’re still available.
With no additional matching, you can adjust the MFJ-1979 to cover the 20M band and higher. I figured this whip coupled with my “Junk Box Coil” should easily cover 40M through 20M with the antenna fully extended. The four-foot height advantage over my 12-foot whip, should yield some performance improvement. With my older, larger coil, operation on 80M might be possible.
To test my assumptions, I made a trip to Evansburg State Park (US-1351, KFF-1351), where I was one activation away from a POTA “Repeat Offender” award. Like my last visit, it was raining, and I seemed to be the only one in the park.
I set up the 17-foot whip and coil on the back of the truck and quickly identified the proper tap for 40M. I used a Sharpie pen to mark the tap location. (The coil now has two sets of marks.) Despite an impending geomagnetic storm, I made my first 10 contacts in about 12 minutes. Not too bad for an early activation on a Friday morning.
The MFJ-1979 17-foot whip mounted on my “Junk Box Coil.”
After about 25 minutes, I switched to the 30M band and marked the tap location on the coil. I picked up eight contacts on 30M before giving 20M a try. It was no surprise that the SWR was a flat 1.5:1 with the entire coil bypassed. Although conditions on 20M seemed a little weak, I logged five more contacts before pulling the plug. I ended up with 25 contacts in the log. No DX or park-to-park contacts today, unfortunately.
For part of the activation, I used a plastic bag to keep the rain off the coil. When I got home, I brought the coil and the whip inside and dried everything off. While I had the whip extended, I measured the actual length. By my measurements, it’s 16 feet 11 inches long.
Based on this brief test, I made a few observations:
Compared to my older 12-foot MFJ whip, I don’t think the quality of the MFJ-1979 is as good. The older whip just seems to telescope more smoothly. Some online reviews mention problems keeping the antenna from collapsing after using it for a while. In an effort to avoid problems like that, I’ll be extremely careful when extending and collapsing the whip.
Performance on 40M, 30M, and 20M should be better than the 12-foot whip, given the additional length. A big difference? Given today’s band conditions, it was hard to tell.
With the 17-foot whip and my coil, I can cover 40M. 30M, and 20M without adjusting the length of the whip. However, the 12-foot whip gives me 40M, 30M, 20M, and 17M without adjusting the whip. This lines up perfectly with the bands on my TR-35.
I won’t be retiring my 12-foot whip anytime soon. I think for most POTA activations, I’ll stick with the 12-foot whip out of convenience. For contesting and activities like Winter Field Day, I will probably go with the 17-foot whip. I have an old 20M mono band QRP rig I want to put back on the air in the near future. The MFJ-1979 should be perfect for that.
I mentioned in an earlier post that I bought my Elecraft AX1 antenna not long after they came out. Although I carried in my pack as a backup antenna for a few years, I never used it much. That changed last year, when I started giving it some serious use. It’s now one of my go-to options for casual, impromptu portable operation.
Of course I bought a few accessories for the AX1. I typically use the AXB1 Bipod with the AX1 attached directly to my KX3. While that works fine, I saw mention of an interesting alternative to the bipod, the Byonics KX3 AX1 Stand. My curiosity got the better of me, so I ordered one.
It’s a clever little 3D printed stand that weighs next to nothing. To use it, attach the BNC elbow adapter to the AX1 and set it in the stand. Scoot the stand up to the radio and connect the AX1 to the radio. That’s it!
The Byonics KX3 AX1 Stand
I set it up at home, and it seems pretty stable. The thing I like about it is that there are no adjustments. Since Byonics makes these stands for specific radios, the KX3 version won’t fit a KX2 and vice versa. That’s not a problem for me, since I don’t currently own a KX2. The Elecraft bi-pod, of course, can be adjusted to fit either radio.
I’m looking forward to trying it out in the field sometime soon.
Sometimes I get excited over some of the most trivial things. This is one of those times.
I wrote about my Junk Box Loading Coil in a recent post. I normally keep the loading coil and my 12-foot telescopic whip antenna stashed away under the backseat of my pickup truck, so it’s handy for spur-of-the-moment activations. I also keep a couple of Jackite poles and some other gear under there. While the coil is pretty rugged, I just didn’t feel right about cramming it in there unprotected. By pure dumb luck, however, I stumbled on the perfect storage solution.
While mindlessly browsing the Internet a while back, I stumbled across something on a Chinese seller’s website (Temu.com) that caught my eye. It was a storage case that was probably made for something no longer sold. I’d provide a link, but products quickly come and go on this website. The website listed it as “Simple Portable Storage Zipper Bag, Travel Electronic Tools Organizer, Zipper Container.” Wow. That’s a mouthful.
I had seen similar cases on eBay, but not in this particular size. Given the listed dimensions, I thought it might be a good fit for my homebrew loading coil. At the time I placed my order, it was selling for $7.98 USD.
This is the case I bought to use with my Junk Box Loading Coil.
The container, along with a few other things I ordered, arrived on my front porch eight days after I placed my order. Voila! The case was a perfect fit for my loading coil. In fact, it looks like it was custom made for it. It’s semi-rigid, so it affords some degree of protection. It’s definitely not elephant-proof, though. There’s an elastic strap inside that helps hold everything in place.
My Junk Box Loading Coil tucked away in its new storage container
I’m not exactly sure what this case was intended to house, but it’s perfect for my application. So now, my coil will stay clean and protected, while waiting under the backseat of my truck for my next POTA activation.
Whenever I buy parts for a project, I always buy one or two extras. Over the years, I’ve amassed a sizable collection of random parts. Some of it will never be used, but sometimes my collection of parts has just what I need for something I want to build. I like when that happens.
A while back I wrote about an old homebrew coil I resurrected and paired with a 12-foot telescopic antenna. The coil, while effective, was built to use with a much shorter whip and is larger than what I need. I scoured my junk box and came up with most of the parts I needed to build a scaled-down version.
I should note that I built this coil specifically to use with my old MFJ-1956 12-foot telescopic whip. In this configuration, this coil covers 40M through 17M. So, if you have a different whip or want to cover different bands, you’ll need to modify the design accordingly.
Completed loading coil. Used with a 12-foot telescopic whip, it tunes from 40M through 17M.
I used the old coil as a guide to determine the number of turns I needed to cover the bands of interest, adding two turns for good measure. Using an online shortened vertical calculator, I figured I would need about 13.4μH to load the 12-foot whip on the 40M band. Using an online coil inductance calculator, I estimated the total inductance of my coil to be 14.8μH. So, it covers 40M with a turn or two to spare.
The new coil assembly measures 8.25 inches end-to-end, making it 2.25 inches shorter than the old coil. While it’s about 3.3 ounces lighter than the old coil, this new coil still weighs in at a hefty 10.8 ounces.
Parts List
With a few exceptions, my junk box provided the parts I needed to build the coil.
5-3/8 inches of 1.5 inch PVC pipe
(2) PVC end caps for 1.5 inch PVC pipe
(4) pieces of nylon grommet edging, 3.25 inches each. (The material I used has about 8 notches per inch)
16 gauge bare copper wire, approx. 12.5 feet
(1) 3/8-24 coupling nut, 1-1/8 inches long
(1) 3/8-24 x 1-1/4 inch stainless steel bolt (bottom mounting stud)
(1) 3/8-24 x 1 inch stainless steel bolt (top bolt)
3/8 inch flat washers & lock washers
(2) #10 x 3/4-inch self-tapping screws
Approx. 6 inches of RG-174 coax
Small alligator clip
Misc: ring lugs for ⅜-inch & #10 screws
Construction Notes
As shown in the accompanying photo, I drilled the end caps to accommodate the ⅜-24 bolts. The 1-1/4 inch bolt was used for the bottom of the coil, along with a flat washer and a lock washer. The 1-inch bolt was used for the top, along with flat washer, lock washer, and the coupling nut.
This is the coil form with the four strips of grommet edging glued on. The ends were drilled to accommodate the 3/8-24 bolts.
The coupling nut was one item I didn’t have in my junk box. My local hardware store is well-stocked, but they didn’t have them with the ⅜-24 thread. I eventually found what I needed on Amazon. It was a little pricey, but I didn’t have any better options at the time.
After cutting the PVC pipe to length, I temporarily installed the end caps. Then, I cut four pieces of the grommet edging to length and glued them on, using Goop® adhesive. Unfortunately, I can’t provide a part number and source for the edging. A local QRPer, Ron Polityka WB3AAL (SK), gave me several pieces many years ago. I’m pretty sure Panduit was the manufacturer. My stash was nearly depleted, but I had enough left for this project.
Before assembling the end caps, I made two short jumpers, each with a ⅜-inch ring lug on one end, and a smaller ring lug on the other. Then I tightened everything up. I left about a ½ inch of thread on the top bolt to go into the coupling nut. I was careful to ensure that my whip antenna would fully thread into the coupling nut.
Before winding the bare wire on the coil form, I installed a ring lug on one end. I drilled a pilot hole in the side of the lower end cap and used a self-tapping screw as a connection point. When you wind the wire on the coil form, try to get the turns as tight as you can. (I didn’t do as good a job winding the coil as I would have liked.) Once I finished winding the coil, I cut the wire to length and installed a ring lug. I used some more Goop adhesive on the grommet edging to hold the turns in place.
The last step was to build the clip lead. For this, I used a piece of RG-174 coax. There’s nothing magical about the RG-174; stranded hookup wire would be fine. I used RG-174 primarily because of its flexibility, plus the shield would be a good RF conductor. (The center conductor was unused.) I crimped and soldered a ring lug to the braid on one end, and soldered an alligator clip to the braid on the other end. Then I used another self-tapping screw on the top end cap to connect everything together.
On the Air
I wrote about my initial tests of the coil in a previous post. Using an antenna analyzer, I determined where to place the tap for each of the four bands. I then used a permanent marker to mark these locations on the coil, so I can quickly change bands without resorting to the antenna analyzer.
This is the completed loading coil installed on my truck for a POTA activation.
With the antenna mounted on my truck, the SWR is higher than I would like on 40M and 30M. This is not unlike other shortened, base-loaded verticals I’ve used in this configuration. An additional counterpoise wire or two might help. Also, grounding the bottom of the coil and feeding it a couple turns up from the bottom would provide a precise match on the lower bands. I’ve used that technique in the past. That configuration , however, is a bit more complicated to implement, given the way I plan to use this coil. So, I just use a tuner to keep the radio happy, and the antenna seems to work fine.
Wrap-up
My older, larger coil worked fine; so technically, this project was unnecessary. But, since I had most of the parts on hand, what the heck. It was a fun project, and I’m sure it will see a lot of use in the future.
WB3GCK QRP Amateur Radio 