Weather-Resistant UnUn

When camping or on vacation, one of my go-to antennas is a simple 29.5-foot wire and 9:1 unun. In these situations, the antenna is usually up for days, and I have to use plastic shopping bags to protect the unun from the elements. For this project, I attempted to build an unun that can withstand the elements.

I had been thinking about this for a while. I wanted something that would protect the internal parts and provide some protection for the coax connection. Eventually, my stash of PVC pipe odds and ends caught my attention. I figured if this stuff could keep water in, it should be able to keep water out. What I came up with is somewhat weird-looking, but it should do the job

This is the completed 9:1 UnUn.
This is the completed 9:1 UnUn.

Parts

Here are the major parts I used:

  • About 2.5 inches of 1.5-inch PVC pipe
  • (1) 1.5-inch PVC end cap (slightly rounded top)
  • (2) 1.5-inch PVC end caps with flat tops
  • (1) SO-239 panel-mount connector (along with some #4 hardware for mounting)
  • A 9:1 unun wound on a T130-2 toroid
  • (1) 10-24×3/4″ stainless steel screw (along with some #10 flat washers, nuts, wingnut, and lock washer)

I have to mention a few things about the parts. The PVC end-caps with flat tops are hard to find. If you search online for furniture-grade end caps, you might find some. For winding the toroid, the Emergency Amateur Radio Club in Hawaii (EARCHI) has excellent instructions you can download. 

Construction

I wasn’t sure how I was going to put this together until I started building it. So, these won’t be detailed, step-by-step instructions. They should, however, give you a general idea of how I ended up assembling it. 

  • First, I glued the two flat end caps together, end-to-end. 
  • While the glue was drying, I wound the unun. I left the leads a little longer than the EARCHI instructions, but I cut them back as needed during assembly. I used some #22 gauge solid hookup wire for the windings.
  • I drilled a 5/8-inch hole through the two attached end caps and installed the SO-239 connector. To keep things simple, I only used two screws to mount it. So, I only drilled two holes for the #4 machine screws for mounting. I also created a couple of weep holes to allow any condensation to drain out. I don’t know if these are needed or not, but they won’t hurt. 
  • I drilled a hole in the rounded end cap for the #10 screw. I made this hole a snug fit for the screw.
  • Next, I soldered the toroid input and ground connections to the SO-239. I left the toroid leads about 1.5 inches long. I used a small lug to attach the gound lead to one of the SO-239 mounting screws.
  • I then soldered a ring lug onto the end of the output wire (antenna connection) and attached it to the stainless steel bolt. I made sure that this output lead was just long enough to make the connection to the bolt. (You probably noticed a splice in this wire. I cut it by mistake, while installing the toroid. Stuff happens!)
  • I squeezed in some foam packing material on both sides of the toroid to hold it in place.
  • Finally, I press-fitted the top end cap. The end caps are on pretty tight, so I decided not to glue the parts together. With a little effort, I can still get inside of it if needed.
This is a view of the toroid. Before I closed it up, I wedged pieces of packing foam on either side of the toroid to hold it in place.
This is a view of the toroid. Before I closed it up, I wedged pieces of packing foam on either side of the toroid to hold it in place.

I don’t typically use radials with this setup, so I didn’t provide for an external ground connection. I rely on the coax shield for the necessary counterpoise. Should I ever need to, I can easily add a ground stud. 

This is a view of the bottom of the UnUn. I added two "weep holes," in case there's any condenstation inside. These probably aren't necessary.
This is a view of the bottom of the UnUn. I added two “weep holes,” in case there’s ever any condensation inside. These probably aren’t necessary.

Field Testing

I took the unun out for a test drive, and it performed as expected. With a 29.5-foot radiator and 25 feet of RG-8x coax, the internal tuner in my KX3 was able to load it up from 80M through 6M.  (This type of antenna is certainly compromised on 80M and 60M, but I have made lots of contacts with them.)

This is the weather-resistant unun in use. I used an adjustable bungee cord to strap it to the Jackite pole. The recessed connector helps to protect the coax connection from the elements.
This is the weather-resistant unun in use. I used an adjustable bungee cord to strap it to the Jackite pole. The recessed connector helps to protect the coax connection from the elements.

The Straight Key Century Club (SKCC) Weekend Sprintathon (WES) was in progress while I was out, so I made a few contest contacts. Running my usual 5 watts, I worked two French stations on 20M. I was also pleasantly surprised to have a station in Hawaii come back to my 5-watt CQ on 15M. So, it looks like it’s working. 

I also inadvertently tested the unun’s mechanical integrity. I accidentally dropped it twice before using it for the first time. No problems.

Conclusion

I admit I might have over-engineered this thing, but it was a fun project, nonetheless. Our first camping trip of the season is two weeks away. Hopefully, we won’t have any rain. But, if we do, my antenna will be ready for it.

73, Craig WB3GCK

Antenna Testing in the Field

While other parts of the country are bracing for snowstorms, the East Coast has had a run of Spring-like weather. I took advantage of one of those days yesterday to do a little antenna experimenting.

I headed back out to the property that my daughter and her husband own. I wanted to play around with some end-fed wires that I plan to use as backup antennas. (The antennas were nothing exotic, but I’ll do a couple of future posts on them.)

I set up my equipment in one of my favorite spots and started experimenting with a couple of antenna configurations. It was a little breezy on top of the hill but nowhere as bad as it was back in January.

Field testing some end-fed wire atennas
Field testing some end-fed wire atennas

I spent most of my time playing around with antennas, but I did make some contacts. The monthly SKCC WES contest was underway, so I worked eight of my fellow members. I also heard a POTA activator in North Carolina, so I gave him a call.

I accomplished what I set out to do and made a few contacts in the process. So, I declared victory and packed up for the drive home.

One of the antennas I used today was the one that had been missing since November. This time out, I couldn’t find the replacement antenna I made up. As I was searching around in my truck for it, I found the missing original antenna. As luck would have it, I also found the replacement antenna when I got home. This time, I put both antennas in places where I’ll be sure to find them. Hopefully, I’ll remember where those places are.

73, Craig WB3GCK

Finally Portable Again

You can tell from the lack of posts here that February hasn’t been a good month for me, radio-wise. Between the snowstorms, freezing temperatures, and family obligations, I haven’t been out portable at all this month. I set out this afternoon to change that before the month ends. 

We’re in a stretch of moderate temperatures this week here in Pennsylvania. The good news is that the snow is melting away; the bad news is that mud is replacing the snow. Coupled with a rainy weekend forecast, I set out for somewhere paved where I could hunker down in the truck. 

That quest lead me back to Black Rock Sanctuary near Phoenixville, Pennsylvania, one of my usual haunts. I used my trusty 19-ft vertical on the back and my KX3 up in the cab.

Snow melting at Black Rock Sanctuary. The rain tapered off, but there was a heavy fog off in the distance.
Snow melting at Black Rock Sanctuary. The rain tapered off, but there was a heavy fog off in the distance.

I had no particular activity in mind for today. I set out to make a few CW contacts and maybe work a POTA activator or two. Since there’s going to be a full moon tonight (the Snow Moon), I also hoped to contact some of my fellow Polar Bear QRPers.

Well, Eric VA3AMX didn’t disappoint. My fellow Polar Bear from Ottawa was my first contact. The 40M band wasn’t great, but we managed to complete the QSO. Eric would be my only Polar Bear today.

I ended up with nine contacts in my log. Among these were three POTA activators (MO, IN, OH) and a SOTA activator in Quebec. I also logged a couple of contacts with South Carolina QSO Party stations. The highlight of the outing was a QSO with OZ8X in Denmark on 30M. 

Despite the lousy weather, it felt good to get out for some portable operating. I couldn’t bear the thought of going a whole month without getting out. Hopefully, Spring is just around the corner.

73, Craig WB3GCK

Winter Field Day 2021

Plans have a way of changing in a heartbeat. I originally planned to do my usual stationary-mobile setup for Winter Field Day. A trip to visit family in central Pennsylvania nixed that plan. Then, at the last minute, an impending snowstorm caused us to cancel that trip. And just like that, Winter Field Day was on again—at least some limited participation.

Due to the last-minute change in plans, Saturday was out of the question for me. Instead, I headed out Sunday morning for a few hours. I went out to nearby Black Rock Sanctuary, one of my regular haunts. I kept things simple and went with my usual stationary-mobile setup: KX3 at 5 watts and my 19-foot vertical on the truck. I also left the laptop at home, opting for paper logging. 

WB3GCK hunkered down for Winter Field Day 2021. Although it was in the 20s outside, it was a balmy 40F in the truck.
WB3GCK hunkered down for Winter Field Day 2021. Although it was in the 20s outside, it was a balmy 40F in the truck.

I made a few contacts on 20M, but 40M was more active. So, I spent most of my time on 40M. As is my custom for Winter Field Day, I dusted off my microphone and made a rare appearance on SSB. 

I found this device in my bag and used it for a few Winter Field Day QSOs.
I found this device in my bag and used it for a few Winter Field Day QSOs.

I was out for about 2 hours until the snow started coming down steadily. I ended up with 24 WFD QSOs—19 CW and 5 SSB. My toes were getting cold anyway, so I packed up and headed home. Although it wasn’t my best showing, I did better than last year. In any event, Winter Field Day is always a fun time.

Now it’s time to break out the snow shovels and get ready for the snow storm that’s coming.

73, Craig WB3GCK

One of Those Days

Did you ever have one of those days where just about everything seems to go wrong? Yesterday was one of those days for me.

I went out to my daughter’s property yesterday to do a little portable operating. The temperature was in the low 30s (F), with a wind chill temperature down in the low 20s. Earlier in the day, my daughter cautioned me about the strong winds on the hill, my usual operating location. Despite all that, I headed up there anyway. I figured I’d hunker down in the truck and be fine.

As I was putting my vertical on the back of the truck, a strong gust of wind had me starting to regret my decision. I pressed on and got everything set up. The wind was whipping the antenna around, but everything was working fine. So far, so good. 

I started on 40M and quickly put a Canadian station in the log. I moved up to 30M and soon worked SKCC Straight Key Month stations, K3Y/5 and K3Y/9.

About that time, I looked in the rear-view mirror and saw my antenna leaning over. The movement from the wind got the top of my antenna stuck in a tree branch. I removed the 20-ft pole and laid it on the ground. I pulled my truck forward a few feet and re-installed the antenna.

My 20-foot Black Widow pole blowing in the wind. It eventually got stuck in a tree branch.
My 20-foot Black Widow pole blowing in the wind. It eventually got stuck in a tree branch.

I got back in the truck and fired up the KX3. I spent the next half hour or so trying to reach stations but not being heard. When I went out to the antenna to change bands, I found that I had neglected to connect the ground. Doh!

After correcting my oversight, I had much better luck on 20M. I worked N4CD who was activating a park in Texas. I finished up with an SKCC QSO with a station on the West Coast in Washington. 

I was mentally celebrating my coast-to-coast contact until I looked in the mirror and saw my antenna wire flapping in the breeze. Sometime during that last QSO, two sections of my pole had collapsed. That was enough for me; it was time to pack up.

But, as they say on TV, there’s more… 

I’ve been using DMR since last year, and I wanted to try going mobile. So, I brought my AnyTone AT-D878UV HT and my hotspot. I had the hotspot in the back seat, using one of the truck’s USB ports and built-in Wi-Fi hotspot. On the drive out, it worked fine. When I started the engine to head home, I noticed that the hotspot’s display was blank. It was connected to the Wi-Fi but not sending or receiving anything. 

When I plugged it in at home, I heard a brief snap. So, I think something in there got fried. I suspect there might have been a voltage surge or something when I started the truck. Doh! I guess I’ll have to start learning about Raspberry Pi and try to rebuild it one of these days. 

Looking back, I guess it wasn’t a total disaster. Despite Mother Nature and my self-inflicted issues, I still managed to put a few decent contacts in the log. I’ve had worse days, I suppose.

Here’s to better days in the future!

73, Craig WB3GCK

Cold Moon Polar Bear Outing

I have a long-standing tradition of operating portable on New Year’s Day. I opted out this year due to a forecast of rain and the possibility of freezing rain. Fortunately, my delayed first outing of the year aligned with a Polar Bear Moonlight Madness Event. 

The Polar Bear QRPers tend to get on the air on the Saturday closest to a full moon. The full moon that occurred on December 30th is known as the Cold Moon

I headed out to my daughter’s property near Birdsboro, Pennsylvania, and set up in my usual spot on top of a hill. Today I went with a 50-foot wire configured as a sloper. I attached the far end of the wire to the top of my 28-foot Jackite pole and ran a 25-foot counterpoise wire off into the brush. I set up my KX3 on a small table and set to work looking for some of my fellow Polar Bears. 

My set-up for the January 2021 Polar Bear Moonlight Madness Event (PBMME).
My set-up for the January 2021 Polar Bear Moonlight Madness Event (PBMME).

As soon as I fired up the KX3 on 40M, I heard K3Y/2, one of the SKCC on-air event stations operating during January. I gave him a quick call and added him to my log. 

I moved down to the 40M QRP watering hole and started calling CQ. Not long after spotting myself on QRPSpots, I received a call from VE3WMB. After chatting with Michael for a bit, I received a call from another Polar Bear, Eric VA3AMX. Nice! Back-to-back Polar Bears!

My fellow Boschveldt QRP member, WA8YIH, wanted me to let him know when I was on the air. I fired off a text message to Ron, and a little while later, we had a QSO. 

This location on top of a hill is ideal for radio; it has good elevation and no RF noise. The downside, though, is that it tends to get windy up there. My CW sending hand was getting stiff from the cold, so I made a few more contacts before packing up. I had a chat with an Ohio station, worked a POTA activator in Indiana, and ended up working K3Y/8 in Michigan. 

Despite the cold wind, it was a fun outing. In particular, I was happy to log two of my fellow Polar Bears up in Canada. I have to admit it sure felt good to get back in the truck out of the wind. 

I’m hoping 2021 turns out to be a better year than the one we just went through. Stay well, my friends.

73, Craig WB3GCK

Post-Christmas Outing

After the hustle and bustle of Christmas, I took some time for what could be my last portable outing of the year. It was a cold and windy day, but I had fun.

I went to one of my usual haunts, Upper Schuylkill Valley Park, here in southeastern Pennsylvania. I typically operate from the parking lot overlooking the river, but that section of the park was closed due to recent flooding. Instead, I opted for a parking lot next to a little zoo. One of the zoo’s residents, a large goat, kept me company during my visit.

My operating location overlooked a small zoo. This guy didn't seem to mind the cold weather at all.
My operating location overlooked a small zoo. This guy didn’t seem to mind the cold weather at all.

The temperature was 29F (-1.7C) with a stiff wind, so I operated from my truck. As usual, I used my KX3 and 19-foot vertical.

I made a half-dozen contacts, starting with a two-way QRP chat with VE3KZ. Bob’s 5-watt signal was a solid 599. In addition to Bob, I worked made three other SKCC contacts. For good measure, I also worked two POTA activators.

My operating location at Upper Schuylkill Valley Park.
My operating location at Upper Schuylkill Valley Park.

I don’t know if I’ll be able to get out again before the end of the year, but I always try to get out on New Year’s Day. I like to start the year off with some Straight Key Night (SKN) contacts.

I hope you are all having a wonderful holiday season. Stay well, my friends.

73, Craig WB3GCK

WES at Black Rock Sanctuary

Today I headed out to Black Rock Sanctuary, one of my favorite winter-time operating locations. My primary objective was to make some contacts in the SKCC Weekend Sprintathon (WES). I was also curious to see if I could hear any ARRL 10M Contest stations.

When I arrived, there was a thick fog blanketing the park; I could feel the moisture hanging in the air. I went with my usual set up, my KX3 and 19-foot vertical, and was on the air in a few minutes.

The WB3GCK QRP-Mobile at Black Rock Sanctuary. You can see some fog over the hills in the background.
The WB3GCK QRP-Mobile at Black Rock Sanctuary. You can see some fog over the hills in the background.

I found lots of SKCC activity on the bands. 40M was wall-to-wall, and there was a fair amount of stations on 20M, as well. I ended up with 18 SKCC stations in my log, including F6HKA. Bert is always good at hearing QRP stations. I also worked a station using KS1KCC, the SKCC club callsign.

When I tuned around 10M, I didn’t hear much. I hadn’t used the 19-vertical on 10M before, and I found that the KX3’s internal tuner could only get the SWR down to 2:1. I suspect that the antenna is not super efficient on that band. Nonetheless, I did work a couple of local stations operating in the contest.

I made a few more SKCC contacts and worked a POTA station in Kansas before packing up. As I was taking down the antenna, the fog had dissipated, and the sun had come out. Isn’t that always the way?

73, Craig WB3GCK

Polar Bear Moonlight Madness – December 2020

The Polar Bear QRP group started scheduling Polar Bear Moonlight Madness Events (PBMME) for the Winter, so I went out to operate for a couple of hours today to see if I could find any of my fellow Polar Bears on the air.

The weather has been a little sketchy; a nor’easter came up the coast overnight bringing some heavy precipitation. Fortunately, my area is far enough inland that we escaped the heaviest weather. It was only a rain event that tapered off this morning. However, with the soggy ground and the predicted high winds for today, I decided to wimp out and operate from the truck.

I drove over to nearby Upper Schuylkill Valley Park, one of my favorite operating locations during the Winter. Mine was the only vehicle in the parking lot today. I used my trusty KX3 and went with my usual 19-foot vertical, mounted on my truck.

My operating location for the Polar Bear Moonlight Madness Event on a dreary afternoon. My truck was the only vehicle in the parking lot.
My operating location for the Polar Bear Moonlight Madness Event on a dreary afternoon. My truck was the only vehicle in the parking lot.

I spotted myself on the QRPSpots and the Polar Bear QRP Ops mailing and started calling CQ on 40M. After one or two calls, W3FSA gave a holler from Maine. John and I chatted for a while, and I went back to CQing. 

I wasn’t having much luck, so I started chasing some POTA activators. I ended up with 8 POTA stations in my log, including fellow Polar Bear, VE2JCW. Jean was doing a joint POTA/PBMME operation, and I managed to find him on 30M. 

I switched over to my straight key and finished up with 2 SKCC contacts. All in all, I logged 11 contacts during my 2 hours of operating. 

Although it was a dreary, windy day, it was a fun day for radio. Thanks to fellow Polar Bear VE2JCW for allowing me to bag a bear and avoid getting skunked. 

72, Craig WB3GCK

Back to the Field

Things are still busy around here, so I haven’t had much time for ham radio lately. I did, however, manage to squeeze in a short outing this afternoon.

I planned to head out to my daughter’s property and play around with an antenna I built a few months ago. As I was loading my equipment into my truck, I discovered my antenna had gone missing. After a brief but frantic search, I gave up. In the interest of time, I ended up taking my Alexloop antenna instead. (Note to self: The shack is seriously overdue for some straightening up.)

My set up with my Alexloop
My set up with my Alexloop

I set up at my usual spot atop a hill and tuned up the loop on 40M. I heard KC5F doing a POTA activation in South Carolina and quickly logged a contact with him. Further down the band, I heard Stan WB2LQF in New York and gave him a call. I’ve worked Stan a few times before; like me, he is a former Navy Radioman.

While I was chatting with Stan, the wind started gusting and almost blew the Alexloop over. I finished the QSO with one hand on the key and the other hanging on to the tripod. I took a few minutes to rig up a tent stake and a bungee cord to keep the antenna steady.

I had to rig up a tent stake and bungee cord to keep my antenna from blowing over.
I had to rig up a tent stake and bungee cord to keep my antenna from blowing over.

I moved up to 30M and called CQ near the SKCC watering hole. I immediately received an ear-splitting call from K1NIE in Ohio. Dick was using an attic dipole and was booming into Pennsylvania. I chatted with Dick for a while before changing bands.

The 20M band was full of contesters, so I gave 17M a try instead. It only took a couple of CQs to get an answer from WBØAUQ in Arkansas. By the time I finished with Bob, my fingers were starting to get stiff from the cold, and it was time to pack up.

It was great to get out, even just for an hour or so. Now, I need to find that missing antenna.

73, Craig WB3GCK