On Sunday 6/12/22, I was checking out the station ahead of our club’s upcoming Field Day. Running through the stacks on Tower #1, I encountered troubling readings on the 20 meter stack.
SWR on each of the three measured independently was fine; however any combination of 2 or 3 antennas sent the SWR to >6:1.
On Tuesday 6/14, I went to the cabinet at the base of the tower. I disconnected the feed lines to the three antenna from the Array Solutions Stack Match. Measuring each antenna with my Rig Expert AA-55 Zoom, I discovered that everything up the tower checked out in 100% working order.
Since I had several new Stack Match relay boxes on the shelf, I simply replaced the relay box.
Along with K5ER, WM5H, and KD5YS, we made the trek to Dayton. Brevity is the key here. We rented an Airbnb house nearby and commuted to the Hope Hotel for the contest activities (formerly held at the Crown Plaza/Radisson downtown). I can only comment on the CTU rooms and the contest super suite room. It was good.
The Green County fairgrounds @ Xenia are head and shoulders better than the Hara Arena. The only possible disadvantage is the grass infield for the flea market, which after a rain, can become quite muddy.
Contest University was informative as always, and seeing all the guys and gals on the other end of the contest QSOs is always a blast.
Eyeball Sprint contest – The most fun 5 minutes you will ever spend in a radio-related activity. Doug, K1DG tells you everything you need to know in this video clip
Of late, I’d noticed that the SWR on the 10 and 15 meter stacks on tower 1 seemed to be getting higher and higher. Sometimes our first reaction is to head up the tower to the antenna to find out what is the trouble. This time, however, I didn’t go with that first gut reaction.
Rather, I began with a very methodical testing routine, with my AA-55 ZOOM connected to the coax in place of the transmitter at position A. I then inserted a precision dummy load at the next coax junction. Next, using the AA-55 I swept the coax on all 6 ham contest bands. I followed this pattern until I found SWR readings higher than 1.2:1.
The first thing I found was my ICE 419B bandpass filter. Even in bypass mode, it drove the SWR higher than 1.2:1. I inserted a brand new barrel connector in its place, and continued my testing.
The next problem found was on the output side of my 10-m coax filter stubs. I replace the stub assembly with another barrel connector, and continued the testing. Likewise, I found the 15-m coax filter stub assembly and the 40-m assembly to be causing SWR problems. More barrel connectors and the testing continued until I reached the distal ends of the six runs of hardline at the inputs of the various Stack Matches at the base of the tower.
The first step at remediation and repair was to test each individual coax stub in the 10, 15 and 40 meter assemblies. I found all of them to be considerable low in frequency relative to what I desired them to do. So, I retrimmed each of them to return them to the proper frequency. Then I reassembled everything, and retested. SWR was flat all the way to the base of the tower.
The second step was to replace the position A ICE 419B with a Dunestar Model 600. Following that, I again retested all the way to the tower. SWR was flat!
Things that make you go “Hmmmm”. My stubs reside in a shed, out of the sunlight and out of liquid rain. What caused them to drift over time and appear too long electrically?
3/27/2022 – With a box of shiny tubing from DXE, and an OWA design from my friend, I tackled an antenna construction project today.
Since selling my Lightning Bolt 2-element 5-band cubical quad a few years ago, I have not had an antenna for 12 meters. My DXCC count is low on that band, so I figured that with the uptick in propagation, now is as good a time as any to tackle this project.
Some time ago I asked around for an OWA design to use a 24-foot boom (salvaged from an old TH6?). Once I had the design in hand, I plugged it into EZNEC 6.0, and agreed with the designer’s conclusions. Download my EZNEC file for this antenna. I made a parts list and placed an order from DXE for the tubing (surely there are others suppliers around, but I can’t find them using Google search) and another from McMaster-Carr for the hardware needed.
With some aluminum flat bar cut to length, a drill press made quick work punching holes in the boom-to-element plates (I used a DXE model as a template).
The Sawzall was employed to cut the tubing to the needed lengths, followed by a thorough deburring of all tubing ends. Measured and marked the “exposed” lengths of tubing, inserted to the marks, and drilled three 1/8″ holes for pop rivets. Pulled the tubing out, deburred the drilled holes, then coated the insertable tip with a copper-impregnated anti-seize compound. Aligned the holes and riveted the tubing together. The halves of the driven element are separated by 2-inches, supported by a 0.75″ fiberglass rod inserted into both halves.
With the elements assembled, I moved outdoors to assemble the boom and install the boom-to-element plates. After that, installing the elements was a piece of cake.
Still sitting on sawhorses, the initial SWR and R,X sweeps are nearly identical to the EZNEC model.
I’ll update this post when the antenna is in service. I think it is going to be a flamethrower!
4/15/2022 – Good Friday, and good Friday! I was off work. Woke up at 0400 and was wide-awake. Decided today was a good day to install the antenna. So, working alone with tractor and pallet forks, along with an 8-foot ladder, I was able to remove the KT-34 and install the 12-meter yagi. Initial tests are promising – worked YV4 and VP2V right away, 100 watts CW.
3/13/2022 – I removed the shunt feed from the tower. The 80-m 4-square outperforms it in every way, and I believe that the shunt feed was detuning the 4-square in the NW-SE direction. Further, the 80-m dipole at 105 feet still performs very well.
This past weekend (Thursday, March 3 to Monday, March 7) was a road trip of 2,200 miles. I drove up to K8AZ for my 9th time as a guest operator for a major DX SSB contest.
As always, I thoroughly enjoy being with Tom and the ‘AZ Crew. Tom has built a fantastic station, and every time I go, there has been an improvement since my previous visit.
During the drive home, I was reflecting on these trips to K8AZ and how many other hams I’ve enjoyed the camaraderie with while there. I’ve shared shack time with 21 hams at the ‘AZ station: AA8OY K3LA K3LEA K8AAV K8AZ K8BL K8MR K8NZ K8RR KE3X N5OT N8AA N8TR ND8L W3YQ W5WZ W8CAR W8WTS W8WWV WB8K WT8C. Lots of fun and memories!
All of the scores are posted on 3830scores.com, just use the search in the top right of the 3830 page.
We played well together and in the contest, with an apparrent 4th place finish.
During NAQP RTTY, SWR and RF PWR bargraph seemed weird. High SWR, low RF output. RF power set to 100 watts. Outboard LP-100A power meter showing SWR in normal range and power in normal range. As contest progressed, we noticed zero bars on SWR meter, and a single bar on RF meter. LP-100A was showing 100-126 watts, with normal SWR. After contest, connected a dummy load to the K3 Ant2 (easiest to do; normal antenna connected to Ant1) and the meter behaved the same. It was midnight, so didn’t do any other troubleshooting.
Within a day or two, got a support ticket open with Elecraft.
12/18/2021 — Checking out the KT34M2 in preparation of the NAQP series in January and February has revealed issues on all three bands.
Some queries to TowerTalk and the responses all pointed toward bad coax/water in coax, or loose connections between balun and front driven element and/or rear-driven element. On 1/13/22, we tested the coax and even swapped with another run. Same symptoms. A call to M2 support; they suggested perhaps water in one or more of the capacitors. We tilted the tower over to access the capacitors. Removed all 16 end caps, finding no water. We did, however, find much insect debris and dirt dauber nests. Cleaned all that out with compressed air and a long rod to push through the 3/8″ inner tube. We also verified all the mechanical connections on the driven elements and confirmed good continuity with an ohmmeter. The SWR curves are improved, but still too low.
Back in January 2018, I met George K7BFI on the air one evening. Turns out we had a few things in common. So while on vacation, I took the opportunity to stop in and meet him at his home in Utah face-to-face. Thanks George and XYL Karen for a wonderful breakfast, and even better conversation!