Tag Archives: Homebrew

Weller 9400

I typically use a soldering station as most of my previous soldering needs were largely soldering PCB. Soldering RF connectors and the like is quite another story. I invested in a Weller 9400 soldering gun this past weekend:


Wish I had gotten one sooner. It heats up in about 10 seconds and makes short work of soldering PL-239 connectors onto coax. It is very convenient to just plug in and use.



2018 ARRL DX SSB Contest

Worked the ARRL DX SSB contest this weekend and managed to get 100 contacts over the course of the past 48 hours. I did not operate to aggressively but did operate with spotting assistance. I worked 46 countries on 40m, 20m, 15m and 10m. 34% were in North America, 30% in South America, 16% in Europe, 7.5% in Asia and 10.8% in Oceania. No contacts in Africa this year. None of the worked countries were counted as new ones. All in all not bad and a lot of fun considering the band conditions were pretty bad (SSN=0 SFI=67). North America was dominated by 20m, South America with 15m, Europe on 40m, Asia split evenly on 40m and 20m and Oceania also split between 20 & 15m. All in all 20m was the more difficult band to work with many really weak signals heard here at the QTH. 40m comes alive in the early evening into Europe and Japan in the early morning. 15m had less overall activity but had many strong signals from central and South America. My score works out to 22,572 with 100 QSO’s. The DX stations responded with power of 1000W about 90% of the time with the lowest power as 100W. Good test of the vertical 1/4 wave antennas!

Fishing Pole Fail

I recently sourced three longer fiberglass fishing poles from Ebay that gave me a fully extended length of 5.9m. I have been using two of them to hold up my 20m half square. Went to check on it this afternoon and found that the lower section had cracked and snapped. Disappointing as the other poles I have been through major abuse without failure. Either a testament to the manufacturing quality or to the strength og the winds around here lately.

40m 1/4 Wave Re-build

I took down and rebuilt the 40m 1/4 wave vertical this past Saturday. I am using the same mast and vertical radiator as before but I have added the radial plate with 20 ground radials. I replaced the coax pigtail with the small vertical junction box I had been using previously. Overall, glad I made these changes as the connections were getting rusty and there was clearly some water getting into the feedline. I will start working to pin the radials down so I don;t have to pick them up when m,owing the lawn. I also plan to put up the 20m vertical element as before so I can have a resonant antenna on 40m, 20m and 15m (3rd harmonic of the 40m). Once the 20m vertical is up I can use it for A vs. B comparisons with the 20m half square. Also looking at a shortened 80m vertical to add to this set of “fanned” verticals.

The 20m Half Square is On the Air

It took several days of off and on work to debug the problems with the EFHW matchbox. I had to disassemble and rewire this several times before finding the issue. I noticed initially that the toroidal inductor seemed sensitive to motion. I ended up completely rewinding the coil then used some hot melt glue to pin down the winding.  Ultimately the problem was with the capacitor. I ended up modifying it so that the capacitance range was maxed out. Seems to be working now and the antenna tuned to 2:1 SWR across all but a small portion of the CW portion of the band. I made some SSB calls and completed the QSO’s however the signal reports were in the 56 to 57 range. I am running WSPR now and will collect some data as a comparison.

Weekend 20m Half Square Experiments or “…Nothing is Ever Easy”

It started off well, I had previously measured the wire 35.4 feet for the horizontal section and 17 feet for the initial cut of the two vertical sections (full wave total wire length for 20m). I used the new longer fishing poles and managed to fit them in the yard. As expected there was significant sag on the horizontal section but was manageable. I hooked up the EFHW matchbox from the linked EFHW project to one end to voltage feed it. It tuned up nicely with a 1m counterpoise:

LOAD Custom

Going inside the shack I made a few domestic Phone contacts with 55 57 signal reports. I did notice SWR was swinging a bit and started to check on it. That is when the real fun started. Suddenly the SWR lock up very high across the band. I thought there might be a bad antenna switch or loose coax connector. I built another ugly balun. Checked the match box with a 3.9K Ohm resistor and started seeing the weirdness. Sometimes is worked, sometimes it didn’t. I opened it up and checked the connections but couldn’t find a definitive wiring problem. I basically rewired it from top to bottom after checking the capacitor and inductor verifying they still worked. It behaved while I set it up but the minute I stepped back in the shack….sky high SWR. Check just the matchbox and it is not responding. Re-wired it a second time. Pretty much the same behavior.

So I have narrowed it down to the toroid. I may have a subtle solder issue one one end as well as shifts due to movement. I’ll debug this some more this afternoon. So far:

The Good: Easy to setup with potential for good gain.

The Bad: somewhat narrow banded

The Ugly: the EFHW matchbox wackiness tying up most of my antenna time this weekend.

40m FT-8 to Asia Working Again

I have been having good luck working DX into Asia on 40m FT-8 the past few mornings. The opening have lasted here well after sunrise until about 8:30am local time. I have made numerous contacts the past few mornings into Japan, Indonesia & the Philippines. The band had seemed to be shifting but it was likely just poor propagation conditions. Glad to be working these contacts again.

Inadvertently Stress Testing a Homebrew Buddistick

I took out my homebrew Buddistick over the weekend to test its performance versus the full size verticals I have been playing with. I haven’t really deployed this in some time so I was able to make some comparisons to some of the antennas I have been working with lately, namely the 1/4 wave ground mounted verticals. Setup up was about as easy as I remembered it but certainly more complicated than the ground mounted vertical. It is also heavier than I remembered it to be. I had it setup with three guy lines and a single elevated radial and it tuned to 1.46 SWR on the 20m band. On 20m it is not a full size radiator and relies on a small coil to bring it to resonance.

Performance was actually quite good on 20m WSPR. Two days in a row I made the WSPR challenge board. It still remains about 20 spots below the nearby station of N5CEY. The number of spots on 1/2W transmit was about equal to the number of receive spots which I am finding to be a good indicator of antenna efficiency. Thais tells me what I already knew, that is, it is a good QRP field antenna.

The antenna went up Saturday afternoon and stayed up through Monday afternoon. Monday it got breezy here at the QTH. Wind speeds picked up to around 20mph with gusts to 35mph. At some point, the camera tripod failed at the point where the PVC pipe meets the tripod. The whole mess came down hard. Fortunately, the whip was spared any damage and the tripod can be repaired.


For my next trick I am going to try and replace the whip with a fishing pole and wire with an elevated radial. Should be much lighter. It has also proven to be much more resistant to the “valley Wind Machine” that builds up around here this time of year.

A new Antenna Analyzer Gadget – RA0SMS miniVNA

It took about a month but yesterday I received a 1-30Mhz miniVNA that I had ordered on Ebay from RA0SMS in Russia. I have previously bought a miniWhip antenna from Anton with good results. This unit is based on a design by RA4NAL.  This is an interesting unit as it is Arduino controlled and provides a two port capability for only $75. Here are the basic specs:


• Frequency range 1-30 MHz

• Calibration using open-short-load for accurate results

• RF Generator with output power of 1,5 V @ 20 MHz

• Low power consumption, 400mA @ 5 V

• BNC connectors for better isolation

• User friendly interface for PC (Windows)

• Export data in several formats – JPEG, EXCEL, ZPLOT, S2P, PDF



This unit receives power and interfaces with a PC through the USB port. Unlike a stand-alone antenna analyzer, this unit requires a PC to operate. The advantage to using a VNA over an antenna analyzer is in testing filters, measuring insertion loss, determining the types of an unknown ferrite toroid, etc. There is a great write up on the uses of a miniVNA on N4SPP website.

I have not had a chance to test this unit extensively but I have installed the software (downloaded from the RA0SMS website) and tested that it powers up, is recognized by Windows 7 and performs a basic sweep. The device was painless to install. I have bought a couple of BNC to binding post adapters as well as a couple of BNC to UHF adapters to facilitate use around the shack. Lastly, I will build a set of Open, Short and load connectors to do a calibration on the device.

The software appears to be full featured but is not supported or in current development. There is a Java based software by DL2SBA that is supposed to work with this (when miniVNA is selected) but I have not tested beyond installing on my PC. I’ll post more on this when I get a chance to calibrate and then put it through its paces.

It’s Been Quiet…too Quiet…

It has been almost two weeks since my lasts posts. Radioactivity has been largely on the back burner due to finishing up family holiday activities, getting back to work at the start of the year and unusually cold weather here in South Texas this year.

Most years we have been able to count our winter in days. This year it will likely be in weeks. Definitely prefer working outside on antennas when its cold versus the extreme heat in summer but the last few cold spells have also been rainy as well. My main antenna right now is the 1/4 wave vertical for 40m. I use it on 40m, 20m and 15m. I also still have up the Ultimax DXtreme end fed but rarely use it anymore. My next activities are to try a 43 foot vertical using a spiderpole and then finally setting up the S9V31 permanently.

Tomorrow I am hoping to operate during the NA QSO party. Operation will be casual. Next weekend is Winter Field Day which I may try and do portable if it is at least dry.