Tag Archives: 1/4 wave vertical

My Ugly Balun

I built an ugly balun today to try and address the SWR swings I was getting on 20m. It actually went together in about 10 minutes. To build it I used a 4″ PVC pipe coupler as a form. I drilled two small holes to run a tie wrap through to hold the end of the coax in place. I had a 25 foot piece of RG-8X laying around with PL-259 connectors on each end. I wrapped 15 turns around the coupler and then tied it off the same was as the other end. Some long tie wraps then are used to hold the winding securely on the form. I replaced the 1:1 current balun I had been using with this. To match up the coax connectors I used two bulkhead connectors and wrapped with electrical tape (for now). Here’s what the finished balun looks like:

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And here it is installed at the vertical antenna feedpoint:

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The balun seems to help with the SWR issues on 20m but I see some shifts in the overall SWR response. I’ll likely have to tweak that over the next few days.I have some ferrite toroids on the way as well and will try and build a choke with those as well. Signal reports on both 40m and 20m SSB were real good tonight!

 

What’s Better than One 1/4 Wave Vertical? —How About Two?…

Next experiment in vertical HF antennas is trying a 1/4 wave vertical “fan dipole”. The 7.2m fishing rods are a perfect support for up to a 20m wire radiator. I set a length of 3/4″ PVC pipe about a foot away from the existing 40m 1/4 antenna. I also removed the last two section of fishing pole as they are too flimsy and are not needed length to support a 20m wire. I connected this wire to the point where the 40m wire connects and after a bit of tuning had three dips in the SWR. 7 MHz is the main tuned frequency, 14 MHz is the new radiator and 21 MHz is the third harmonic of the main radiator. Here is the SWR plot:

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Here is what is looks like:

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So far this works well as before on 40m and 15m. The performance on 20m looks a little shaky still as I am seeing my SWR swing around a bit when transmitting. This indicates to me that my feed line is picking up RF at that frequency. I’ll be building an Ugly Balun soon to try and clean that up. The antenna hears very well on 20m with very little noise so I f I can solve the SWR issue I should be in good shape.

 

Working 40m and 17m this Weekend

I reconfigured what has become my main antenna, the 40m 1/4 wave vertical. This is still a temporary installation but I am growing increasingly happy with the results I am getting. I frankly can’t remember the last time I used the horizontal end fed. I have had to roll up the radials on occasion to mow the yard and have not yet deployed my permanent radials. Currently I am using the 30 foot travel mast from SOTAbeams to support the vertical wire and have four 27 foot radials deployed. I am using my homebrew 1:1 current balun at the feedpoint and running to the shack with 50 ft of RG-8X.

If I get the chance I’ll start operating around 6:30 am local time on 40m JT-65. I can usually snag several contacts in Japan with the occasional contact into Australia, Indonesia or the Philippines. The action is over by about 7:30am local time as the band closes quickly after sunrise.

Saturday afternoon, I was checking the bands and came across a strong VK station on 17m SSB. We exchanged signals reports in the 54 to 55 range. I moved over to JT-65 and found that there was DX activity including another VK contact. Today Sunday I am finding about the same conditions, great 40m propagation to the far east in the early morning and some light DX into Europe & South America on 17m in the late afternoon.

 

Vertical Weathers a Thunderstorm

We had some much needed rain at the QTH last night. I had taken down to work on the Homebrew Buddipole early last evening but left the 40m vertical in place. The storm blew through at about 4am and dropped over an inch and a half of rain with gusty winds up to 25 Mph. My wife went outside early this morning and came in to tell me we had debris in the back yard and oh by the way your antenna is bent. Doh!

Went outside expecting the worst. I have heard stories of fiberglass tubes breaking off in high winds. I was relieved to find that the antenna was indeed bent near the top, but only because the vertical wire had blow into and tangled into a tree branch holding it over. I shook it loose and it popped back vertical instantly. Three sections had telescoped back in near the base so after pulling them back out I am back in business. This SOTABeams travel mast has taken some real abuse!

40m QSO’s with 1/4 Wave Vertical

Most of this week was sent collecting WSPR data on the 40m 1/4 wave vertical. The vertical is holding up better to the breezy days after placing some duct tape on the joints of the travel mast. The vertical radiator is a 32 foot length of insulated #14 speaker wire. There are only four 27 foot ground radials deployed at this time. There is a 1:1 current balun at the feed point and about 50 feet of coax to the shack after that. Here is the SWR plot:

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SWR is under 1.5:1 across the whole band with a resonant point 7.125 MHz. This antenna has been a solid performer on 40m without a tuner. I am noticing that the band starts opening up to DX about an hour before dusk. Last night I made several SSB contacts with Europe after 10pm local time.

Switching to 40m JT-65 at that time was very interesting as well  as the propagation conditions can be somewhat visualized with pskreporter. I really tested the JTDX software last night and have gotten the hang of the user interface which is subtly different from WSJT-X.  I set the IC-7100 with AGC-off and the bandwidth filter set to 3.6 kHz. Rather than search and pounce, I would look for a quiet spot at the extremes of the band and call CQ DX. This strategy worked well with many European stations answering. Over time, I can see my signals fading on the pskreporter map as eastern Europe’s morning progresses. As dawn approaches in Western Europe, stations start coming online and start to see my signal. At the same time, the opposite terminator starts approaching New Zealand and Australia and my signals starts picking up there as well. I knocked off at about midnight local time and picked up at about 7am and repeated. This time JA stations were answering my CQ and I was running a JT-65 “pile-up” with several JA stations calling at the end of a QSO.

Very pleased with the antenna performance on this band. 20m is acceptable through a tuner but the WSPR data indicates some degradation in performance over a resonant vertical or even the end fed antenna.

Operating this Weekend with a 1/4 Wave Vertical

The winds have died down a bit here at the QTH and the travel mast has been up about a week now. The duct tape on the joints may have something to do with it. On 40m, the antenna is a winner. Made contacts on SSB to Europe in late afternoon early evening on Saturday. Making JT-65 contacts into Japan is like shooting fish in a barrel on early mornings. On 20m, I run the antenna through the tuner and also made some DX into Europe and the South Pacific. I switched between the vertical and the horizontal DXtreme end fed antenna and found that the vertical can definitely hear signals that the horizontal cannot. Propagation conditions seems to be shifting these past couple of weeks. 40m is solid into Asia early morning and Europe in the early evening. 20m has been weak in the morning but picks up in the late afternoon. 17m has been really hurting lately with some small windows opening up from time to time. All in all a good weekend of radio activity.

Not Even in May Yet and Already Near 100° F…

…and did I mention the winds? Been hard to play with the vertical antennas these last few days. It is very hot outside and the wind is blowing up to around 30 MPH. The tests I was doing with the end fed in vertical configuration had to be halted yesterday as the mast collapsed again. I have a major construction project about to begin next week in the backyard so this is not the right time to deploy the radial field.

After giving it some thought I sent up the 40m 1/4 wave vertical as before. This time I am using duct tape on the travel mast and it seems to be holding together better. The other big change is that I am using only four ground radials each 27 feet long. This will make it easier to pick up if the construction requires me to move. How does it work with only four radials? Surprisingly good! Made several contacts during the Florida QSO party on 40m SSB without issue. Used the tuner to match on 20m and 17m and made several solid contacts on those bands as well including an SSB contact to Spain on 20m. Will be running WSPR tests on various bands over the next few days as NO5V/6. Hope the duct tape holds!

Next Iteration of the Vertical Antenna – End Fed with Radial Field

I reconfigured the 40m 1/4 wave vertical as and end fed vertical by removing the 1:1 choke balun and installing the 9:1 matchbox as before. One big difference was that I connected the radial field to the ground lug of the matchbox. I have run 24 hours WSPR on 20m with the following results:

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Not bad at all with 132 unique spots thus far (on a fairly bad day of propagation indices). Will try this on other bands soon.

Running 40m 1/4 Wave vertical on 20m

Overall I am very impressed with the 40m performance of the 1/4 wave vertical. For grins I am running 20m WSPR by running through the antenna tuner. The tuner found a match and after only 8 hours had enough unique receives to make the WSPR challenge yesterday. The count is now up to 123 and I expect to be on the board again with a very decent showing. I will continue testing on 17m then over to 80m and 160m. Not expecting much on the low bands but am interested in the results. I am not going to run on 15m because it is resonant on that band as a third harmonic to the 40m primary.  I’ll leave 12m and 10m on the DXxtreme as that antenna has proven itself well on those bands (when they are open).

Update on the 40m 1/4 Wave Vertical

Ran WSPR last night on 40m with the 1/4 wave antenna. Here is the Map as of this morning:

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Started running some JT-65 this morning and while difficult to run pile ups, I am getting QSO’s with JA by calling CQ. On my third one since starting this morning:

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Overall I am very pleased with the performance of this antenna. I’ll be doing some tests on 15m as well although the band has been quiet.