Monthly Archives: December 2016

Testing End Fed Verticals

I installed a piece of 2″x2″ angle aluminum in the ground outside the shack to support my vertical travel mast. This works very nicely with the tie down straps.

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I tested the EFHW on 20m yesterday on WSPR and found that it was hearing and being heard quite well on 1W. I shifted this to the end fed matchbox that I have had for some time. This requires the tuner but allows for multi-band operation. I used the same wire as the EFHW of around 30 feet. I modified the coax arrangement so that the air chock is at the window panel instead of the feedpoint. This gives the remaining feed line as part of the counterpoise. This seems to work well. I am getting reports comparable to the EFHW on 20m with this antenna. I was able to have a good ragchew with a station in AZ on 100W SSB using this antenna. I am keeping this up through 00UTC today and see if I score in the WSPR Challenge.

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40m Loop Update

I ran 1W WSPR on the 40m Magnetic Loop Antenna for about 18 hours before impending inclement weather forced me to bring it down.Here is what is looks like when taken down:

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Very compact. Longest PVC pipe is about 3.5′ long. Here are the WSPR results:

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The antenna held up well over night. Only issue is the captive nut came loose. Epoxy does not seem to do the job so I’ll have to come up with a fix. Also thinking about how to bring the tuning adjustment down to a more reasonable height.

The RigExpert AA-230 Zoom

One page that folks following my blog seem to gravitate to is my review of the Mini60 antenna analyzer.It is the Sark 100 copy sold on Ebay and produced in China. I personally have found this analyzer to work quite well and I have used it exclusively to test out my antennas. Your mileage may vary.

Now that I am doing some additional antenna work I have purchased a RigExpert AA-230 Zoom. This unit is a bit pricey compared to MFJ units and certainly to the Mini60 but from what I have done with it thus far it is well worth it. I’ll publish a comprehensive review later but for now I am sold on it. It is light, provides accurate and quick scans, has an impressive array of features including cable TDR testing and a great USB interface. The software works great with a PC and can save files in a format that Zplots can read.I used it for the first time in the field on the 40m loop and it made short work of tuning it. The interface takes a little getting used to but overall is very smooth to handle.

I will not be getting rid of the Mini60 as for quick and dirty measurements it still can’t be beat for the money. The RigExpert will be for more advanced testing and data collection and will of course help me with 2m antenna work.

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Preparing for CW Academy

I have installed the Vibroplex Iambic Key to the FT-450D and setup the keyer to practice CW sending. My first class is next Tuesday and per the class instructions I have been spending about 30 minutes each day going over the 1st lesson.This is actually encouraging as I can already recognize four characters! We have a test session on Saturday afternoon to try the virtual classroom using Skype as well as introduce ourselves.

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40m Magnetic Loop Antenna

Finally got around to finishing the 40m magnetic loop antenna. This antenna is designed to be easily deployed and used as an NVIS antenna with up to 100W. The heart of this antenna is the hi-voltage capacitor I designed and previously discussed. Before setting up the new antenna I made a few changes to the capacitor:

  1. Wrapped exposed copper with electrical tape
  2. Replaced the steel 5/16″threaded rod with a two food nylon rod. This was to minimize coupling effects while tuning
  3. Made a new center post with better hole alignment. This helps keep everything from binding.
  4. Epoxied the capture nut into the center post.

Here is the capacitor in use on the new antenna:

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The 40m loop consists of 22 1/2′ of RG-213 coax. The length was selected to match the capacitance of my prototype capacitor. Here is the design points via AA5TB’s spreadsheet:

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The rest of the build involved cutting pieces of 1/2″ PVC pipe to length to support the antenna. I hauled the whole thing ip a tree branch with the feed point just about 1″ off the ground. Initially the SWR was a bit high but it settled into about 1.4 when I removed two turns from the toroid. Here is the SWR plot through 50 feet of RG-8X feedline:

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Here is a view of the antenna deployed on a tree branch.

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I have been running WSPR on 40m now for about an hour and transmitting 1W. Here are the contacts thus far:

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This seems to be working well so far. My only complaint is that I have to stand on a ladder to tune it. I’ll need to work on that. I’ll run some additional tests now that its built.

Shack Deep Cleaned!

OK so today I did a deep cleaning of my workstation and therefore my ham shack. Aside from the numerous dust bunnies I also added some organizational items. I added a new surge protector just for devices powered by wall warts. I replaced my homemade window feed panel with an MFJ-4603.This is easy enough to install, just cut to length and add the weather stripping. This gives me two additional UHF connectors to test antennas with as well as ports for random wire, balanced line, N connector and F connector. The coax connectors were in good shape after twp years covered in Silicone fuse tape and electrical tape. I moved the MFJ-915 Line isolator to the outside right before the HF antenna coax comes in the shack.

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Next up was the ground straps. When I originally setup he shack, I striped some coax of the shield braids to use as ground straps. I replaced these with some 1/4″ braid made for the purpose. I used this stuff from the rigs and tuner to the feed  panel. One the outside I used a 1″ braid ground strap and added a bronze clamp to the ground rod. I was shocked to find that the previous braid was only loosely connected to the ground rod and I started to suspect that might have been the cause of my receive noise. Sure enough once I tested the IC-7100 I noticed better background noise even on a K4 day.

Everything is back up now and I made some contacts on 20m and 15m this afternoon. The shack is much cleaner now and I may have solved a problems that had been bothering me for some time. I now also have multiple ports to test antennas with!

Great Day to Be Outdoors!

Living in South Texas has some advantages especially in mid December. Great day here, sun was out and the temp around 78°F. Took out the FT-817ND and setup for solar operation with the DXtreme end fed antenna in vertical orientation. This end fed antenna needs an antenna tuner but allows me to operate on multiple bands. I used the LDG Z-11 Pro II tuner and ran at 45W today. Solar conditions were pretty bad with SFI of 72 and a sun spot number of zero. That’s right…zero…nada. I only made a few stateside connections on 20m. The ARRL 10 meter contest was going on today and I found this band was open. I logged contacts in Argentina and New Zealand without any difficulty.

Some notes on my operation today…first up it was bit breezy had gusts up to 30 mph. The travel mast worked great but I did have two instances where one of the segments broke loose and brought the wire down.I am going to think through some 3d printed clamps to keep this from happening in the future. I found I am short one PowerPole “Y” harness if I need to use the radio, amp and tuner. I switched from the two 15W panels to the fold-able 52W panel so I could free up the power connection. Duh, I just remembered I have some power distribution blocks that would solve this problem! Will try these next time. This time of year the sun angle is way different than the summer. Makes finding a suitable position for the solar panel a bit tricky. Overall no issues running the portable station at 45W. Finally, there was a lot of noise on the bands today. Suspect it was external man-made noise as the radio Noise blanker would help.

Feels good to get outside and play radio again!

The Santa Net

I’ll be checking in to the Santa net tonight on 3.916 Mhz at 7:30pm Central to make sure he gets my wish list for this year. Hoping I’ve been good enough to rate a deluxe Vibroplex Iambic key for use in my CW academy class, a RigExpert AA-230 Zoom antenna analyzer and a new MFJ window feed panel so I can test additional antennas with my main rig. Been working hard on this all year as last year I ended up with a lump of coal.

Low Radioactivity Lately

Holidays, work and poor weather and band conditions have all led to a period of low radio time for me since about Thanksgiving. What spare time I have has been devoted to working to get a 3D printer operational. I am looking to use this to build components for antennas. My activities on 3D printing can be seen at my bonobots blog. Aside from this I did manage to test the DC-DC converter to run the Gateway netbook from 12V battery power. Worked great! This will allow portable digital operations.

I got notification that I am on the class roster for the winter CW academy classes. I signed up for this several months ago as there is a waiting list. The classes begin in January and run for 6 weeks and is basic CW training using the Koch method. I need to find a CW paddle for the class. The class is a true class in that we meet online using Skype and video and basically all train at the same time twice a week.