April 8, 2017
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Hurricane season officially begins on June 1st. Our local club is gearing up some activities to support ARES operations in the event of a storm. We will be setting up a 2m digital simplex net on Thursdays at 7pm local time on 146.580 simplex using MT63 2000. Net control will be Cliff, N5CEY.
I will be net control for an HF voice and HF digital net on Saturday afternoons. Times and digital modes are yet to be determined. NVIS operations on HF will be desirable for these nets. I suspect that my current antenna (the DXtreme 53′ end fed) works fairly well as NVIS as it is up horizontal no more than 20 feet up. This net will give me a chance to test the 40m magnetic loop as NVIS. I am also thinking of modifying the homebrew buddipole to work NVIS as well. There is a PDF file that shows a simple way to modify a Buddipole to work NVIS portable. Yet another option is to build an easily deployable NVIS antenna for 40m and 80m per these instructions (thanks DX Engineering).
I am looking into a few choices for HF digital modes. MT63 1000, PSK31, Olivia and NBEMS. I am thinking of eventually asking net participants to limit power to 20W max to simulate off grid operations.
Last but not least, getting more local hams to test their HF rigs on Winlink using WINMOR. I cranked up the IC-7100 this afternoon and easily sent some emails on 40m to a node in Houston on 20W. Here is a good tutorial on setting this up.
December 28, 2016
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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:
- Wrapped exposed copper with electrical tape
- Replaced the steel 5/16″threaded rod with a two food nylon rod. This was to minimize coupling effects while tuning
- Made a new center post with better hole alignment. This helps keep everything from binding.
- Epoxied the capture nut into the center post.
Here is the capacitor in use on the new antenna:
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:
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:
Here is a view of the antenna deployed on a tree branch.
I have been running WSPR on 40m now for about an hour and transmitting 1W. Here are the contacts thus far:
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.
October 6, 2016
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I have been monitoring the Hurricane net on 14.325 today. Also using Broadcastify website to monitor FT Lauderdale Ham repeaters. Our local Echolink node has been configured to monitor traffic on the local nets as well. I am interested to see how traffic is passed around during this storm. God bless everyone in the path of this storm!