Conservation of Energy

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Archive for January 7th, 2007

AD5X Portable Vertical Antenna

Posted by on January 7, 2007

Vertical Antenna

Saturday, January 6th, Dennis (N5DRB) and I complete the first of our AD5X portable vertical antennas. Using an MFJ antenna analyser, we were able to tune the antenna all the way from 80m to 10m, with low SWR and close to 50 ohms on all major bands (after careful adjustment of both top whip length and coil tapping below 20m.)

After that we couldn’ wait to get the K1 hooked up and start operating. We chose 20m initially, and as soon as we powered up, the band came to life. Our first contact was with a HI station in the Dominican Republic (about 2000 miles) and later we had a brief exchange with an 8R station in Guyana (3000 miles). Also worked a station in Virginia at 3 watts using a PAC12 vertical. Needless to say, we were both pretty pleased and there were plenty of smiles…

Here’s another picture of the center loading coil, looking up. You can also see the 4 guy ropes clearly.

Loading Coil

This version has two x three foot sections of 1/2″ tube making up the lower vertical section, the full lengh MFJ coil with the fibreglass rod, and the MFJ 10′ whip as the top section. Dennis added some brass screws to secure the brass couplings, and crafted a nice four point guy ring which fits neatly over the top of the coil section.

While the extra length has enabled the antenna to tune down to 80m, it also made it a little tricky to assemble and tune, as the top of the coil section is at about seven feet! A step ladder was required! So we may have to rethink the extra length for it to be truly portable…

Can’t wait to get mine finished and running!

You can get more information on the original construction here:

And Phil Salas has lots of other interesting articles and presentations on his web site

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Under Construction

Posted by on January 7, 2007

This will be the web-log of Jim Scott, AD5YU. My main motivation for writing this is my frustration with many of the email reflectors that seem to have attracted the lowest form of web life that think whining, complaining and criticising are the only useful topics.

So I’m switching to a pull format instead of a push one – I won’t email anyone, but if you want to know what I think, you can visit this site and get the information you want when and if you want it…

Comments, questions, contributions and suggestions are all welcome – but please keep them relevant to amateur radio and of a positive nature.

Thanks for visiting – I’ll have a lot more stuff up here shortly.


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