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Home A 160 Meter Vertical Buddipole Antenna Experiment part 2

Moleculo

Ham Radio Nerd
Apr 14, 2002
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In Part 1 of this topic, I showed how I accomplished creating a 160 meter vertical using mostly Buddipole parts, although I ended up using a Chameleon shock cord extension and whip which I already had for the length above the load coils. For this segment, I acquired a cap hat from a local ham that has 3/8-24 threads for use in mobile or portable antennas. I believe the cap hat originated from Chameleon, but I'm not 100% sure.

I put the cap hat between the shock cord extension and the whip:
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The immediate, expected effect was that the low SWR point moved down lower in the band than desired. So now I needed to re-tap the coils. The capacity hat made the tuning process easier as adjusting either coil became more forgiving than without the cap hat. Before, the process was super finicky trying to figure out which coil to adjust to achieve the lowest SWR, but with the cap hat I could adjust either to move the low SWR up and down the band. In the end, I found that the best combination was to leave the top coil tap in the original position and then adjust the lower coil tap for the desired frequency. I ended up taking coinly a couple of turns out of the lower coil, but the process was much easier and more forgiving to adjustments with the cap hat installed.

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Here's the new SWR plot; 1.74:1 at 1.903 Mhz, which is just slightly better than before. It has just a hair wider bandwidth, about 10khz more under 3:1.

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I also tried this antenna with only 1 load coil and the cap hat, but there just wasn't enough length in the antenna to get it resonant in the 160 meter band - it was closest around 2.2 Mhz. So, I had to go back to my original idea and use two of the low band coils. Now its' time to make some more contacts!
 
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