Radio W4KAZ

Thanks for stopping by the virtual KazShack. Feel free to comment - I often approve them.

Pollenating the Antennas – 80m Folded Dipole

Spring Fever, Hay Fever, and on the positive side, Antenna Fever.

The antennas are still in somewhat dis-array. But chugging right along in its 9th year of service is the trusty 80m folded dipole. The dipole serving the KazShack is cut according to the cookbook dimensions for folded dipoles outlined in the ARRL Antenna Book. In the ?? edition, the most recent available here, it is the lead off in Chapter 15, Portable Antennas. For those without the Antenna Bible, it was also re-published WITH permission from the ARRL, in the March 2002 edition of the CARC “FEEDLINE” newsletter. See pages 5 and 6.

I didn’t realize it had been in service so long. Given its construction from 300 ohm TV twinlead, I expected the wires to fail. It has required a repair, but that was due to damage from falling limbs. That is a problem with all of the antennas here.

It has occupied two seperate locations. Its first install favored the northwest, and it was really a killer into the upper Midwest, even with just 100w. It currently is oriented favoring a compass heading just to the east of due north. This improved the signals from Europe and the New England states, but is really a compromise.

The wonderful thing about folded dipoles is the hugh SWR bandwidth. The local version favors the CW/80m end, but the 2:1 SWR bandwidth is from about 3580kc to 3800kc. It is still well below 3:1 SWR at the bottom of 80m. It goes above 3:1 at around 3970kc. The internal tuners of both the FT-920 and K2 can bring the match down to 1:1. Sweet.

This antenna is a keeper. The only problem I have with it is that the construction article does not delve deep enough into the theory. I would like to reproduce the antenna using 450 ladder line, but don’t understand the methodology of the matching section well enough to scale the antenna. Hmmm. A conundrum.

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