[Elecraft] Antenna?
Mike Morrow
kk5f at earthlink.net
Sun Jul 4 09:47:20 EDT 2004
Jeff Imel wrote:
> The HF Pack organization sponsors and annual antenna shootout...
> http://tinyurl.com/2lzgm
That is a pretty interesting site. Thanks for the URL.
It confirms the very dismal performance of *all* those "popular" HF short loading-coil verticals in comparison to the most simple, basic, inexpensive quarter-wave vertical. TANSTAAFL!
Likewise, the horizontal antenna comparisons confirm the overall superiority of a simple dipole over other horizontal types being tested.
A comparison of all tested horizontal and vertical antennas against the half-wave horizontal dipole would have been interesting. I'm sure it would have shown a very significant advantage of a horizontal dipole over any vertical tested.
At campsites I've made several side-by-side tests of various verticals versus a resonant dipole and have *always* found found verticals to be very poor performers, when directly compared to a cheap horizontal dipole. Plus, don't forget the counterpoise or ground required by the vertical.
If one chooses to use a multi-band dipole for portable operation, I'd suggest staying away from *trap* dipoles. Aside from the traps being heavy and bulky, the traps really narrow the bandwidth of each band compared to that of a single band dipole. That's why, for the seven-band portable dipole that I put together, I use small, lightweight, home-made PVC insulators with manually connected jumpers around them to change the band of resonance.
The second-best portable antenna I've ever used was a random-length dipole, center fed with 450 ohm ladder twin lead and a tuner. The main problem presented was the routing of the excess twin lead. Every camp site is different, and it *does* make a difference if you coil up the excess or allow it to lay on the ground. The resonant dipole allowed me to return to the joyful and trouble-free world of RG-8X coax! Also, most small tuners aren't real balanced line tuners, so there are losses in the ferrite balun that nearly all such tuners use to support balanced line feed.
I think I'm going to build a light-weight four-band version of my portable dipole for the four bands on my K1. Right now, I just use the seven-band version that I originally built for my old TS-50S.
73,
Mike / KK5F
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