On Sun, 2007-12-09 at 21:00 -0500, Bwana Bob wrote:
> Well, the embassies that I saw were all in an urban area at the shores
> of the Med. There was no room for big antenna arrays. The HF antennas
> had to fit completely on the embassy rooftops, hence most were fairly
> short dipoles.
>
> Regarding the B&W broadband dipole, I don't know why so many amateur
> emergency groups buy them for EOC's. You only need a broadband antenna
> if you're doing frequency hopping or using unskilled operators who can't
> use an antenna tuner. Autotuners take care of the skills issues, and
> most amateur radio emergency comms takes place on only a couple of
> bands, and usually on spot frequencies. There is a real penalty with a
> resistively loaded antenna like that: Its only about 12% efficient on 75
> meters.
That's why when we have HF emergencies or exercises those of us with
real antennas have to relay traffic to and from the EOC. Some make it
worse by running a few hundred feed of coax from the bunker to the
antenna.
It was like that when the night of Y2K came around.
The rest of the trouble is that the leaky dummy load is ingrained in
accepted EOC hardware.
>
> Hey, remember the Teletron Slinky Dipole from the late 60's and early
> 70's. Their ads claimed that they were used by the army and state
> department. Maybe they were part of the evacuation kit, of a backup
> antenna for the attic. I built a Slinky Dipole for my attic. Two
> slinkys, and a 1:1 Radioworks balun. It is resonant at about 7.5 MHz.
> With a tuner, it will load on 80 meters, but it is about 12-15 deb down
> from my outside 80 m dipole.
>
>
> 73,
>
> Bob WB2VUF
>
73, Jerry, K0CQ
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