[Elecraft] OT: HF discone

[donovanf at starpower.net]

Its a somewhat improved version of the Happy Accident Ground Plane 
in January 1957 QST 


http://p1k.arrl.org/pubs_archive/38955 


73 
Frank 
W3LPL 

----- Original Message -----

From: "Walter Underwood" <wunder at wunderwood.org> 
To: "Elecraft QTH.net List" <elecraft at mailman.qth.net> 
Sent: Friday, December 7, 2018 11:45:37 PM 
Subject: Re: [Elecraft] OT: HF discone 

The lower element is a cone, but I think the analysis for the discone is pretty different. At least, that’s what I understood from the L. E. Cebik article. 

The WWV antennas don’t need to be wideband, because they have one for each frequency. 

"The WWV antennas are half-wave vertical antennas that radiate omnidirectional patterns. There are antennas at the station site for each frequency. Each antenna is connected to a single transmitter using a rigid coaxial line, and the site is designed so that no two coaxial lines cross. Each antenna is mounted on a tower that is approximately one half-wavelength tall. The tallest tower, for 2.5 MHz, is about 60 m tall. The shortest tower, for 20 MHz, is about 7.5 m tall. The top half of each antenna is a quarter-wavelength radiating element. The bottom half of each antenna consists of nine quarter-wavelength wires that connect to the center of the tower and slope downwards to the ground at a 45 degree angle. This sloping skirt functions as the lower half of the radiating system and also guys the antenna.” 

https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwv <https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwv> 

wunder 
K6WRU 
Walter Underwood 
CM87wj 
http://observer.wunderwood.org/ (my blog) 

> On Dec 7, 2018, at 3:02 PM, Fred Jensen <k6dgw at foothill.net> wrote: 
> 
> I think one or more of the WWV antennas in Ft. Collins are semi-discone designs with the guy cables acting as the skirt. 
> 
> 73, 
> Fred ["Skip"] K6DGW 
> Sparks NV DM09dn 
> Washoe County 
> 
> On 12/7/2018 2:43 PM, Ken G Kopp wrote: 
>> There is/was an HF discone at a missle silo in Southern AZ that has/had a 
>> coax cable available for public use. Just drive up and connect your mobile 
>> rig. (:-)) 
>> 
>> There's another for HF use at the FAA aircraft control center in SLC. 
>> 
>> 
> 
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