[TowerTalk] Help in ID'ing an unusual antenna spotted....

[Tom Anderson]

Ron:

The log periodic in the photo is very similar to the one at the Denton 
TX (30 mi north of Dallas/Fort Worth)regional FEMA installation.  Only 
difference is the elements on each leg of the V-shape are straight and 
don't have the interconnecting aluminum in the S shape as the one in 
Hawaii.  The Denton FEMA southwest regional office is more underground 
than above ground, something like 2-3 floors are below ground.  The only 
way you'd know it was some type of govt. installation is 1. the high 
fence with concertina wire across the top, 2. the sign that says FEMA, 
and 3. the antennas, plus 4. the guard shacks. Its just a big mound of 
dirt above ground.  Of course it sits next to the Texas Department of 
Public Safety's (state police) area office.  I've been invited to tour 
the place before as a RACES member, but never had a chance yet to 
schedule a tour, although I've driven by it many, many times. Often 
wished I had that log periodic when trying to work a rare DXpedition hi hi.

I also understand that the Denton FEMA office has a number of vertical 
HF/VHF antennas that are in underground protected "tubes" and can be 
raised or lowered when needed.  However, all I've ever seen are the 
antennas that are permanently installed above ground since I don't get 
to Denton that often.

With the heavy rains and flooding we've had in North Texas the past 
several days I'm sure the FEMA offices have been busy.

73 de Tom, WW5L
Tarrant County RACES and storm chaser volunteer



Ron Hashiro wrote:
> A couple of weeks ago, we were in Hawaii for the first time, and  visiting 
> the famous "Diamondhead" Crater on the edge of Honolulu. 
>  
>   There is a military installation inside the crater, and the main  tourist 
> attraction is to climb the inside of the crater to the old military  bunkers 
> that are built along the rim of the crater overlooking the ocean and  Honolulu.
> 
> <snip>
> 
>   Just thought I would throw it out for any info or if anyone had ever  been 
> assigned to that Diamondhead installation.
>  
>   73
>  
>   Bob   _ww4t at aol.com_ (mailto:ww4t at aol.com
> 
> 
> -------------
> 
> Bob,
> 
> That installation is the log periodic HF antenna used by Hawaii State 
> Civil Defense for its HF communications with FEMA.  The equipment is 
> tied to Harris ALE HF equipment, in a EMP-proof vault.  The vault is 
> located within the Emergency Operating Center, which is a converted 
> World War I artilery ammo bunker.  On your visit, you saw the gun 
> emplacements along the shore side of Diamond Head crater, and there are 
> some other old gun emplacements on the ridge line opposite -- towards 
> the mountain ridge.
> 
> http://ronhashiro.htohananet.com/travel/d-head.html
> 
> If you look at the photo of the fish-eye lens, it would be on the far 
> side of the crater.
> 
> I am the head of State CD RACES, and our operating position for HF and 
> VHF/UHF voice is along side the HF vault.
> 
> http://ronhashiro.htohananet.com/am-radio/hawaii/scd.html
> 
> That log periodic is unusual, in the sense that it is not just a flat LP 
> antenna like most installations.  There is an LP on the top, angled 
> down, and an LP on the bottom, angled up.  They meet at a vertex.  I'm 
> not 100% sure of that particular design.  My understanding was that it 
> was salvaged and reused from a military radio station.
> 
> The antenna sits on a tower, with a rotator.  I'm not positive if its 
> sitting on a thrust bearing.
> 
> You can see a similar antenna at this site.  It appears to be a Collins 
> antenna.
> 
> http://jproc.ca/rrp/inuvik.html
> 
> Hope this helps.  Thanks to Kimo, KH7U for notifying me of this posting.
> 
> Ron Hashiro, AH6RH
> Honolulu, HI
> 
> _______________________________________________
> 
> 
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