[Milsurplus] "Vegetation Antenna"

[John Vendely]

These things were called "ADSIDs", for Air-Delivered Seismic Intrusion 
Detector, containing VHF transmitters which were air-dropped along the 
Ho Chi Minh trail to monitor enemy movements as part of the large, 
sophisticated, complex Igloo White program.   The systems were FM in the 
160 MHz range--sort of a terrestrial sonobuoy--with the antennas 
disguised to look like vegetation.  I suspect the frequency range was 
chosen so airborne sonobuoy receivers could be used.  EC-121 (Lockheed 
Constellation) aircraft with banks of receivers orbiting nearby relayed 
sensor data to a large processing center in Thailand where the data was 
fed to large IBM mainframes.   Attack aircraft were then dispatched to 
the trail according to patterns of sensor hits.

Harris Corporation made the Igloo White sensor RF modules, and there was 
a display case with Igloo White components down the hall from my office 
there, its purpose now largely forgotten.

There were also acoustic sensors called ACOUSIDs, and even seismic 
sensors made to look like bits of dog excrement known as--you guessed 
it--TURDSIDs.   A friend of mine got some of these in the late 70s as 
surplus and we decided to dissect one and test them.  The internal 
mercury button cells on some were still good, and when shaken 
vigorously, they would send out bursts of RF...

73,

John K9WT

On 12/26/2022 7:23 PM, Hubert Miller wrote:
>
> I can’t locate the emails right now, but there was recently some 
> discussion of ‘vegetation – looking antennas’.
>
> Here’s a scan from an article in ‘Vietnam’ magazine, December 2018.
>
> -Hue Miller
>
>
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