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Project 6.€ - Electromagnetic Attenuation Measurements - T.D. Hanscome
OBJ FCTIVE
To make electromagnetic attenuation measurements as a function
of time at S-band (2160 MC) and X-band (94CO MC).
PROCEDURE
Equipment used at this shot consisted of a transmitter installed
at approximately 5N00' from the tower on a line to the receiver in a
tower on Parry.
The receiver output was delayed 2 microseconds and
lisplayed on oscilloscopes having sweep speed of 5 microseconds per
centimeter, 50 microseconds per centimeter, 290 microseconds per centimeter and on a Brush recorder (resolving time 10 milliseconds).
Sweeps were triggered by "blue box" signels.
One receiving antenna
was aimed at the shot tower to observe direct electromagnetic effect,
The receiver scope on this system was swept at 5 microseconds per centimeter,
.
RESULTS
Electromagnetic Effect
The channel directed to this effect operated.
No direct electro-
magnetic effect was observed during the first 50 microseconds.
The
upper limit of electromagnetic effect is about 115 db below 1 watt at
the receiver input (9375 MC, 40 db antenna gain, 10 MC band width).
9450 MC Transmission Path
The channel devoted to attenuation at 9450 MC operated success-
fully: Preliminary indications are that the attenuation at this distance
(calculated for 10? electrons per cc produced by prompt gamma rays) is
in the order of 15 db.
The recovery was fast and the signal level was
adequate for telemetering use after approximately 10 microseconds.
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