Chapter 7
RAD IO~FREQCENCY ATTOCATION
7-1
EXPERIMENTAL PLANNING AND ISSTREMENTATION
Several missile and antimissile systems depend wholly upon radio-frequency
transaission for guidacce.
Considerable concern has therefore been expressed
en the effects that very high-slritude quclear detonations might have on such
traospission.
Radio-frequency signals undoubtedly suffer severe attemustion
in the highly ionized ataosphere containing a ouclear explosion.
Apparent
shifts in phase of che transmitted signal because of refraction could conceivably resule.
Radio-frequency effects studies were undertaken by Sandia
Corporation in an attempt to measure these effects as a functionof distance,
frequency, and time.
The Sandia efrort was begun at the request of the DOD in
December 1957, only four months before the scheduled Teak firing date.
7-1.1
Method of Measurement
Several methods for making the measurement had been considered.
The tech-
nique used was based on establishment of four transmitting starions so spaced
at altitude to enable receiving stations to look through the center of the
burst as well as through the fringe areas.
Each station io space consisted of
two missiles each of which carried a transaitter, ome operating at a frequency
of about 225 m, che other at a frequeacy of about 1500 ac.
stations were used.
Two receiving
Each housed eight receivers, four of which were high-
frequency and four low-frequency.
The output of each receiver, proportional
co signal strength of the received signal, was recorded on both paper and a3gnetic cape.
The 60-ke I-F of che low-frequency receivers was directly re-
corded on magnetic tape to perait detection of large variations in phase.
An
attespt to measure phase shifts of less than 100 cycles per second was made by
first oixing che 60-%c I-F with a stable and manually adjustable local oscilLatics Getuce recoraing on the paper oscillograph.
The range of attenuation
measurable by the celemetry system was calculated co be approxinately 35 db at
225 m and 40 db at 1500 2c.
al