FIGURE 7-14. Hypothetical Six-circuit Network Controlled by Three Sounded Paths.

TM 11-5820-917-13

FIGURE 7-14. Hypothetical Six-circuit Network Controlled by

Three Sounded Paths.

represent over-land paths, but because path 5-R is slightly shorter, F-mode

frequencies propagating well on that path should also be propagating well on 4-R

Path 6-R should also provide an upper bound on F-mode

most hours of the day.

frequencies for 4-R. Es conditions on 4-R, 5-R, and 6-R can vary substantially,

however.

d. Establish the time reference of the Chirp sounder network carefully. Decide

which path will be "Path 1" on the RCS-4B, and establish its Chirp sounder sweep

start time (e.g. on-the-hour, 1 minute after the hour, etc) relative to an agreed

time reference (e.g. a time standard or synchronized watches). There will be less

confusion if Paths 2 and 3 are set for sweep start times after Path 1. The start

times should be separated by at least 5 seconds, but all should begin within a 20-

second interval. When setting up the RCS-4B, it is advisable to start the Path 1

clock as soon as possible as it should then provide the most accurate time reference

for synchronization.

e. Automatic Chirpsounder synchronization will be accomplished the easiest

by using the full 100-watt output power of the TCS-4B and attempting synchroniza-

tion during daylight hours. If all path lengths are under 200 km, setting sweep

limits of 2-16 MHz should also increase probability of successful automatic signal

acquisition and synchronization. Remember that all TCS-4B's being received by

one RCS-4B must use the same sweep limits.