Attached
A new high power r.f. pulse transmitter was developed
for ionospheric absorption measurements using vertical incidence
pulse technique. Since the emphasis was to explore the 0 region
it was designed to operate over the frequency range 1.8 MHz to
2.2 MHz. The target output power of the transmitter was 50 kW (rms)
while the tested mexlrmm power was 44 kW.
The absorption measurements were taken daily during a
period of one month on two frequencies, 2.0 MHz and 2.2 MHz. The
average noon absorption measured was 62.3 dB for 2.0 MHz and 57.9
for 2.2 MHz. In additionJ the average virtual height was 99.3 km
for 2.0 MHz and 100.9 km for 2.2 MHz. The present series of
~servations made using the new r.f. pulse transmitter is in good
agreement with the earlier measurements taken in Colombo during
the pe~iod of 1964 to 1970 under similar solar conditions.
