Test of TBA-1a Transmitter Including Comparative Tests of TBA Transmitter
[Technical Report, Other]
NAVAL RESEARCH LAB
Pagination or Media Count:
The object of the tests was to determine the relative merits of the Model T.B.A. equipment functioning as a crystal controlled transmitter and the Model T.B.A.-1A equipment, non-crystal controlled also to determine the relative performance of the Model T.B.A. equipment functioning without crystal control provision for self-excited operation having been incorporated as an emergency feature and the Model T.B.A.-1A which was designed expressly for operation without crystals. Recommendations - In view of the results obtained during the tests of the T.B.A.-1a equipment, it is believed that a complete re-design of the frequency establishing circuit is indicated. The inherent mechanical weakness of the entire Master Oscillator stage together with uncertain contacts at the supply voltage terminals and the lack of proper control in ambients above 30 deg centigrade C constitutes an assembly which is not suitable for use in the Naval Service. Further it is suggested that in crystal controlled transmitters such as the T.B.A. the maximum frequency drift specified should not exceed .005 percent. The present specification figure of .01 percent is believed to be too liberal. In but two cases out of eight tests on the T.B.A. transmitter did the frequency drift exceed .0019 percent and in both of these tests the thermostat had lost control in an ambient temperature of 43 deg C.
- Electrical and Electronic Equipment
- Test Facilities, Equipment and Methods
- Radio Communications