Technical Discussion : USSR (Russian) SW transmitters never sold to West ...
>From what I can gather, high power SW transmitters in the USSR were all based on 'Class B' (push-pull) amplification schemes. Class B amplifiers (for AM modulation) max out at around 60% efficiency. Most 100 kW transmitters in the west (due to the 1970s energy crisis) long moved over to PDM, PSM or a combination of the two schemes used by Thales. The transmitter size was never an issue either -- the transmitters seem to be about 2 or 3 times the cubic volume of their western equivalents. Most of the transmitters lacked anything like the fully programmable automation that became a standard feature in the 1980s. RNZI and several SW relay sites are unstaffed or minimally staffed due to transmitter automation. The USSR pioneered the use of HRS 8 / 8 / 1 curtain arrays, where the west seems to have settled on HRS 6 / 4 / 1 (HRS 12 / 4 / 1 is used by VOA) and HRS 8 / 4 / 1 for directive broadcasting. Yet, I do not expect the Russian SW transmitters to ever be sold in the west. China may innovate here -- myself I have been expecting the Chinese to unvail a HRS 6 / 4 / 1 ALLISS like shortwave transmitter system that is 500 kW capable. I expect the design to be tubeless, period. The west has begun to ditch tube base transmitters on MW and LW (and FM too). The module based amplifier system is not hard to design, and only slightly bulkier (in cubic volume) than tube transmitters. There are enough Chinese EEs to devise such a transmitter system. China does actually need such a transmitter system like ALLISS, as it can aid in jamming. ---[Start Commercial]--------------------- World Radio TV Handbook 2003 is out! Order it now! http://www.amazon.com/exec/obidos/ASIN/0823059677/hardcoredxcom ---[End Commercial]----------------------- ________________________________________ Hard-Core-DX mailing list [EMAIL PROTECTED] http://dallas.hard-core-dx.com/mailman/listinfo/hard-core-dx http://www.hard-core-dx.com/ _______________________________________________ THE INFORMATION IN THIS ARTICLE IS FREE. It may be copied, distributed and/or modified under the conditions set down in the Design Science License published by Michael Stutz at http://dsl.org/copyleft/dsl.txt