|[AMRadio] Smoothing Choke|
ltaft at charter.net
Thu May 4 12:40:14 EDT 2006
Typical values for a Gates BC-1G 1 KW broadcast transmitter 2500 VDC
supply are 5-15 hy at 1 amp swinging choke with 8 uf filter cap. The
load is 500 ma continuous for the class C final ( 2 833s in parallel)
plus another 500 ma variable for the class B modulator ( 2 833s in
push-pull). The audio frequency response is speced at 30 to 12,000
cycles per second. The broadcast people used a single supply with the
final acting as a fixed minimum load to get around the filter resonance
problem at low frequencies.
Collins also used a cap across a choke for parallel resonance. For the
20V3 there is a 10 hy choke with a 0.08 uf cap across it in parallel to
a second 10 hy choke (no cap) to an 8 uf cap to ground. Again, the
final is a fixed load for the single supply. Tubes are 4-400s.
Audio speced at 50 to 10,000 cycles per second.
Old technology. Still good as long as the limits are understood.
Jim candela wrote:
> I understand your feel for the nostalgia, and passion for pursuing it.
> All of us more or less on this group have some common ground here.
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