On Thu, Jun 17, 2004 at 08:02:25PM -0500, Stuart Rohre wrote: > The use of the conversion from 5 MHz VFO is indeed how the USB vs. LSB > convention got started. With 9 MHz IF you got 4.0 MHz (80M) and 20M, (14 > MHz.) 9 -5 in one case, 9+5 in the other, with opposite Sidebands. > > The first use of such was probably the Central Electronics or similar tube > transmitters in the early SSB days of the 1950's.
Ah, memories! > In 1967, I had my electronics class, that I taught in 9M2 land, build a > transistorized transmitter using the dual band scheme from "The Transistor > Radio Handbook" by Les Earnshaw, ZL1AAX, who later came to USA and founded > Kachina Communications, of the first PC radio fame. > > This is a neat way to get two bands from one VFO and common components of > the times. Only partially true. If the 9 MHz IF generates USB, then subtracting the 5 MHz VFO would give 4 MHz but it would still be USB (subtracting the IF from the VFO frequency would invert the sideband, however). The Central Electronics transmitters used the phasing method of generating SSB, so it was relatively easy to switch between USB and LSB (compared to using filters). 73, Bob N7XY _______________________________________________ Elecraft mailing list Post to: [email protected] http://mailman.qth.net/mailman/listinfo/elecraft You must subscribe to post. Subscriber Info (Addr. Change, Unsub etc): http://mailman.qth.net/subscribers.htm Elecraft page: http://www.elecraft.com
