[Boatanchors] [Swan] SWAN 250C six meter rig question

[N4ch at aol.com]

Hello All,
 
Regarding the query about the Swan 250's VFO  frequency:   The "original" 
Swan 250 had an IF at 10.7 MHz, and  was single conversion.   The injection 
was low side, meaning  that for 50.0 MHz operation, the VFO injection was at 
39.3 MHz.    The VFO itself ran at one third of this frequency (subsequent 
tuned circuitry  picked off the third harmonic of the VFO itself), meaning 
that at a transceive  frequency of 50.0 MHz, the VFO itself was running on 
13.1 MHz.    There's some info on all this in a product review of the Swan 250 
in the July,  1967 issue of CQ Magazine.   There's also a similar write-up 
of the  subsequent 250-C in another CQ review; see the August, 1969 issue for 
 that.   Also note that in the later 250-C there was another important  
change (besides the obvious receiver front-end changes, mechanical dial  
"bandset" for the VFO, addition of the meter's receiver "S" meter function,  
etc.).........the 250-C's IF got moved to 10.9 MHz instead of the original  10.7. 
  This means that in the 250-C, the VFO injection is 200 KHz  lower than it 
was in the 250 (at Fo = 50.0 MHz, the injection is at 39.1 MHz,  which 
means that the VFO itself is running at 13.033333 MHz now).    ALL the Swan 
tube-type rigs (350, 500, 700, the 250 series, all the  "Cygnets", etc.) 
remained single-conversion; the VFO injection was always either  above or below the 
IF, with the difference always being the IF frequency  itself.
 
73, Herman, N4CH.