[Milsurplus] Low power DFing

[Ray Fantini]

Is it possible that the main reason for one or more stages of isolation
by RF amplifiers in radios of the period was not as much to prevent the
LO from leaking out as to provide better selectivity on a radio with a
low frequency IF, The second image of a receiver with a 455 Kc IF is
only 910 Kc away. not a lot for the old low Q systems of the time so you
get the improved image rejection by having multiple RF amps before the
mixer. Maybe all the shielding was to keep other signals out of the
receiver more then to keep people from receiving the LO?
Myself I have read many accounts and claims about tracking the LO, but
also know of accounts of aliens in area 51.
Some yeas back did some work with a research company and dealt a little
with the TV tracking thing and at that time we looked at the horizontal
phase ( 15.75 Kc) and compared it to a off air reference. the horizontal
stage of the television produces several watts of power and is poorly
shelled in comparison to the LO. Wonder if the British still try to
trace radio and TV use, think of the problems today with home computers,
PICS and microcontrolers in just about everything, still waiting to see
this billboard thing.
Ray Fantini KA3EKH