Pixie 2 freq change question
 

Greetings,
I have been planning to mod my pixie 2 as to switch between multiple
xtals/inductors for changing between 80/40/20 etc...

I was going to use a rotary switch to change to the different inductor and
xtal, depending on the selected band. However, I realize that the inductors
will be about 2 inches from the main board since it will be wired into the
rotary switch. Will this additional wiring greatly change my inductance? I
assumed that it would, but I wanted some more experienced opinions.

Thanks...

James Shrum
KC9FFX

I was going to use a rotary switch to change to the different inductor and
xtal, depending on the selected band. However, I realize that the inductors
will be about 2 inches from the main board since it will be wired into the
rotary switch

James-

At these frequencies the difference in inductance will probably require a
slightly different capacitor setting, but that shouldn't be a problem.

I would be more concerned about coupling of energy from the coils back into a
circuit at an earlier stage, such as to the crystals. This might result in an
unexpected oscillation at some frequency other than intended, in addition to
the intended frequency. If that occurred, there would be mixing of the two
frequencies, generating sums and differences of the fundamentals and their
harmonics.

You might consider two separate switches for inductors and crystals, keeping
them separated as much as possible. Otherwise, look for a multiple-wafer
switch with a LONG shaft to separate the wafers.

73, Fred, K4DII
(My amplifiers oscillate, but my oscillators don't!)

I was going to use a rotary switch to change to the different inductor and
xtal, depending on the selected band. However, I realize that the inductors
will be about 2 inches from the main board since it will be wired into the
rotary switch

James-

At these frequencies the difference in inductance will probably require a
slightly different capacitor setting, but that shouldn't be a problem.

I would be more concerned about coupling of energy from the coils back into a
circuit at an earlier stage, such as to the crystals. This might result in an
unexpected oscillation at some frequency other than intended, in addition to
the intended frequency. If that occurred, there would be mixing of the two
frequencies, generating sums and differences of the fundamentals and their
harmonics.

You might consider two separate switches for inductors and crystals, keeping
them separated as much as possible. Otherwise, look for a multiple-wafer
switch with a LONG shaft to separate the wafers.

73, Fred, K4DII
(My amplifiers oscillate, but my oscillators don't!)