Rick Disney wrote:

Greetings ,

Got my hands on a Heathkit HW-101..It's low preset is 3.5 and the center
tuner only
adds 500 hz...Navy Mars operates at 4470.5. ..Any help?


Easiest would be to move the 3.5 - 4.0 band up to
say 4.2 - 4.7, but you would have to sacrifice
the original band.

You might be able to switch components the "pad" the
existing components in and out to get both the ham
band and Mars.

Start with getting the manual and schematic from:
http://bama.sbc.edu/heath.htm

Examine the schematic and rig to determine which
coils/capacitors are switched in for the 80 and
40 meter bands. You'll see that the circuit is the
same for each band, but the values of the components
are different. Remember to do this both for the
transmitter and receiver portions of the transceiver.

Once you have a firm understanding of how Heath
switches from one band to the other, you will be
able to "functionally" design (specify what components
to use, and where they need to go in the circuit, but
no component values determined yet) for your new band,
which should start at something like 4.2 or 4.3 mHz.

The manual probably has a theory of operations or
circuit description section which will help you
to understand those circuits.

Next, you establish component values that will make
your new circuit work at the design frequency -
4.2 or 4.3 mHz.

Next, determine how you can incorporate the new
components into the rig. Are you willing to give up
the 3.5 - 4.0 range, or any other band? Can you
add a switch to switch in new components, such that
you don't have to give up any existing band?
Essentially, you need to figure out whether major
surgery is required, and whether you are willing to
do it.

73's

Rick KAØDIZ