These are photos of my rack mount preselector. It's where I test all the latest refinements, newer circuit components,
and design improvements.
The circuits of the tuner and preselector have changed over the past few years as I've learned more about "raw RF
signal processing" through trial and error ... and actual usage.
This first image is of the entire
system consisting of 3 rack panels.
You can blow up the images by
right-clicking the photo, select
<save image as> and view it in
your own picture viewer or browser.
The panels are 1/8" aluminum,
primed and painted with beige
lacquer. Then the rub-on letters
were applied (get them at the art
store), and finally, several (very
light) coats of clear top-coat were
applied for protection.
No, there's nothing wrong with your
monitor screen. The panels are
quite dirty (okay, I appologize for
that) from all the on-going work I've
been doing, but water and soap
will fix that.
The second pic is a close up of the
left side ... likewise the third pic ...
is the right side.
On the previous page, page 2, is a
photo of the tabletop preselector. It
is just a simplified version of the
rack mount version shown here.
The preamp is just a low noise
device which has variously been a
MMIC or JFET transistor. The
actual device is a matter of choice,
but I opted for something that
would be low noise and provide
about 15-20 dB of gain (check out
Ramsey Kits for their very
inexpensive broadband preamp).
The gain control is active with, or
without, the amplifier in-circuit. This
arrangement allows it to act as an
RF Gain control when the preamp
The R&D model: Preselector Type-1