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Did you ever have one of those weekends, home all alone with
a basswood box, some litz wire and a couple of variable capacitors? This is what
can happen! You have been warned!
Ok, so I am a crystal set junkie. Good thing that some of you buy
these from me or I would be crowded out of my little happy home. This set is
much like my #43 crystal clear crystal set. The coil form
is a little different. Winding information can be obtained on my
spider web coil page. Look for the table
near the bottom and pick the 164 microhenry coil. Any spider, rook, cylinder
or toroidal coil can be used. This coil is made with
165/46 litz wire.
The main feature of this set over some of my earlier ones are the
aforementioned variable capacitors. These are three section capacitors with
a total of 420 pf. The antenna capacitor is using one section, 170 pf. The
detector capacitor uses all three sections. These capacitors also have a nice
vernier built into them. I can turn the knob several turns to move the capacitor
plates from minimum to maximum. This will be helpful in tuning in those dx
stations.
The detector is the hobbydyne, with a high performance germanium
diode. A schottky diode would also work well here. The output is meant to drive
an audio matching transformer. This keeps the tank circuit from being loaded
down, and the sensitivity and selectivity at maximum. A 47k ohm resistor across
a crystal earphone will also work.
I mounted the coil slightly different on this set too. Since there
is a long tang on this coil form, I attached it to the back of the box. A single
label on the front tells what to connect where and which control is which.
Breaking my old time look tradition are those 1960's crazy knobs.
I don't think I have ever seen them used anywhere but I once had a lot of them.
I needed a knob with an 1/8 (3 mm) inch shaft.
73 and good crystal DX. Dave - N2DS
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