Instruction manual

VLF1 • 5
Take a quick look at the schematic. The low frequency signal from your
antenna is fed into J1. It passes through a low-pass filter made up of L1, L2,
L3,C1,C2,C3, and C4. The signal then passes through transformer T1 which
produces 2 identical copies of the original signal, with one being inverted.
Next is the magic step that creates the high frequency signal for your
receiver. The 4053 analog switch alternately switches between the input
signal and its inverted version at a frequency of 4MHz. This 4MHz comes
from the crystal oscillator made up of the 7404 and its support components.
The result of this switching is to produce a 4MHz version of your input signal!
That’s it, after being amplified by Q1; this signal comes out of J2 and on to
your receiver.
RAMSEY Learn-As-You-Build KIT ASSEMBLY
There are numerous solder connections on the VLF1 printed circuit board.
Therefore, PLEASE take us seriously when we say that good soldering is
essential to the proper operation of your transmitter!
• Use a 25-watt soldering pencil with a clean, sharp tip.
• Use only rosin-core solder intended for electronics use.
• Use bright lighting, a magnifying lamp or bench-style magnifier may
be helpful.
• Do your work in stages, taking breaks to check your work. Carefully
brush away wire cuttings so they don't lodge between solder
connections.
We have a two-fold "strategy" for the order of the following kit assembly
steps. First, we install parts in physical relationship to each other, so there's
minimal chance of inserting wires into wrong holes. Second, whenever
possible, we install in an order that fits our "Learn-As-You Build" Kit building
philosophy. This entails describing the circuit that you are building instead of
just blindly installing components. We hope that this will not only make
assembly of our kits easier, but help you to understand the circuit you’re
constructing.
For each part, our word "Install" always means these steps:
1. Pick the correct part value to start with.
2. Insert it into the correct PC board location.
3. Orient it correctly, follow the PC board drawing and the written
directions for all parts - especially when there's a right way
and a wrong way to solder it in. (Diode bands, electrolytic