Ramsey Electronics PM10DC, Руководство пользователя

Страница: 22 / 40

PM10DC
y
22
ASSEMBLY (DIRECTIONAL COUPLER)
We are now going to build the directional coupler transformer. This is the part
that does all of the work for us. The binocular core is made of a special mag-
netic material which is good up to very high frequencies and can handle a
fairly strong magnetic field without saturating.
The key to building this part for best performance is patience and accuracy.
For best directivity the part should be built in a complete mirror image on ei-
ther side of the binocular core. This is quite difficult and performance relies on
how well you put this together. We provide enough wire to make two of these,
just in case you mess up. Just follow our steps and you shouldn’t have any
problems. Bless your luck and buy a lotto ticket if you get it right the first time
around!
ˆ 1. Cut two 1 1/8” pieces from the #16 bus wire.
ˆ 2. Using small needle nose pliers, bend each wire using the pattern
above. Try to get the bend dimensions as close as possible, and keep
bends nice and square (as possible), and the wires nice and straight. Use
the pattern above for actual size. Hold your wires up against this to verify
dimensions.
ˆ 3. Cut off a 12” section of the thin magnet wire. We will wind 6 turns of
this wire through one outside section of the binocular core as shown.
Turns in binocular cores are defined by how many times the wire passes
through the hole, not complete turns. Leave 1 1/2” of extra wire on each
end. Try to keep the windings side-by-side, and not crossed over each
other. This prevents strange coupling effects at higher frequencies. Ideally
we want the windings to be as close to each other as possible, and all to
one side of the core.
ˆ 4. To make it easier to wind the second half without messing up the first
half, use a small piece of scotch tape to hold the windings in place, mak-
ing sure to tape down the ends so they don’t dangle and get in the way.