Telamon wrote:

1. DC voltage. (DC input) This is connected to the power supply.
2. AC voltage. (RF output) This is connected to the radio.
3. DC + AC voltage. (RF input, DC output) This is connected to the
antenna/amplifier.

Port 3 to 2 is connected with a capacitor of very low reactance (zero)
to the signal you want to pass through these two ports.

Port 1 to 3 are connect with an inductor, which passes DC voltage from
port 1 to 3 but blocks RF (high Z) going from 3 to 1 so the RF only sees
a path from 3 to 2.

Port 3 and 2 are coax cable and port one could be two terminals. One
terminal is common grounded with the coax shield grounds. Using a ground
independent power supply to the terminals on port 1 allow you to have
either a positive or negative power supply to the remote amplifier.

--
Telamon
Ventura, California

It is clear you work in the microwave satellite part of electronics.

In the "good old days", circa 1990, most text and other refference
sources
reffered to them as "power injectors" or "diplexers". Your discription
of it's
function is correct. A power source is isolated from the RF with an
inductor,
or strip line version, and a capacitor blocks the DC from the receiver.

MiniCircuits has very nice, as in wide band, inductors. Since I may use
the same coax for VLF. LF, MW, HF, or VHF my power inject, bias
"T" or diplexer has different inductors in series because I couldn't
find
a single inductor to cover from 10KHz through ~500MHz. I found that by
using smaller chokes that were effective at UHF, with larger chokes for
each decade decrease in frequency. One of the changes I am making
is to use the MC wide band inductors to allow a smaller package to
be used. Space is at a premium in my "shack".

My shack is the 2nd bath with the plumbing removed and covered.
It is 5' by 10'. I prefer the word cozy over cramped.

Terry