About Us

Telamon · October 1st 06, 05:22 AM posted to rec.radio.shortwave

In article .com,
wrote:

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.

Most broadband bias-Ts have several inductors in series. At the RF line
you start with the smallest value inductor and work your way up to
larger values. With several inductors in series you might run into some
problems with the inductors ringing so you may need to have resistors
across some of the larger inductors. Since you are only interested in DC
on the bias port and not modulating the carrier from that bias port you
should be able to do it. You may manage to do it with two inductors in
series and so not have any problems with ringing.

--
Telamon
Ventura, California

Thread Tools	Search this Thread
Show Printable Version	Search this Thread: Advanced Search
Display Modes
Switch to Linear Mode Switch to Hybrid Mode Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
New odd question	jawod	Antenna	5	September 11th 06 06:02 PM
Wellbrook ALA 100 with Rotator - Construction Details	Guy Atkins	Antenna	4	July 23rd 06 07:49 PM
Wellbrook ALA 100 with Rotator - Construction Details	Guy Atkins	Homebrew	4	July 23rd 06 07:49 PM
Wellbrook ALA 100 with Rotator - Construction Details	Guy Atkins	Shortwave	4	July 23rd 06 07:49 PM
Wellbrook Antenna Arrives	Jay	Shortwave	1	December 10th 05 05:16 PM

Menu

About Us