[Heathkit] help needed

[Jim Shorney]

On Sat, 15 Dec 2007 09:06:49 -0800, Edward B Richards wrote:

>Can someone guide me to where I can find information on a simple
>resistive splitter/combiner? I want to split the output of a video camera
>two ways, one to a monitor and one to the modulator for ATV. Everything
>is 75 ohms. I can't find it in the ARRL handbook. Thank you.

There are several considerations here. Are the monitor and the modulator both
actually 75-ohm resistive loads, or do they just have a 75 ohm connector? Can
either be reconfigured for high imedance? Does the monitor have loop-through
capability? 

If your modulator has a monitor output, it's easy; I'm assuming that it
doesn't, or you wouldn't be asking the question.

A resistive splitter will incur loss that you may or may not be able to
recover with gain in the monitor and/or modulator. If the monitor has
pass-through capability and can be configured for high impedance, you're set.
Loop the video through the monitor and put the modulator at the end of the
line. If the modulator can be configured for high impedance, use a "T"
connector to pick off video for the modulator and put the monitor at the end
of the line. If neither scenario works for you, this handy little circuit
from the computer world can be scaled down to a single line of video with two
(or more) outputs:

http://www.anatekcorp.com/driving.htm


--
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