[amsat-bb] "Reverse" bias-tee ??

Scott scott23192 at gmail.com
Sun Nov 26 20:02:39 UTC 2017

Hi everyone.

The schematic makes me think "yes", but I wanted to check before making a

Normally a bias-tee is used to inject a DC voltage onto your coax to power
a pre-amp.  Since some pre-amps aren't powered off the coax, but rather
from a separate pair of pins, I was wondering if you can use a bias-tee AT
THE PRE-AMP to extract the DC voltage off our coax for connection to those
external power pins on the pre-amp?

Running a separate cable to power the pre-amp is not the end of the world,
but it would be convenient if I could turn on the bias voltage available on
the Airspy or RTL-SDR and then extract it up at the antenna to power a

Thanks for any recommendations!

-Scott,  K4KDR

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