[amsat-bb] Re: bias tee circuits and components for 2.4 GHzdownconverter

kc6uqh kc6uqh at cox.net
Sun May 11 19:36:31 PDT 2008

Anything over 0.5 uH should work well, suggest you use 1.5 feet of # 28 to 
#36 enameled wire from an old transformer on a 1/2 watt carbon resistor 10K 
or larger. Put some of your Wife's fingernail polish on it to hold the wire 
in place. A small flame will burn the enamel off the ends of the wire and 
clean the soot of with a pen knife or sandpaper,  wrap and solder the ends 
of the wire to the resistor leads. Use a quality small ceramic capacitor 220 
pF to 1000 pf as a blocking capacitor, keep leads very short.

----- Original Message ----- 
From: "Michael Tondee" <mat_62 at netcommander.com>
To: "amsat-bb" <amsat-bb at amsat.org>
Sent: Sunday, May 11, 2008 10:01 AM
Subject: [amsat-bb] bias tee circuits and components for 2.4 

>I have a  Pacific Monolithics surplus MMDS downconverter here that I would 
>like to get up and running on S-band. It has an 122 MHz IF and I want to 
>whip up a bias -tee to power it. I've looked at the circuits in the 
>Satellite Experimeters handbook and my problem is finding an rf choke of 
>the right value that is readily available in my area. Shouldn't I be able 
>to just wind  something with an air core out of magnet wire or something 
>similar that will do the trick? According to the circuit I have I'd need 
>about a 1.5 uh choke for 146 Mhz and it isn't critical so that's probably 
>close enough for my downconverters IF frequency. I hate to spend shipping 
>charges to get one little choke or ferrite core for winding a choke on 
>here. Most places have a minimum order and I don't need anything else at 
>this time. I'd also welcome links to any other circuits that might be out 
> Thanks,
> Michael, W4HIJ
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