[eagle] Re: 70 cm Receiver - Replacing U8 made no difference
John B. Stephensen
kd6ozh at comcast.net
Wed Jun 6 09:01:29 PDT 2007
That matching network has the largest impedance transformation so it may be that it is not accurate enough. I'm looking onto changing the second mixer to something that will consume less power and a mixer with an input impedance closer to 200 ohms might solve this problem. I'm considering moving the RF amplifier and first mixer to a separate box so that we can keep the SAW filters warm (at least -30 C) during eclipses.
----- Original Message -----
From: Juan Rivera
To: John B. Stephensen
Cc: 'EAGLE' ; Bill Ress ; Dave Black (Home) ; Dave Black (Work) ; Dave hartzell ; David Smith ; Don Ferguson ; Juan. Rivera (Home) ; Juan.Rivera (Work) ; Samsonoff at Mac. Com
Sent: Tuesday, June 05, 2007 02:56 UTC
Subject: 70 cm Receiver - Replacing U8 made no difference
Changing the second Mixer, U8 had no affect on the passband ripple. We've now replaced the matching network and the mixer with no change at all. What do you suggest for the next move?
Please see the Eagle Receiver page http://www.amsat.org/amsat-new/eagle/EaglePedia/index.php/U-Band_Receiver
Under Project Status I've started a new log titled Troubleshooting Resumes. It has before and after pictures of the passband ripple
Juan - WA6HTP
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