Re: a simple spur fix




You give the number of turns necessary, and the core IDs, but what is the gauge of wire used???


David A Posthuma, WD8PUO

1 (616) 283-7703


From: <> On Behalf Of Ashhar Farhan
Sent: Friday, November 09, 2018 10:35 AM
Subject: [BITX20] a simple spur fix


so, there is one spur fix that is now consistently working for me.

among rhe solutions, i was looking for one that would be easy to apply.

first, the distortion in the 45 mhz amp is creating harmonic distortion. so a 0.3uh in series with a 10 pf is used across TP13 (output of the 45 MHz IF amp going to the front end mixer). 8 turns on T30-6 gives you 300nh.

second, there is a cross talk inside the Si5351 where the 12 mhz from the bfo leaks into the local oscillator. A 5uh in series with a 47 pf across C202 of the LPF will suppress it. 35 turns on T30-6 gives you 5uh.

- f


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