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Re: the cause for the spurs, found!

 

allison,

i tried with just a regular 2n2222a in place of the 2n3904 (as per your recommedation). instead of the 220 ohm collector load, i used a bifilar transformern with the center tap going to the final mixer. here are the results :
(even with the 2n2222a, the performance is acceptable)

On Sun, 4 Nov 2018, 02:47 ajparent1/KB1GMX <kb1gmx@... wrote:
Great you found the likely cause of the 2IF spur.

Now why is the 45mhz IF distorting?

Two things, it needs to be clean to at least -6 or so DBM and how much gain is needed to
get to that from the ouput of the 45mhz crystal filter.

I'd suggest starting with transistors that actually have performance at 45mhz.

Allison

IMG_20181031_134930.jpg
IMG_20181031_134909.jpg

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