Re: LPF kit for ubitx v3

jim
 

Just a FYI I made some measurements of CLK0 and put a simple LPF on the raduino board to cut some of the 'cruft'

Jim

On Saturday, February 9, 2019, 10:08:40 AM PST, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:


As I have said previously, I have not made my own measurements of spurs with a spectrum analyzer.
I vaguely recall posts that verified Raj's solution of replacing L5,L7, though a quick look at a couple threads didn't find any.
Anybody out there who has done a thorough check for spurs after replacing L5,L7 on a stock rig?

I have my doubts in that I can't understand how swapping L5,L7 would clean up
the 90mhz harmonic in the 45mhz IF amp, or the 12mhz crosstalk from CLK0 into CLK1.
Seems replacing L5, L7 would mostly reduce coupling from the power amp back into the 45mhz IF.
But defer to those who have taken the time to make measurements.

And would prefer to recommend only the easiest, least error prone fixes to the group.

Jerry


On Sat, Feb 9, 2019 at 05:17 AM, Curt wrote:
Jerry, I am not sure how you concluded that only the shielded inductors may be enough? 

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