Re: Proposed fix for Harmonics Issue


Howard Fidel
 

John:
Thanks for your support. I am a true believer in the KISS principle. I have spent my professional engineering career putting out "fires" with simple elegant solutions and designing new products. Now in my "retirement" years (actually I still work part time, teaching) I have time to get back to a hobby I started in juniorĀ  high school that launched my career in medical electronics. It has been a lot of fun working on the uBitx, and it has exposed me to many engineering issues that I didn't face in the medical area. My plan from the beginning is to use it as a learning experience to launch my next project which will be a SDR transceiver. These harmonics and spur issues have been a distraction but also a great learning experience. It is great to see so many of us working on solutions.

Howard


On 8/12/2018 9:02 AM, John KC9OJV wrote:
Howard,

Your solution seems to be the "holy grail" elegant fix for this problem. Even if the board layout impedes the success of this idea it points to a version 5 modification that could be easily implemented in India. On another note, I don't have a lab grade spectrum analyzer but I do have a RF Explorer analyzer and I loosely coupled it yesterday looking at 40 and 20 meters. The harmonics were present and objectionable. I installed a contester's 6 band switchable bandpass system and the harmonics were sufficiently suppressed. Apparently external filtering is an effective interim solution. Thanks so much for the good thinking on this vexing trouble!

John
KC9OJV


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