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On Thu, Nov 26, 2020 at 03:15 AM, Lawrance A. Schneider wrote:

I have version H0.3 . ?But again, the terminals are there so why not populated? ?My 75 year old eyes and hands will be having a hard time. ?Plus, I have 0 (zero) SMD caps.

Larry,
? ?There are other pads on the board that are unpopulated also.? Designers usually add areas like that for future features or increased performance.? The tinySA meets its specifications without the caps and most users won't even be bothered by the 48MHz harmonics which are greater than -80dBm.? For those users who have a need for slightly greater noise performance the caps offer a way of achieving that.

?All currently manufactured tinySA's are version 0.3, in later production runs it looks like the caps were added based on the feedback of early users.? Sometimes being an early adopter has its disadvantages.

?- Herb

Some more explanation:
The optimal value of the capacitors is a balance between the speed of the serial communication bus and the spurs the bus is creating.
The optimal capacitor values could only be decided after testing with a larger quantity of products by a broader set of users and this took some time as you can imagine.
Once the testing came to a conclusion we adapted the capacitors in production and I decided to publish the information on how buyers of the limited quantity early products could, if they felt the need, adapt their tinySA to have a bit? less spurs at the 48MHz harmonics.
If you are not bothered by the already fairly low level? of the 48MHz harmonics or find it difficult to add the tiny components I suggest not to add the capacitors as these harmonics can be easily recognized because they are on a 48MHz grid and have some FM modulation.

I thank both Herb and Erik for their prompt replies,

larry

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EA1AWY Javier Muriedas (Gijón, Asturias, Espa?a)