How much better is the new antenna or amp? Use FT8 dB to see.

[admin]

Don't shoot the messenger; this isn't about the merits or otherwise of FT8, but all the same there is a lot of it about and it's a useful comparison tool.

Disclaimer: This is a scientifically really scruffy method, easy to refine and maybe better than nothing.

Your FT8 logs contain lists of contacts, each with a sent and received signal report in dB. The FT8 software tries to decode everyting down to its lower limit of usually -24 dB. It will always do this so the weakest signal logged will always be -24 db.

However, the strong signals are different. They have numbers in dB that extend up as far as the antenna and rig can perform. With the old antenna , rig whatever we are comparing, export the FT8 logs as a spreadsheet and sort by signal strength -sent or received, whichever or or both that interests you. Now take the highest 20 or so of each and average the result. Now do it again with logs from after your "improvement", and compare. Better Tx? Better Rx? Now you have a measure.

Why scruffy? let me begin to list a few of the math / statistical abominations: It assumes that original signal strengths are the same, before and after the comparison. Propagation, different stations etc may make this far from so. And for the math buffs, whose squeals of anguish already reach these rural parts, yes, you can't just average dB. The whole point of these are that they are a logarithmic scale, not linear, so averaging means nonsense. (Strictly, it would be necessary to convert to a linear scale, average and compare these averages. Too lazy!)

I told you it was scruffy but better than nothing! It's easy to see if things are obviously better or worse with at least something maybe better than just anecdote?.