The compliance of my uBitx with these rules is summarized here:
You have written "Second: the alignment as it comes out from HF signals will show far better harmonic suppression than being reported here. For instance, the -38 dbc on 20 meters and -30 db on 40 meters will almost disappear if you balanace it out with the bias on the IRF510s. The factory alignment works like this : First crank up both the IRF510s for 100 ma standing current on each, then tweak one of them to null out the harmonics. It is like balancing out the carrier on diode modulator."
Your filter designs and components as supplied are adequate for the PA filtering application. Removed from the board and laid out in a linear fashion with no relays, the filters exhibit well over 55 dB of attenuation at the 3rd harmonic and higher for each band. The primary limiting factor is the strategy of running the input and output of each filter through at least one common relay; lower bands do this with two or all three of the relays. Input to output crosstalk within the relay becomes the first and most substantial contributor to the "blow-by" of harmonics bypassing the filters. The second factor is the "daisy chaining" of the low frequency signals through multiple relays. Finally, a high power PA harmonic filter must have extremely high overall isolation between the input and output of the assembly. The long traces and circuitous routing on the board to connect all of these relays contributes to lack of input/output isolation. When laid out on the board and routed through the relays the filters exhibit on the order of 25 dB attenuation at harmonic frequencies; far too little to be compliant.
The relays per se are not the problem.
It may be possible to make the uBitx compliant with only better PA filter layout: No sharing of relays between filter inputs and outputs, no daisy-chaining of relays, more straightforward PCB layout. However, due to the "45 MHz - carrier" spur issue such filters would need to be BPF rather than LPT. Alternatively, a 4-6 filter assembly, switched in conjunction with the PA filter and placed between the first mixer and the drive chain would likely clean up the signals to the point that the existing filter arrangement may work.
Based on the discussion here and a parallel one on the Facebook uBitx page, I do not believe my results are "sample of one" or the result of a defective unit. That, however, remains a possibility until someone publishes data assembled with similar care to refute them.
I love the concept of uBitx. I want it to work and work well. I sympathize with the pragmatic concept that "it makes less spur power than an high power commercial rig" but that is not the rule. And you can already see the number of people who connect the uBitx to linear amplifiers on the assumption they are starting out with a compliant radio but they are not.
I cannot, in good conscience, put my unit on the air as it stands. Each amateur radio operator needs to be guided by his or her conscience in this matter. But if the decision is made to go ahead it should be made with the full knowledge that it is a violation to do so.
Thanks for soliciting responses and for listening.