The synodic Jupiter-Saturn cycle 19,85 years

Stars wobble, and Jupiter is the main contributor in our system followed by Saturn.

There are many theories on such/similar influence on the sunspot cycle, focusing on barycentre, angular momentum, torque and so on. Geoff Sharp has summed some up at landscheidt.info

I will make a simplyfied analysis only looking at Jupiter and Saturn, and disregarding orbital eccentricity. Also I make the assumption that the smoothed maximum ISN is a useful measure of the sunspot cycle strength.

First the heliocentric angle between Jupiter and Saturn at solar minimum, and the corresponding ISN of the cycle.

If we assume that conjunctions and oppositions of Jupiter-Satrun can be treated equally, we can compress this data into 0-180 degrees (and a 9,93 year cycle).

We observe that when JuSa-angle is ~20-100 degrees at solar minimum, we get strong sunspot cycles (ON). Otherwise we get weak cycles (OFF).

There is a change in behaviour at 105 degrees, and the OFF-sector is divided in two. If we shift this data 105 degrees, we get a clearer picture:

There are some weak ON-cycles marked by dotted line. We have to look at those later.

Next step is looking at where the type A, B and C-cycles lie in this chart.
First the B-type. Looks "OK"

Then the C-type. Notice that the ON-cycles tend to be weak. And so far no OFF-cycles.

Finally the A-cycles:

1-The A-OFF cycles look very weak.
2-The A-ON cycles look very strong
3-But there are two A-ON cycles that are surprisingly weak (SC7 and SC20). Must investigate those two later.