I think there could be a solution to this jamming. Or, at least, a partial one.
(Note: I don't claim to be the originator of this idea - only the first one to mention it in this thread.)
P59DX (14001 KHz): "CQ CQ DE P59DX P59DX UP"
Same as usual. Except, P59DX answers his or her callers on *their* transmit frequency. Frequency hopping spread spectrum on CW.
K1JX (14017 KHz): "K1JX K1JX"
P59DX (14017 KHz): "K1JX 339"
K1JX (14017 KHz): "TU 599"
P59DX (14017 KHz): "TU"
This requires no more work for the DX station. It's still turning a single tuning knob, picking out callers, answering them, and putting them into log. No extra transmissions.
For the callers, it's about the same amount of effort. They still have to find the right place to call, using whatever patterns they discern. In order to hear the DX and be heard, it encourages them to find a clear frequency, which they should be doing now anyway.
But, overall it uses bandwidth - already taken up by callers - to jump around the jammers. It's much harder to jam a moving target. No need for the UP cops.
I guess the same could be done on phone.
You could, and I am certain somebody will, argue that this might slow the rate down from the theoretical best that's possible from the current approach. But, that's the rub, isn't it? We can't get close to the theoretical best because of the associated crap slowing things down.
As for FT8, well, Fox and Hound operation is a great idea. That assumes that everybody follows the "rules". If somebody doesn't call above 1000 Hz, they won't be copied by the Fox. But, they could also park themselves right on the Fox's frequency and jam every caller who gets moved there by the software to give a report to the Fox. Their intent may not be to jam - they're just showing their ignorance. But, the result is the same.
Some DXpeditioners have told me that the reason why they use MSHV instead of F/H is because of this. If they copy me at 2344 Hz when I'm calling them, there's a good chance they'll copy my report or closing "RR" from that same frequency.
If everybody used wider filters for FT8 operation so that the effective band was wider, many of these problems would go away. But, a lot of radios don't come equipped for using more than 2700 Hz or so receive bandwidth. That gives about 2000 Hz for Hounds in F/H mode, and often not even that much. In some radios, you can't even install a wider filter as an option. That doesn't help.
Of course, an FT8 DX station could use the same frequency hopping idea as described above. Answer on the caller's frequency. That's already built into the software as a check box option.
Yeah, people would have to change some of their habits. So?