Would running the thing through a UPS (uninterruptible power supply) fix this?
A regular consumer grade UPS would probably improve the situation, but to
fix the issue is a stretch.
An up-scale UPS will have power conditioning but they are pricey.
What I haven't seen mentioned here is there are two types of portable generators.
There are rectified generators where the frequency is dictated by engine RPM (these are the older style, cheaper generators) These are akin to the generator on a pre 70s car.
Then there is the newer type with the output regulated by field, and the output wave is controlled by an electronic regulator ("inverters" like the Honda EUs) These are akin to a modern alternator found on a modern car.
For Bobo: When I went looking for a gen set for the race trailer EVERYONE told me to buy an Onan (a Cummins company). Onan had to be the best cuz all the big mobile homes and semi trucks have Onan gen sets.
Onan was one of the first companies to manufacture gen sets in China... and they're still considered the industry standard.
Reading Honda websites, they will only admit to manufacturing gen sets in France... but all the Honda gen sets have GX motors. Honda GX motors have ALWAYS been built by the Jaing Dong (sp?) motor corp. of China.
I am going out on a limb here by saying the vast majority of consumer level gen sets are made in China... so I think you should stop using "Made in China" as an insult.
Oh... and "inverters" DO NOT output a sine wave. They output a square wave, synthesized to look like a sine wave. That is the difference between a "good" inverter and a "bad or cheap" inverter, how well that wave is synthesized. To synth that wave is not easy (actually to reproduce a sine wave digitally is impossible), therefore not cheap.
If your old gen set is too loud: put a bigger muffler on it. (Talk to any lawn mower repair shop, NOT Canadian Tire or Princess Auto).
The 2000va Champion inverter can be "stacked" in parallel, but you have to get the cables from a US distributor.
We found it was cheaper to charge the batteries in the race car using the alternator on my 4.3L Chev than to use a 3500va 6hp gen set with a battery charger.