Yeah I had a feeling, I have no idea what impedance they are. 14W needs 275 ohms, 20W needs 240 ohms (ideally), that is kind of a big difference. 275 ohms could underdrive this lamp 20%. I assume it is somewhere in the middle.

It is good to note that the more generic “14-20W” preheat fluorescent reactor ballasts have a tendency to underpower F20T12 tubes and 8 inch 22W circline fluorescent lamps.

Agree with F20T12, did some promising calculations in Discord, don't feel like repeating them here lol.

Here is a link to the ballast that @WorldwideHIDCollectorUSA reccomends:
https://www.ebay.com/itm/157608346025

Here is a link to a cheaper more generic F20T12 ballast, results may vary:
https://www.ebay.com/itm/186408657366

Thanks!

From my experience, I have had beautiful results with running 8 inch 22W circline fluorescent lamps on Advance LC-25-TP preheat fluorescent reactor ballasts. When running at the correct 120V 60Hz supply they are rated for, I have seen them draw roughly 25W or so with ballast losses included and also draw somewhere around 360mA without a power factor correction capacitor, which is close to the 380mA lamp current required of them at least in North American terms.

Here is one on eBay for a pretty cheap price:

https://ebay.us/m/eAnMcB

I have known about them being a pretty good choice because  I have understood 8 inch 22W circline fluorescent lamps to have similar electrical characteristics to the F20T12 fluorescent tube and have read accounts of collectors saying that the Advance LC-25-TP reactor ballasts were able to properly power F20T12 fluorescent tubes.

https://www.ebay.com/itm/386127196994
https://www.ebay.com/itm/133905787340
https://www.ebay.com/itm/325559801630
https://www.ebay.com/itm/147077151898
https://www.ebay.com/itm/386127196994

Really? I will have to look. It doesn’t have to be, but it would be preferable. I’ll look into it.

Does it have to be 35w? There are a few 70w ones on ebay right now

I know little about ballasts and just need one available online that will properly drive an FC8T9 22 watt fluorescent lamp. id like it to be preheat (but with an external starter), so something like the robertson 3P10041 will not work for me because it has an integrated starter. Thanks in advance.

Glass lamps have "etches". But are they ever really etches? No, they are stamps. With ink. We never actually etch into the glass of a lamp. If we did, then they would be very very durable and last practically forever (like they do with some vacuum tubes), but we don't. Anyway, they don't last forever and can just just wipe right off if they are old enough. This obviously isn't good if you are trying to replace or identify a lamp that has an illegible etch (I've been there).

Sometimes there are etches that are on the inside of the glass, that way they can't rub off. That works great, why don't we do internal etches anymore? Maybe they are not always practical for all lamp shapes. I would also imagine that could be problematic for sodium lamps with a high vacuum outer envelope.

If you wanna get really fancy you could do those ceramic decals that are found on labware and the like. They are still on the outside, but very very durable (I can't even scrape them off with HSS lathe tool). These decals are not expensive, and can be fired at the same time that the lamp is being annealed (assuming the lamp gets annealed).

I feel like a lamp company having durable etches would be a nice low-effort edge over competitors. And nice for us too. Idk