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kc0yef, I've never seen nor worked on one, so this is only a guess.
On the bottom photo looking at the outside, do you notice the small notches (or are they raised bumps?) near the "M", "F" and "H" near the bottom? I'm assuming there is a fourth one 180 degrees from the one near the "H". Try grabbing at least two opposite ones and turning that ring clockwise to loosen. Be careful, especially if you suspect it is plastic (my guess) and acts as a seal.
Once removed (it might be the retaining ring/outer bearing race) you should see the outer bearings (if metal), or another metal ring (if plastic). Hopefully this helps. Additional pictures posted might prove helpful.