That's a nice Channel Master dish, great find and a keeper! I have one trained on 103W for Ku.
The fellow that had my aformentioned dish had been using it as a mini-bud, and had fabricated a bracket that I didn't think worked properly. It held the C-band LNBF too high and above the designed focal point, so when the dish was re-focused to compensate the focal pint would be a bit distorted. If one were to shorten the bottom support rod (or fabricate another one that is about an inch shorter just for C-band mini-bud testing) about an inch that would drop the LNB mount assembly about 2-3 inches, making it possible to find the poroper focal point for the feed horn placment. Might make up another dB of signal, when every dB counts!