You can use the windings in a transformer for inductance, maybe not ideal because that would be fairly space inefficient for the amount of inductance you get. Worth a shot for testing, definitely. I wound one using a steel quick link. You really need a lot of inductance to keep the cap manageable. I ended up with a ferrite rod and that worked even better than iron, but cost more and are more fragile. Once it's potted, it won't matter, though.
If you were listening to a repeater the CW you heard was probably the repeater identifying itself. Probably heard the call sign in Morse every 10 minutes.