[NostalgiaRadioTime]

It almost sounds as if your antenna is directly grounded to the chassis and not going to the variable capacitor (tuner), based on the fact that the radio gets louder when you touch any part of the chassis.

You should try what Terry suggested. Tune the Hippo to around 700 on the dial, which is where you said WLW initially appeared before the recap. Then place another AM radio next to the hippo and tune it 455kc higher on the dial than the hippo (or, around 1155 on the dial). You should be able to hear WLW through the other radio, or at least a "whistle" as you rock the dial on the other radio around 1155. To verify, turn off the hippo and leave the other radio on. You should hear a change in the sound at 1155 on the other radio. That would indicate the OSC on the hippo is working. If the OSC isn't working you won't receive anything but the strongest station.

You could try reversing the leads on the loop antenna. Sometimes if they're hooked up backwards it can cause problems.

Have you attempted an alignment? Without a signal generator you'll have to do it by ear, but it's pretty straight forward.