[Raleigh]

If you have a frequency counter you should be able to see if the RF is working. I'm not sure if the frequency counter will count the audio, but maybe if you play with the ranges it will. Update: I found that my frequency counter will sometimes count 4 KHz on some ranges, but most of the time it wants to count the RF frequency regardless of range or RF frequency.

I have the same Paco signal generator you do. If yours is working and set to modulated RF, you should be able to hear a tone on any radio with just a wire connected to the positive output of the generator and held near the radio. No loop is needed. I do always connect mine through a .01 uf cap, but it doesn't make a difference for this test if I don't. I wouldn't connect the signal generator to a radio without the capacitor.

If your RF is working you should be able to interfere with most radios by tuning through the frequency of your frequency generator, even without the audio tone. You'll get squealing on either side of the tuned frequency, but probably not exactly on it.

It doesn't seem to matter whether I connect my loop across + and - terminals, both sides to +, or leave one end open. It also doesn't make too much difference if I use a loop or just a wire.