So many projects and the list is growing. How can you do RF work without a scope? Maybe a good RF meter would be a reasonable substitute. Even my cheap DVM has a 200mv DC scale. With a RF detector built into a probe this becomes a sensitive RF meter. If you rectify an AC signal and send the signal to a DC meter you read peak. RMS is .707 peak so the 200mv DC is about 140mv RMS. For signal tracing and checking to see if a circuit is oscillating you just need a relative reading. So the last project added to the list is one of these.
As always the project is open to modification. Either of these two would be a good start. Ummm? I had a TV antenna come apart when the tree hit it in one of the hurricanes. I saved that aluminum tubing for just such an occasion as this.
A little tubing, a finishing nail filed to a point, a diode, capacitor and resistor. Need two to check an amp input and output. Using the same meter and probe will give a relative reading that could be used to determine gain. You could use a signal generator and 'calibrate' the meter against it.