I have the opportunity to get a hold of a couple of HP Signal Generators

[vortalexfan]

Originally Posted by Polaraligned

What test equipment do you have at your disposal? An oscilloscope and frequency counter would be nice. Maybe modulation is not working? How are you coupling signal into radio? The readout on these is just a frequency counter as they are not synthesized, so the internal cavity oscillator is working, but you still may not be getting output if the attenuator is not working. It is just hard to say from what you are describing without trying to look for signal output on oscilloscope. These are very difficult units to work on as is ALL HP equipment. If you are not experienced with these it may just be better getting a working unit. Did your friend say the unit was working?

I do have an oscilloscope, would I just hook the output of the signal generator up to one of the inputs on the 'scope and see if it picks up a signal?

As for how I was coupling it up to the radio, I was using some 50 ohm BNC clip leads and clipping them to the proper coupling points on the radio.

[Polaraligned]

Originally Posted by vortalexfan

I do have an oscilloscope, would I just hook the output of the signal generator up to one of the inputs on the 'scope and see if it picks up a signal?

As for how I was coupling it up to the radio, I was using some 50 ohm BNC clip leads and clipping them to the proper coupling points on the radio.

Yes, you should be able to see a clean sine wave on the oscilloscope with modulation turned off. If your o-scope has a 50 ohm input use that, otherwise a high impedance input is ok but the amplitude will be a little off. Sinewave should still be clean.

Clipping the 50 ohm output to the radio is dangerous for the signal generator. You should use a .01uF or so capacitor to isolate the signal generator from the radio.

[vortalexfan]

Originally Posted by Polaraligned

Yes, you should be able to see a clean sine wave on the oscilloscope with modulation turned off. If your o-scope has a 50 ohm input use that, otherwise a high impedance input is ok but the amplitude will be a little off. Sinewave should still be clean.

Clipping the 50 ohm output to the radio is dangerous for the signal generator. You should use a .01uF or so capacitor to isolate the signal generator from the radio.

Ok. I've got a BNC to BNC cable I'll try hooking the signal generator up to the 'scope and see if I get a clean sine wave.

[vortalexfan]

It took me a while to figure out which hookup on the 'Scope to hook the signal generator up to to test the signal generator, but I was able to figure out that the signal generator is indeed working as I was able to get a clean sine wave onto the 'scope.

See picture below.

[jr_tech]

Does the frequency indicated on the signal generator display correspond reasonably well with that measured by the scope?

jr

[vortalexfan]

Originally Posted by jr_tech

Does the frequency indicated on the signal generator display correspond reasonably well with that measured by the scope?

jr

I'm actually working on the signal generator that doesn't have the digital readout right now, and for some reason when I hook my stand alone frequency counter up to it, it doesn't register on my frequency counter, and when I used it to "radiate" a signal to my Zenith Royal 2000-1 radio it did put out a signal including a test tone but it was kind of weak unless I touched the large N-type RF output plug with my hand then the signal came in loud and clear...

[Polaraligned]

Originally Posted by vortalexfan

I'm actually working on the signal generator that doesn't have the digital readout right now, and for some reason when I hook my stand alone frequency counter up to it, it doesn't register on my frequency counter, and when I used it to "radiate" a signal to my Zenith Royal 2000-1 radio it did put out a signal including a test tone but it was kind of weak unless I touched the large N-type RF output plug with my hand then the signal came in loud and clear...

Well, signal generators put out a low amplitude signal. Turn up the amplitude on the SG all the way and turn up the sensitivity on the frequency counter.