[Eric Adams]

Hi guys,

I have an unusual problem: I have an Eico model 324 signal generator that I bought mainly for FM rf alignments. I use my HP 601A (which only goes up to 11Mhz) for everything else. The problem is that it is hooked up to my B&K 1801 frequency counter and when I go above 45Mhz the 1801 goes crazy and won't show any accurate numbers. I know that the 324 is putting out a signal because I can pick it up all across the FM band.

Any ideas as to what the problem is? Am I missing something?

Thanks,

[morzh]

Is the signal amplitude adequate for 1801?

[Eric Adams]

I have no idea. How would I know? I do have it turned up to full to get a reading at 40Mhz. Is there anything that I can do?

[morzh]

Eric


All I have to recommend is reaing the specs and then measuring your signal to see if it conforms.

[Radioroslyn]

As Mike sez it could be the level of signal or your generator's output may be loaded if harmonics. The counter can't make up it's mind which one to lock onto.
Terry

[morzh]

Terry

A good counter amplifies signal, clips it and locks to its edge, so harmonics should not matter - as you know a counter will count rectangular pulses as well as sinewave, and the rectangle is as chokefull of harmonics as it is possible.

Of course if you have non-periodic waveshape, all bets are off.

[Eric Adams]

OK, I'm tired of messing with this EICO 324. I'm thinking of getting an FM signal generator for accurate FM alignments.  I use my HP 601A with the sweep and a scope for the IF alignment and I want to be just as accurate on FM RF.
What do you guys think? What do you use?

Thanks,