Re: Frequency counters
Update on the project so far, after playing around with the Black Star frequency counter in conjunction with the sig gen, I discovered that switching between ext and int modulation the frequency on int mod was miles out of calibration. This was checked on a scope and the waveform was nothing at all like an AM signal should look like either. So I stripped the sig gen down and discovered that the lead from a cap was almost grounded before it reached the range switch. This was re-routed and the frequency checked again. Result, no difference between int and ext modulation setting and the scope showed something resembling an AM signal now. To try and increase the output voltage available, I tried a 390 ohm resistor between the 1k pot and ground thinking that it should help to provide something in the order of a 40% increase in the voltage available, this seems to be the case so far.
The chinese frequency counter also arrived so I quickly coupled that up and it works very well and the accuracy against the Black Star is also very good indeed so I'm still thinking of connecting this directly to the sig gen and mounting it on the top, freeing the Black Star for other uses.
Now I just need to think about a power source for the counter, I don't think the 6.3v heater winding is man enough to power it as well, seeing as the 6.3v is already down to 6.15v and after rectifying and smoothing, this is going to be in the realms of 7.3vdc. Counter needs 9v to 15v @160ma, so maybe an external power brick is the way to go, any thoughts?
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