Re: Unexpected measurements
Peter Russell <peter.russell@...>
My power supply is home brew 5A with a big capacitor and a LM338.
I've done a bit more work and It seems that the problem was the factory setting of the drive preset.
I've just acquired a rather nice oscilloscope - OWON DS7102 - so I put it to use measuring the voltage at the output bnc connector (into 50 ohms).
Not having used a 'scope for about 20 years, I fell into the obvious trap of measuring the peak - peak voltages and calculating from that! Oh dear, I really should have known better.
Anyway, once I realised my mistake and did it properly, that led me to adjusting the drive level. I've now got it to a point where all bands are happy ( except top band, but who cares about that).
Measured values are now .....
5Mhz and 21Mhz are a bit of a puzzle, but I'll delve a bit further and see what the drive levels are like.(Could this be a filter thing? I'm not sure what the bandpass filters are tuned to.)
Back to the workbench!
On 17/01/2019 17:14, Curt via Groups.Io wrote:
I agree this seems weird. You did not mention the type of power supply used nor its current, but perhaps its a good low noise supply used with your other rigs?---
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