Re: v5 12m/10m Spectrums

Curt
 

My concern is whether we are measuring a power ratio or a voltage ratio - I am suspicious we could be measuring the latter -- see

https://en.wikipedia.org/wiki/Decibel#Voltage

I am thinking that if the ubitx is loaded at 50 ohms that the instrument may be taking valid data.  But perhaps a conversion to power ratio is necessary.  40 dB in voltage corresponds to an amplitude ratio of 100, while in power it is 10000.  yes note this can be the difference between having spurs at - 43 dB or - 23 dB when the unit is power! 

See if you instrument offers a tutorial on this.  I am thinking that even though voltage is being sensed, possibly the instrument knows how to do the conversion to power (??). 

As I possess a ubitx (v4) with spurious around -33 to - 35 dBc in the upper bands on SSB - I was hoping your v5 to be much better, but I don't want us to jump to that conclusion without careful evaluation.  [The greater news - my box is compliant on SSB up to 17m, and now good on CW - 'just' with a relay transplant to add a second set of relays on a daughter board]. 

Curt

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