My ADE25 module has locations for caps on the inputs and outputs but
they are stuffed with 0 ohm resistors..
It seems to work ok, should I be worried?? Should I put in caps??
What value.
It also has an unstuffed location for an R next to the C.? Same
question.
What 3db pad are you talking about?
73,
Gary
WB6OGD
On 1/26/2020 2:13 PM, m0wid wrote:
toggle quoted message
Show quoted text
Mixer problem - SOLVED
The ADE25 mixers are fine.? They work in a different way to the
ADE1 and needed a capacitor to decouple from the 3dB pad.? The
ADE1 have transformers, so no problem.? A good learning
experience.
The spurs at the harmonic frequencies are I think really are
there.? If spur reduction is turned on the levels of the harmonics
and the fundamental change significantly each scan, so the
readings cannot be trusted.? I can see the harmonic on my Hermes
Lite 2 SDR.
If I run the signal through a low pass filter then the levels of
the harmonics in Tiny-SA drop significantly, but they are still
present.? Interestingly the Nano-VNA measures the attenuation by
the filter at the harmononic frequency of around 30 db, but the
signal on the spectrum only drops by half that.? Further
investigation needed.? Adding a fixed 15db attenuator drops all
the signals by roughly that amount.
73
Dave M0WID
