Specifying DATV power output.

[M0DTS]

The carrier output depends a lot on the way the modulator is adjusted it seems, just been checking here and depending on how it's setup i can get a large difference in carrier level (no mod). Interestingly the LO level on mine usually comes out about 6dB higher than the sideband tones when no modulation is on.

The best way then is the sideband test where the tones always reach roughly the same level after adjustment.
The in-Phase setting gives both the upper and lower sideband tones and their levels are just about 3dB lower than a single sideband tone.

Here's some photos, USB is just the same as LSB, it would not let me add more than 3 photos!

No Modulation

No Mod.jpg (138.31 KiB) Viewed 4081 times

LSB

LSB.jpg (147.36 KiB) Viewed 4081 times

In Phase

In Phase.jpg (105.33 KiB) Viewed 4081 times

Rob
M0DTS

[G4EWJ]

Interesting. The carrier suppression seems to be a little worse for the in phase test.

I wonder if it would be useful to have another test mode which alternates between sidebands at a few hertz?

Brian