Telamon wrote:

In article , dxAce
wrote:

Telamon wrote:

In article , dxAce
wrote:

The past few evenings I've tuned up to the top of the 75 meter band to see
what
effect DRM on 3995 has on the band and it's atrocious.

DRM = QRM

That's one of the neat things about technology is predictability.

DRM claims about better audio in the same bandwidth is BS as are the non
adjacent channel interference clams.

Yep, I just checked the signal a few minutes ago on 3995 and it wipes out at
least the top 10 kHz of the band.

How about below? The upper harmonics are a sure thing but I expect the
DRM signal to spread out as far below the frequency transmitted on.

Digital signals spread out above and below the frequency they are on.
Upper frequency spread is from multiple carrier mixing products and
higher frequency harmonics of the fast switching edges and phase noise
or random jitter. The low frequency spread is from data dependent
effects or data dependent jitter and the data mixing with the carriers.

Well I did mention the top 10 kHz of the band. Apparently the signal is centered on
3995, and it is certainly audible both above and below that point.

In the few times I've checked recently I've not noticed any amateur use of that
range when the DRM signal is on.

It's a mess!

dxAce
Michigan
USA