I observed something pretty significant tonight while doing some comparisons
between the Main and Sub receivers. I hadn't used the Sub on anything but
AM since the II arrived. It's 2.030, resets done.
Set up for a wide bandwith in LSB/USB (4-5Khz+), both radios seem to sound
about the same. As the bandwidth is narrowed on the Sub receiver, I think
there is a PBT shift (not reflected in the settings) taking place as well.
For example, with both Main and Sub tuned to the same LSB signal at about
1.8 Khz bandwidth, I have to set the Sub's PBT to somewhere around +500 to
match the response of the two receivers. I'm sure it's the Sub that's not
working correctly because as you narrow the bandwidth you can hear the
response get "tinny", as though PBT were sliding to cut the low end side of
the signal. The Main responds normally and just loses high frequencies as
the bandwidth is narrowed.
On USB, the situation is the same, except the Sub PBT has to be offset in
the other direction by the same amount.
Everything seems fine on the CW modes. As far as I can discern audibly, the
problem manifests only on SSB modes.
I've checked and double checked, and all of the other parameters are set
identically on the two radios.
Has anyone else observed this odd behavior? Note to ditsbits in progress
....
Grant/NQ5T
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