[Orion] Quirky/buggy Orion VFO A/B switching of MODE

[Grant Youngman]

> When NR is on, the AN does not function.
> I can tune in a carrier,  turn on AN and carrier disappears.
> Then turn on NR and carrier is back.  Can toggle carrier on and off 
> with NR or AN.

It's always been like that, although there was some improvement made in 
1.364.  I haven't fiddled with it much since the changes were made -- 
perhaps there's some optimal settings of aggressiveness for both 
controls that will work better than others.

To some extent, the two may not be entirely compatible.  NR works by 
building bandpass filter(s) around signal.  A heterodyne certainly qualifies 
as signal and not noise (like maybe a CW signal, etc.).  Then you turn on 
AN, and it's going to want to eliminate that very same signal.  So it smells 
like a "whose on first" situation.  And of course, thu usual disclaimer -- 
that may have no bearing on "fact" -)

One interesting thing AN does in AM mode is to eliminate the carrier (as 
well as other things like look like heterodynes, etc).  I've occasionally 
found this to improve AM readibility, although I haven't kept enough hard 
data to be able to characterize under what circumstances that helps.

Grant/NQ5T