[Premium-Rx] PLL trouble with WJ-8718 (MFP)

[Tim Shoppa]

Gene Anderson <sidhu at ms12.hinet.net> wrote:
> Another oddity is that I used to have a different problem.  Before this
> tuning issue occurred, I would occasionally get a loud raspy buzz that
> was visible also as spikes on the signal monitor.  I could get the sound
> to go away by turning the receiver off and then on again, but it would
> often come back.  Now that problem is completely gone (without any
> intervention by me) and this new problem has taken it's place, as if
> they are mutually exclusive.  Not sure if that could provide any further
> clues.

My WJ-8716 (which may or may not share many of the PLL mechanics of your 8718)
exhibited bad PLL instability which would occur in some parts of
each 10kHz segment. The pattern repeated every 10kHz and
this became apparent after a few months of non-use.
Then, like yours, that problem went away.
Maybe electrolytic capacitors in the PLL loops reforming after
non-use? Very random guess.

The click-every-10-kHz you hear seems to be perfectly normal on
these radios. It is moderately disconcerting compared to analog
tuned radios but IMHO not much worse than other synthesized radios
of the same and even later era. My very definite impression is that 
the WJ-8716 or 8718 was best used when it just
sat on a single frequency for a long time. The tuning rates available seem
like poor matches to my bandscanning, and I don't really like
the slow AGC behavior when tuning through a band of signals
with radically different signal strengths (e.g. ham bands). Here
I'm not comparing the WJ radios with other "premium" radios, but just
comparing it with low-end ham gear of the 60's and 70's, which
generally did well with the tuning rates and AGC action.

I know, maybe we're supposed to love our premium radios just because
they're premium radios. But the WJ-8716 line, while it may be well
suited to channelized and utility communications, is not well suited to tuning
around bands looking for something interesting.

Tim N3QE