----- Original Message -----
From: "Robert Mcgraw" <rmcgraw@blomand.net>
I don't agree with the central ground point utilization unless it is the
station power supply which is the only DC zero voltage point. That DC
voltage point should be connected to the external ground {if used} and
should be connected direct to each piece of equipment, transceiver, amp,
tuner and etc. Although Jim and I don't agree, I don't daisy-chain
equipment grounds. And I don't suggest using an external ground as I've
found those to be more problematic than problem solving.
It's the central point of everything. The ICE AC power protection is
mounted on it as well so it's ground is referenced at that point supplying
all equipment in the console. The chassis of each piece of equipment is tied
to a copper ground buss that runs behind all equipment that is tied to the
central panel as well. The central panel is also bonded to the electrical
panel as required by electrical code.
I'm not sure what you are calling an external ground...the central ground
point panel is tied via 2/0 to the tower grounding system which consists of
probably 2 dozen 10' rods and lots of 2/0 copper. You don't want your
antenna system to depend on the building electrical ground to sink off
strike currents.
The tower has taken direct strikes 3 times this year so far with no
equipment damage to date. Was stuck once last year and lost a hot air
workstation for some strange reason. It was plugged into an outlet that was
switch off and across the room.
On the Centurion, no harm at operating at max rated plate current {abt
0.8A} and max rated grid current {abt 240ma}. If you're not attaining
these, this says the amp may not be loaded correctly for the drive
applied.
Mine will attain those numbers for plate and grid currents I just choose not
to run it full up all the time. I'm a bit confused though...you can't load
for max plate and max grid for two different output powers unless you are
miss tuned. Maybe I mis-read your post.
If you tune for resonance (plate dipped), drive to max plate, max grid all
equals max output...which is a good tune then you reduce drive to desired
level which will drop both plate and grid currents but resonance should be
maintained requiring no further adjustment.
We maybe saying the same thing...not sure.
Cecil
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