LONG- delete now if of no interest.
Aloha from "a gent in Hawaii",
> I seem to recall a gent in Hawaii that needed help with
>an 8K Ultra...
Yep, that's me. Wire came loose on a relay which brings
in a different input tuning coil for 15/10 meter bands.
Simple problem, simple fix for an apparent defective
coil in the new relay. Found "open" after shipment of the
amp from the mainland.
> Guess he has a SWBC license, right?
Nope, Amateur Extra Class, KH7M, former
AH6NB.
>Because that amp would have to be VERY carefully run
>to keep it at legal limit, and even then, you would have
>instantaneous peaks over the legal limit....
My 8K is tuned up into a Bird "Termaline" Coaxial
Load Resistor (aka, Dummy Load) Model 8890-
300, 3kW continuous dissipation, 5kW short shots.
Amp is pulsed, a la Rich's method, but using an
AEA Morse Machine keyer at about 50 wpm dits.
Tune up for max output into the Bird with drive power
sufficient to show 3 kW into the load as read on a
new Bird 43 with a 5 kW slug.
Then, replace the 5 k slug with the Bird 2500 watt
slug. Reduce drive to show 1500 watts into the
load; but this time using key down, 100% power,
that is, the pulser is off.
Rig is then switched to whichever band's antenna
I am choosing to use at that time through a Palstar
AT4K antenna tuner and remote antenna switching
relay, the Ameritron RCS-8V. AT4K is set up to
provide a 50 ohm load for the 8K using an MFJ-259B
meter put in place of the 8K line with whatever
feedline/antenna combination to be used as
the load on the output of the AT4K. Once set, the
tuner is reconnected to the feedline from the 8K
which has the Bird and VFD indicators also in
series (see the following for use).
On air, instantaneous power output peaks are
monitored constantly using the new RF Applications
VFD RF power/VSWR meter. The VFD readout of peak
power is essentially instantaneous, well half second or so.
Much faster and seemingly more accurate than with
that firm's P-3000 indicator I had been using.
The Bird 43, with the 2.5 kW slug also remains in line,
but the read out is not fast enough to monitor moment
to moment peak Pout. But, I can always reach over
and depress the TUNE button of my Omni VI+ transceiver
and find out immediately what the peak continuous P out
would be; then the Bird gives a reading which is
accurate to within +/- of 5% of 2.5 kW, or 125
watts. So, should the Bird happen to read exactly
1500 watts on the scale, I know I am within 125
watts out of that reading. This satisfies the FCC
requirement, as I understand their usual procedures.
Just to be safe, however, I usually have the drive
into the Henry reduced such that my TUNE Pout
constant carrier reading is kept to about 1425 watts.
Then, should the Bird be reading the actual power
5% low, my real peak output could never be higher
than 1496 watts (1.05 x 1425 = 1496 from
P + .05P = 1500 ). I know such an operating
set up certainly is acceptable to the FCC.
So, as I could afford what I believed to be the best
available amplifier, had a desire for same, plus wanted
the cleanest possible, legal QRO signal I could muster,
I chose to buy the 8K. Using Rich's pulser tune up
procedure, sets the 3CX3000A7 triode on essentially
an absolutely linear transfer characteristic operating load
line.
I know my IMD's are absolutely as low as the laws
of engineering design and tune-up can bring them to be!
I am always complimented on my signal quality,
clarity, and "cleanliness". And I can run any mode
I choose, RTTY, PSK31, CW, SSB, or even
AM up above 29 MHz, real nice! And very legal
as I am very careful, and proud of my rig, station,
and signal on the air.
The 8K amplifier pedestal sits in the adjoining room
to my small operating room. So I escape the added
blower sound and output heat from the pedestal, one
of the very nice features of Henry's Ultra amplifier
remote control designs.
I am working on a KH7M web page with a friend here
on Kauai. Will have pictures of my operating room,
and the 8K innards, including the 325 or so pound
power supply deck! The RF deck weighs about
65 pounds, so the total 400 pounds is the very
sturdy pedestal cabinet and all that iron in the
transformers, choke, etc. of the PS.
Hope that clarifies my use and pleasure with my
Henry Ultra 8K amplifier.
We have no need/use for Ferrari or Porsche automobiles
here on Kauai. Very few miles of our ONE highway are
even posted to allow 55 mph speeds. And the total
road length end to end is about 85 miles, with lots of
25 and 35 mph max sections; maybe 6 areas, with
a length each of 3 or 4 miles at most where 55 is
posted as allowed. However, there are Mercedes,
a handful of Porsche's and I have seen one Ferrari.
Those folks own their machines for the joy of
possessing a fine piece of engineered machinery, I
would guess. They certainly cannot operate them
anywhere near the design capability. Those cars
are also kept in immaculate physical condition, so
there is pride of ownership also involved.
Pretty good analogy to my feelings about my
Henry 8K.
73, Jim, KH7M
On the Garden Island of Kauai
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