Peter said:
<However, this sort of discussion suggests that there are
hams
out there who build equipment. These days, I wonder if that is
that still allowed ?
73
Peter G3RZP>
Yes, there are still quite a few here in ZL.
My next project (which should keep me out of mischief for a
year or two) is a separate amplifier for each HF band for CW
contesting. (the old Heathkit Warrior takes too long to re-tune)
I've been agonizing over the configuration - GG or AB1, and
am seeking guidance from the group.
I have a 1.9 metre (6'4" approx) rack/cabinet, 2750vdc, .75A
CCS power supply, and enough 4-400s, sockets, fans, etc.
etc. to build five two-tube amplifiers - a few tuning caps, both
single gang and split-stator, 5 kv or better, loading caps for pi-
network etc., selection of plate RFCs (National R175 to ART-
13, B&W 800 type and a 4 mH pie-wound specimen that
would cope with 160 metres at many milliamps. And some
meters to monitor the milliamps.
Rig is an Elecraft K2 - 10w out, but can be increased to 100w
out with the soon-to-be released KPA100 option.
Although we don't have close neighbours, I'd like to minimise
TVI in our house, so class C is not an option <g> but push-pull
or parallel can be chosen for the particular advantages of
either - a swinging link coupled PP configuration on 10 meters
is by no means daunting, and could confer great benefit - in ZL
TV Channel 2 is centred on 55.25 Mhz, so Alex N2NNU's
comments re 2nd harmonic supression are very pertinent for
the ten metre amp.
I have used 4-400s in GG before in an all-band home-brew
amp which was very docile.
Maybe someone on the list has done this exercise before -
comments/guidance would be much appreciated.
Apologies for the bandwidth, but I'd rather be clear than cryptic.
TIA and 73
Ken ZL1AIH
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