My main amp is an ACOM2000A. But when I need instant on for a QUICK
qso I use my backup amp the L4-B. I run 3400V on the plates in the
L4-B and comfortably get 1500W on SSB and CW. I have the original
cooling fan, so I do not use it for RTTY.
I have no interest in cheating and running more than the legal limit.
By the way for those that don't know, our legal limit on 30M is 200W PEP.
- Paul KW7Y
At 09:04 PM 12/5/2016, Jim Thomson wrote:
Date: Sun, 4 Dec 2016 16:27:18 -0500
From: "Mark Bitterlich" <markbitterlich@embarqmail.com>
To: "Bill Turner" <dezrat@outlook.com>, "Amps group"
<amps@contesting.com>
Subject: Re: [Amps] The cost of amplifiers, radios
Bill,
The Henry 8K does 160, and all WARC bands. Of course it is also pretty
expensive and out of production. Also very heavy, but you can remote the
power supply and RF Deck from the operating position by quite a distance.
And yes, it has a loud fan. Just my own personal opinion, but I believe the
tube it uses (3CX3000A7) is actually one of the best on the market .....
cheap for the power it develops.
You are correct, the majority of the other models do not do 160, and use
individually switched Pi Input "modules" that make operation on some of the
WARC bands less than a "plug and play" operation, not to mention the tapped
coil(s). Still, they are pretty amazing amplifiers. Just saw a Henry 5K
Classic for sale for $3000. Two 3CX1200A7's (sadly, now a pricey tube), but
it will also put out serious power.
I really like the idea of cheaper amps with one pre-set for each band,
(common parts, etc.) but logistically hooking them all up to one exciter
would tend to be a PITA.
Obviously I own an 8K and enjoy it very much. I have tuned it into a 4.5:1
VSWR on 160, with 1500 watts out on CW to work Navassa (an 80 meter OCF, was
all I had at the time!). Worked perfectly. No computer controllers
protecting it, so if you get REALLY stupid, you let the smoke out.
Mark
WA3JPY
## The 3CX-3000A7 tube used in the 8K and other amps is a superb tube.
IMD3 is -59db pep...at 5 kw pep out..and more and lower power levels.
Instant on, rebuildable tube. 50 ohm input. 225 w CCS
grid dissipation, and even more when in GG mode, with grid bonded to chassis.
You can use the grid as a dummy load for a FT-1000 D. With 5 kw
out, the grid
only dissipates aprx 80-90 watts. Nobody ever blew the grid out of
a 3x3 tube,
even 11m ops.
The henry 3K ultra is also a 160-10m amplifier.
## typ 3CX-3000A7 in GG with 4800-5000 under load runs as follows.
50w in = 1.5 kw out.
100w = 2.5 kw
150w = 3.5 kw
200w = 5.2 kw
## the 3CX-3000A7 is still used in a lot of FM broadcast TX, like
energy onxix..and others.
## using several small amps, each tuned on a different band is
simple in most cases. I string
all 4 of my L4B amps in series, nose to tail. Then either tune each
amp on a different band, or
cw + ssb on the same band, or cw and 2 x ssb segments, like for
80m, or any possible combo
you can imagine. Low bands at night, high bands during the daytime etc.
## That works, provided the amp in question will handle full power
on BYPASS mode.
## I use a simple rotary switch, to switch the key lines to each
amp. IE: keyline from xcvr to
input of rotary switch. Then 1 output to each amps key line, so 4
in all on the output of the
small rotary switch. Then only one amp can ever be keyed at any
time. Dead simple,
and effective. If one amp ever blew up, I still have 3
spares. Modifying a drake L4B to
include 160m ( in addition to 80-10m) is not an issue either,
fairly Simple really. The oem
156 uh plate choke is ample for 160m, as is the oem Bifilar fil choke.
Jim VE7RF
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|