Nice Commercial (i.e., Advertisement)!
-----Original Message-----
From: kmarch <kmarch@ix.netcom.com>
To: amps@contesting.com <amps@contesting.com>
To: <amps@contesting.com>
Date: Monday, July 12, 1999 7:40 PM
Subject: [AMPS] Fw:
>
>FYI
>-----Original Message-----
>From: John Devoldere (ON4UN) <john.devoldere@village.uunet.be>
>To: dx-news@jerseycape.net <dx-news@jerseycape.net>; ham*topband
><Topband@contesting.com>; dx@qth.net <dx@qth.net>;
ham*contest_announcements
><CQ-Contest@contesting.com>
To: <amps@contesting.com>
>Date: Monday, July 12, 1999 3:45 PM
>
>
>One year of using the ACOM 2000 Automatic HF linear amplifier. (by John
>Devoldere, ON4UN)
>
>
>Early 1998 I was approached by Vasko, LZ1JK, to "life" test a new automatic
>amplifier he had developed. I was happy to do so, especially after I found
>out how unique this new amplifier really was. After 1 year of thorough
>testing, it's time to share my experiences with my fellow amateurs.
>
>
>ACOM may not yet be a well known name in the world of amateur radio
>equipment, but no doubt soon will be. ACOM was the company which for many
>years produced the Alpha 91b amplifier, the most popular of the Alpha (ETO)
>amplifiers. The company not only produced that amplifier, they build it
>almost exclusively with parts made in Bulgaria and other Eastern European
>countries. This together with the lower labor cost as compared to the West
>made it possible for Alpha to sell a top notch amplifier at an attractive
>price. The Alpha 91 soon obtained the reputation of being every bit as good
>as the more expensive amplifiers made in the USA. Through all the expertise
>Vasko and his company acquired during the years of being a subcontractor
for
>Alpha, they gained all the knowledge which made them decide to develop an
>amplifier of their own.
>
>ACOM set out to develop a 1500 Watt (continuous duty!) output amplifier
with
>full autotune (not memory tune) features, using two GU74 (4CX800A) tubes by
>Svetlana, the same as used in the Alpha 91 amplifier. You can find these
>tubes new on the flea markets for typically 50 to 60$ (the 3CX800's used in
>many US-made amplifiers cost at least 5 times as much). Their goal was to
>make an improved version of the Alpha 87A "memory tune" amplifier, which is
>considered by many to be the top of the range amplifier on the amateur
>market.
>
>
>The improvement turned out to be the fact that the ACOM is a true autotune
>amplifier, while the Alpha 87A is in reality a memory-tune amplifier,
>capable of memorizing two sets of tuning setting (per band segment), one
for
>nominally 50 Ohm and one for an impedance which must be pre-programmed by
>the user through manual tuning.
>
>
>The ACOM 2000 is the first real auto-tune amateur HF-amplifier I have seen.
>By pressing a simple button on the remote control panel it fully
>automatically tunes itself completely within about 0.5 seconds. The
>auto-tune function is not limited to recalling preset values, it actually
>tunes for a conjugate match for whatever load within the must be .." 2:1
SWR
>circle on 160m and within the 3:1 circle on all other bands, and does that
>fully automatically, with no human intervention at all. I have been queried
>whether t his was achieved by using a built-in antenna tuner. No, the
>matching is done with a classic Pi-L network, of which the tune capacitor,
>the bandswitch and the load capacitor are driven by stepper motors,
>controlled buy the logic from the logic control board. The amplifier has an
>absolutely blank front panel (except for an AC on-off switch), which makes
>it possible to "hide" the amplifier in any convenient place. All control
and
>monitoring functions are grouped on a small remote control box, which can
>easily be positioned next to the keyboard during operation. The ACOM
>amplifier can be connected via an RS232 connector to a PC for either remote
>control or testing. It even has a built in processor that keeps track of
all
>the important data (currents, voltages, temperatures), and in case of a
>breakdown you can down load the measured values via a modem to the factory
>for further diagnosis.
>
>The Acom 2000A amplifier tunes automatically (change band-switch, loading-C
>and tuning-C) for any frequency between 1.8 MHz and 29.8 MHz. There is a
>possibility to do manual tuning as well, but who would want to use that?
>Settings of the Pi-L network components are memorized for the various band
>segments. The width of the band segments depends on frequency: 1.8-2.2 MHz:
>25 kHz, 2.2-5 MHz: 50 kHz, 5-15 MHz: 100 kHz, 15 to 21.9 MHz: 150 kHz, 21.9
>to 22.5 MHz: 200 kHz, 22.5 to 26.5 MHz 250 kHz and above 26.5 MHz: 300 kHz.
>In the Acom 2000A you can load into memory those presets values (obtained
>through automatic tuning is less than 1 second) for up to 10 different
>antennas (per band), each one having slightly different impedances, and
that
>for each of the band segments. This adds to a total of not less than 490
>sets of pretune-values. The correct preset values, matching a particular
>selected antenna can be recalled from the remote control panel (which band
>section, which antenna). Alternatively one can use a computer program to
>control this selection via the RS232 connector. The same program could also
>control the antenna selection, making matching of antenna selection and
>amplifier tuning full-proof. When used with the ACOM 2000S automatic
antenna
>selector and the ACOM 2000SW remote antenna switch, you are always 100%
sure
>that you have selected the correct setting for each of the antennas.
>
>
>The workmanship of the amplifier is exactly the same as we know from the
>Ahlpa amplifiers: it is perfect, in a class by itself.
>
>
>The remote control unit (hardly larger than a calculator) has an
>alphanumeric LCD display where you can read about any imaginable parameter
>of this amplifier, including quite uncommon things like filament voltage
and
>current (separate for each tube) and tube cooling air outlet temperature!
>You can measure anything you can imagine. A true luxury! When you switch on
>the linear the display will tell you how long you have to wait until it is
>all warmed up. No need to get nervous, you know exactly how many more
second
>you have to wait until it will play. An there will be no more time waiting
>with tuning up. Just apply drive (on any band) and off you go!
>
>
>At full output the amplifier runs very "cool" and you can hardly hear the
>blowers (a squirrel cage blower for the tubes and a muffin fan blower for
>the power supply). The ACOM 2000 can be pushed to the 2000 Watt output
level
>(depending on the exact mains voltage) and that for approx. 85 watts of
>drive.
>
>
>The amplifier automatically senses the driver RF signal, and switches to
the
>appropriate band segment after a band change on the exciter. To change
bands
>all you really need to do is sending a short dot, or say "a" ("b" is fine
as
>well) in phone, and the amplifiers will tune up in a fraction of a second.
>
>
>Needles to say that the use of this amplifier has greatly increased the
>flexibility and efficiency at the OTxT contest station. The amplifier has
>been used in every contest since early June 1998, and has performed
>flawlessly ever since: we have had not a single problem with it. It must be
>said that Vasko did a really outstanding job! On your operating position,
>you just put the remote control unit next to the computer keyboard, and off
>you go. A pleasure to have and to operate! I have truly never experienced
>anything like that in my whole radio amateur career.
>
>
>The amplifier has a serial RS323 port for connection with a PC. Using a
>suitable program, all functions of up to 15 amplifiers can be controlled
>from the PC.
>
>
>Inside the amplifier various microprocessors do various tasks. One of them
>continuously monitors and logs all the measurement data (voltages,
currents,
>temperatures, settings of variable C's etc). In case of a failure (it never
>occurred to me) you can connect the amplifier to a telephone line, and via
a
>built in modem, the relevant data will be down loaded to the factory
service
>center, where a the problem will easily be diagnosed. This too is a unique
>approach in servicing amateur radio equipment!
>
>
>ACOM has set an attractive end user price limit for all countries where the
>amplifier is sold. It is without any doubt that the amplifier will be a
well
>selling product. The amplifier can easily be run at 1000 Watt output by
>merely reducing the drive level. This is important for countries where 1500
>Watt is not allowed,
>
>
>The manual is extremely well done with lots of pictures and a schematic. A
>service manual is available as well.
>
>
>At this time ACOM is still setting up sales channels in different areas.
>Potential US customers check www.hfpower.com (e-mail: info@acom-intl.com).
>Outside the USA, contact ACOM at acom@aster.net for details on the current
>distributors list.
>
>By the way, tehre's a picture of the ACOM2000 in my shack on page 15-6 of
my
>new LOW BAND DX-ing book.
>
>Ghent, July 10th, 1999
>
>
>
>
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>
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>
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