[AMPS] Decision time Approaches
km1h@juno.com
km1h@juno.com
Sun, 18 Oct 1998 16:53:26 -0400
On Sun, 18 Oct 1998 08:05:18 -1000 "Jim Reid" <jreid@aloha.net> writes:
SNIP prior to wandering
>But I wander. The tubes in the Henry units intrigue me; they are
>"instant on"!. My present linear mandates a 3 minute wait before
>it will operate after powering up. What is different here? Some sort
>of un-needed cathode warm-up or chemical emission enhancement
>process required in 3CX800's not needed in 3CX1200D7's or the
>3CX3000A7 triodes? Any comments about the tubes Henry is using;
>guess they have used them for decades, or so, hi.
Instant on are the tungsten filament tubes.....3CX1200, 3-500Z, 3CX3000,
etc....actually instant-on should add a good 15-30 seconds for safety.
In those amps you apply the RF directly to the filament.
Other tubes such as the 3CX800, 8877, 4CX250 series, Russian tetrodes,
etc use indirectly heated cathodes. It takes some xxx amount of time for
the filament to heat the cathode up to the proper level. The filament is
isolated from the RF which is applied to the cathode.
Hope that rather brief explanation does NOT add to the confusion.
73 Carl KM1H
>
>To get real high (out of the rules) power out, one must have an
>intermediate driver amplifier to boost ones transceiver power
>up to the 300 to 400 watt level.
>
>So why go to the 8K, or why would I even consider it? Because of
>my natural conservatism; it would represent margin and headroom,
>probably better linearity of the triode transfer characteristic in the
>Pout range of interest to me; and probably very long lasting, under
>utilized components. Now the 8K spec says it will draw 40 amps
>from the 240 volt, single phase supply. However, I presume that
>is only at, or near max output, as I am sure Henry does not have
>the triodes biased in Class A , hi! Though that seems to be
>where a triode is most linear in the transfer characteristic.
>
>Before ordering, I guess I have to stew about the decision a bit
>longer,
>and I need to know the exact dimensions of the controller sitting on
>the
>desk, and of the height, etc. of the remotable unit. Does Henry
>supply
>the mating cables, etc. Seems unusual, but Henry uses a BNC
>connector as the input to the amp.
>
>Yesterday, I had the great pleasure of visiting the Pacific Super
>Contest
>Station, KH7R over on the far North tip of the Island of Oahu, just
>above
>the world famous Waimea Bay beach and world class surfing.
>
>Wow!!
>Six towers, one per band, up to three beams per tower, inc 3 ele on
>40! Eight over eight on 10, etc. Plus, at least 12 Henry 3KA, D,
>and
>Classics sitting around; one at each of five band stations, and a
>bunch
>of spares sitting toward the center of the LARGE contest operating
>room. The place was a bee hive of activity in preparation for next
>weekends CQWW SSB test! I was fascinated by the strategy planning
>in progress: Band captains were pouring through computer print outs
>of
>when various prefix's were first heard last year on each band, etc.,
>etc., etc. Just amazing activity, both the the many, many pieces
>of
>equipment and towers, as well as the CT computer network, and
>all that planning on going. However, I took careful note of all the
>Henry's sitting around with carefully marked control settings, etc.
>Never knowing which may be pressed into service on which band,
>the attached crib notes on each amp told exactly what control
>settings to dial up to get a quick head-up on any of the contest
>bands (except 160, there a solid state unit from one of the Japanese
>companies is used, as I recall).
>
>Anyway, I digressed again, hi. Lets see. Oh yes, noticed that
>the
>power switches were on the base of the Henry's at KH7R; that would
>seem to defeat part of the feature of the remote capability of the
>Ultra, if one had to go to the remote unit to turn things on when
>a linear was felt needed in a hot DX pileup a building!
>Also, wonder if the Henry is internally by-passed when not
>required, so that all that is needed to bring the linear on line
>is to just switch it on.
>
>Oh yes, the Ultra's have vacuum relays, which can approach
>QSK CW, and they are pretty quiet, so my Ten Tec OmniVI+
>should get along with an Ultra just fine in QSK mode.
>
>So anything else I ought to consider before giving up on my Alpha
>87A of great service these past seven years to go on to a Henry Ultra?
>
>73, Jim, KH7M
>On the Garden Island of Kauai
>(Queen Emma gave Kauai the Garden Island designation after
>her visits here in the 1860's, 70's, where she had a home not
>quite a mile from this QTH just above the mouth of Lawai stream).
>
>
>
>
>--
>FAQ on WWW: http://www.contesting.com/ampfaq.html
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
>
___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
or call Juno at (800) 654-JUNO [654-5866]
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm