<<<Hi Rob - Agree with most all your comments - As I dig into the Centurion
deeper , there are a lot of corners cut that I would have done differently.
>>>
My biggest dissatisfaction is with the power supply. If your hv xformer
ever quits replace it with the Dahl plate xformer he makes for the
centurion.
<<<For instance the meters are lousy - and I am sure for another $20 they
could
have bought nicely damped meters - but the $20 probably translates into $40
at selling point- which I would glady pay ! The fan is marginal and for
virtually zero extra cost they could have almost doubled the cooling with a
fan from the same vendor that fits the exact same space and mounting ( their
answer to this is that then they get too many complaints about noise) - My
25 year old L7 handles that with a 30 cent thermostat in the airflow and a
30 cent resistor.>>>
I think they were really responding to requests for a quiet amp. Many of
the Centurion eham reviews comment positively on how quiet it is. I guess
it isn't an issue for light duty cycle modes. Like you, I prefer more
cooling. I'm experimenting with ways of moving more air through the rf deck
without leaving the pins undercooled.
<<<But it seems TT design philosophy is to do it as cheaply as it can
possibly
be done in some respects , but in other areas , it looks like they made it
about as hard on themselves as possible! But I guess that comes from years
of making my living designing RF stuff to make a profit. Everybody has their
own approaches.>>>
I like the led wattmeter, but i'd much rather have the aforementioned dahl
plate transformer, but that probably costs more than a qsk circuit and led
wattmeter which are marketable.
I originally thought these were nice accessories, and I do find the
wattmeter convenient, however I have learned to appreciate a stout power
supply, and lots of forced air.
<<<I have not measured the input swr across all the bands with a MFJ , but
the
Orion internal SWR (subject to some suspicion) -shows better than 1.4 over
the cw portions which is all I use 99 percent of the time. I do notice some
shift in swr at low power (300-500 watts out ) versus 1000-1300 watts out
but I think thats to be expected. The amp runs with something around 2800
volts fully loaded >>>
with the stock plate xformer, mine was at 2.8 or 2.9 kv (as measured on the
f.p. meter) and sagged to 2.5-2.6 kv upon being keyed. With the dahl I'm
getting 3.1 kv down to 2.8. at ~1.2 kw out I'm seeing 2.6 kv and 700 ma Ip
(on 40 m.). this is when driven by a Mk V. With a 200 w. PA turned down to
100 w., the Mk V doesn't fold back with 1.5 vswr.
<<<RE: Varying the length of exciter-amp jumper is an okay solution
if you spend your entire ham existence operating on only one band.
As I said , at least right now on CW , it works OK - just for grins when I
can't find anything else to do , I think I will try a even longer length to
see what happens - I suspect at the "wrong" length , even longer , the phase
angles will add up wrong again. Since its so easy to drive to a KW which is
about all I usually run , I toyed with putting in a 2 or 3 db resistive
pad - (would probably help SSB IMD too )>>>
In my experience, you will chase a moving target. An okay length on one
band will cause problems to pop up on another. Not knowing what YT1VP
wrote, I didn't know what was going on. I only vaguely knew that changing
the length of the feed between the exciter and the amp made a difference and
that there must have been some weird reactance in the line. I kept making
the jumper shorter and shorter, not wanting to have to adjust another
matching network manually. I finally gave up and started using rigs with
either an autotuner or a PA that didn't care.
<<<99 percent of what you say - you are preaching to the choir !>>>
I can't take credit for that stuff--it's way over my head--give credit to
YT1VP
<<< I had fun working with the guy who started Gates (Harris ) transfer
into
solid state and who built the first 100 KW switching mode transmitters . >>>
was that hilmer swanson?
73 hank
rob/k5uj
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