Centaur 411

[Duane Calvin]

I ran some tests on my new Centaur 411 last night for power and got the
following results:

        POWER OUT     XMTR   XMTR 
 FREQ   411   Bird    SWR    DRV W    Ig    Ip   Notes
 ----   ----  ----    -----  -----   ----  ----  ------------------
 1800    450   575    1.5:1    80     135   640  arc 1st pass
 1900    130    50    1.5:1   100     140   750   "   "   "

 3500    540   600    1.7:1    90     130   640   "   "   "
 3990    530   520    1.7:1    90     125   600   "   "   "

 7000    500   510    1.5:1    90      90   625   "   "   "
 7350    500   520    1.5:1    90     140   600   no arc

10100    510   630    1.3:1    80     110   650   "   "

14000    500   520    1.6:1    90     130   610   "   "
14350    500   530    1.5:1   110     100   700   "   "

18100    460   460    1.7:1    85     115   625   "   "

21000    380   360    1.6:1    70      80   550   "   "
21450    290   250    1.6:1    75      80   615   one SNAP!

24900    350   210    2.5:1    30      70   310   no arc

28000    350   370    1.8:1    55      70   580   "   "
29000    400   440    2.0:1    65      85   700   "   "
29700    320   320    2.1:1    70      80   725   "   "

XMTR Driving: ICOM IC-765, autotuner disabled, full avail. pwr
Bird Model 43 peak-reading wattmeter; MFJ Versaload "cantenna"
style dummy load (ceramic resistor in 1 gal transformer oil).

I've included the measured Ig and Ip readings as well for
completeness, and in case they present a helpful clue.

Two full sets of measurements were taken and the results closely
correlated.  Arcing occurred many times in the TUNE capacitor
on 160 and 80 meters on the first pass through the measurements,
and once on 40m.  After tuning at the high end of 15m the first 
time, there was a loud snap (discharge) from somewhere inside.  
On the second pass through the measurements, no arcing was heard.

Sitting in front of the amp for the length of time it took to make
all the measurements each time made the fan noise all the more
difficult to listen to.  My only reference so far is an Alpha 76
(1.5KW, brick-on-key) which is almost silent.  It would seem that
something quieter could be found (I'd even be glad to install it!).

I'm concerned about the power reduction noticeable from 17m up.  
The high end of 160 is of little concern to me, but there is a
problem there too.  10m is derated in the specs, but I don't see
any better performance on 12m or 15m.  

Hopefully, there is some problem on my end, but my results appear 
to be similar to Paul's, mentioned earlier.  

  Duane, AC5AA


Duane A. Calvin
ac5aa@juno.com  -or-  duanec@prodigy.net
day:  dcalvin@austin.ibm.com

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