Mea culpa (KPA-500)

[ynkedragon]

Thanks Wes, N7WS, for sending me back to my calculator.

500 watt output is indeed 7dB greater than 100 watts, not the > 5 dB I previously stated.

Even better.

73, Blair K3YD







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[k6dgw]

[hidden email] wrote:
> Thanks Wes, N7WS, for sending me back to my calculator.
>
> 500 watt output is indeed 7dB greater than 100 watts, not the > 5 dB
> I previously stated.
>
> Even better.

7 dB is 1.1667 International Standard S-units.  10 dB [1KW vs 100W] is
1.6667 ISS-u.  1.1667 ISS-u can make a fair difference in a pile-up,
0.4999 ISS-u more -- mabye not so much.

Capital Costs:  The KPA500 is alleged to cost around $700. A good 1-1.5
KW solid state amp generally runs something over $2,000 and up.

Operating Costs:  @ 50% efficiency, 2KW averaged over the 48-hr CQ WPX
CW [30% duty cycle, our hypothetical contester calls CQ continuously] @
$0.16/KWh will run him $28.80 and presumably other 48-hr marathons would
do likewise [CW WPX SSB, CQ WW CW, CQ WW SSB, ARRL DX CW, ARRL DX SSB,
ARRL SS CW, ARRL SS SSB] $230.40 for electricity.  Snack food, aspirin,
coffee to keep you awake through all these contests, and all the chores
you have to do before/after the contest to "make it up" to you-know-who,
are fixed costs -- equal for both amps.

KAP500 looks like a good deal to me.  Of course, there's the opportunity
loss during NAQP's where you don't use the KPA500, but the six of them
each year only last 10 hours each.

This does not factor in replacement costs, which could be substantial in
the case of the "big" amps.  How much do 500 2N2222's cost?  You can do
the math.

[Andrea is *very* happy our income when I was employed did not depend on
my cost-benefit analysis skills :-)]

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2010 Cal QSO Party 2-3 Oct 2010
- www.cqp.org
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[Ken Kopp-3]

Fred, I --think-- the estimated cost of the KPA500
you reference is in error by almost a factor of three.

73! Ken Kopp - K0PP
       [hidden email]


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[Richard Squire - HB9ANM]

Fred,

I'm afraid you got mixed up with prices here.
$700 is the price for the P3!
My guess is you'd have to multiply that by a factor 3 or so...


"Capital Costs:  The KPA500 is alleged to cost around $700. A good 1-1.5
KW solid state amp generally runs something over $2,000 and up."

73
Richard

[k6dgw]

Richard Squire - HB9ANM wrote:
> Fred,
>
> I'm afraid you got mixed up with prices here.
> $700 is the price for the P3!
> My guess is you'd have to multiply that by a factor 3 or so...

I must have mixed up the P3 thread with the KPA500, there have been "a
couple" of posts on both subjects :-)  If you're right, $2,100 is likely
outside my budget ... unless Wells Fargo will let me run a deficit like
the guvmint.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2010 Cal QSO Party 2-3 Oct 2010
- www.cqp.org
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[N5GE]

On Wed, 21 Apr 2010 15:03:06 -0700, Fred Jensen <[hidden email]>
wrote:

Call the Chinese Consulate in your area.  They will give a loan and
let you just pay interest on it forever, but you will have to let them
advise you on how to live.

>I must have mixed up the P3 thread with the KPA500, there have been "a
>couple" of posts on both subjects :-)  If you're right, $2,100 is likely
>outside my budget ... unless Wells Fargo will let me run a deficit like
>the guvmint.
>
>73,
>
>Fred K6DGW

TOM, N5GE BT 73 ES GUD LUK
AR DE N5GE SK

http://www.n5ge.com

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