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[Amps] Solid State HF amps and kits

To: <amps@contesting.com>
Subject: [Amps] Solid State HF amps and kits
From: stevek@jmr.com (Steve Katz)
Date: Fri, 19 Apr 2002 07:43:42 -0700
Jim, I have some comments and questions contained below.  If you'd answer
them, perhaps I and other readers might have a better understanding of what
you're trying to say.

73 de Steve, WB2WIK/6


> Do you know what fabricated PCBs cost, even in short runs?
        [Steve Katz]  I think I do.  I use Circuit XPress for short runs,
and after paying the $500 setup charge per layout for Gerber file transfer,
a PCB the size and quality of the AR347 amp board is about $50/each for the
first 10 or so, diminishing to about $25/each in 100+ lot runs, assuming
high grade FR4 and 2 oz copper, tinned, plus silk screening.
> With the art work in hand, I could go to a custom board house and have
> one-off boards custom-made for less than what CCI is asking.  In a
> quantity
> run, the price would fall well below two dollars a board very quickly.
        [Steve Katz]  If you can get me these boards for $2/each, seriously,
I'd like to place an order with you today for 1000 pcs.

> And -- did you happen to check the price of the active devices for that
> 1000-watt CCI amp?  You probably will not believe me when I tell you that
> it's over $900.
        [Steve Katz]  If you buy all the parts one-off, I'm sure you're
right.  But CCI didn't design the amp, Motorola did, and I think they sell
the BOM pretty reasonably.

> On the other hand -- most of the RFE amps use the 2SC2879 device, which
> sells in small-handful quantities at about $15. each.  Properly biased and
> heatsinked, these are good for 100 watts each all day long.
> 
> So on the one hand you've got CCI selling amps made from expensive,
> hard-to-power, hard-to-cool Motorola devices, and on the other hand you've
> got RFE selling amps made from cheap, easy-to-power, easy-to-cool Japanese
> devices.*
        [Steve Katz]  I don't understand the "hard to cool" comment.  Is the
device Rthj-c higher?  What's the Rthj-c of the 2SC2879?

> The RFE amp goes straight out the door and under the dash of a semi for
> about 20% of the cost of the CCI amp -- which requires some relatively
> sophisticated work to power up.
        [Steve Katz]  All I can say is the obvious, which is: "If it's so
great, why don't they just apply for certification?"  It's not expensive to
do so.  They'd have to lock out 22+ MHz per CFR47 requirements, but could
include a retrofit kit to put 12/10m back in for licensed amateurs, same way
everybody else does.  I don't get their gripe.

> Are you starting to get a clue about the political and societal
> ramifications of the RFE decision?**
        [Steve Katz]  Not really.


> Jim N6OTQ
> 
> 
> 
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