TheSG-500, PW-1 and Quadra were reviewed in QST. The SGC has a 3rd Order
IMD of -28 dB and 5th Order of -48. The PW-1 is -36 and -41 respectively.
The Quadra as -32 and -44. None are anything to write home about. Also,
the SGC had spurious and harmonic (worst case) of -49 dB vs. -60 for the
PW-1, -50 for the Quadra.
1 kW MOSFET amps should be able drop below $3K since prices are dropping for
the components. Typically, broadcast amps are made from pre-built 'pallets'
of 300 or 600 Watts from 3rd party suppliers. Even Harris doesn't make its
own amp modules, but outsources the work. A "no frills" amp without the
auto tuner, which is only needed if your loads are not near 1:1, even with a
nice switching power supply that competes in price with a tube type rig
should be only a few years away.
Ron Castro
Chief Technical Officer
Results Radio, LLC
----- Original Message -----
From: "Rob Atkinson, K5UJ" <k5uj@hotmail.com>
To: <tentec@contesting.com>
Sent: Sunday, July 16, 2006 4:27 PM
Subject: [TenTec] Solid State Amps
> I'm not sure how many hams want a no-tune amp--tuning a tube plate to low
> Z
> doesn't really bother me that much, in fact I prefer to do it myself, not
> trusting some logic circuit to tune and load for me. however I know one
> of
> the great things about the PW-1 is that it follows the icom exciters
> making
> them 1 kw transceivers which I must admit is pretty nice. Also, it's
> easier to remote the amp when it's no-tune. But I think a lot of hams
> make
> buying decisions based primarily on the purchase cost. Since they aren't
> transmitting around the clock every day of the year, operating costs
> aren't
> that much of a consideration. If I transmitted all the time, a 90%
> efficient s.s. tx would be attractive to me. So, in other words, I
> understand the broadcast industry moving to s.s. but their reasons mostly
> do
> not apply to hams, at least for now. If a s.s. 1.5 kw ham amp or even a
> 1
> kw ham amp can hit the $3K mark, then things will change.
>
> re the SGC, I did not know about the IMD problem. Ron, do you know how
> the
> PW-1 does in that department? it has a reputation for being a pretty
> robust
> s.s. amp--i heard the 1 kw pep spec is conservative.
>
> 73
>
> rob / k5uj
>
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