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Re: [TenTec] SB220-Tubes and QSK

To: tentec@contesting.com
Subject: Re: [TenTec] SB220-Tubes and QSK
From: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
Reply-to: geraldj@storm.weather.net,Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 03 Nov 2007 19:23:04 -0600
List-post: <mailto:tentec@contesting.com>
On Thu, 2007-11-01 at 18:32 -0500, Rob Atkinson wrote:
> Hi Chuck,
> 
> We've pretty much veered off from ten tec gear so I'll sign off by
> saying that I think at this point, the problem with a marketable s.s.
> ham amp is that several areas in the design start getting expensive
> above 1 kw.  The PA transistors are still fairly pricey, but also
> because of the power (and perhaps the spectral purity requirement) you
> need a relatively high d.c. voltage from the p.s. (48 v. usually I
> think) and a lot of current so the p.s. gets pretty expensive.  I
> think you also need separate QRO bandpass filtering on the antenna
> side (8 bands, 9 if six m.) so the combination of power and the need
> for operation from 160 to 10 m. makes the filtering/combining/ant.
> tuning costly on the antenna side of the PA.  There was an outfit at
> dayton this year with an operating legal limit s.s. amp that looked
> like a beauty but I think they wanted a nice piece of change for it.
> The company's name was Dishtronix I think.    Anyway, tube amps remain
> a lot cheaper in watt/dollar terms and in the ham market price is more
> important than electric service expense and mean-time to failure
> maintenance costs as hams aren't broadcasting (well, most hams aren't
> hi hi).
> 
> I've heard that the s.s. broadcast rigs have become very
> reliable--what problems there are seem to be mostly in the power
> supplies.  Harris is selling 200 kw to 2 mw s.s. rigs now.
> 
> http://www.broadcast.harris.com/product_portfolio/product_details.asp?sku=WWWDX200AM
> 
> http://www.rwonline.com/reference-room/special-report/2006.03.29-05_a_rwf_yingst.shtml
> 
> 73,
> 
> rob / k5uj
> 
> 
> 
There are a couple solid state HF amps advertised in QST the past few
months. Round about $4k for each.

73, Jerry, K0CQ

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