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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