On 8/20/2011 12:34 PM, Jim Thomson wrote:
> Date: Fri, 19 Aug 2011 19:05:55 -0400
> From: "Roger (sub1)"<sub1@rogerhalstead.com>
> Subject: Re: [Amps] Any new tube research?
> On 8/16/2011 2:01 PM, John Lyles wrote:<snip>
>
>> As a designer of power amplifiers using both tubes and transistors, I
>> see a good trend in solid state, with 1200 watts or more per device. But
>> I don't expect to see a megawatt in a device, something that I can and
>> do see with new tubes. Ham radio will eventually quit using tubes except
>> for nostalgia reasons;
> I really don't see wide adoption of SS legal limit amps until the
> devices can be made more rugged, can be cooled more easily, and become
> available at much lower prices. Prices are based on tooling set up
> costs, number of units produced per batch, amount of silicon in the die
> compared to the base wafer size, and yield efficiency. At present they
> are just too fragile and the protective circuitry (which is more
> complicated than the amp) really pushes the prices far too high for wide
> spread adoption.
>
> Except for quite expensive and complex amps (or medium power) I really
> don't see solid state amps becoming wide spread. 800 to 1000 watts
> seems to be the current limit or dividing line between the high priced
> spread and the rest of the pack.
>
> ## I looked at a buddy's 1kw CCS commercial marine SS amp... and it was
> the most complex thing I have laid eyes on [2-30 mhz]. 4 x RF modules, with
> 4 x mating power supply's. Then the usual mess of combiners, then complex
> control
> and protection circuits. My FT-1000D is easier to work on, and figure out.
I had one of the Tokyo Hy-Power HL-1.5Kfx amps. It ran an honest KW out
160-10 and 800 watts out on six meters.
It was auto band switching(with band data signal from the exciter), but
power fell off rapidly with even a small increase in SWR. As I use a
manual tuner with my antenna analyzer I was able to pre-tune on any band
using the preset logged data from the tuner and a fine tune only took a
couple of seconds so I could change bands quite quickly ... faster than
I can with my current manual tune amp.
>
> ## My problem with these SS amps is the eff on all of them sucks. 50% isn't
> good, and that's only when they are run at full bore. Reduce the power output
> a bit, and presto, ur now down to 36% eff. Heat generated stays the same!
> TX imd is nothing to write home about either.
I never measured the efficiency, but the fans were almost silent and the
amp ran cool pushing it for all it was worth. I never put it on a
spectrum analyzer so I have no idea as to the IM, but I did regularly
receive unasked for complementary signal reports./ They did recommend
you add an auxiliary fan if running digital.
>
> ## another buddy had am Icom SS amp, VERY expensive. It had just gone out
> of warranty, when
> he had a spike come in on the 240 vac line....which took out EVERY transistor
> in the amp. The repair
The HL-1.5Kfx was a bit pricey for the power level, but was handy.
> bill was gawd awful. By using groth type, or similar turns counters for
> both my vac tune + load caps,
> I can switch bands.. like from 16-15m, in 45 secs flat. Just set the turns
> counters to the logged
> pre-sets. One setting will easily cover 14.100 to 14.300 on both a
> 3CX-3000A7 and a 3CX-6000A7,
> plus most other bands. None of us will ever be able to afford a SS 5-12 kw
> pep output cw/ssb amp in our
> lifetime's.
>
> ### Almost forgot something. These SS wonderbars also require the mating
> 2-10 kw, full automatic ant
> tuner's...so they don't blow up in your face. Most of em don't appear to
> enjoy operating into a 2:1 swr.
The one I had would just back off on the power, unless the SWR was too
high and then it'd just trip off. A quick re-tune with the analyzer
through the AT5K and it was back in business.
In my opinion that little amp had some good protective circuitry, but
again it was pricey.
You could probably build at least two YC156's ... or more, including
power supplies... for the price of that SS KW.
I know I could purchase a new legal limit amp with lots of overhead
that'd run digital 24X7 for about the same price. True, it weighs 3
times as much, I have to tune it up when changing bands, and when
working hard the fans are noticeable. <:-))
73
Roger (K8RI)
>
> ## I can see a place for SS amps up to maybe 500 w out...and with mating
> switching type supply's and also
> the requisite mating auto tuner, and clean IMD. [which usually implies sky
> high idle current, low eff, loads of heat, etc]
>
> Later... Jim VE7RF
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|