"Bob" wrote in message
...
AJ Lake wrote:

If you only tested your tube receiver against *some* receivers then
your claim about outperforming *all* SS receivers would be invalid.

I've tried them against the *very* *best* receivers available today, and
they win in /every/ respect. They're actually hybrid receivers - I
happily
use semiconductors where they're more appropriate (like in synchronous
demodulators, audio filters, audio amplifiers, local oscillators and so
on), but the really crucial parts - the RF amplifier, first mixer, IF
amplifiers and product detectors all use bottles.

There's one crucial parameter that's carefully omitted by most
manufacturers, which is the behaviour of their receivers in the presence
of
strong adjacent frequency interference. The intermodulation, de-sensing
and other disasters inherent with semiconductor designs mean that I'll get
better results /every/ time.

I've designed /commercial/ solid-state receivers, and there's just *no*
*way* to get results as good as can still be obtained from valves in
crucial parts of them!

I haven't seen /any/ digital processor
that assists me in actually picking signals out of QRM.

*You* not having seen any doesn't mean there aren't any.

I've tried most of the stuff on the market, and /none/ of it can really
enhance a truly good receiver. They /might/ compensate for the obvious
shortcomings of some of the more average receivers!

pseudo-selectivity given by digital filters with all their nasty
artifacts)

Selectivity is not usually my problem. With close neighbors and a low
wire antenna, it's man made noise that is my problem. Digital does
well with this.

I'm in the happy situation that I don't suffer from too much of that,
despite living in a city (London). There are some really effective
noise-cancelling methods that have been published over the years - one
approach I used successfully in my old QTH was the counterpoise method
that
was published years ago in RADCOM.

I'm happy for you if you're happy with your digital Rice Box

Yes we have hams here that are also 'Rice Box' prejudiced.

I'm not prejudiced at all - as soon as Far East Asia produces something
even
half as good as I can build, I'll save time and effort and buy them! In
the interim, I'll continue with what I consider to be the real essence of
our hobby, and build the gear myself!

Prejudice for everything produced in Asia is silly these days.

Not at all - they /still/ can't make a good mobile phone! 8-)

Bob

The biggest issue is manufacturing costs. DSP can do a few neat tricks, but
most of those were doable with analog circuits. DSP also adds to the noise
floor. What they are really doing is saving money on quality physical
components like filtering. I had my TS2000 right next to my TS830 and the
830 sounded so much better I almost took the 2000 back. There seemed to be
some high frequency noise that I really couldn't hear but I could sense it
and it gave me a headache after a while. It actually FELT noisy. It wasn't
until I hooked it up to my SP230 that I honestly couldn't tell the
difference in the audio and performance of the 830 and all was well. BUT
the TS830 had better adjacent frequency performance because of the 8 pole
crystal filters. I would still have that radio but I had to move and made
the choice for general coverage. I still have a TS130, and I use that at
Field day to swap out those new high dollar big shot radios that can't hack
the signal overload. It seems the TS130 uses Bandpass filters in the front
end, injection and exciter stages in addition to the 8 pole crystal filters.

There are RF tubes that can do up to 10 meters with plenty of gain and much
better overload capabilities than what's out there now. It might cost a
fortune to use that quality of filtering in a general coverage receiver, but
you COULD build a really first class hybrid that blows away what's out
there.