Sony ICF-SW55 versus ICF-SW77
John Struthers
Can anyone comment on Sony's new ICF-SW55 radio receiver in comparison
to the ICF-SW77 ? What are the performance and design differences ?
Thanks in advance.
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Name: John Struthers - GM8CVN
Organization: Hewlett-Packard Ltd Queensferry Microwave Division
Email: jo...@hpqmola.sqf.hp.com
Address: South Queensferry, West Lothian, EH30 9TG, Scotland, UK
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Opinions expressed are my own, and are not intended to be an official
statement by Hewlett-Packard Company
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Michael Schuster
>
>Can anyone comment on Sony's new ICF-SW55 radio receiver in comparison
>to the ICF-SW77 ? What are the performance and design differences ?
This is a difficult question, since the SW-77 is a moving target. Reviews
of pre-production samples, and of the first production run, have pointed
out various performance problems which cause a virtual recall of this model
worldwide. Initially, for instance, the 1992 WRTH receiver reviews (by
Jonathan Marks) said that bells and whistles notwithstanding the cheaper
SW-55 out performed the SW-77.
If you stick to recent samples of the sets, the SW-77 basically has
synchronous detection (which can reduce the effects of mild fading
distortion), more memories, more precise readout and perhaps a more
stable BFO. It is also much larger and uses more battery current.
The SW-55 has been noted by netters to have a couple of problems which
SONY, to date, has not admitted to. First, there seems to be a mechanical
problem with circuit board fabrication/assembly which can lead to
intermittent BFO operation in some samples. Second, the BFO tends to
"pull", or change pitch slightly with variations of signal strength.
This is similar to, but not nearly as bad as, the first production runs
of ICF-2002. You would think that in the FOURTH GENERATION product of
this class Sony would finally get it right, but ....
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Graham Oberem
>Can anyone comment on Sony's new ICF-SW55 radio receiver in comparison
>to the ICF-SW77 ? What are the performance and design differences ?
A friend of mine is buying a Sony 2010 and called several well known
suppliers. He found most of them out of stock but was told by at
least one vendor that the Sony 2010 is being discontinued and that the
ICF-SW55 is the replacement/next-best-thing.
This surely can't be true. The 55 doesn't even have a synchro detector
system.
Any comments?
Graham, N7UGT
Seattle
Edward Peschko
>Any comments?
>Graham, N7UGT
>Seattle
I`m looking for information on the SW-55. Is the 2010 a better
radio. And exactly what is a sunchro detector? Any information would
be appreciated.
Thanks
Michael Schuster
>
> I`m looking for information on the SW-55. Is the 2010 a better
>radio. And exactly what is a sunchro detector? Any information would
>be appreciated.
The 2010 is a more capable receiver. It features a synchronous detector
like the SW-77; the SW-55 does not.
Briefly, a synchronous detector phase locks with an incoming carrier and
replaces it with a strong stable internally generated one. This
reduces the distortion cause by mild to moderate fading of the signal.
It on some radios it also allows tuning to one sideband in order to
reduce the effects of adjacent channel interference.
John Struthers
schu...@panix.com (Michael Schuster) writes in article
<1992Apr20.2...@news2.cis.umn.edu>
<1992Apr22....@news2.cis.umn.edu>
> The SW-55 is an excellent radio but some units seem to suffer from a
> quality control problem which can lead to intermittent BFO operation.
> The BFO circuit tends to change pitch slightly with strong variations
> in signal strength; this makes it sound a bit "warbly". You could not
> use this radio for fax, RTTY, or morse decoders, for instance.
Has anyone else observed this behaviour in the SW-55 ? What impact does
it have on the readability of strong SSB signals ? Are Sony aware of
the problem ?
Thanks, John S
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Name: John Struthers GM8CVN
Michael Schuster
>
[details of SW-55 BFO 'pulling' on modulation peaks deleted]
>Has anyone else observed this behaviour in the SW-55 ? What impact does
>it have on the readability of strong SSB signals ? Are Sony aware of
>the problem ?
Sony is =not= aware of this, and I'm not entirely sure it's a "problem".
Sporadic reporters in different countries have all noted it, however.
I mentioned this to Larry Magne (who's only tested one SW-55 with no such
problems) and he believes it's probably unit-to-unit variability. Danny Goodman
had one "fixed" by his SONY repair center who said nothing was wrong with it.
Under duress they exchanged it for a new one, which also had BFO shift on
strong modulation peaks.
Someone near me has an SW-55 and absolutely swears there is no problem. So
the unit-to-unit variation may really be operative here. Magne will test
another Sw-55 in a few weeks looking exactly for this sort of thing, and
get back to me.
So ... it's only a problem if the one =you= buy has it <grin>.
The problem is subtle. SSB signals are perfectly readable, they just warble
ever so slightly when very strong. Considering the fact that with a radio
having only resolution to 100 KHz you NEVER get perfect SSB sound anyway,
it's probably a minor gripe. As to what this would do for someone attempting
WEFAX or RTTY demodulation ... I'd imagine it could be disastrous.