"Richard" wrote in message ...
"Ian Smith" wrote in message
...
"Richard" wrote in message
...
http://www.home.earthlink.net/%7Esrw...rundig-100.htm

"FM? Whazzat?


snipped

I found FM performance to be excellent from my old Grundig
Satellit 1400 (c.1983). Got many a continental European from up here
in Scotland, during Sporadic 'E' lifts in the summer.

--
Ian Smith, Renfrew, Scotland. 55.868733°N 4.399517°W, 7m asl

Yep.

Reading some comments about the Sony ICFM33RDS, and the bit I text I quoted
to start the thread, I've somehow got the impression that many modern
portable PL sets are "rap" with a capital "C"on FM. Radio Shack DX-397 and
the Sony 7600GR quoted as not being that good. Not sure how expensive these
radios are, but, the ICFM33RDS is only£35, so maybe poorish FM performance
is to be expected for this set. If I pay say £80 or £100 for a PLL radio,
maybe FM performance would get to as good as the old Grundig. I don't want
the RX to be deaf on FM, or have images from localstations all over the
band.

You've made a classic mistake, that because shortwave receivers carry
relatively high price tags, that they then offer superior FM broadcast
reception.

In the first place, a higher price tag may reflect the limited interest
in shortwave. If you have to design something out of the ordinary,
it will cost more than an average design. And if fewer people are
interested, then you have to recoup the cost by a higher price.

But more important, any design concerns will be put into what
the radio is intended for, ie shortwave. And for anyone
who understands radio design, there is virtually no overlap
between what's good for an FM broadcast receiver in the 88 to 108MHz
range, and a shortwave receiver. One is for FM reception, the other
is for AM reception. One is for wideband signals relative far
apart in a part of the spectrum that is at least three times the
upper frequency of the other, while the other is for narrow signals
with narrow spacing between channels and still at a relatively low
frequency. Shortwave and the FM broadcast band are not close
together. All of this means that there is very little where
the designs overlap. What you are buying is a shortwave radio
(and maybe/likely that circuitry is used to tune the AM broadcast
band since the frequencies are adjacent and the mode and signal
bandwidth would be the same) and an FM broadcast radio in
the same box. Traditionally, shortwave radios did not include
an FM band, with a few exceptions; it changed as small shortwave
receivers from Asian companies became the norm. In other words,
the FM BCB section is thrown in as a marketing matter.

Since that FM section does nothing for the main selling point
of the radio, that shortwave reception, then any money put
into that section will take away from the design of the
shortwave section. So realistically, one might as well
put in as cheap an FM section as possible, since it's just
added circuitry, and one can so very easily pick the
same sort of circuit that is in any average FM radio.

Buying a shortwave radio will not automatically give better
FM reception, and depending on specific design, it may be
inferior to what you could find elsewhere.

Car radios are often good, because they require sensitivity yet
also the ability to withstand strong signals. FM reception is
a key part of the design, so it gets the attention. I have various
digitally tuned Delco car radios around the house, and they are
the best FM radios I've ever had. I have no idea of the absolute
performance, just that in my passing contact with relatively low
end receivers the FM section is great. On FM, the PLL is well
designed so I don't get spurious responses. The sensitivity seems
good, yet it doesn't overload. It is rare to find a station where
it doesn't belong. Selectivity is pretty good. The other day,
conditions were great and a non-local station was booming in.
It's adjacent to another non-local station but which comes in
regular (though it's strength varies). There was no problem
that day from adjacent channel interference.

FM broadcast receivers intended for good performance will also
be good contenders. Note that you have to go for something
with a beyond average design. Just as in those shortwave radios,
FM (and AM even moreso) are considered not so important in a "hifi"
situation, so they put little money into the tuner section. You would
have lousy FM radios in consumer equipment twenty and thirty years
ago, and you have it today, whether they are digitally tuned or
not. Such receivers are intended for local reception (who would
be interested in that noisy signal from a bit further out, especially
since the ads and traffic reports aren't local?) so weak signal
reception is not a concern in the design. And as with a lot of
FM receivers, they tend to be too sensitive, but that never becomes
useful for weak signal reception because that sensitivity also
means a tendency to overload on the local and strong signals.

Michael