On Wed, 27 Sep 2006 04:13:19 GMT, Telamon
wrote:

In article g40vCXBzNU8x-pn2-Q82zQcWLtrec@localhost,
"Count Floyd" CountFloyd@MonsterChillerHorrorTheater wrote:

On Tue, 26 Sep 2006 03:55:29 UTC, weatherall
wrote:


Wrote:
DE11 kinda pricey . .

http://tinyurl.com/rl6n2

I think the price of the DE11 is too high based on what it gives you.
The Tecsun PL200 is full-featured, receiving all of the 3-30 mhz
shortwave spectrum, but it is a single-conversion radio.
Damn, you would think in 2006 that single-conversion radios were not
even being made! I have an old S-38 and an HE-10, both single
conversions, but they were made in the '40's and '50's! They still
pull in great DX on the BCB though and the tubes keep my room warm in
the winter!

Snip

That's because the age of the design has nothing to do with whether it
is 1, 2, or 3 conversion. There were double and triple conversion
receivers back then.

What determines the number of conversions is cost.
You can make a fairly respectable single conversion receiver, but
there are a couple things you need to do to get reasonable image
rejection, and selectivity. Raise the IF frequency to several Mhz, and
put a tuned rf amp in front of the mixer. That usually required a
crystal filter for good shape characteristics and good selectivity.

Triple conversion is more about being able to put the final IF down
low enough that you can get very sharp skirts, and narrow passbands
without an especially high Q filter. I.E. a bandwidth filter with a Q
of 100 gives you a 10Khz passband at a 1Mhz IF, but at 50Khz, it is
only 500Hz wide, very suitable for CW, and an L/C filter costs a lot
less than a real multipole crystal filter.