On 13 Dec 2010 21:01:30 GMT, Sébastien MEDARD wrote:

I understand better what is the purpose of this kind of map (on SDR-
Radio.com software for example). Where you can see an OM, you are pretty
sure to see this kind of map.

Hi Sébastien,

If you mean the "gray line" map - yes.

When I used to teach RTTY there were only two tones.

The reason why they call you OM ? )

Touché

This will reveal the "Law of Diminishing Returns" (the more you add, the
less you get back).

Interesting. What would be the best ratio?

You mean the best number of turns? Depending upon band, maybe as many
as 6 to 10. One is good enough. There are many options to balance.
One correspondent here, years ago (silent key), wrote extensively on
this subject - google this group (or the internet) for Reg Edwards,
G4FGQ. For instance, google the keywords in:

RJELOOP1 *
Performance of Transceiving, single-turn, magloop antennas of various
regular shapes.

RJELOOP2 *
Performance of Transceiving, single-turn, magloop antennas of
rectangular shape.

RJELOOP3 *
Analysis of receiving, multi-turn, square, loop (or frame) antennas,
ELF to HF.

I will try to find one when they are cheaper.

Try:
http://www.bookfinder.com/search/?au...ic&st=sr&ac=qr

OK. But today we probably ask more to radios than yesterday, no?

No, probably less. Being an OM, (40 years ago) I also taught classes
for repair and maintenance of Collins' famous receiver, the R-390.
EVEN NOW (40 years later), this is probably the best receiver for its
price (and even two to three times its price).

The real science of low noise is found in the distance to the source.

Lapalisse would have said exactly the same thing. He would have said that
the real science of good reception is found in the distance to the source
too )

So, my comment was a lapalissade? Certainly.

73's
Richard Clark, KB7QHC