On Sat, 11 Dec 2010 16:21:29 -0800, Richard Clark wrote:

On 11 Dec 2010 23:28:18 GMT, Sébastien MEDARD wrote:

For now, I tried a lot of different things... The best result were on
loops.

Hi Sebastien,

This is a good lesson.

Thanks. I think I will try long wire again... I don't like to give up
without fighting a little bit. But perhaps I will try it outdoor putting
my receiver in the car outside any city or in a place where I get some
place. So everything about antenna tuners need more investigation.

A big loop (1.6mx4 = 6.4 meters), one turn, with an air variable
capacitor + an inside loop connected to the coaxial cable seems to give
better ways to give something to eat to my receiver.

This is an excellent antenna for BCB and Tropical Bands.

The problem seems to be related to wave propagation... I need to test
that a little bit more but... It is easier to receive radio broadcast
during the night. I need to know what are the differences between night/
day for wave propagation. What should I listen during the night and what
I should better listen during daylight...

I need to know a little bit more about digital transmission modes... To
be able to recognize digital patterns (on the waterfall display) to be
able apply the good settings for decoding... Easy for CW... Easy for RTTY
used by HAM... But what is the pattern for Meteo Faxes for example...?

By the way... I searched for good free software to decode meteo faxes...
But it seems not easy to find something free and easy to use... Do you
know shere I could find something interesting?

Sometimes my air
capacitor was not powerful enough, in the lower bands if I remember
well... To improve that I will have to add a fixed capacitor (lets say
300pF) in parallel (to be bypassed) or more depending on the band I am
listening to.

This is a great solution.

This is something I found on a website.... When you don't know anything
about electronics... Your learning curve is quite flat ))

For now I am just experimenting (with some simple wire), but I think I
will build a more solid one...

A big loop (1.6mx4 = 6.4 meters), one turn, with the the universal
balun from Wellbrook. Don't know why, but, it gives very good results,
far better than a long wire in my flat, or a short wire on my balcony...
At this time it seems there is a Ham Contest in Italia... I can get them
fully on 80m LSB/CW/RTTY... Well I live in South of France, so it is
easier for me ))

One point to consider, this large loop will not perform the same when
its diameter is large when compared to the wavelength you are tuning to.
Your longwire with tuner will probably be better in the 50M band and
higher.

I need to make a tuner first... Then I will tell you about it.

However, experimentation may prove different, especially if you
can tip the loop over (or change its angle to earth).

Well.... not so easy for now... My "experimentation board" is a big wood
shelf with a lot of books on it... Not so easy to flip, rotate or.... But
it is well oriented (east-west)

My next tries will be on a multiple turns loops. With or without matching
loop inside. I will try with simple wire but connection ribbon cables
could be a good alternative... (like old hard drive ribbon cable)

I was wondering... It seems loop antennas are a never ending story. As
far as I know, it seems there is no book that makes a good overview of
the different loop designs, with accessible schematics for preamp or
tuning stuff, how to avoid QRMs... There could be a very interesting area
both for SWL and HAM...

Perhaps the "Joe Carr's Loop Antenna Handbook" may be interesting, but it
is quite expensive and an Amazon reviewer says it is not so
interesting... What about the "Joe Carr's Receiving Antenna Handbook" ?

Sebastien.