AM arial

[Thunderchild]

i need to buuild an am arial to pick up shortwave (specificly around 15 MHz) any ideas in the way of size and method. i was thinking a square frame with the appropriate number of rings of wire i have a flat roof (S italy) so size is not a serious problem

[Ralph]

This is a good place to start: http://www.messaggeri.it/xradioamatori.htm
It's actually in english although it looks like you'd understand it even if it wasn't! There's lots of links in the Antenna section. What you probably want is a quarter wave dipole tuned to 15MHz. I'll have a look on my shelf later, I should have some stuff somewhere.

[David H]

Anything a fraction of the wavelength is good, and of course looping or dividing it somehow to avoid such a tall single one is a good idea. The alternative is a long wire which can be stretched out horizontally so it doesn't get in the way or need holding up. Remember many vertically mounted square or similar compound antennas will be directional, so be biassed towards the two sides for reception. Ralph's ideas are correct, as a dipole is a popular way to reduce size but keep efficiency.

[Thunderchild]

well actually being directional is perfect for me one of the reasons for the square loop antenna as i wish to get the BBC world wide service and here in S intaly that is quite difficult especially at night so being directional will help cut out some of the other starions and increase gain in that direction. theorectically the arial should be something like 5/10 meters and thats not bad actually i could do a diopol but being directional will be handy too. is it possible to do a large yagi type arial ?

[Thunderchild]

incidently it looks like the site linked in the first reply is run by an italian but lukily living in italy i understand that too although all the pages i have found so far r in english :-)