El 09-08-11 1:14, DrYattz escribió:
My 15 year old son is exploring shortwave radio, and has purchased a
Realistic DX-394a. We're experimenting with various antenna
configurations, now trying an inverted L. The layout so far can be
seen at:

http://i258.photobucket.com/albums/h...t/antenna2.jpg

So, a single strand wire crosses the yard at a height of about 14-18
feet, stretched east-west, insulated at each end, and another length
of wire connected to it drops to below a window, then passes through
the wall and to the Hi-Z antenna input. (The diagram shows a
lightning arrestor, but that isn't attached yet.)

But it seems to offer little or no advantage over the little
telescoping antenna. In fact, the best reception is when we touch the
antenna lead wire to the telescoping antenna. Do you suggest:

1) an antenna tuner?

2) coaxial cable running from the radio (Lo-Z input) to the end of the
75 foot run?

3) a north-south run?

4) a completely different configuration?

5) anything else?

Rees Chapman
winwinsit at gmail period com




Hello Rees,

Mostly it isn't the problem to get sufficient signal, but to get
sufficient signal to noise ratio. If you can operate it outside the
house (with a seperate 12V battery), try this and see whether the
reception improves. Move around to find sweet spots. You may have
interference from indoor electronic equipment and this will be less
when you are outside. Don't run an extension cord to feed the receiver
as this may carry interference from inside towards the receiver.

As this receiver is rather sensitive, a large antenna may result in
worse reception due to overloading the input circuitry. Here a so
called preselector can help, expecially when you have some strong
nearby transmitters. If you like constructing, building such equipment
can be a nice project.

If outside reception is better, you may need coaxial cable to
"transport" the antenna signal to receiver without picking up
interference from indoor equipment.

Don't hesitate to come back with other questions or suggestions.


Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM