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Old February 23rd 06, 09:29 PM posted to rec.radio.shortwave
David
 
Posts: n/a
Default Boost Existing Radio Ferrite Antenna

On Thu, 23 Feb 2006 19:19:28 GMT, Telamon
wrote:

In article .com,
"bpnjensen" wrote:

You could get a big ferrite rod from a supplier or off EBay, wrap
several dozen antenna windings around it, and then place it next to and
hopefully parallel to the ferrite inside your old radio. Ground one
end of the wire, and string out the other end of your wire as you wish.
Coupling effects should increase your reception. This would be cheap
and noninvasive, and portable too.

If you can open the radio up, you could even place the new wrapped rod
next to the old one (making sure that there is no direct conductive
effect) and try that. If you do this, watch out, though - if too
close, the stronger signal may overload your inexpensive rig.

Otherwise, wrapping insulated wire around your existing ferrite core
and stretching the remainder around your apartment might work just
fine.


I vote for the second idea using the existing core with another winding.
The purpose of the core is to increase the inductance per turn. This is
accomplished by concentrating the magnetic field of the coil and as such
will make it harder to magnetically couple between two coils with cores.

You could make an air coil tape it on the outside of the case near the
internal antenna coil inside the case.

This is messy but you could wrap the wire around the outside the radio
case so it's coupled to the internal core with the antenna one one end
and ground on the other.

If you're going to the trouble of opening up the case, why not connect
directly to the antenna cicuitry though a suitable DC block?