On Wed, 28 Dec 2005 02:16:10 GMT, Bob Miller
wrote:

On Wed, 28 Dec 2005 01:40:32 GMT, David wrote:

On Wed, 28 Dec 2005 01:03:28 GMT, Bob Miller
wrote:

On 27 Dec 2005 13:03:44 -0800, "RHF"
wrote:



IMHO - For the Shortwave Listener (SWL) using a Receive Only
Random Wire (Single Wire) Antenna the Pre-Selector is the
better of the two devices to use. Especially when used in
conjunction with a 9:1 Matching Transformer along with a
Coax Cable Feed-in-Line.

The 9-1 matching transformer works great if the antenna impedance is
450 ohms and it is being matched to a 50 ohm antenna input, a 9 to 1
transformation. But what if the impedance of the antenna is 2000 ohms,
or 10 ohms or 800 ohms? It's a crapshoot with a long wire, because you
don't know what the impedance really is.

An antenna tuner, on the other hand, can be varied to match a wide
range of antenna impedances to a 50 ohm input.

bob
k5qwg


True, but for a modern receiver insignificant.

The main thing is that you're not exceeding the impedance of the
transmission line.

And the impedance of the transmission line is ... ???

bob
k5qwg

RG-58 is 50 Ohms, RG-59, RG-6 is 75 Ohms.