On Mon, 2008-01-07 at 23:00 -0600, Bob McGraw - K4TAX wrote:
> Folks, if we are going to discuss this, lets get some data either in dBw or
> uV values. Otherwise, what's an S-9 signal and a S-2 signal?
>
> Frankly, with >60 dB isolation, a signal on the inactive input won't be
> heard above atmospheric noise on the active input.
>
> 73
> Bob, K4TAX
>
>
And that minuscule coupling can be eliminated when the inactive input
isn't being used by covering the coax connector with a cap to shield the
center pin.
Otherwise DowKey makes relays that improve the isolation by grounding
the center conductor of the open connector.
But its hard to achieve much over 50 or 60 dB isolation because two
single shielded (if Belden quality) coaxes side by side will couple that
much. It takes double shielded or hard line to achiever more isolation.
Take off 30 dB isolation of the coax came from Radio Shack.
73, Jerry, K0CQ
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|