Topband: rx antenna switch

[Dick Wilborg]

In fact, the Radio Shack A/B & A/B/C TV switches are quite good. What makes
them especially useful is the fact that in addition to 100+ db isolation
between ports, the unselected ports are automatically internally terminated
into 75 ohms!
The only problem I have occasionally had is the internal 75 ohm resistors
get burned from nearby lightning.  Sometimes repairable!  Otherwise, just
buy another.
Great for Beverages!
Cheers,  Dick   W1ZC

-----Original Message-----
From: topband-bounces at contesting.com
[mailto:topband-bounces at contesting.com]On Behalf Of Brad Rehm
Sent: Thursday, September 04, 2003 3:18 PM
To: Michael Tope; kb5njd at arrl.net; topband at contesting.com; Ronald Gorski
Subject: Re: Topband: rx antenna switch


>Has anyone actually used one of these switches successfully for this
>purpose?  Could the fact that they are advertised as "high isolation"
>indicate that these are not just simple switches and may not pass a
signal
>in the HF/MF range?

A few years ago, I met the designer of a few of these Radio Shack
switches.  He happened to mention that they had paid close attention
to maintaining constant impedance and achieving good port-to-port
isolation in the design.  There were no networks or gimmicks in the
switches he had been associated with.  From business associations, I
know there are some good RF guys in the Tandy Towers in Fort Worth.

The only problem I've had with one of my switches has been that the
mechanism goes bad and the switch stops toggling.  But they're not
expensive....

The fact that they're 75 Ohm devices shouldn't be important for top
band applications.

73,
Brad
KV5V

_______________________________________________
Topband mailing list
Topband at contesting.com
http://lists.contesting.com/mailman/listinfo/topband