[TowerTalk] remote antenna switch

[David Robbins K1TTT]

> 
> At 10:26 AM 3/13/2006, larryjspammenot at teleport.com wrote:
> >What are the cases for a remote coax switch with unused antennas being
> >Grounded, or UNgrounded? For example, I have a 5-band quad with an RCS-8V
> >remote coax switch. So there are four unused bands on the quad with one
> >active, since I have five separate feedlines.
> 
> Grounding is nice for dissipation of static.
> Of course, one can also dissipate static with a suitable RF choke (so that
> it's an open circuit to RF)to ground.

of course for yagi's built with certain types of matches there is no need
for either of these.

> 
> You might want to ground or not ground because it would change the
> interactions among elements (I use this to make automated measurements of
> interelement impedances in my phased array)
> 
> Depending on where the switch is located (electrically!), "grounding" one
> of the incoming feedlines has the effect of either shorting, opening, or
> putting some reactive load on the antenna it's hooked to.
>

leaving an open ended feedline will also have the same effect depending on
the length of the line.  you can only eliminate the effect by routing to a
dummy load that matches the feedline impedance.


David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
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