[CQ-Contest] Receive antenna switch

Herbert Schoenbohm herbs at vitelcom.net
Thu Jan 15 00:20:48 EST 2015

John,  For a two wire Beverage with two separate feed-lines (eliminating 
the need for a relay a the feed point) it is important that the unused 
feed point is terminated in the feed-point impedance to reduce 
inter-coupling of noise and signals from the opposite direction.

Herb, KV4FZ
On 1/14/2015 8:44 PM, john at kk9a.com wrote:
> The AY Technologies http://www.aytechnologies.com/ RAS-12 has momentary push
> button switches for each radio and it has eight ports. It also has a
> built-in preamp. This is a great product and it is very easy to use. I am
> not sure if unused are terminated, why is that important?
> John KK9A
> To:	cq-contest at contesting.com
> Subject:	Re: [CQ-Contest] Receive antenna switch
> From:	Herbert Schoenbohm <herbs at vitelcom.net>
> Date:	Wed, 14 Jan 2015 12:56:00 -0400
> I use here a retired Dynair 12X1 passive video switcher. One nice feature is
> that each unused RG-6 cable which runs to reversible two wire Beverages is
> terminated. With feed line length equal to 1/2 wave (includes the cable
> velocity factor.) the 75 ohm termination appears at the unused port at the
> feed box. The only down side is that the push buttons move a connection on a
> long bus inside and take a finger pressure. It would be great if someone
> would market a desk top remote with momentary light touch switch or with a
> computer interface. I have several Ameritron 8X1 along with the RCS 12 but
> that only gives me 8 positions. it also does not terminate the unused ports.
> The DX-Engineering 8X1, (RR-8B) which can be driven by the desktop RCS-12
> has provisions for unused port termination, but to use a 5KW switch for a
> bunch of Beverages seems a git of a over-kill. Hopefully something will be
> on the market soon as there seems top be a need for something that will
> control many Beverage inputs.
> Herb Schoenbohm, KV4FZ
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