[amsat-bb] Re: Running Power to the Polarity Switch

w6zkh@comcast.net w6zkh at comcast.net
Fri Nov 20 06:59:45 PST 2009

I just rebuilt my rotor/antenna system here, and I am using the "spare" 2-#18 conductors in the rotor cable for each rotor as my 12 volt line to each of the yagi's. In the house, I just run to a DPDT switch and use a WallWart for the 12 volts. David, I think that long black wire goes to +12 volts, not negative, as I noted one wire went to the boom for the return, suspecting he used the coax as the ground point. I may be wrong. 


----- Original Message ----- 
From: "i8cvs" <domenico.i8cvs at tin.it> 
To: "David Wing" <david at cdwing.com>, "AMSAT-BB" <amsat-bb at amsat.org> 
Sent: Thursday, November 19, 2009 11:07:56 PM GMT -08:00 US/Canada Pacific 
Subject: [amsat-bb] Re: Running Power to the Polarity Switch 

----- Original Message ----- 
From: "David Wing" <david at cdwing.com> 
To: <amsat-bb at amsat.org> 
Sent: Friday, November 20, 2009 4:58 AM 
Subject: [amsat-bb] Running Power to the Polarity Switch 

> I'm making good progress to get my KLM and Cushcraft antennas mounted on 
> roof.I think I'll be able to wrap it all up this weekend. 
Hi David, 

Happy to hear about your progress. 
> I do have a question about the polarity switch on the Cushcraft 30 element 
> 440 antenna. The switch has one lead that seems to be intended go to 
> and the negative lead goes to the boom of the antenna. Do I need connect 
> -12vDC to the coax on my feed line in order to complete this circuit? 

No .........run please a separate wire for the -12 volt DC 

> Seems 
> easier to just disconnect the wire from the boom and run it to a dedicated 
> -12vDC lead. 

A dedicated wire for the -12 volt DC is best 

My switch on my KLM is fed with dedicated leads for + and - 
> and it seems that would be the easiest way to deal with the Cushcraft. 
Yes, I agree 
> Am I missing something obvious here? I have wires to spare and can so 
> not a big savings to me to run the -12vDC on the coax if that is the 
> why this was designed this way. 
To run power supply to the above relay I have used a coax cable RG-58 
The inner conductor for +12 volt DC and the braid for -12 Volt DC 
> Pointers and suggestions welcome. 
> 73, David 
73" de 

i8CVS Domenico 

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