MOVs and shielded rotator cables are also recommended in the ARRL antenna book 20th edition and I use them for that purpose for decades. Andrees rotator cable can´t be laced to the tower as it is a three segment crank up tower.
73 Peter -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Jim Brown Sent: Sonntag, 23. August 2020 23:04 To: [email protected] Subject: Re: Topband: Rotator Potentiometer shunt fed twr On 8/23/2020 12:39 PM, [email protected] wrote: > Bypass the rotor with thick ground lead from the rotating pipe mast to the > tower Yes. This solves other issues. use ceramic bypass capacitors on the pot contacts and MOVs or low > voltage spark gaps to ground on all lines to the rotor and controller. MOVs are a very bad idea, and I see no benefit from the caps. > Use screened rotor cable, with the screen grounded to the tower at top and > bottom. I don't see the need for this. If the rotator cable is laced to the tower (most prefer the inside of a tower leg) it will be at the same potential as the tower all the way along the height, thanks to capacitance between the cable(s) and the tower. Remember, this is RF, not DC, and the current we're talking about is antenna current, which is near a maximum at the base an minimum at the ends of the elements of the Yagi(s) that serve as top loading. 73, Jim K9YC _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
