[TowerTalk] Protecting rotors from lightning?

[jeff millar]

Ted...

I can tell you what I did. I put a box on the tower near the rotor that 
contained a long bakelite terminal block. At each terminal I put an MOV 
to ground with a low inductance braid connecting all the MOVs. Wire the 
lead to the rotor and the lead to the house to the terminals. This put 
an MOV to ground on each line to the rotator. The ground side of each 
MOV connects to the box, which connects to the tower, which connects to 
the rotor case. This prevent an significant build up of voltage between 
cable and case or between any two conductors.

This was a VHF installation, so the Preamp power and relay control lines 
got the same treatment.

Here's some commercial versions
http://www.transtector.com/productdetail?item=1101-859
http://www.transtector.com/productdetail?item=1101-756

For best protection, put one at the top and one at the entry of the 
rotor cable to the shack. I chose to add MOVs to the inside of the rotor 
controller from each control line to case. But that's a compromise 
compared to protecting at a common entry point for everything.

On the wire thing, my last installation used 6 pair Telco wire with 
several in parallel for the motor lines (crude but effective).

jeff, wa1hco

Ted Rappaport wrote:
>   
>> From: Ted Rappaport <trappaport at austin.rr.com>
>> Date: November 20
>> Subject: [CTDXCC] Protecting rotors from lightning
>> I am putting up two m2 rotors and am wondering the best way to protect
>> them and the shack from lightning. would anyone be willing to have a
>> phone conversation with me today or over weekend?
>>
>> Also does anyone have any 306 wireman cable for the m2? Seems like
>> there is a world shortage and I need some runs very soon. Lihgtning  
>> smart alternatives?
>> tnx ted n9nb
>>