[TowerTalk] control cables lightning protection

[Kostas Stamatis]

Tnx all for your help.
I like the Grant's idea with TVS.
I use a yaesu g1000 rotor and my control cable uses 12v.
Grant can you help me what exactly i need to buy? Mouser is good for me.
If i have understand ok, this is something like a diode and  i should 
connect it between controller and rotor, looking to rotor. ok?
I have found in my local electronic store some arrestors like this
http://www.karson-arrester.com.hk/catalog/001.pdf
What do you think about it?

Tnx agn
73 Kostas SV1DPI

----- Original Message ----- 
From: "Grant Saviers" <grants2 at pacbell.net>
To: <towertalk at contesting.com>
Sent: Friday, June 24, 2011 9:17 PM
Subject: Re: [TowerTalk] control cables lightning protection


> Vishay makes Transient Voltage Suppressors (TVS) in clamp voltages from
> 10 volts to several hundred volts.  A common size can handle a 1500 watt
> surge.  They are very fast, I think faster than MOVs and have a sharper
> knee so the clamp voltage doesn't rise as much as MOVs with increased
> current.  Both unidirectional (diode in reverse) and bidirectional (for
> ac circuits) are available around $1 each qty 1.  For low power
> circuits, they are a good choice.  I think the construction is basically
> back to back heavy duty zeners for the bidirectional version, at a price
> far below stud mount zeners.
>
> for one TVS source - see Mouser
>
> http://www.mouser.com/Circuit-Protection/TVS-Diodes-Transient-Voltage-Suppressors/_/N-5g3g?P=1z0z819Z1yzv44xZ1z0x7vi&Keyword=tvs&FS=True
>
> OTOH, MOVs are available for 10,000's of joules in the screw mount
> sizes, for motor, power contactor, or mains transient suppression.
>
> Grant KZ1W
>
> On 6/23/2011 11:52 PM, K8RI on TT wrote:
>> On 6/24/2011 1:15 AM, Kostas Stamatis wrote:
>>> Hello to all...
>>> I want to protect from lightning and static charges my rotator cable as 
>>> a
>>> controller cable for a switch. I have seen some solutions in 
>>> DXengineering
>>> but i would prefer a reliable homebrew solution. Anyone with some ideas?
>> Diacs were mentioned, but those are more of a control device.  Neon
>> lamps (NE-51s) work well with tube input and control but are a bit high
>> in voltage for rotator control.
>>
>> For low voltage protection, I'd (1) keep the cables inside the tower and
>> bypassed to the tower at the rotator and base of the tower.  The problem
>> with solid state circuits is the need for a low clamping voltage.  They
>> make some huge Zeners with a 3/4" threaded base which will handle huge
>> current. Used are normally very cheap, but new are very expensive.  the
>> nice thing about the big zeners is you can get one just a few volts
>> above the maximum working voltage of the circuit. These are one place
>> where I do favor MOVs.  As the rotator lines are low voltage and
>> relatively protected by their very nature *IF* they are protected at the
>> rotator and base of the tower the voltage is unlikely to rise very high
>> and MOVs may last a very long time...but no guarantee.   The same with
>> the massive Zeners.
>>
>> There's the possibility of using 0.1 uf disk ceramics (You need a low Z
>> at 1 MHz) on each of the leads at the rotator, and those or zeners or
>> MOVs at the base of the tower and bulkhead connector at the station
>> entrance.
>>
>> I think most rotator damage comes from cable pick up, or from wiring
>> pick up in the house with the current going back to the rotator.
>>
>> 73 and good luck,
>>
>> Roger (K8RI)
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