[TowerTalk] Protecting Control Lines

[Steve, W3AHL]

A much better part in my experience would be the Littelfuse TVS diode series, such as:

http://www.littelfuse.com/products/TVS+Diodes/Axial+Lead/5KP.html

They have 1 ps turn on time, lower clamping voltages and are very reliable.   I did extensive testing on them about six years ago, primarily for an industrial fork lift computer.  They handled high repetitive rates of sustained currents (from the motor counter EMF) and ESD discharges over 30KV with no problem.  I've seen them used on CAT6 Ethernet transient protectors also.  Other manufacturers make similar parts, but Littelfuse was by far the best when I was evaluating them.   The 15KP series is even better, but aren't readily available from stock anymore and haven't gotten rather expensive at $25+ each in small quantities.

For DC circuits use the type A unidirectional model.  For AC use the type CA bidirectional version.

They are available from Digikey for about $3.50 each.  Search for 5KP.

Steve, W3AHL

Date: Fri, 8 Oct 2010 00:14:24 -0400
From: Mickey Baker <fishflorida at gmail.com>
Subject: [TowerTalk] Protecting Control Lines
To: towertalk at contesting.com

Are the devices sold for "lightning protection" of rotator and control lines
all simply gap+MOV protectors? Perhaps GDT?

Is one better than another? I respect your opinion, but do you have a
technical, non-anecdotal reason to believe which is better?

They seem damn expensive for what they are, so I'm considering building one.

Has anyone built a protection block?

I found these resettable fuses/MOVs while shopping to build one:
http://www.circuitprotection.com/catalog/2ProDS.pdf

Anyone used these?

(I don't have any relationship with any component manufacturer - this isn't
a plug.)

73,

Mickey N4MB