Originally Posted by holl_ands
There are three general types of coax surge protectors (aka Grounding Block):
1) Air Gap--relies on a spark jumping across an air gap:
Which SHOULD be inside a protective enclosure to keep out dirt & dust (most are not).
They also act as a high current conductor when overwhelmed by a high voltage event:https://www.tselectronic.com/pico/grb_hrl.html
I've yet to see any specs on breakdown voltage (probably quite high), reaction time
(probably quite slow) and current capability vs time to destruct....
but for house entry points for OTA Antenna, SAT & Cable, they "meet NEC code"....2)
Gas Tube (e.g Holland GRB-AR
) with internal spark gap:
Very careful construction means the breakdown characteristics can be controlled
inside the gas filled tube. Holland even provides detailed specs:http://www.hollandelectronics.com/ca...Protection.pdfhttp://www.l-com.com/item.aspx?id=20928
But, since they still rely on an "air" gap, the breakdown voltage is fairly high
(90 volts for GRB-AR), so don't expect them to provide very much protection to attached
electronics equipment. Also note the higher current ratings for the Toner Cable devices.
3) Solid State devices
(e.g. MOV & Silicon Avalanche, such as Holland SA-1F
have a much lower breakdown voltage (25 volts for the SA-1F) and hence will leak off
static electricity build-up and thereby prevents excessive voltages being applied
to sensitive electronics equipment. But when the solid state device is overstressed,
it will blow, meaning the only protection is whatever air gap was (hopefully???)
intentionally designed into the device.
I've seen many coax MOV type devices listed, but very few quote specs....
If you check the current specs for the Holland devices, note that neither device
will sustain high current conditions for more than a handful of microseconds---
whereas a lightning strike will typically last for many milliseconds.....so don't think that any
of these devices will provide much protection against a direct lightning spike:http://www.atlanticscientific.com/lightning.html
MOV (& Si avalanche) type devices, such as are found in most "Power Surge Protectors",
are usually combined in parallel to increase the overall energy absorbion rating (joules).
As power spikes are absorbed, individual "crystals" within each device are sacrificed,
eventually making each device inoperative....hence the need to parallel individual devices:http://www.extremetech.com/article2/...1155237,00.asp
Unfortunately, this can also slowly degrade RF signals going through Coax Surge Protectors,
which can result in significant signal attenuation that increases over time...so test frequently....
=========================================The best approach is to use a combination of either #1 or #2 for protection
against large (but very rare) surge voltage events and and a solid state devices
to drain off static electricity on a daily basis.
PS: If you have reception problems, carefully check to make sure that these devices
are not contributing excessive loss--esp if the device has undergone one too many spikes...
For more info:http://www.arcelect.com/lightnin.htm
NOTE THE USE OF THREE DEVICES!!!http://www.panamax.com/PDF/IEEE_Guide.pdfhttp://en.wikipedia.org/wiki/Surge_protector
Explains Static Electricity Buildup:http://www.renewwisconsin.org/wind/T.../Lightning.pdfhttp://www.nottltd.com/article.htmlhttp://www.atlanticscientific.com/lightning.html
OTA TV Antenna Grounding info contained in C-M Installation Guide:http://www.channelmasterstore.com/v/...l%20master.pdf
SAT Dish Grounding References (also apply to OTA TV Antennas):http://www.mikeholt.com/mojonewsarch...s~20020303.htmhttp://www.sadoun.com/Sat/Installation/Grounding.htm