Don't get hung up on the term "lightning arrestor". A lightning arrestor's job is to shunt damaging voltage spikes to ground and limit the potential for damage.Yes they do bleed off static but without the static being bled off the potential for a strike is MUCH greater.The picture above of the Polyphaser unit is interesting and typical of all decent units. It has DC blocking,the two wires that are connected to the antenna jacks form a capacitor that allows RF to pass but not the DC electrical energy.The small coil allows for the DC enegy to pass through to the gas discharge spark gap that is grounded yet exhibits a high impedance to any RF.All in all not a bad concept.Simple yet effective.
And what happens to the end of the cable when lightning does hit? You do realize that the insulation on a piece of coax is only good for a few hundred to a few thousand volts don't you? Imagine around a half a million to a million volts coming down that coax cable looking to get out. If it does not find a path out it WILL make it's own. Simply laying a disconnected cable over the desk or on the floor will not protect anything that is nearby in the event of a direct strike.Several years ago a friend of mine "simply unplugged " his coax as a storm was approaching.Lightning hit his A99 directly and it just plain disappeared. :shock: Unfortunatly so did a large piece of his kitchen cabinets and wall where the coax was routed. Lawson was thrown across the kitchen. He had been leaning against the counter near his radio.What good did unplugging the coax do to him? A lightning arrestor MAY have prevented the strike in the first place by bleeding off the charge that was building up on the antenna and certainly would have reduced the damage done if a strike had occured anyway by shunting some/most of the energy to ground.It was interesting to note the structural damage to the house was NOT at the antenna mounting point but rather inside the house walls along the path of the coax cable.At least that's what the fire dept. told him.Some hams I know have lost a good HF rig even when the coax was unplugged and laying near the radio. The surge induced in the cable took out the radio without even being connected to it. Does this happen all the time? Certainly not. Can it happen at any time. Certainly so.You are right it is not rocket science but it is a good lession in physics.Trust me I used to simply disconnect the cable and throw it over the back of the desk as well. Then as a broadcast engineer I started to learn more about what happens during a strike both direct and induced and I changed my mind. I had a strike many years ago that I am sure struck the tower. It was during a sever storm and I saw the flash,heard and felt the BOOM that rattled the windows, and actually heard the frying sound of the dischage from inside the house.All three things happened at exactly the same time and the flash was at the end of the house where the tower was.I found no damage to the tower or antennas but some ground was torn up around the tower base near the ground rods.I still think I was lucky dispite my preventative measures that worked.You may get lucky and never have a problem but the reason is not because unplugging the cable was the cure.It was simply because you were lucky. If you have ever seen the aftermath of a direct strike you will know what I mean.Twenty two years in the business with a total of 14 towers in the air,yep I saw some damage.I was also lucky considering what could have happened.
dont people just unscrew there coax during a storm anymore? its not rocket science.
And what happens to the end of the cable when lightning does hit? You do realize that the insulation on a piece of coax is only good for a few hundred to a few thousand volts don't you? Imagine around a half a million to a million volts coming down that coax cable looking to get out. If it does not find a path out it WILL make it's own. Simply laying a disconnected cable over the desk or on the floor will not protect anything that is nearby in the event of a direct strike.Several years ago a friend of mine "simply unplugged " his coax as a storm was approaching.Lightning hit his A99 directly and it just plain disappeared. :shock: Unfortunatly so did a large piece of his kitchen cabinets and wall where the coax was routed. Lawson was thrown across the kitchen. He had been leaning against the counter near his radio.What good did unplugging the coax do to him? A lightning arrestor MAY have prevented the strike in the first place by bleeding off the charge that was building up on the antenna and certainly would have reduced the damage done if a strike had occured anyway by shunting some/most of the energy to ground.It was interesting to note the structural damage to the house was NOT at the antenna mounting point but rather inside the house walls along the path of the coax cable.At least that's what the fire dept. told him.Some hams I know have lost a good HF rig even when the coax was unplugged and laying near the radio. The surge induced in the cable took out the radio without even being connected to it. Does this happen all the time? Certainly not. Can it happen at any time. Certainly so.You are right it is not rocket science but it is a good lession in physics.Trust me I used to simply disconnect the cable and throw it over the back of the desk as well. Then as a broadcast engineer I started to learn more about what happens during a strike both direct and induced and I changed my mind. I had a strike many years ago that I am sure struck the tower. It was during a sever storm and I saw the flash,heard and felt the BOOM that rattled the windows, and actually heard the frying sound of the dischage from inside the house.All three things happened at exactly the same time and the flash was at the end of the house where the tower was.I found no damage to the tower or antennas but some ground was torn up around the tower base near the ground rods.I still think I was lucky dispite my preventative measures that worked.You may get lucky and never have a problem but the reason is not because unplugging the cable was the cure.It was simply because you were lucky. If you have ever seen the aftermath of a direct strike you will know what I mean.Twenty two years in the business with a total of 14 towers in the air,yep I saw some damage.I was also lucky considering what could have happened.