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Whats this coax in a fruit jar stuff?

Cat Driver

Active Member
Feb 2, 2007
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Lake of The Ozarks
I read in another forum about sticking the radio end of the coax in a fruit jar when there is a thunderstorm near. :shock: :LOL:

I never heard of such silly crap. :p

If lightning will travel a mile through air it'll surely travel 6 or 8 inches out of a glass jar. :idea:

Ronnie
 

Yup. And when the charge gets to the end of the cable it's going to keep going in the form of an explosion that will fill every square inch of everything around that jar with about a bazillion slivers of glass.

I think some of the folks who come up with these ideas must have been drinking sumpin' out'n thet thar fruit jar.
 
While this will not work if you have direct strike, it will prevent the static build-up from jumping to your equipment and destroying sensitive components. A better solution is to get an antenna switch which grounds the unused positions and has a grounded off position.

Rich
 
I guess some folks think that since glass is an insulator it will prevent the lightning from getting out of the coax end somehow.I agree the best thing is to disconnect the antenna at point of entry and ground whatever cable is left inside the house.Somehow I do not think a mason jar makes a very good plasma container.I have jokingly refered to high voltage filter capacitors as canned lightning before but I have never seen anyone sucessfully bottle lightning, well except for a layden jar, but you get my point. ;)
 
Lighting is a funny thing, this could turn into a long thread. What do you do with the coax ? What Hamming X said is the best. I have allways disconnected and hung the coax on hooks on the wall behind my radio table or let it lay on the floor. If you get a direct hit I don't think it really matters what you do with it except what Hamming X said. I got a direct hit 9 years ago that took out $3000 worth of stuff, luckly home owner insurance came through. One guy I know has not disconnected in 15 years and has never had a problem.
 
I know a lot of TVs cant be wrong--been hooked up for many years without a problem.

I think a good solution is use a lightning arrestor.

Better would be to ground the coax outside the home, not inside, with a switch or grounded connector.
 
do not buy a "lightning arrestor".

these things are very cheaply made, and are for static discharge, not lightning.
also, they wont handle much over 200 watts.

i have personally seen pictures of what a KLV1000 will do to one.
not good.

it is a false sense of security they provide.

the only real way to deal with a direct lightning strike is with a "polyphaser"
they cost about 60.00 and are what the broadcast stations use for their remote towers.

a polyphaser and a well grounded station are the only safeguards from a direct hit.
loosecannon
 
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loosecannon said:
the only real way to deal with a direct lightning strike is with a "polyphaser"
they cost about 60.00 and are what the broadcast stations use for their remote towers.

a polyphaser and a well grounded station are the only safeguards from a direct hit.
loosecannon

I don't know what you can buy for $60.00 but it certainly is not what the broadcast stations use on their towers. I was a commercial broadcast engineer for 22 years and I only wish I could have gotten something for ten times that price that would protect my gear.I had three phase power protection on one transmitter and each of three MOV's in that unit cost more than $60.00.One FM transmitter had an LEA protection unit on it's single phase power line that cost $3000. Most of the protection comes from grounding,grounding, and more grounding.Nice wide strap at least 4 inches wide and NOT soldered but rather bronze welded and tied to an extensive ground system is what does the trick.The AM towers had lightning arrester balls at the base to shunt the arc to ground,a high impedance to RF coil at the antenna tuning unit to bleed static off before it could build up enough,another lightning spark gap, a series blocking capacitor of around 10-20 Kv rating to help block the DC, and the coax cable was grounded at the point of entry into the building and again just inside the building.The FM antennas were grounded to the tower which was grounded at the base and all cables had the shields tied to the tower every 20 feet and were grounded at the base of the tower at the point of building ebtry and again just inside the building.The grounding cables outside the building were as big as your thumb,I forget the actuall gauge but was at least OOOO .I might buy a $60.00 protector to put on something at home in case I forget to disconnect it but there is no way it will protect a broadcast installation that just screams "Hit me!" every lightning storm.
 
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i apologize for the confusing statement.
i definitely could have worded that better.LOL

the person who turned me onto the polyphasers is a broadcast engineer, and i know for a fact that what he recommends to the amateur and cb camps is NOT what he uses at the broadcast facilities that he services.

the point i wanted to make is that 60.00 is the absolute LEAST ammount of money that you need to spend on a piece of equipment meant to protect you from lightning.

agreed that without proper grounding, the polyphaser would be useless.

i wanted to point out the distinction between a "lightning arrestor" which is next to useless, and a polyphaser which is a big step up in protection.

i am sorry for creating confusion.
doesnt polyphaser make products that are used in the broadcast industry?
i was led to believe that they do.
0000 is the ground cable that i use.
i got over 100' of it for free!
thanks for clarifying, i think this is an important subject that still is very misunderstood by many radio operators.
loosecannon
 
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Ok loosecannon,I thought you meant that a $60.00 device was all you needed to protect your tower and gear from a strike. :shock: Now I see what you meant,I think. :? I see a lot of people refer to "a polyphaser" when in fact Polyphaser is simply a company name sort of like saying I'll go buy a Kellogs when in fact you mean a box of Corn Flakes. Polyphaser makes some of the best lightning protection units available and they have everything for all power levels and applications. I believe the $60.00 units are simple an MOV meant to shunt voltage spikes and are meant for an individual piece of gear not a whole station.
 
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right on.

still learning this stuff, and it helps to know who to listen to.
(and who not too!)

would you mind making a recommendation on something that would be satisfactory for a station, say about 1,000 watts, that could withstand a lightning strike?

we are assuming that the station is already properly grounded to a single point ground. (including the house wiring and everything else)

i guess price is an issue, but you get what you pay for so...

thanks for any insights,
loosecannon
 
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This may sound like a cop out but I try and not reccommend what someone SHOULD buy for lightning protection but I will suggest they NOT buy a particular item. The reason being that lightning is so hard to fully protect against and I do not want to be responsible for something going wrong. In order to fully protect a piece of gear or a whole station multiple things must be done. Each coax line should have a lightning arrestor installed similar to This One. Also the AC power source must be protected with something like This as a bare minimum. Don't forget to protect your computer Telco line. Even something as simple as placing a few turns in any cable before it comes into the house will offer enough inductance that it will impede the flow of a strike and make it want to seek ground elsewhere.We always had a one turn loop in the feedline,which was simply c o p p e r tubing,going from the tuning hut to the tower.Yes even one turn can help believe me.

As for myself I have a 40 foot tower that is WELL grounded at the base.The antenna mast is bonded to the tower using 1 1/2 inch wide braided c o p p e r strap for flexibility around the rotor.I have a gas discharge tube type arrestors on my main coax feedlines. The cables themselves,coax,rotor control etc., all come down the tower and end in a large single loop at the base before coming in to the house underground.This helps choke off any energy from a strike.The telco line is protected by a surge supressor in the basement at the point of entry. The shack power outlets have MOV's (metal oxide varistors) installed in the outlet boxes and the power bars are Belkin (?) with surge supressors built in and an alarm that sounds if the protection should fail at any time.I am working on redoing my cable entrance to the house and plan to have a panel where all the coax cables, rotor cable, antenna relay cables, etc will terminate and be protected at a common point in the basement. Also a neat access panel with grounding will be installed in the wall behind the desk in the shack.I'm working on it now but my requirements keep changing as go. LOL. My cable type precludes me from simply unhooking them and tossing them out the window so they must be well protected as they will always be terminated inside the house. I use Andrews LDF4-50 which is 1/2 inch heliax and is quite rigid.During the summer months I always leave my antennas dicsconnected at the shack end just in case. During the winter I just leave everything connected as usual.Lightning is one of those things you can never do too much to prepare for.
 
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loosecannon said:
do not buy a "lightning arrestor".

these things are very cheaply made, and are for static discharge, not lightning.
also, they wont handle much over 200 watts.

Depends on which one you are talking about.

Maybe you were thinking of this plyphaser lightning arrestor?

polyphaser-02.jpg
 
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dont people just unscrew there coax during a storm anymore? its not rocket science.
 

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