First Home Antenna - Grounding Question

[W9DTC]

I'm thinking about purchasing an Arrow J-Pole Antenna to opperate my soon to arrive FT-7900R. This is my first Ham radio and antenna at home.

I understand I can probably mount this to a plumbing riser comming out of the roof, or possibly on the facia near the top of one of my gables. That all seems pretty simple. Then I just need to run proper coax down from the antenna to my radio. My question/concern is regarding proper grounding. This concern is related to not only getting a good signal but also in relation to possible lightening hazards.

Any input would be greatly appreciated!

 

[lbfd09]

A simple answer will not do, particularly with you being in Indiana.

Here are so good links that talk about lightning and grounding for such.

Lightning protection for Amateur Ham Radio

Ham Radio Lightning / Grounding


Welcome to the hobby.

 

[W9DTC]

The first link seems to suggest I should have the biggest ground possible.

The second obe seems to be full of dead links.

Thanks for the info

 

[Spud]

More info

With the Arrow J-pole antenna you mentioned, the grounding will not make any significant difference in your transmitted or received signal.
The primary reason for providing a good connection to ground is to incourage any lightning strike (or the majority of it) to follow that preferred path to ground.
Any time that there is storm activity with potential lightning in your area, you should disconnect the coax from your equipment and place it a fair distance away from equipment or people.
The use of a good ground system will increase the level of protection for your house but no ground system, coax switch or lightning arrestor system can provide complete protection for you or your equipment.
Number 10 copper wire from the antenna that follows the shortest path to an 8 foot copper ground rod beside the house should be a reasonable ground system for the antenna system that you are proposing.

Even without any outdoor antenna system, lightning can still strike a house and get into the electrical wiring or metal plumbing of the home, causing plenty of damage. (This is a fairly common occurance where I live in Colorado but I have been lucky over the last 30 years.)

Another note: Anytime your place takes a lightning hit (even if you do not find any damage), contact the local fire dept and have them respond to investigate. Our local dept has equipment that they used to detect heat sources inside the walls and other areas of the building. It is not unusual for wiring or other metal in the structure that has been significantly heated by the lightning strike to cause a fire to start well after the strike occurred.


73,

The Spud

 

[WA4VBC]

I don't claim to be an expert in the area of grounding, so from a legal viewpoint, use this advise at your own risk. However, I would take exception to the advise to disconnect the antenna cable. I would rather have the antenna cable properly grounded at the point of entrance to your house and a good lightning arrester (properly grounded) at the radio end. If you want to disconnect the cable, then it should be properly grounded when disconnected and not floating. Sid.

 

[LtDoc]

If whatever you mount that 'J'-pole with is metal (mast/tower) then use that as the 'conductor' to a good safety ground system. A typical metal mast will provide much more 'conductance' than a wire will, so why not use it? A simple/single ground rod is NOT adequate for a safety ground. Lots of 'debate' about that, but reading the NEC should at least give you a fair idea of what's adequate or not. (National Electrical Code). Also keep in mind that those recommendations are the -minimums-.
- 'Doc

 

[Spud]

A reply

David stated that he was mounting the J-pole on a plumbing riser on his roof. I assumed that this is a PVC riser and described a basic ground system for that type of installation. (It is better than having no ground path other than the coax.)
I certainly agree that a 1 to 2 inch diameter ground-mounted metal mast would provide a better conductor for the eneragy of a lightning strike than any copper wire. Using a metal pole to support the antenna is a better option if it is bonded to a good ground system with heavy copper straps at the base.

A good lightning arrestor bonded to a good ground system at the entrance point into the house will provide additional protection.

I also agree that grounding the end of the coax after disconnecting it from the equipment is certainly preferred to leaving it floating but I would surely not leave it attached to the equipment (unless it is insured for replacement value). Not everyone has the option of grounding the coax at the equipment end.

Keep in mind that the primary goal is to have the energy follow a preferred path to ground. Even on the commercial communications towers that I have worked on, not all of the energy follows the preferred path every time. You just hope that the portion that does not is small enough to avoid any damage to structures or systems.

73,

The Spud

 

[W9DTC]

Thanks for the info all.

As I mentioned, this is my first radio. I figure I'll have to play with it as a mobile unit for a while before I build up the home base antenna (the radio arrived yesterday, but my mobile antenna is still out on somebody's delivery truck someplace... hopefully today!). I do believe I'll go ahead and run a ground wire directly to a ground rod if/when I do this. Better safe than sorry. The plumbing riser is PVC, so that isn't going to get the job done. Additionally, my house is pretty much the highest thing around for several hundred (if not a couple thousand) feet... and then is only slightly shorter than anything else for miles (this area of Indiana is flat, flat) I believe I'd be a fool to not install an ample lightning mitigation system.