[SJRA-Members] Roof Mount Tower Install. Instrs.: Would you add or change anything?

[John Jones]

Thanks Bob. I have received SO much conflicting information about this
subject. My shack's RF ground is a copper bus bar that's attached to the
house ground and my end fed antenna's ground wire is attached to it too. I
was told that they HAD to be attached to it in order to be in compliance.
When it comes to grounding, you can ask two people and get three different
opinions. Ugh!  I wonder if the Construction Office issuing the permit is
going to require that I use a licensed electrician to do the ground and get
it inspected. I'll see. If not, I suspect that I'll add a ground rod like
you suggest and ground the antenna to it. My house ground is in a location
where's it's surrounded by my patio, driveway, and walkway so it would be
really hard to link this new ground rod to it. Hard and expensive.

On Wed, May 6, 2020 at 10:49 PM Bob Beyer <bob_beyer at verizon.net> wrote:

> Hi John,
>
> Grounding can get complicated and a well thought-out, comprehensive ground
> system would ultimately "bond" a house's electrical ground to an overall
> ground plan (that's plan, not plane).
> Among other things, this would include a number of distributed ground rods
> exothermically welded to a specific kind of heavy copper cable running
> around the house in a continuous ring and buried beneath the surface of the
> ground.
>
> However, if you're just going to do single point grounding of the tower
> and mast and not setup a comprehensive ground system, I would by no means
> recommend you connect it directly to your home's electrical panel.
> That would effectively be like extending a lightning rod from your
> electrical panel to the a point at least 6 ft. above your roof.  "Hit me!
> Hit me!"
>
> Years ago I had a ham friend who was a licensed electrician.  In addition
> to many commercial and residential jobs, he worked on the installation of
> the Tokomak Reactor at Princeton Plasma Physics.
> One day his 75' crank-up tower was struck by lightning and it burned out
> his submersible well pump.  He said that in his experience, most lightning
> damage he saw "came in on the ground" of the electrical system.
> While this seems counter intuitive, it actually does occur.  As I
> understand it, a lightning strike can momentarily elevate the potential of
> a home ground to a voltage potential greater than the potential of the AC
> mains feed into the home (typically 240 VAC).  At that instant, flow from
> the energized ground can occur back toward the AC power lines by passing
> through any electronics, appliances, lights, etc. in circuit.  Putting a
> lightning rod on your roof and connecting it to your electrical panel would
> be an ideal way to create the potential for this to occur as I see it.
>
> Also, the electrical code may not allow this kind of ground connection
> either but I am not certain of that.
>
> Unless you are going to setup a complete grounding system now (time
> consuming and expensive), I suggest that you drive one or more ground rods
> into the ground and connect the mast and antenna to them with the heaviest
> gauge wire you can afford. Something like No. 4 or even larger.
>
> If you want to learn more about good grounding practices, there is an ARRL
> publication written by Ward Silver, N0AX, called "Grounding and Bonding for
> the Radio Amateur".  Amazon carries both the paperback and Kindle versions.
>
> If there are electricians in the audience or those with more experience
> and expertise than me, I am happy to be corrected on any of this.
>
> Bob - KE2D
>
>
> -----Original Message-----
> From: sjra-members-bounces at mailman.qth.net [mailto:
> sjra-members-bounces at mailman.qth.net] On Behalf Of John Jones
> Sent: Wednesday, May 06, 2020 10:05 PM
> To: sjra-members at mailman.qth.net
> Subject: [SJRA-Members] Roof Mount Tower Install. Instrs.: Would you add
> or change anything?
>
> Thank you everyone for your advice. I purchased the K4KIO Hex Beam Antenna
> with all six bands (20 - 6), ice cords, snap on balun, and universal clamp
> for masts 1.25" - 2.5".   https://www.k4kio.com/
>
> I'm mounting it on a W8IO Roof Tower (Model IO-45) and a 1.9" OD x 0.150"
> wall x 72" length 6061-T6 aluminum mast.  Please see *Page 5* of the
> attached installation instructions and give me your thoughts. If anyone has
> a roof tower like this one, I'd love to hear your grounding
> recommendations. Did you ground it to its own ground stake or to your
> house's main ground?
> http://www.w8io.com/rooftower.htm
>
> *NOTE: The antenna, roof tower, and mast have already been purchased so
> there's no need to recommend alternatives. *
>
>