[TowerTalk] Crank Up Tower Conductivity

[Chris]

So a lightning bolt comes down through two miles of AIR (which is an insulator), but it won't jump a gap .010" between the sliders on the tower legs?

Also, aren't crank up towers Ufer grounded by default, since the anchor bolts go a decent depth into the concrete?

Chris
KF7P




On Oct 24, 2017, at 11:39 AM, Don W7WLL wrote:

> That was the question I have Steve and I don't truly think it is a non-issue, particularly with the crankup tower instructions I've read re lightning protection.
> 
> My interest was piqued by the discussion of the requirement to ground all cable legs, the number of ground rods to use, wire/strap size, etc. This is just not feasible that I can see with a crankup so was interested in best approach. Should I have more ground rods. If so, how should they be placed or spread? Should I depend on a single base ear tower ground where that ear is attached to the tower ear by just the pressure of the galvanized bolt fastening? We suffer a lot of salt buildup on everything and depend of course on anti-seize to ensure the bolts can be later separated. I see no way to utilize the solutions suggested for fixed rigid towers such as the hefty and costly clamps to crankups.
> 
> So, is the cable system within the crankup tower sufficient for a lightning strike? The cables are well lubed (I live on the ocean and use the lube and lube process recommended by the local marine cable rigger who installs tons of rope cable on the fishing and crabbing fleet). As well, the cables are connected only by contact to the pulley wheels and the thimble contact at the ends.
> 
> Yes, the tower sections certainly touch in some way but my inner tower section facings are lubricated, so am unsure just how robust the contact area is.
> 
> Summary - just wondered what others did with their crankups re creating a grounding system as robust as those that have been discussed for fixed towers (or can you?).
> 
> Don W7WLL
> 
> 
> 
> 
> -----Original Message----- From: k7lxc--- via TowerTalk
> Sent: Tuesday, October 24, 2017 8:11 AM
> To: patrick_g at windstream.net ; towertalk at contesting.com
> Subject: Re: [TowerTalk] height of ground rod at tower base
> 
>> The movable sections of a crank-up tower are never so perfectly balanced
> that they don't touch each other.? I suppose you could connect a wire
> from each section to the one below such that it reaches from clamp to
> clamp when the tower is fully raised and "bulges outward" in a non
> interfering manner when the tower is lowered.
> 
>   Isn't the tower already continuously conductive?  What about the cables that connect each section? Isn't this a non-issue?
> 
> Cheers,
> Steve     K7LXC
> TOWER TECH
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk 
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>