[TenTec] OT: THHN Wire in Germany

[Robert Mcgraw]

I agree with Jim on this.  I use insulated #12 or #10 solid wire.  I
don't just push the end through the insulator hole but make a complete
loop or turn through the insulator hole, folding the wire back on itself
and secured with a copper split bolt clamp.  This prevents the wire
working through the insulator as it tightens around the insulator with
stress.  The clamps are the kind used for making electrical connections. 
They can be found in the electrical department of local hardware or
electrical supply stores.  They are not wire clamps typically used for
securing guy wire ends.  The split bolt clamps are suitable for
connecting the feed line to the antenna wire.  No soldering needed.

73
Bob, K4TAX




> On 4/24/2013 10:05 AM, Joel Hallas wrote:
>> FWIW, my experience indicates that solid wire is more likely to break
>> from
>> metal fatigue than stranded. Stranded also seems less likely to kink
>> during
>> installation -- death to wire under stress.
>
> Yes and no. In my experience, with antennas under considerable stress
> (see previous post in this thread), the key is to make every single
> termination (end insulators, center insulators) in such a manner that
> the movement at any point is minimized.  I've had failures of both solid
> and stranded copper of comparable size, and the cause was HOW I rigged
> those connections, not the choice of stranded or solid.
>
> As an example, I loop the ends of a dipole through egg insulators, and
> secure the ends in place by placing multiple clamps on the wire where it
> has doubled back on itself.  I use either split-bolt connectors or
> U-clamps for this.  I do something similar at the center insulator,
> bringing the wire through either another egg insulator and down to the
> feedline connector, or through a thimble to the mechanical element of
> the center insulator, and then loop it down to make the electrical
> connection. Whatever the method, I try to rig that loop to minimize any
> movement when the antenna or feedline move in the wind.
>
> Another important point -- solder degrades the mechanical strength of a
> joint, and will often CAUSE failure.  I've learned that split-bolt
> connectors are a far better way to make both mechanical and electrical
> connections, and I often use several of them at the feedpoint -- at
> least two for the mechanical connection, and usually two for the
> electrical connection.
>
> In my experience, both copperweld and Flexweave are LOUSY for antennas
> because their mechanical properties are poor.  They may be OK for low,
> short antennas with little stress, but they do NOT hold up with flexing
> nor with pulling stress.  I bought several spools of Flexweave and built
> some antennas with it. All were on the ground within a year or two. My
> ham friends in Chicago have had similar experiences under much less
> stressful conditions. My neighbor, W6GJB, a very smart aeronautical
> engineer who works in the space program,  built an 80/40 fan dipole
> using stranded copperweld and very good construction techniques (I
> helped him do it). It lasted two days when we strung it between a couple
> of his redwoods.  We rebuilt it using the hard drawn copper I described
> in an earlier post.
>
> 73, Jim K9YC
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