Towertalk
[Top] [All Lists]

[Towertalk] tower joint Conductivity ???

To: <towertalk@contesting.com>
Subject: [Towertalk] tower joint Conductivity ???
From: stevek@jmr.com (Steve Katz)
Date: Wed, 20 Nov 2002 08:15:49 -0800

> A 1.5 volt battery may not be enough to breakdown any contact
> 'resistance' in the tower joints.  I'll bet a KW of RF (or even 100W)
> does a lot better :-)
> 
        [Steve Katz]  Actually, my DVM uses 4.5V.  At 20 Ohms, that's 225 mA
through the circuit.  Still, not very much.  Your suggested experiment might
be useful, I'll try it next time -- although the 70' R25 I was writing about
is long gone (at least for me!).  R45 and 55 are pretty common AM BCB
antennas, as I see just driving around.  I wonder if the BC stations do
something special to enhance conductivity?  They probably do.  -WB2WIK/6


> Someone suggested using a CURRENT SOURCE set to 1 AMP
> and then measure the Voltage across the antenna joints.  Sounds
> like a better solution to me.
> 
> Tom  N4KG
> 
> On Tue, 19 Nov 2002 11:05:40 -0800 Steve Katz <stevek@jmr.com> writes:
> > Interesting subject.
> > 
> > I'm sure this varies a great deal, but I measured the resistance 
> > from the
> > top to the bottom of 70' of R25 that had been up for a couple of 
> > years, and
> > it was very high.  (Measurement made by attaching #12 insulated 
> > copper wire
> > to the top plate of the tower, running that wire to the bottom of 
> > the tower,
> > and measuring the resistance from "top" to "bottom," assuming that 
> > 70' of
> > #12AWG pure copper is zero.  It's not zero, but it's damned close.)  
> > In that
> > case, I measured more than 20 Ohms through the tower.  Banging hard 
> > on the
> > guy wires could change it very slightly, but not as much as I 
> > thought it
> > would.
> > 
> > I don't think I'd want 20 Ohms in series with my 50 Ohm antenna, but 
> > that's
> > just me!
> > 
> > -WB2WIK/6
> > 
> > "If everything seems under control, you're just not going fast 
> > enough." -
> > Mario Andretti
> > 
> > > -----Original Message-----
> > > From:     Pete Smith [SMTP:n4zr@contesting.com]
> > > Sent:     Tuesday, November 19, 2002 8:21 AM
> > > To:       towertalk@contesting.com
> > > Subject:  Re: [Towertalk] tower joint Conductivity ???
> > > 
> > > At 10:45 AM 11/19/02 -0500, k7lxc wrote:
> > > > >  Should I use conductive grease?
> > > >
> > > >     I would. But hard to predict the conductivity of the whole 
> > tower.
> > > 
> > > 
> > > I may be living in a fool's paradise, but I figured that with 2 
> > bolts per 
> > > leg per joint, plus the zinc-on-zinc contact of the legs on top of 
> > one 
> > > another, pressed together by the weight of the tower and guy 
> > forces, the 
> > > conductivity between sections ought to be pretty decent.
> > > 
> > > 
> > > 73, Pete N4ZR
> > > Sometimes a tower is just a tower
> > > 
> > > 
> > > 
> > > 
> > > _______________________________________________
> > > AN Wireless Self Supporting Towers at discounted prices, 
> > > See http://www.mscomputer.com 
> > > 
> > > Wireless Weather Stations now $349.95. Call Toll Free, 
> > > 888-333-9041 for additional information.
> > > _______________________________________________
> > > Towertalk mailing list
> > > Towertalk@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/towertalk
> > _______________________________________________
> > AN Wireless Self Supporting Towers at discounted prices, 
> > See http://www.mscomputer.com 
> > 
> > Wireless Weather Stations now $349.95. Call Toll Free, 
> > 888-333-9041 for additional information.
> > _______________________________________________
> > Towertalk mailing list
> > Towertalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> > 
> 
> 
> ________________________________________________________________
> Sign Up for Juno Platinum Internet Access Today
> Only $9.95 per month!
> Visit www.juno.com
> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices, 
> See http://www.mscomputer.com 
> 
> Wireless Weather Stations now $349.95. Call Toll Free, 
> 888-333-9041 for additional information.
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>