We're up to three different confirmed sources now...
Have heard of the lamp cord trick. This will be used on 15 meters, so
the dielectric is really important.
I used 75 TL some years ago and I remember well how difficult it was
to dress and strip without nicking the conductors or creating a
flashover point. Zip cord does take care of the nasty stripping
issues. But also after a while, the little groove gets filled with
stuff and the characteristics really degrade when it's wet.
Easiest way to get the conductors free at the end is to melt the
plastic off the end with a torch Have a second pair of hands get the
wires with needle nose pliers in each hand. Pull the wires straight
apart as you melt the plastic just further enough to get the length of
free wire you need. Let it cool and strip what's left on the wire as
needed.
Do it outside so the fumes can blow away. Keep a hose handy. Easy to
set it on fire.
The stuff is light, and won't flutter destructively in the wind like
the ribbon/ladder lines. Also doesn't seem as affected by water on the
surface.
Just a pain to work with.
Thanks again, all. 73
Guy K2AV
----- Original Message -----
From: "Steve Katz" <stevek@jmr.com>
To: <n8de@thepoint.net>; "Doug Faunt N6TQS +1-510-655-8604"
<faunt@panix.com>
Cc: <olinger@bellsouth.net>; <towertalk@contesting.com>
Sent: Tuesday, June 17, 2003 5:45 PM
Subject: RE: [TowerTalk] Source of 75 ohm twinlead?
> I hope Van Gordon really has some of the 72 or 75 Ohm stuff, and
it's just
> *listed* under "450 Ohm Ladder Line" as a misleading heading,
because I
> haven't seen any for sale in years. None listed in the latest
Belden
> catalog, or any other transmission line catalog I have. As a last
resort a
> few years back I tried some PVC insulated #18 ga lamp cord whose
only label
> was UL1950 600V 6A or something like that, and it actually measured
quite
> consistently at about 70 Ohms, even at 100 MHz (used a 70 Ohm dummy
load and
> directional coupler with signal generator and RF microwattmeter). I
tried a
> few different six or eight foot lengths cut from different parts of
the 500'
> spool, and sure enough, 70 Ohms with very little deviation. Wonder
how
> consistent it is from brand to brand and spool to spool? The PVC is
> probably a bit lossier than polyethylene, but most of the loss would
be in
> the skin resistance of the wire.....-WB2WIK/6
>
> "Success is the ability to go from failure to failure with no loss
of
> enthusiasm." -Winston Churchill
>
> > -----Original Message-----
> > From: Don Havlicek [SMTP:n8de@thepoint.net]
> > Sent: Tuesday, June 17, 2003 2:31 PM
> > To: Doug Faunt N6TQS +1-510-655-8604
> > Cc: olinger@bellsouth.net; towertalk@contesting.com
> > Subject: Re: [TowerTalk] Source of 75 ohm twinlead?
> >
> > 450 home ladder line is NOT 75 ohm twinlead!
> > I have some of the 75 ohm, but not enough to help you.
> > Don
> > N8DE
> >
> >
> > Doug Faunt N6TQS +1-510-655-8604 wrote:
> > > VGE/ Van Gordon Engineering, 216-481-6590, seems to be
advertising it
> > > in the July 2003 WORLDRADIO, page 11; 13ga at $0.20/foot. It's
listed
> > > under "450 OHM LADDER-LINE".
> > >
> > > 73, doug
> > >
> > > From: "Guy Olinger, K2AV" <olinger@bellsouth.net>
To: <towertalk@contesting.com>
> > > Date: Tue, 17 Jun 2003 16:44:33 -0400
> > >
> > > Hi,
> > >
> > > Does anyone have a source of 75 ohm twinlead, in the USA or
> > > overseas. Seems to be much rarer these days. It's just the
bill for
> > > a colinear matching problem.
> > >
> > > _______________________________________________
> > >
> > > See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
with
> > any questions and ask for Sherman, W2FLA.
> > >
> > > _______________________________________________
> > > TowerTalk mailing list
> > > TowerTalk@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/towertalk
> > >
> >
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
with
> > any questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless Weather Stations", and lot's more. Call Toll Free,
1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
|