[Antennas] spencer dipole from Mccoy's book

2002年1月03日 18:36:07 -0600

Chris,I use 1/4 nylon rope interwoven between the windows...Tie it to the
center or better the support as I use a yardarm off the tower.And,tie it to
the house with a EYE-bolt...has worked for years and since I started doing
this no wind damage...john
----- Original Message -----
From: "Chris BONDE" <[email protected]>
To: <[email protected]>
Sent: Thursday, January 03, 2002 6:21 PM
Subject: Re: [Antennas] spencer dipole from Mccoy's book
> OK. Thank you. The stuff I have now is "window-ed" line. I have been
> calling it ladder line. 450 ohm.
> The windows are put into the line VS the rungs are put between the lines.
> I remember helping a ham make some ladder line. He was using his
> daughters' "Toni" hair curlers (plastic). Put the wire in the ends where
> the elastic was to go, heat the end a little, just right, and push closed
> around the wire.
>> Someone said put paste wax on the ladder line. Will do next time. I put
a
> twist in the run of the line to stop wind whip. A twine rain loop is just
> under the roof eve.
>> Any other suggestions for the keeping of the parallel transmission lines?
>> Chris opr VE7HCB
>>> At 06:14 PM 2002年01月03日 -0500, you wrote:
> >snip
> > > OKnow please tell me the difference between window line and open
ladder
> > > line. I have wondered about what the rain would do to the line. So
it
> > > makes the line "lossyer"?
> > > Chris opr VE7HCB
> >
> >Hi Chris,
> >
> >The only difference in Window line and true ladder line is the method
that
> >is use to separate the two conductors. Window line is manufactured by
> >embedding the two parallel conductors in PVC or Some other plastic and
then
> >cutting windows in the insulation to reduce the detuning effect of rain
or
> >wet conditions and it also make the line less prone to wind loading.
> >
> >True open wire line usually has the conductors held apart by some type of
> >spacer such as wood, plastic I've even used clothespins before.. the
> >impedance of the Line is a result of wire size and spacing distance. 300
> >ohm line is usually encased in solid poly or pvc. it is ok when dry but
> >maybe as lossy coax when wet..
> >hope this is of some help to you
> >73, Dave
> >
> >P.S. as someone has already mentioned keep the line about 3 times the
> >distance between conductors away from conducting surfaces and you should
be
> >all set..
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