[Antennas] spencer dipole from Mccoy's book

[Chris BONDE]

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 2002-01-03 -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..