I have never used ladder line until this project and part of the
issue with it, particularly the 300 Ohm line is that it can be quite
fragiel. At present it is neatly spread out, some of it inside and
the rest outside my shack window. One of the articles I read was
from a very happy doublet user who said he had his excess ladder line
coiled up in his shack without affecting the performance of the
aerial. One of the main challenges in using balanced line feed is
that the length is critical moreso than the actual lengths of the
aerial elements. The doublet is often referred to as an "Antenna
system" because of the feed system being part of the aerial itself.
Today i have had contacts on 20 40 and 80 meters which is a vast
improvement from earlier this week when I could only talk on 80.
73
Ian, VK3vin
At 08:57 PM 3/05/2013, you wrote:
>Ed,I would appreciate you and the other guys on the list that use ladder
>line tellling me what you do with the excess ladder line. I have tried
>using ladder line several times but without success and I blame my
>ignorance on this. My tower is only about 40 feet high and is right
>outside my radioshack window and this leaves me about 55 feet of excess
>ladder line. I never knew what to do with this. Thanks much,
>
>-----Original Message-----
>From: For blind ham radio operators [mailto:[log in to unmask]]
>On Behalf Of Ed Malmgren
>Sent: Thursday, May 02, 2013 11:45 PM
>To: [log in to unmask]
>Subject: Re: Doublet Antenna
>
>Hello Ian, Perhaps you know this but if you twist your feedline about one
>turn every 0.5 meters the wind will not blow it around so much. I have
>built probably ten dipoles over the years and good luck. 73
>Ed K7UC
>
>--------------------------------------------------
>From: "Ian Westerland" <[log in to unmask]>
>Sent: Thursday, May 02, 2013 9:11 PM
>To: <[log in to unmask]>
>Subject: Re: Doublet Antenna
>
> > Hi Colin. It is a centre fed di pole with open wire feed line instead
> > of coax. So you have the centre insulator witht the 2 wires which you
> > can have as a flat top or inverted v. The length depends on what you
> > want and how much space you have to fit it in.
> >
> > Mine is an inverted v configuration cut for 3.58 Megahertz
> > 65.4 feet long, or 19.92 meters.
> >
> > The feed line which is the tricky part of the aerial is 30.4 meters or
> > 102 feet long hanging down as close as possible to 90 degrees from the
> > wires.
> >
> > This comes down to a 4:1 balun, into about 1 meter of RG-213 coax into
> > the LDG KT-100 tuner.
> >
> > There is a lot of interesting and helpful information on the internet
> > if you type into your search engine, "Doublet antenna" including a
> > very helpful chart with recommended feed line lengths for 80 and 40
> > meters. It also shows how some lengths of feed line are to be
> > avoided. The recommended feed line lengths are in green and the ones
> > to be avoided are in red.
> >
> > Hope that helps. Stay in touch and hopefully we will have a QSO one
> > day. I hear some good signals from Canada regularly at night.
> >
> >
> > 73
> >
> >
> > Ian, VK3vin
> >
> >
> >
> > At 12:49 PM 3/05/2013, you wrote:
> >>can you describe the basic design and construction of the antenna?
> >>IE element length and feedline length?
> >>I've never experimented with a doubllet style and wouldn't mind trying
>it.
> >>
> >>73
> >>Colin, V A6BKX
> >>----- Original Message -----
> >>From: "Ian Westerland" <[log in to unmask]>
> >>To: <[log in to unmask]>
> >>Sent: Thursday, May 02, 2013 8:28 PM
> >>Subject: Doublet Antenna
> >>
> >>
> >> > Hello to all on the list. Someone posted a question about doublet
> >> > antennas a couple of days ago and i have just made one for multi
> >> > band operation between 80 and 10 meters. It has been a challenge
> >> > but the results so far are really better than I thought they would be.
> >> >
> >> > The antenna is cut for a low frequency of 3.58 megahertz in our 80
> >> > meter band, fed with 300 Ohm feed line, through a 4:1 balun into an
> >> > LDG TK-100 tuner. The results on 80 meters are the best I have had
> >> > from any antenna used so far including the standard coaxial fed
> >> > dipole although there seems no real reason why this should be the
> >> > case. Maybe it is the lower loss feed line doing the job.
> >> >
> >> > I have encountered problems on 40 meters that seem to be related to
> >> > the length of the feed line but results are improving with a little
> >> > fine tuning and experimentation with feed line length. The doublet
> >> > is 9 meteres off the ground at present, but during next week it
> >> > will be raised by another 3 meters so it will be 12 meters or 40
> >> > feet at its apex.
> >> >
> >> > I will post to the list again on the doublet when I complete the
> >> > project but at present, even though it is not at its optimum, I am
> >> > more than happy with its performance on both transmit and receive.
> >> >
> >> > Ian Westerland, VK3vin
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