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Date: | Fri, 3 May 2013 15:16:41 +1000 |
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Thank you ed. I didn't know that so will put it into
action. Anything I can do to improve it is good.
Cheers.
IanAt 01:45 PM 3/05/2013, you wrote:
>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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