Hi Shaun.
The inverted Vees should fit in your yard just fine. The lower height will
probably limit your DX somewhat, but the system should still play. My
guess is that your vees will be a little shallower than mine, and that will
affect tuning to some degree because the impedance will be different, but I
think that with the tube rig, it will still be satisfactory. If your fence
is metal, you may wish to avoid the loop as metal in the near field of the
antenna can make it fairly miserable to match.
The year after we had the Field Day exercise that I described, we tried the
loop from a different site. Unfortunately the cars in the parking lot were
in the near field of the antenna on 80 and 40 meters and every time someone
moved a car the SWR changed! We quickly converted the antenna to a G5RV
and had much less trouble. If the fence isn't a metal fence, then you are
probably okay with the loop, but you are going to have a near vertical
angle of radiation especially on the lower frequencies so you'll probably
be the strongest signal on the band inside of about 500 km, but
substantially weaker outside of that radius. That will probably be the
case on 80 and 40 meters, but you'll probably be ok abouve 10 MHz.
The good news is that you have some pretty good usable space there. Almost
twice as much usable space as I have here -- I'm trying not to turn green
with envy!
73, de Lou K2LKK
At 03:48 PM 3/30/2008 +1100, you wrote:
>ah. I see how that would work. still, I can't go mroe than 20 feet. if
>it helps, the dimensions of my block here are as follows.
>from boundary to back fence is 175 feet. and from side fence to side
>fence is 65 feet.
>at least I know that much so I know what I've now got to work with.
>
>Shaun
>web sites:
>http://www.myspace.com/blindmanshaunoliver
>http://blindman.homelinux.org/~blindman/
>skype: brailledude
>
>
>On 30/03/2008 3:04 PM, the old scribe known as Louis Kim Kline was able
>to impart this pearl of wisdom:
> > Hi.
> >
> > If you string them as inverted vees, I think you'll have better results
> > with 50 ohm coax. If they were going to be strung as flat top dipoles,
> > then you could run 75 ohm, but putting them in a vee configuration
> tends to
> > lower the impedance of the antenna, and 50 ohm coax should match better.
> >
> > 73, de Lou K2LKK
> >
> >
> >
> > At 01:45 PM 3/30/2008 +1000, you wrote:
> >> i was actually considering using 75 ohm coax as the transmition line.
> >>
> >> Shaun
> >> web sites:
> >> http://www.myspace.com/blindmanshaunoliver
> >> http://blindman.homelinux.org/~blindman/
> >> skype: brailledude
> >>
> >>
> >> On 30/03/2008 1:28 PM, the old scribe known as Louis Kim Kline was able
> >> to impart this pearl of wisdom:
> >>> Hi Shaun.
> >>>
> >>> I couldn't tell you exactly to the inch, but it was around 67 ft. for the
> >>> 40 meter antenna, and around 130 ft for the 75 meter antenna. If you
> >>> calculate it for 3800 KHz and 7100 KHz, it will work.
> >>>
> >>> Mine was up 35 feet at the feed point and sloped off to for metal fence
> >>> posts driven in the ground a few feet beyond the end points of the
> >> inverted
> >>> vees. I used end insulators and ropes to attach the ends to the
> >>> posts. Although theory says you should use a balun on such an antenna, I
> >>> never bothered to put one on the antenna, and never had any problems with
> >>> it. I left that antenna for my sister (KA2GLP) when I moved into the
> >>> city, and she is still using it.
> >>>
> >>> 73, de Lou K2LKK
> >>>
> >>>
> >>>
> >>>
> >>> At 10:46 PM 3/28/2008 +1100, you wrote:
> >>>> what were the rough lengths of your dipoles?
> >>>> for me to work it out in meters, I use the formula 300 divided by f.
> >>>> also, did you use any baluns? I want to make my own but not quite sure
> >>>> how to accomplish that just yet, I need to make sure the toroid I use is
> >>>> the right rating and size. thanks in advance.
> >>>>
> >>>>
> >>>> Shaun
> >>>> web sites:
> >>>> http://www.myspace.com/blindmanshaunoliver
> >>>> http://blindman.homelinux.org/~blindman/
> >>>> skype: brailledude
> >>>>
> >>>>
> >>>> On 28/03/2008 9:15 PM, the old scribe known as Walt Sebastian was able
> >>>> to impart this pearl of wisdom:
> >>>>> Hi Shaun,
> >>>>> I had a temporary antenna up for five years or so. It was cut for
> 75, 40
> >>>>> and 20. Before you cut different antennas for 10 and 15, check the
> >> SWR on
> >>>>> your lower band antenna and see if it is ok. 40 should resonate on
> >> 15 and
> >>>>> 75 may resonate on 10. Don't quote me but it is a possibility.
> >>>>>
> >>>>> I got on a rag chew group on 10 meters with a group. The only antenna
> >>>> that
> >>>>> I had cut for that band was a 4 band vertical. I would transmit on
> >> it and
> >>>>> listen on my 75 meter dipole. One time I forgot to switch back and
> I was
> >>>>> asked what I did. I told them. A friend came over and was going to
> >> build
> >>>>> me a small 10 meter inverted vee but he checked the SWR on my 75 meter
> >>>>> antenna and it showed a very good reading. He said, you don't need
> a 10
> >>>>> meter antenna, you got one. I hope this helps, 73.
> >>>>>
> >>>>> Walt
> >>>>> WA4QXT
> >>>>> New London CT
> >>>>> [log in to unmask]
> >>>>>
> >>>>>
> >>>>> __________ NOD32 2980 (20080328) Information __________
> >>>>>
> >>>>> This message was checked by NOD32 antivirus system.
> >>>>> http://www.eset.com
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>> No virus found in this incoming message.
> >>>> Checked by AVG.
> >>>> Version: 7.5.519 / Virus Database: 269.22.1/1349 - Release Date:
> >> 3/29/2008
> >>>> 5:02 PM
> >>> Louis Kim Kline
> >>> A.R.S. K2LKK
> >>> Home e-mail: [log in to unmask]
> >>> Work e-mail: [log in to unmask]
> >>> Work Telephone: (585) 697-5740
> >>>
> >>>
> >>> __________ NOD32 2984 (20080329) Information __________
> >>>
> >>> This message was checked by NOD32 antivirus system.
> >>> http://www.eset.com
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >> --
> >> No virus found in this incoming message.
> >> Checked by AVG.
> >> Version: 7.5.519 / Virus Database: 269.22.1/1349 - Release Date:
> 3/29/2008
> >> 5:02 PM
> >
> > Louis Kim Kline
> > A.R.S. K2LKK
> > Home e-mail: [log in to unmask]
> > Work e-mail: [log in to unmask]
> > Work Telephone: (585) 697-5740
> >
> >
> > __________ NOD32 2984 (20080329) Information __________
> >
> > This message was checked by NOD32 antivirus system.
> > http://www.eset.com
> >
> >
> >
>
>
>
>
>--
>No virus found in this incoming message.
>Checked by AVG.
>Version: 7.5.519 / Virus Database: 269.22.1/1350 - Release Date: 3/30/2008
>12:32 PM
Louis Kim Kline
A.R.S. K2LKK
Home e-mail: [log in to unmask]
Work e-mail: [log in to unmask]
Work Telephone: (585) 697-5740
|
