Curron,
As with all similar questions, you will need to give us more information
before we answer.
Jim's answer might be right but it might not be.
It all depends on several factors.
Up front, my opinion of this antenna is, if I could have just one antenna
for the rest of my life, this is exactly the antenna I would choose. IMO,
no other antenna covers so many bands in so many directions as well as this
antenna.
Scott's article is excellent. I strongly recommend you download and read
it. Pay particular attention to what he says about antenna tuners. There
is a lot of mis-information floating around about how to match openwire fed
antennas. Without a doubt, a symmetrical tuner is by far the best way to
go.
If you are going to run more than a couple hundred watts, it's the only way
to go.
Otherwise you may find yourself up to your antlers in common-mode-current.
If you use an asymmetrical tuner, it is much better to use a 1:1 balun than
a 4:1 balun - even if you have to play with feedline lengths. This assumes
you have a fairly decent ATU. Most auto-tuners won't work here.
If you must use an asymmetrical tuner and want to run high power AND your
matchbox won't get by without a 4:1 balun, then you must insert a 1:1
Guanella between the matchbox and the 4:1 balun. Otherwise you may find
yourself up to your antlers in CMC.
450 Ohm windowline (i.e. Wireman) will work and is what I usually use for
portable work, but for home use it is better to build your own openwire.
Use spreaders that snap in place; something like this:
http://www.73cnc.com/product_p/ls250.htm
My favorite (by far) are here:
http://www.dx-wire.de/lng/en/huehnerleiter-spreizer/?language=en
They come in 4 different widths. He will ship to stateside.
I have seen a couple other similar products in the states.
Don't fool with spreaders where you must thread the wires through the holes.
You'll end up as crazy as me.
Curron, here are some questions:
>> What bands do you intend to work with this antenna? (list them all,
don't just say other bands)
>> Will this be your only antenna? If not, list the others you have or plan
to have.
>> When working 80m with this antenna, is your main interest DX? Or do you
wish to rag chew all around the states?
>> Which antenna tuner were you planning on using (make and model)
>> How much power will you be running.
Again, if at all possible, you should use a symmetrical matchbox. There
aren't a lot of these on the market.
I have compiled a fairly comprehensive list on my web, divided into low
power and high power matchboxes.
> www.dj0ip.de/antenna-matchboxes/symmetrical-matchboxes/low-power-atu-s/
> www.dj0ip.de/antenna-matchboxes/symmetrical-matchboxes/high-power-atu-s/
If you can find an old Johnson Viking Matchbox (either the 275w or Kilowatt
version), I strongly recommend installing the modification I show on my web
site:
www.dj0ip.de/antenna-matchboxes/symmetrical-matchboxes/j-viking-upgrade/
This will significantly improve its matching range and provide a better
match on several bands.
In summary, if you are looking for an @ss-kicking DX antenna for 80, as Jim
said, there are better antennas.
But if you're looking for a good performing omni-directional antenna on 80
that will also work well on all other bands, this one is perfect for the
job.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Curron
Sent: Monday, December 29, 2014 7:51 PM
To: tentec@contesting.com
Subject: [TenTec] Antenna help
Need some help folks...
I would like to get some input on building an 80 meter sky loop antenna that
I will use on 80 and other bands with an antenna tuner. I have some nice
tall pine trees to run the corners to and I plan on joining the loop to the
house with 450 ohm ladder line. Just under the edge of the house I will
install a balun and bring it into the house with low loss coax. Please make
any comments or offer any advice you can. I am hoping to learn from your
experiences. Some questions I have are:
- What kind of wire should I use for the loop antenna
- What type of rope that will hold up to the UV and time (so much just falls
apart these days)
- What balun, 4:1, 1:1 ?
- Is 450 ohm feed ladder line the best to use? This part will be about 80
feet long. Will this length be a problem?
- Has anyone ever had any issues using
delrin for the insulators? Is there a better?
- I am thinking about placing a screen door spring on each corner to allow
the trees to sway in the wind. anyone ever tried that. Or should I just
counter weight to opposing corners of the loop?
- How's the best way to protect this
setup from lightning?
Thanks in advance for any help!
73
Don kb3drw
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