Discussion in 'General Technical Questions and Answers' started by KB7QPS, Mar 15, 2009.
I have an inverted vee that's been up for about 30 years in the same place. Works for me!
I recently put up a Carolina Windom 160 special and I like it a lot. The antenna has an interesting horizontal and vertical radiating pattern. It really doesn't perform well on 160, but it's good to go above that. Some bands don't even need a tuner. If you want 160 as well, you can go with the regular Carolina Windom 160, assuming you have 233 feet between your trees.
For those of you that have long antenna (100+ feet) made from copper, do you have to support them at all? Or is the #10 or #12 copper wire strong enough to support itself normally?
I had steel electric fence wire up for many years without problems. But I haven't tried copper.
My 160 meter Doublet is supported in the center and on each end. I have a pully on a rope about 60 feet in a tree. I have a rope ran through the pully so I can raise and lower the antenna. This is for the center "feed point" of the doublet. Each end about 120 some odd feet runs down to a 20 foot mast stuck in a tire with concrete. No extra support used. The wire I used is AWG#12 THHN stranded, because I have a bunch of it. I had a bit of a dillema bringing the ladder line into the shack, so I ran about 15 feel of RG213 to a 1 to 1 balun mounted just outside the shack. Then 450 ohm STRANDED ladder line to the antenna. I recomend stranded over solid for ladderline because solid can sometimes break inside the insulation and finding that break can be a pain.
With all of the space that you have plus the trees, you are already a step ahead. My doublet works pretty well but is way to low for DX. Since I put up my Inverted L sometimes I switch over to the doublet just for receiving.
So a long story for your short question
Support in the center and on both ends.
I think the bottom line is
WIRE + TREES= FUN TIME FOR RADIO.
jUST A QUICK COMMENT, For long runs of wire I like to install what I call a 'fuse' not an elecrtical one, but a mechanical 'weak point' where it can be eqasily reached and bring the antenna back up to operation quickly if a branch or some other act of God decides nature is more important than Ham Radio.
I use springs at the pully line bottom attachments that include one one weak attachment to the stabalizing mount, with a VERY long cable to the other side of the sping, In other words a force on the antenna wire will be met with a sping through a pully to allow for 'travel' with resilence and increasing resistance, IF it overcomes something, that something is the weak attachment on the far side of the spring(the mechanical fuse), but there is still a long, loose cable going to the 'pully line' that can simply be raised again and the spring reattached to its' mount. No broken antenna wires that way, no big effort to reraise the antenna.
That's a good way of putting it. I have a lot of options and opportunity where I live to install a really cool antenna. I'll have to take a walk around the woods and see what my best options are.
Thanks for all your suggestions.
I think I have a plan
After doing some more internet research, here is my antenna proposal:
I have space for a full wavelength 160m dipole. (Roughly 500' long). I will have to feed it with 150' of ladder line connected to my MFJ Versa Tuner V. The antenna wire will be made from 12 ga copper wire. I am trying to source out the copper wire right now.
How does this sound for an antenna setup?
What direction should I face it? Straight east/west would make the most sense to me. It is easier for me to face it northeast / southwest. (My QTH is Seattle, WA.)
Thanks again for our suggestions.
Half wavelength doublets are easier to feed. Full wavelength antennas fed in the middle are high impedance.
The classic length for a 160 meter doublet would be 270'. The biggest deal will be to get it as high as possible in the air. That's where the real gain is to be had with a doublet.
Orientation makes less difference than you think. On 160 meters, your antenna needs to be 40-80 meters up before it starts really being directional. Unless you can get it that high, it's pretty much an omnidirectional NVIS antenna.
How you run it depends on your interests (DX vs Domestic) and the bands you intend to use. On 20M and up, it will have some directivity off the ends of the wires. My wire runs NNE - SSW, qand from Washington, DC, covers most of the US plus Europe and Africa. Try it. If you don't like it, try re-orienting it and see what happens.
What you're proposing sounds FB to me - it's more or less what I use. I support mine at the ends and in the middle. One caution - sometimes ladderline gets a bit unhappy when it gets wet, but it still works OK.
You may have read that on QRZ but it's a non-issue unless the coupler is placed right at the feedpoint without a feedline.
Grain of salt.
The feedline transforms that impedance with the installation proposed here. 150' of balanced feedline to a full wave doublet brings the impedance much closer to what you would want for the coupler to load into.