New Antenna

[KI4SYC]

I would like to put up an Inverted Vee cut for either 40m or perhaps 80m if I realize I have the room. Does anyone have any plans to share? Perhaps a Doublet Inverted Vee for 40m and 20M? Any help will be appreciated.

[KF4HAY]

I helped a friend put up a flat top 40 meter dipole, which was about 64 ft. long, end to end and about 15 ft. high. He is very happy with it. If you hear him, (KI4VBK), ask him how he likes it.

[KI4SYC]

Thanks for the help from the Bluegrass state. I'll look into your suggestion. However, I won't be hearing anybody anytime soon as my 80m Dipole is down along with the 40m/20m Dipole(s) slung underneath.

[W9GB]

If you spend more than $15 in materials (raised $5 due to copper prices) to build a 40 meter dipole -- you spent too much.

Need photos?
http://www.mtechnologies.com/dipole/index.htm

Adobe Acrobat (PDF) version of the web page article (above)
http://www.varaces.org/techrefs/DIPOLE_101.pdf

HyGain's 40/80 Trap Dipole (manual for ideas)
http://www.hy-gain.com/man/pdf/DP-2BDQ.pdf

w9gb

[KE5FRF]

Do you have a tuner?

Why not try an all band doublet?

If you have the room, you simply take 135 feet (or so, not critical to be exact) of wire and cut it in half at equal lengths. Build a center insulator out of PVC or some other material, and feed the antenna with balanced feedline. Many recommendations will be made on the impedance of the feedline, but many use 300 ohm and others use 450 ohm. Some guys even use 600 ohm. If you decide to use 300 ohm (as I do), get the ladder-line stuff and avoid the TV twin lead (though it DOES work).

You'll also need a balun if your tuner isn't designed for balance feedlines. I recommend the DX engineering 1:1 balun if you use 300 ohm feed. You may want a 4:1 balun for other feedlines. It really depends on your tuner's impedance range.

This antenna will get you on all bands, and can be set up as an inverted vee. The 135 feet isn't critical. Some use 80,100 feet (or so) on 80 meters with good results. Somewhere inbetween there is a lenght that can be troublesome. I'd suggest you refer to the Antenna Handbook or L Cebik's webiste (Google it) for suggestions. The guys at DX engineering are also helpful over the phone.

Setting it up is no problem as an inverted vee. Try to keep the angle of the vee obtuse or >90 degrees. Try to get the feedpoint as high as you can, supported with a tower or a tall tree. Try to get the ends off the ground as high as possible. 10 feet would be the minimum recommnedation for safety purposes as well as performance. If you can't get the antenna straight across, you can put bends in it (as slight as possible) and it will still perform well. On 80 meters, hight is most critical if you want to realize the optimal "gain" of the antenna. This is still true even on 40 meters. On 20 meters, given most amateur back-yard installations, 35-40 feet will work OK and you will see a good pattern with some lobes. The higher bands will also have gain with narrower lobes and deeper nulls. This will be to your advantage (gain) in some directions but a disadvantage to the direction of the nulls.

Remember, when we refer to "gain", antennas have no "gain". All they do is perform (favorably or not) as compared to an isotropic radiator. Gain denotes a concentration of radiated power in a favorable manner compared to a half wave dipole at resonance.

So, if you are limited in space and the number of antennas you can put up, a doublet is a good solution.

[KA0SPM]

Bazooka, Bazooka, Bazooka. Find directions on internet, there are lots of them. Buy cheap satellite or catv coax and make it. Covers whole 40m band, is very quiet no exposed copper or aluminum, cheap to build. Nothing is better. 80m version can cover most of the band if not all below 1.7 to 1 swr tunes like gang busters. I gave up on wire antennas unless its a loop because of a bazooka.

[K3STX]

If you want to use COAX as your feedline, for 80 meters put up an 80 M inverted vee, for 40/15 meters put up a 40 meter inverted vee. If you want ALL band, get a tuner, use ladder-line, and make it as long as possible. The 80 M inverted vee would be best for this, but it is BIG! Like all antennas, higher is better.

A G5RV (only 102' long) is a great all-band antenna if you have a tuner and you can limit the length of coax feedline.

Just do SOMETHING, then try to fix it later! THAT is how we all do it!!

Have fun!

paul

[KF4HAY]

Myself, I used a 246 ft. wire fed in the middle with about 60 ft. of ladder line up about 25 ft. at apex and only about 7 ft off ground at the ends. I used a MFJ 969 tuner and covered all bands. It worked well on all bands and was resonant on 20 and 10. I would like to make the wire longer and get it up higher, when I get another radio and tuner, to see how much better it does, although I was well pleased with it before.

I sold my hf rig and tuner for some stupid reason last fall, so I'm stuck on 10 meters now.

[W4INF]

Quote[/b] (KE5FRF @ Aug. 19 2007,20:20)]Why not try an all band doublet?

Ill swear by a doublet! Mine worked GREAT! Worked 80-10 with 66ft length, and 75ft 300ohm to a 4:1 BALUN.

[K8JD]

A half wave dipole (doublet) is certainly not a new antenna design! Need plans? # total Length in feet= 468/Freq in mhz...thats IT! Quarter wave on right, other quarter wave on left, coax connects in middle.....rig connects to other end of coax...Simple enough?