Tell Me About the Inverted V Dipole and 1/4 Wave Ground Plan

[Ramius]

I have already built a 1/2 wave horizontal dipole that I have used on a few occassions. As I have heard, the polarization is horizontal, and not vertical, like many other CB operators may be using. This is probably why I had some problems talking to others. Additionally, the feed point is 70 ohms, while I am only using 50 ohm coax. Since I have moved to a new location, I can place something more permanent in my yard. This has lead me to look at the 1/2 wave inverted V dipole, since it has a 50 ohm feed point. I would also like an omni-directional antenna as well, and I was wondering how well the inverted V dipole would work for that.

I am also looking at the 1/4 wave ground plane, because it also has a near or less 50 ohm feed point, and appears to be omni-directional.

Assuming I can mount these antennas from 0 to 30 feet, which would be better for local communication? Which would be better for long range/skip?

I have also heard of people using 300 ohm twin lead line used for TV antennas instead of coax. Does this perform well?

[Redfox]

If you want to work DX, mount the dipole 1/2 wavelength above ground. For the 1/4 wave vertical, height isn't as important. What's more important is laying down a good radial field. It's mighty hard to lay down 120 radials when the antenna is 20 feet off the ground.
Let us know what you end up puttin' on the air. Now you've flung a cravin' on me to put up a dipole again. :D

[Ramius]

I built my first dipole out of a small piece of 1/2" PVC with a SO-239 connector mounted to it. Attached to that, some solid c*pper house wire. My typical SWR was around 1.2 and it was placed horizontally, about 10-15 feet off the ground. It worked okay, considering I made contact with a person at his base station 4 miles away, but others had a hard time hearing me.

Since then, I moved 15 miles to a new home, and I tried the antenna again. It was pretty cold out, so I didn't spend much time setting the antenna up properly. I just drapped it over the side of a deck, about 15 feet off the ground. Sure enough, I picked up the group from my old neighborhood. So I know I can receive for at least 15 miles, but everyone still had a hard time hearing me. If I set it up properly, I am sure the dipole would have worked better.

People have told me that I should be using a vertical antenna, because that is what others are using and the polarization will be the same. Most of the high areas that I could mount an antenna have some draw backs, such as near by power lines (about 20-30 feet away). This is another reason why I was looking at the inverted V dipole, because I may have to erect a support pole. If that's the case, I'll try to build one out of 1" PVC.

I read on some board that grey conduit PVC should not be used with antenna building, but the white PVC is fine. Any comments on this?

[highdrive]

Well first of all, congrats on building your own antenna. If you chose to build an inverted v, it will be somewhat directional. You could easily put one together with a pvc elbow and four copper poles. On one side of the v, slide a smaller diameter pole inside the bigger pole. That way you will be able to tune without cutting. Remember each side should be equal length...so you might have to look up the formula in an arrl book. I have mine laying horizontal with a mount that fits on my mast. It works ok local but even better in skip land. If you wanna good but cheap groundplane...you could just order a starduster m400 clone...or make something similar. It will talk great local and dx.----73's

[231]

Height is might for local talk and 15' is hardly half wavelength for 11m. That means that yes, with a flat topper you are/were transmitting horizontally, but the pattern is/was pretty much omni because of it's height. If you were to get it up higher, you'd indeed see some directionality to it. And you need to trim/lengthen the legs to bring it to 50ohms. Each application layout will dictate a slightly different approach, but still...you need to adjust the legs accordingly. This will be true on an inverted "V" or "sloper" as well. I would also recommend you make a coaxial choke balun for the feed point.

I happen to be a fan of the inverted "V" myself. I've used all 3 and frankly, it's the easiest for me and work pretty well. I ran a sloper at the office for quite awhile without any problems. It would have been considered vertical polarized, but that's an option for you too. If you have a tree around, simply hoist up one of the legs and pull the feed line at least 45º from the other leg. Again, you'll need to trim up the legs accordingly as the vertical polarized dipole is physically shorter than horizontal.

Hope that helps a little at least on the dipole options.

[DX_MONKEY]

Hey Ramius, Welcome to the site

Nah guys our man here can set up a good base now and I think he's really asking......what's the going best omni base antenna I can put up?

That's seems to be the IMAX 2000. It's a long high gain no-radial vertical. I think it's a co-phased 5/8 but not sure. $99 or it's venerable little brother the Antron 99 for what $55 or thereabouts. I reckon some of the site sponsors here sell both or one of them. Otherwise available from the usual other sellers.

These simple, easy assemble-tune, easy-up verticals have excellent gain in a heavy duty package. Tens of thousands in use. FYI

If you need extra wide-banded for your various 11 meter needs then the 1/4 wave ground plane is the best performer many times giving a full 2 mhz or more 1:1 match. The old favorite classic was the Starduster, a 9' radiator with three ground plane radials at a 45 degree angle. All aluminum. An Italian company is making a good replica and they call it an M 400. Search/google for ( m400 antennas ).

good luck and welcome aboard











do what the Monkey say !!