You need this to ensure success
You need this to ensure success
When the government's boot is on your throat, whether it is a left boot or a right boot is of no consequence. — GARY LLOYD
The nation we live in is the nation we have built by design, each successive generation raising the wall of tyranny a little higher. - Chris Griffin
HAH!! Never saw the add before..funny
Yeah...I'm a furry...Deal with it!
Yea, my EOSS buddies are into VHF/UHF.
Don't forget that a dipole can be vertical, and an OCF dipole with the shorter leg down might be practical. Tried it with a box kite a few years ago with some friends, and it worked well. Fed with ladder line attached to the kite string so as to not put strain on the feedline... and the 30% lower part of the OCF dipole had a separate line so you could pull the antenna more vertical, with the feedline arcing away at about a 70 degree angle.
Was setup to play QRP on 40 meters, and it kicked ass.
"Where would we be without the agitators of the world to attach the electrodes
of knowledge to the nipples of ignorance?" ~ Professor "Dick" Soloman
Yeah I thought of that too... Multiple balloons/kites for larger configurations....but little hops for us here at Lapin Labs.
Yeah...I'm a furry...Deal with it!
You'll want something for a counterpoise to work against the antenna. A ground, or one 1/4 lambda radial should do.
If it's a war on drugs, then free the POW's.
Unless it's a dipole.
"Where would we be without the agitators of the world to attach the electrodes
of knowledge to the nipples of ignorance?" ~ Professor "Dick" Soloman
Ren, it's actually quite simple.
If you're loading the antenna as a 1/4 wavelength vertical, or variation thereof (3/4, 5/4, etc. depending on the band) then you need radials or an equivalent counterpoise. If you're loading it as an end fed 1/2 wave, or an Off Center Fed (OCF) dipole, then you don't.
You can, with a decent tuner, load a 1/4 wave without radials, but I don't recomend it. Getting a good SWR match is one thing, but radiated signal (if any) is something else. A 1:1 SWR on a poor antenna installation may mean that you're warming the wire, but not radiating.
Also, the radials (counterpoise) do have an effect on the radiation pattern. NVIS verticals have advantages for local communication, but if you want your signals to travel beyond the horizon, you need the radials.
Remember that essentially, the 1/4 wave vertical represents the "hot" half of a dipole. The radials represent the other half. No radials, then you're relying on the reactance or conductance of the actual earth beneath the antenna. If the earth under the antenna is a poor conductor, the antenna won't work well.
I speak from long and hard learned experience on this one!
73
“Nobody is going to feel sorry for us. 90% of the people don’t care, the other 10% are glad it happened.” — Clint Hurdle, 2019
BAN THE DH!
Fudd's First Law of Opposition: If you push something hard enough, it WILL fall down.
Teslacle's Deviant to Fudd's Law: It goes in, it must go out.
"The 2020 election wasn't stolen, and speaking the truth is only a crime in countries ruled by tyrants" - Liz Cheney
“Nero fiddled while Rome burned. Trump golfed.” — Bernie Sanders
In other words, you're transmitting into a dummy load. Even notice how you get a perfect 1:1 SWR on a dummy load?Originally Posted by W3WN
Think of the 1/4 wave vertical section as half of a dipole. The radials work much like a mirror and take over the function of the missing half.
Last edited by NQ6U; 03-18-2011 at 11:13 PM.
All the world’s a stage, but obviously the play is unrehearsed and everybody is ad-libbing his lines. Maybe that’s why it’s hard to tell if we’re living in a tragedy or a farce.
Exactly!
I never really understood how this works until I took a Physics class in college. Sadly, I lost the textbook in the aftermath of a heavy post-hurricane rainstorm a few years back, so I can't quote from it. Regardless, seeing the physics behind the theory was most illuminating. And the calculus backs up the common theory... a few radials are better than none, and after about 30 -40 radials (evenly scattered around the vertical section) are usually more tha sufficient... beyond that, you're achieving minimal gain for a lot of effort. After about 60, the gain is virtually negligible.
That, and the lovely calculus of the impedance vs. wavelength. Good old f(x) as x->0. As you get closer to a half-wavelength, you approach infinite impedance. But the impedance doesn't go sky-high until you get close, and that's why a 5/8 wave antenna will work... it's close, but not close enough.
“Nobody is going to feel sorry for us. 90% of the people don’t care, the other 10% are glad it happened.” — Clint Hurdle, 2019
BAN THE DH!
Fudd's First Law of Opposition: If you push something hard enough, it WILL fall down.
Teslacle's Deviant to Fudd's Law: It goes in, it must go out.
"The 2020 election wasn't stolen, and speaking the truth is only a crime in countries ruled by tyrants" - Liz Cheney
“Nero fiddled while Rome burned. Trump golfed.” — Bernie Sanders
'WN said:
Had a great practical demonstration of that here. Back when I could actually hear signals here, I was working on getting a random wire out the window going -- I used #26 magnet wire hung out the window. It tuned OK without a ground. But then when I hooked up a ground, things got exciting. Seems the wire was laying on some metal. Without a ground, there was so little power in the antenna that it didn't arc. Soon's I hooked up the ground (radiator) I realized that I had to get the wire away from the building.You can, with a decent tuner, load a 1/4 wave without radials, but I don't recomend it. Getting a good SWR match is one thing, but radiated signal (if any) is something else. A 1:1 SWR on a poor antenna installation may mean that you're warming the wire, but not radiating.
But never did -- by that time the hi-rise next door had wiped out any chance of ever hearing anyone...sigh.
If it's a war on drugs, then free the POW's.
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