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19 votes
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What is the effect of using different number of radials with ground plane antenna

An ideal vertical doesn't have radials: it's half a dipole sitting upon a perfectly conductive, infinite plane. Under these idealized conditions, its radiation pattern is identical to a dipole's ...
7 votes
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When and why does the size of a ground plane or radials matter?

Perhaps consider that the objective of the ground plane is to present a low impedance. At the feedpoint, the hope is to have all the current go into the antenna, and none of it on the coax common-mode....
7 votes
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Radials on a vertical, spread out evenly or not?

The purpose of the radials is to increase the effective ground conductivity, thus reducing losses. As you propose to have 16 radials but in four groups, I'd expect the efficiency to be somewhere ...
6 votes

What is the effect of using different number of radials with ground plane antenna

Elevated radials not equal to ground plane A common misconception is elevated radials (as counterpoise) perform the role of "ground plane" in an antenna system including dominating the far field ...
  • 590
6 votes

Radial length for vertical antennas?

Rule of thumb: if the radials are elevated, at least two resonant radials for each band. If the radials are buried or lying on the surface, at least 16 radials, each at least a 1/4 wavelength at the ...
6 votes
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Vertical Antennas

First: do you know about pskreporter? You're definitely getting heard, including one spot on 40m from New Zealand. Sometimes FT8 takes some patience, and it seems like no one wants to come back to you ...
  • 9,552
5 votes

Are Elevated Radials Necessary for Elevated, 5/8-wave "Ground-Plane" Antennas?

Elevated radials are required in order to increase/optimise the radiation possible from any such elevated "GP" monopole or whip antenna. If the elevated radials are symmetrically arranged and lie in ...
  • 2,892
5 votes

Ground radials: Electrical difference between 14 gauge and 18 gauge? Lifespan difference?

Larger wire will have less resistance. However, the resistance of the radials in either case is negligible compared to the soil resistance, so I wouldn't worry about it. Longevity would be my concern....
5 votes
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How low can a vertical dipole be mounted?

Here is an analysis of a vertical, 1/2 wavelength, 2 meter dipole suspended at various heights above ground: As you can see, as you raise the bottom end of the antenna from near ground level up to ...
  • 18.2k
5 votes

Using two short mobile HF antennas to make a vertical dipole

To begin the discussion, it is helpful to understand the effects of shortening any antenna to a length below resonance. In all cases, the directivity of the antenna is reduced but this tends to be a ...
  • 18.2k
5 votes
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Using threaded rod for VHF radials

I was about to say it would have no impact - In my experience thread has no effect. I've used threaded rod all over antennas though not usually for the whole element. But scratching a bit found this ...
  • 8,340
4 votes

Radials on a vertical, spread out evenly or not?

The effects of using unequal length buried radials on the radiation patterns of a monopole are not very significant, as shown by the NEC4.2 analysis below.
  • 2,892
3 votes

How low can a vertical dipole be mounted?

The voltage is high near the end of any dipole. If you locate the bottom end of a vertical dipole at --and especially below!-- the ground, you are greatly increasing the losses. There is really no ...
  • 7,604
3 votes

Using two short mobile HF antennas to make a vertical dipole

People can and do use a pair of mobile antennas to make shortened dipoles. A "hamstick dipole" is one example. One application for such an antenna is in a mobile station which for whatever reason ...
3 votes

Dielectric Constant of Insulation/RF Permeability

Developing this comment of W2ASC (above): But, given the fact that radials are effective even when buried in a few inches of soil, my assumption was (and still is) that whatever difference exists ...
  • 2,892
3 votes
Accepted

Hobby Wire for Ground Radials

Sure it will work. Metal wire is metal wire. The electrons don't care about the packaging. 24 gauge wire is thin enough you might be concerned about the resistance of the wires, which will decrease ...
3 votes

What Are Some of the Most Important Characteristics Applying to the Radiation of Monopole Antenna Systems?

VERTICAL MONOPOLE, EARTH, and BURIED RADIALS as FACTORS in ANTENNA SYSTEM RADIATION EFFICIENCY Considerations: The components shown in the ...
  • 2,892
3 votes

Which is Better to Use with Vertical Monopoles: Buried Radials or Ground Screens?

The information below is extracted from the "benchmark" 1937 I.R.E. paper* of Brown, Lewis & Epstein of RCA Laboratories, and is based on their accurately measured data for these systems. IMO, ...
  • 2,892
3 votes

What is the effect of using different number of radials with ground plane antenna

Below are NEC4.2 analyses showing the intrinsic, free space radiation patterns of (1) a ground plane antenna having two pairs of co-linear, λ/4, horizontal radials spaced at ±90°, and (2) a comparison ...
  • 2,892
3 votes

Radials on a vertical, spread out evenly or not?

As long as the radials are symetrical it will make no noticable difference. A single radial opposite the other half of a dipole or 2 radials opposite each other will yield a reasonable pattern. The ...
3 votes
Accepted

What are the effects on an ATAS-120A screwdriver antenna with a limited ground plane?

Will this significantly change the omnidirectional nature of this antenna? Yes. For 270 degrees of azimuth, you have no ground plane. Or another way of looking at it: you are missing 3/4ths of your ...
3 votes

Do the Horizontal Conductors of a Ground Plane Antenna Adequately Decouple Its Feedline?

Below is a NEC4.2 comparison of the v-plane patterns of a 1/4-wave ground plane antenna mounted 5m above level Earth and using 4 x 1/4-wave, horizontal radials, with / without a coax transmission line ...
  • 2,892
3 votes

What do radials really do for a vertical antenna?

Both #1 and #2 are the same. Accelerating currents are what sum up to create an EM field. And the law of conservation of charge requires that the currents be balanced. If you have a quarter wave ...
  • 12.6k
3 votes

radials for 6 band Hustler vertical

20-foot (6.1 m) radials are certainly better than nothing; your Hustler would work with 20' radials, just not as well as it would with longer radials. 20 feet is longer than a quarter-wavelength for ...
  • 8,932
2 votes

When and why does the size of a ground plane or radials matter?

In broadcast AM radio it is standard practice to use quarter-wave towers (because half-wave towers are expensive and more of a maintenance headache). These towers require a ground plane to reflect the ...
  • 2,051
2 votes

What do you connect antenna Radials to?

Radials are grounded to the feedpoint. For instance, the shield of the coax feeding the quarter-wave antenna. For AM radio broadcasting stations, there are radials every 3 degrees (120 of them) ...
  • 2,051
2 votes
Accepted

What do you connect antenna Radials to?

The radials are not connected to the earth. Here's a photo of a ground plane antenna. They are connected together as shown to the coax shield. This shield should be connected to the common on the ...
  • 7,604
2 votes

Can I ignore the radial elements of a 2m/70cm antenna if it's on a metal roof?

You can remove them and instead attach the shield of the transmission line to the actual roof! It will make a great ground-plane, probably much better than the radials that are currently attached. ...
  • 2,855
2 votes

Do Buried Radials for Vertical Monopoles Need to be No Longer than the Monopole Itself?

Below is a NEC4.2 study comparing the fields radiated by an eighth-wave, series-fed vertical monopole driven against sets of thirty buried radials of 1/4 and 1/8 wavelength (other things equal). The ...
  • 2,892
2 votes
Accepted

Ground-Plane radial sizing, is there such thing as too long?

Infinitely long radials are ideal. So to directly answer your question: no, there is no such thing as "too long". However, infinitely long radials work because the current in the radials ...

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