Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [vertical-antenna]

Use this tag for questions related to vertical antennas, the construction, characteristics and performance.

Use this tag for questions related to vertical antennas, the construction, characteristics and performance.

116 questions
23
votes
2 answers

What makes a 5/8 wavelength vertical desirable?

An ordinary 1/4 wavelength vertical is smaller and resonant without any loading coil or matching network. What's the advantage to a 5/8 wavelength vertical? Why 5/8 in particular, and not something longer or shorter?
Phil Frost - W8II
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17
votes
8 answers

Should I chose a vertical or a horizontal HF antenna?

If I only have the budget for one HF antenna, should I chose a vertical or a horizontal antenna?
Timtech
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11
votes
2 answers

How to reduce RF in the shack when using vertical HF antenna (no radials)

What can be done to reduce RF in the shack (riding back along the coax) when using a vertical 10M antenna (without radials due to space constraints)? The antenna is an IMax-2000 at 32' elevation (20' over roof) with a 125' coax LMR-400, SWR is under…
Ron J. KD2EQS
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10
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3 answers

Can a 1:1 transformer be used as a protection from static electricity?

It's well-known that under certain conditions verticals and dipoles can gather static charge, which is a common reason of transceiver damage. There are several ways to solve this issue. Some hams suggest to place a 100 kΩ high-power resistor to the…
Aleksander Alekseev - R2AUK
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9
votes
7 answers

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

Consider these three cases: My understanding is that when building or installing an antenna designed to operate over a ground plane (e.g. a quarter-wave vertical), the size of the ground plane does not matter (e.g. the earth, possibly coupled using…
Kevin Reid AG6YO
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9
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2 answers

Marine VHF whip antennae - what are they?

For marine VHF (156~162 MHz), the most commonly used antenna is a 1/2-wave dipole or a collinear array in the form of a fibreglass rod. Collinear arrays are used to increase gain in some antennas. Dipoles/collinear arrays by their nature do not need…
user5314
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8
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2 answers

calculating all specifics for a 5/8 antenna

So, I've built a couple 1/4λ ground plane antennas for Airband and Marine band. I don't transmit, I'm just listening, etc. So, constructing ground plane antennas with the radials and getting the impedance to be 50Ω is rather easy, not so for the…
polemon
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8
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5 answers

Does mounting a ground plane antenna upside down change the takeoff angle?

A typical gain pattern for a quarter wave ground plane antenna is: Image from a similar question and see watermark. For a situation where the signals of interest are below the antenna in elevation (e.g. antenna on a hill/mountain), would mounting…
hazzey
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8
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3 answers

Vertical antenna on HF?

What are some of the advantages and disadvantages of using a vertical antenna on high frequency? Are there any better antenna types that I should use?
Timtech
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7
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7 answers

What is the attraction of vertical antennas for HF?

I understand that MW broadcast stations use vertical antennas because that polarization works much better for groundwave propagation. But in amateur radio, I would assume the focus for communications on the HF bands would be via ionospheric…
natevw - AF7TB
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7
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2 answers

Practical 80m vertical wire antennas without radials?

We'd like to install an antenna for 80m at our club/contest station. Our club, OH2K, is housed at a school, and we can't fill the roof with a radial mesh. The roof is not metallic itself, either. We already have a horizontal dipole, but would like…
oh7lzb
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6
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2 answers

Tuning/trimming a ground plane antenna

I've built a ground plane antenna with a 19.5" vertical and 4 20" radials. Currently, at 147.135 MHz my SWR is 3:1, clearly not ideal (and even bad for the transmitter!). I'm reluctant to start snipping radials because I really don't know if the…
David Hoelzer
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6
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5 answers

Grounding a vertical antenna from a balcony

I have a multiband vertical antenna mounted onto the railings of my balcony apartment high up on the 6th floor of an apartment building. The antenna is not grounded. This antenna comes without radials. I can see at the side of my building, a ground…
Engineer999
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6
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2 answers

Base vs center loading a vertical antenna

I currently use a homebrew 40/60/80m vertical consisting of a 5M aluminium tube with a multi tapped coil at the base. The ground plane is the metal roof at my house, and the antenna is not centered in it, but it's next to one of the edges. I read…
hjf
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6
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2 answers

Multiband vertical antenna not working as expected

I built a vertical out of a 5M aluminium pipe. It tunes fine (and wide!) on 20M. I decided to add a loading coil to operate it on 40M, and it also worked fine, albeit not so wide. While I was at it, I extended the coil for operation on 80M as well.…
hjf
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