Questions tagged [vertical-antenna]

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

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3
votes
2answers
944 views

Can I use a 1:1 current balun to feed a 1/4λ vertical?

I have an LDG RBA-1:1 current balun, and I was wondering if it behaves as a common-mode choke that I can use for a ground-mounted quarter wave vertical w/ 16 radials. The other choice I have is a 4:...
1
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2answers
793 views

What is the best type of feedline for a base UHF VHF ground plane antenna with a distance of around 50-75 feet of coax?

I'm going to be putting up a Comet GP6 UHF/VHF Ground Plane Antenna. It will be chimney mounted to a mast, and the total height is around 40 ft. The upper half of the chimney starts at the first ...
0
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2answers
127 views

Proper magnetic mount placement on roof

I have a Nissan Versa 2012 (hatchback). It comes with one of those default antennas at the back/center of the roof, for listening to AM/FM radio stations. I have a dual band mag-mount (TRAM 1185), ...
5
votes
3answers
1k views

Size of ground plane disk for vertical antennas?

I’m looking for information about the diameter of a ground plane disk that I can use with a regular car radio and car type antennas in my home. DIY would be best, or any other ideas for a antenna that ...
2
votes
2answers
135 views

How Does the Low-Angle Radiation of a Horizontal Dipole Compare to That of a Vertical Monopole?

Conventional wisdom based on the far-field (only) patterns calculated by M-o-M software such as NEC show that low-angle radiation from a horizontal dipole is very low, and zero in the horizontal plane....
5
votes
1answer
998 views

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

Currents at the base of an elevated, 5/8-wave, vertical ground-plane (GP) transmit antenna are lower than when that vertical conductor is 1/4-wavelength. Does this mean that the performance of the ...
5
votes
1answer
5k views

Radial length for vertical antennas?

I plan on installing a vertical antenna soon. I expect it to cover from 80 meters to 10 (or perhaps 6). I plan on putting down 32 radials. I am wondering if 16 66' and 16 33' radials will be just ...
1
vote
2answers
192 views

What can I do about my strong RF noise?

I have a problem with strong and constant received noise, from S7 to S9+20. I've shut off the power, both in my house and two neighbors' houses. I took my portable rig with a Hustler antenna and ...
1
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2answers
156 views

vertical 40m antenna takeoff angle

I built a 40m vertical using the W8AMZ design https://www.amateurradiosupplies.com/v/vspfiles/assets/images/40m_vertical_monopole_-_manual.pdf Seems to be working for the most part. But I'm not sure ...
2
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1answer
207 views

Improving coverage of AIS receiving station

I have just set up my first AIS receiving station with compliments of Marinetraffic.com. They have supplied me with a Comar SLR350Ni receiver and a http://www.sirioantenne.it/en/products/vhf/gp-3-e ...
0
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3answers
207 views

Should Hams Using Skywaves Be Concerned About Their Groundwave Radiation?

Comments posted on various websites relating to amateur radio posit that the groundwave is unimportant for skywave paths. Is this concept correct?
4
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3answers
402 views

Antenna suggestions for 160m band in smallish yard?

I have a decent-sized but not huge yard (roughly 50x100' / 15x30m) and I'd like to get on the 160-metre band. It's hard enough to get out on this band so I'm looking to do something reasonably ...
3
votes
2answers
2k views

Stabilization of an antenna pole with anchoring cables

I am mounting my first antenna. It is a TRAM 1481 (about 16' height), which will be placed on a 20' pole, on my home's flat roof (about 25' height). To properly stabilize the pole/antenna: - How far ...
3
votes
2answers
1k views

How low can a vertical dipole be mounted?

An answer to this question suggests that raising a vertical dipole sufficiently can create the effect of a phased array. How about the opposite. How low can a vertical dipole be mounted? Can a ...
4
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1answer
514 views

How Does the Performance of Elevated Radials Differ from That of Buried Radials?

NEC4.2 provides some information about this topic that may be of interest to some readers.
4
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1answer
188 views

How Does Earth Conductivity Affect the "Takeoff Angle" of a Vertical Monopole?

NEC4.2 gives some insight into this ...
8
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2answers
12k views

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 ...
5
votes
4answers
1k views

Can a vertical antenna be used for NVIS?

I know that verticals are normally chosen for their low angles of radiation without obscene heights, but I'm not especially interested in DX and am primarily looking for local coverage via NVIS. I've ...
3
votes
2answers
2k views

Using two short mobile HF antennas to make a vertical dipole

Instead of using a metal vehicle roof or multiple radials as the counterpose to a shortened vertical antenna, can one use two of them, one pointed downward to construct a balanced vertical dipole, and ...
4
votes
3answers
621 views

Radials on a vertical, spread out evenly or not?

To have a groundmounted quarter wave vertical with a decent efficiency you need at least 16 radials. So normally you would spread them out on the ground evenly around the base. This would give an ...
0
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2answers
1k views

Do the radials of a quarter or 5/8 wavelength antennas connect to the braid of the coaxial cable?

I'm studying for my foundation license (in the UK) and I have these diagrams: Do the radials in a quarter or 5/8 wavelength antennas connect to the braid/shield of the coaxial cable? If so, how does ...
2
votes
1answer
1k views

How do I specify that wires are connected in 4NEC2?

I've been trying to get acquainted with the 4NEC2 antenna modeling program. Perhaps this is obvious, but it's not clear to me that wires with one end in the same place are connected. I'm attempting ...
3
votes
1answer
842 views

Corrugated Metallic Roof used as a ground-plane for short loaded vertical?

My house has a corrugated metallic roof. 2500 sq. ft. The roof is grounded via couple cables. What's your comment on using the roof as the ground for a short center-loaded vertical 80M antenna? ...
9
votes
7answers
13k views

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 ...
2
votes
1answer
1k views

Dual-band rubber duck gain on 2m vs. 70cm

Using a dual band "rubber duck" like the stock Baofeng antenna and/or the physically longer NA-771, which band will give the best results between two mountain tops given the same input power? ...
1
vote
3answers
235 views

How to calculate/estimate the effect of having conductive material nearby an antenna

I have a system with a 1/4 wave whip antenna and above the antenna there is a mess of aluminium they're not connected but are nearby. I would like to figure out what effect this would have on the ...
8
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5answers
5k views

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 (...
7
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7answers
8k views

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 ...
2
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3answers
1k views

Diamond X200A Lightning Protection

Please forgive the naive question, as I've been away from the hobby for too long, but want to make sure I do this right. We just added an addition to our house, and I lost my usual mounting place for ...
3
votes
2answers
6k views

2 Meter horizontal or vertical dipole polarization?

When should I use one polarization over the other on 2 meters? I've looked at the radiation patterns for horizontal dipole and seen how it changes based on mounting height. I haven't been able to ...
9
votes
2answers
2k views

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. ...
6
votes
2answers
4k views

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 ...
0
votes
1answer
182 views

How does a multi-element vertical work?

For example, Diamond makes the X700HNA which is stated as a 4x5/8 vertical on 2m. Does this just mean that it is 20/8 wavelength long vertical? Or is there some magic to phasing the 5/8 segments? I'...
4
votes
2answers
626 views

How should I mount a mobile antenna on a vehicle with a non-conductive body?

I would like to mount a self tuning antenna, ATAS-120, matched with the FT-857D transceiver. I would like to make this pair function on an ARGO 8x8 amphibious vehicle with a polyethylene body. There ...
4
votes
2answers
2k views

Does antenna width/shape affect resonant frequency like length does?

I was wondering if I made an antenna from a Rohn 25G tower, would it have the same resonant frequency as a pole of the same height (assuming guys are insulated)? Also with the Rohn antenna, the waves ...
1
vote
1answer
140 views

Magnum 257 & Firestik 3' Tuning

Trying to tune a Firestik antenna connected to Magnum 257 on my '98 Jeep Wrangler. Having trouble with SWR reading as it is reading too high (~4) after I set needle on FWD and then switch back to REF. ...
5
votes
1answer
2k views

How to calculate or estimate surface area of required ground plane for a mobile antenna?

I don't have conditions for installation of a fixed 2 m/70 cm antenna at home, so I'm thinking of using a mobile magnetically mounted antenna on a conductive plate instead. So my question is: What ...
4
votes
2answers
4k views

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

I'm looking for a dual band base station antenna, and find that many of them have short radials around the base. Due to the specifics of my installation, I need to remove them. However, it is being ...
3
votes
1answer
1k views

recommended capacity bottom-hat clearance above metal roof

In a few days I'm expecting to mount a Cushcraft R7000 multi-band (HF) vertical antenna on top of a metal mast that will be attached to the outside wall of a large metal shed. The aim is to have the ...
3
votes
1answer
141 views

How does inductive base loading cause low feedpoint impedance in verticals?

As an extreme example, take mobile HF antennas. These can have very low feedpoint impedances, maybe as low as $6\Omega$. The ideal impedance of a quarter/wave vertical is $36\Omega$, but electrically ...
0
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1answer
7k views

Vertical Antennas: Compare Cushcraft R9, no radials to 43 foot vertical with ground radials

Small lot, must go vertical. Which antenna will preform better, with less noise, good DX. Cushcraft R9, NO ground radials. Or, 43' with ground radials.
3
votes
1answer
1k views

Antenna Tripod for a vertical antenna

I'm considering buying a vertical HF antenna (Such as the Cushcraft R8), and a tripod antenna stand, such as the MFJ-1918, and setting it up on my back porch when I'm operating (Which won't be all of ...
2
votes
1answer
3k views

What is the theoretical performance of a 2m 1/4 wave ground plane antenna when used at 70cm?

If I have a 2-meter 1/4 wave ground plane antenna with 1/4 wave radials bent down at approximately 45 degrees, what kind of performance in terms of SWR and gain pattern can I expect when using it on ...
22
votes
2answers
15k views

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 ...
11
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2answers
4k views

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' ...
7
votes
2answers
2k views

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 ...
17
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8answers
33k views

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?
8
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3answers
1k views

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?

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