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Questions tagged [vertical-antenna]

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

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longest practical feed line length

So for a HF vertical antenna (DX commander Rapide), what is the longest feed line that that I can practically use using high-quality coax? I realize shorter is better, but my HOA (my wife) is raising ...
KQ4QKF's user avatar
  • 1
0 votes
3 answers
107 views

generic antenna tuner term: impedance matching vs real tuner

Generally, an antenna tuner is nothing more than an impedance matcher. Badly termed, as it does not tunes any antenna. For loop antennas though this is not the case. The antenna tuner does not do any ...
kellogs's user avatar
  • 205
0 votes
2 answers
75 views

Minmum spacing between two receive-only omidirectional antennas

I need to mount a VHF receive-only omni (166Mhz to be specific) and a UHF receive-only omni (434Mhz) on a pole and plan to use a T-bracket at the top to space the two antennas apart. How much distance ...
TvE's user avatar
  • 101
2 votes
2 answers
110 views

How do I ground my first HF rig?

I want to preface this question saying that I am very new to HF and just got my general license. I have only operated using 2m/70cm handhelds and am completely unfamiliar with antenna setup. I ...
Sprock3t's user avatar
0 votes
1 answer
48 views

Radials with centre-loading coil

Does a centre-loaded HF antenna need radials? If I put a loading coil 1,5-2m (5-6,5 feet) high, do I need to put radials out on the ground? Feed point would still be near the ground.
S54KZ's user avatar
  • 1
2 votes
1 answer
205 views

Operation of an off-center fed vertical for 10 meters

I am looking for a smallish omni-directional 10 meter antenna for installation in my attic. I notice that MFJ sells one called MFJ-1790. They call it an off-center fed vertical, and it has two ...
gschro's user avatar
  • 157
3 votes
1 answer
183 views

Impedance of linear loaded 1/4 wave element

I am in the process of planning a multiband vertical antenna and have a few questions I would be grateful for any advice on. So I plan to have 1/4 wave elements for bands 20-10m with a common ...
owen81's user avatar
  • 31
2 votes
3 answers
551 views

Monopole antenna with no ground connection

I have a SDR device and have a question about using a monopole antenna with them, but the question could be applied to any device which uses an antenna. SDR comes prepacked with a monopole antenna ...
Dan's user avatar
  • 311
3 votes
1 answer
225 views

What are the pros and cons of mounting an HF vertical on raised bank?

My garden has, at one end, a wall of large (chest freezer size) randomly placed granite boulders loosely filled with earth and stones. Currently my vertical is in the garden about 10m east of the bank....
quanglewangle's user avatar
2 votes
1 answer
224 views

Will a multi band vertical 'choose' correct radial?

For elevated radials. If I put up a 40m/80m fan vertical can I do the same for radials, that is cut some for quarter wave on each band? Radials will be about 2m off ground.
quanglewangle's user avatar
3 votes
2 answers
934 views

How to establish RF ground for 1/4 wave vertical in apt on 3rd floor (about 35ft above the ground)

I am struggling to understand how to introduce an MFJ-931 artificial RF ground into my current system and am hoping for some help to sort out best practices. Although my use-case seems pretty common, ...
A Bit of Help's user avatar
0 votes
1 answer
248 views

Is 100m too long for hf feed wire?

I have room to erect a DX Commander, multi-band vertical, and to give it a good number of radials on a good clear site. Problem is I would need to run about 80 - 100m of coax feed from operating ...
quanglewangle's user avatar
5 votes
1 answer
346 views

What is this vertical antenna with radials pointing up

I work next to "Koninklijk Marine Kadettenkorps Afdeling Oostende" (Royal Marine Cadet Corps Ostend). They have an antenna that I've been wondering about for years now: It is a vertical ...
Dieter Vansteenwegen's user avatar
3 votes
2 answers
602 views

HF vertical 1/4w antenna on a tin roof?

I would like to build a 1/4 ~ vertical antenna on my tin roof for a ground plane. Does the angle of the roof matter? Should the antenna be vertical, or perpendicular to the roof? Would it be better ...
marc's user avatar
  • 33
3 votes
2 answers
816 views

HF Vertical antenna with no radial and loading coil but only ATU for 80m to 10m in a boat

I am new to HF antenna designs. I want to build an antenna for my fishing boat. My question is - if I use an ATU (like the ATU-100) and a 10m aluminium pipe as an antenna and fix it with a mast, will ...
Asif Rahman's user avatar
1 vote
1 answer
2k views

What balance (radials or counterpoise) do I need for a vertical hamstick as a stealth antenna?

I'm just getting back into operating after a long break. I'm currently in a ground-floor apartment of an old four-plex and I'm trying to set up a stealth-like antenna for HF. I decided on the Shark ...
GVDub KE6EPC's user avatar
4 votes
1 answer
132 views

What is the radiation pattern and feedpoint resistance of a raised feed point vertical?

If you put a vertical 1/4 wavelength antenna on a pole of about 15 feet and tie the base of the pole to a massive grid of radials and the ground itself how does it affect the radiation pattern and the ...
david's user avatar
  • 141
2 votes
3 answers
4k views

cut or lengthen to reduce swr on vertical wire antenna

Have tried measuring antenna wire using formula 234/frequency for 1/4 wave vertical but this gives high swr. How do I lower swr on a wire vertical antenna. Do I Cut or Add? wire'
Doug's user avatar
  • 21
2 votes
3 answers
793 views

Why does an HF "monopole" need dozens and dozens of radials while a VHF/UHF "ground plane" antenna only needs four?

It's a bit counter-intuitive that for an HF vertical antenna (such as a quarter wave monopole) the best advice is to put as many radials and as close to the proper length as possible. The typical VHF/...
natevw - AF7TB's user avatar
5 votes
1 answer
370 views

Parameters needed to calculate inductor value to achieve proper phase delay?

I'm thinking about trying a coil in my collinear 5/8λ antenna, instead of the 3/8λ phasing delay line between the lower and upper elements pictured below. I figure that a coil with a certain ...
Louis Seaman's user avatar
  • 1,025
4 votes
2 answers
1k views

Can I use my CB mobile antenna with a 10 meter radio also?

I have a mobile mounted CB antenna that has an SWR of 1.5 on channel 20. Is it possible to use it with a 10 meter radio? I do not have enough room on my car for an additional antenna, so if it is ...
diodes123's user avatar
3 votes
3 answers
827 views

Antenna options for a small urban garden

I've narrowed down my antenna options to fit a small urban garden. It's tough, space is tight and a neighbour three doors down reports everything I do to the council so I'm routinely inspected for ...
rcx935's user avatar
  • 411
2 votes
3 answers
325 views

Ferrite unun transformer to match antenna resistance loads of <50Ω?

For LF/MF (2200m/630m), I am interested in the situation of a vertical antenna with capacitance hat top-loading, where the vertical antenna is VERY short compared to wavelength, and the antenna is ...
photosynthesis's user avatar
2 votes
3 answers
1k views

radials for 6 band Hustler vertical

I don't have room for quarter length radials for my Hustler 6 band vertical (10through 80 meters). Can I use 20 foot radials? If so, how many? The hustler is a Hustler 6-BTV 6 band HF vertical ...
Jim Patch's user avatar
3 votes
1 answer
394 views

Phasing stub length for colinear 5/8λ?

I've been designing a "Super J-Pole" for 10M in MMANA-GAL, but I'm designing it having two 5/8λ sections. However, I came across this picture: Various J-Poles types diagram indicating the ...
Louis Seaman's user avatar
  • 1,025
2 votes
1 answer
284 views

Using Decoupling Stubs to Allow a Vertical Yagi to be Mounted on a Metal Pole

A while a go i asked a couple of questions on this site about mounting a vertical yagi antenna on a metal pole. One of the answers given to the first question talks about using decoupling stubs to ...
Andrew's user avatar
  • 3,683
2 votes
3 answers
1k views

Why half-wave dipole is the most efficient one in comparison to other electrical lengths of that antenna?

I have a problem on the understanding of a half-wavelength antenna. Namely, why is the half-wave antenna has a highest power emission. Considering Far Field factor F($\theta$), which is known from the ...
Pierre Polovodov's user avatar
3 votes
2 answers
1k views

Mounting a vertical antenna on a fiberglass mast

I have a multiband SE-X80 HF vertical antenna which works ok from 20 meters to 10 meters with a tuner. It is attached to the railings of my apartment balcony at the moment. This is the antenna : https:...
Engineer999's user avatar
2 votes
1 answer
72 views

How Accurately Does NEC-based Antenna Software Calculate Vertical Monopole Antenna System Radiation Efficiency for "Far-Field" (Only) Conditions?

A common belief among amateur radio operators is that the radiation efficiency of a vertical monopole driven against the Earth is much less than that of an elevated, horizontal dipole of the same ...
Richard Fry's user avatar
  • 2,922
4 votes
1 answer
920 views

How does the material of a fishing-pole mast affect antenna performance?

I'm a newly-licenced ham and currently starting out with HF. My home doesn't allow for a permanent setup. I can therefore only operate portable from parks and such, with limited TX power (my rig goes ...
Ivan R2AZR's user avatar
4 votes
3 answers
629 views

RF ground confusion

I'm a bit confused by RF grounding. Let's take a HF 1/4 wave vertical antenna for example. When current flows through the centre of the coax to the antenna, my understanding is that the current then ...
Engineer999's user avatar
3 votes
0 answers
105 views

Is this author correct about using a λ/2 of wire for a coil to get the proper delay on a λ/2 collinear antenna?

Is this author correct about using a λ/2 of wire for a coil to get the proper delay on a λ/2 collinear antenna? Improving the Super-J August 5, 2012 by John S. Huggins I agree with him that there has ...
Louis Seaman's user avatar
  • 1,025
6 votes
5 answers
2k views

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....
Engineer999's user avatar
5 votes
2 answers
517 views

Can coax be run through the center of a radiating element without currents being induced on the coax shield?

I run a λ/2 vertical dipole for 20M that's fed to a 1.5:1 balun at its center with coax that is perpendicular to the dipole (parallel to the ground), for about 30 feet before it comes down to the ...
Louis Seaman's user avatar
  • 1,025
3 votes
1 answer
1k views

Can I use electrical ground / earth as my RF ground?

I live on a high floor in an apartment block and have a radial-free multi-band vertical antenna attached to my terrace railing. This is the antenna : https://www.thunderpole.co.uk/amateur-radio-...
Engineer999's user avatar
4 votes
2 answers
5k views

What do radials really do for a vertical antenna?

I have read everything I can find about monopole (vertical antenna) radials, and also watched many YouTube videos that touch on the topic. I see conflicting information about what they do, where a ...
User5754448's user avatar
3 votes
2 answers
479 views

Vertical antenna with feedpoint below ground plane?

What happens when a groundplane antenna's vertical element, bottom feedpoint, and/or bottom loading coil move down and encroach into the area below the plane formed by its own perpendicular elevated ...
Bitbang3r's user avatar
  • 401
3 votes
2 answers
313 views

Avoiding radio damage with closely spaced VHF/UHF antennas

I've mostly been using a discone in the attic so far, but now I want to get proper antennas up for 2m/70cm and gmrs. I'll probably get common commercial vertical antennas. I'm not sure how much I ...
Brad Mace's user avatar
  • 421
1 vote
1 answer
421 views

Unable to tune 20m vertical with trio of Hustler resonators on top

I just built a homebrew antenna that consists of a full-length quarter-wave vertical sized for 20m, with a "top hat" consisting of a Hustler VP-1 and trio of Hustler mobile resonators (RM-...
Bitbang3r's user avatar
  • 401
2 votes
2 answers
252 views

antenna element with "doubled up" nested aluminum rods for added stiffness

I'm building a full-size quarter-wave 20m vertical antenna (approx. 18 feet long, plus a trio of Hustler mobile resonators at the top to add 30, 40, and 80 meters). To make the top 12-14 feet stiff ...
Bitbang3r's user avatar
  • 401
5 votes
3 answers
783 views

What do you call antenna that combines multiple Hustler resonators (using a VP-1) above a shared mast?

I know that a Hustler MO-3 54" mast with something like a RM-20S resonator on top is officially an example of a center-loaded quarter-wave vertical... ... but Hustler also allows you to mount ...
Bitbang3r's user avatar
  • 401
3 votes
3 answers
326 views

Is The Lowest Antenna Terminal Feedpoint SWR Always Optimal?

Intuition might lead one to believe that the antenna configuration with the lowest SWR(50) across its input terminals would provide the best radiation efficiency for the antenna system. But is that ...
Richard Fry's user avatar
  • 2,922
-1 votes
1 answer
77 views

Using inverted Yagi antennas to gather and cohere RF from the sky

Imagine a group of eight or more vertical masts. On each mast is a Yagi antenna pointed upward toward the sky. The elements are inverted with the idea being that the incoherent RF coming down is given ...
Tom Fosdick's user avatar
1 vote
2 answers
663 views

Troubleshooting 5BTV antenna

I have a Hustler 5BTV antenna i resurrected after a previous monopole succumbed to birds. It is giving me a world of trouble trying to get it tuned for resonance. For those not familiar with the ...
t252's user avatar
  • 697
0 votes
0 answers
311 views

How to stabilize an antenna

I have an antenna on a building. It is made of steel and is about 10ft long. It wobbles a bit in high winds. It is not going to do a Tacoma Narrows but it is a bit annoying. Can I tie stainless steel ...
user avatar
4 votes
3 answers
2k views

Is the Boom Strictly Necessary in a Vertical Dipole?

I'm planning to build a vertical dipole for 4m and a club member pointed out that my design needs to allow for a boom that should be at least a 1/4 wave long. Why does a vertical dipole need a boom ...
Buck8pe's user avatar
  • 989
5 votes
1 answer
781 views

How does this W6NBC "derivative of the classical slot antenna" work?

Via the https://ham.stackexchange.com/a/9883/1362 answer regarding a slot antenna for a 2m mobile application, I was introduced to this (pdf) interesting antenna design: The designer John Portune (...
natevw - AF7TB's user avatar
0 votes
0 answers
100 views

what frequencies is this antenna cut for?

I just bought a magnet-mount whip antenna at a garage sale. It has no brand markings anywhere on it. it is 32" long overall but is broken up into three segments by what appear to be two small ...
niels nielsen's user avatar
1 vote
2 answers
338 views

Does Improving Earth Conductivity Near a Buried Ground Rod Improve Antenna System Performance?

The suggestion has been made on various ham-related websites that improving the conductivity of the Earth around a ground rod produces a worthwhile improvement in the e-m radiation from a vertical ...
Richard Fry's user avatar
  • 2,922
1 vote
4 answers
900 views

Why are many ground radials preferable to a single ground stake buried 1m deep?

Surely a 1m copper stake provides better ground connectivity for a vertical dipole?
Adam Palmer's user avatar