Questions tagged [antenna]

Questions about the design, selection, building, testing, mounting, or properties of antennas. See also specific tags: [antenna-theory], [antenna-construction], [dipole], etc.

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3
votes
2answers
1k views

HF SWL antenna wire? Will plain 16-Gauge copper wire work well enough?

Planning to set up a HF antenna for RX-only. However, I can't decide what kind of wire to use. I want to buy something new. My first thought is to buy a spool of 16 Gauge copper wire, but am hoping ...
3
votes
2answers
521 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 ...
6
votes
3answers
214 views

Will an iron chimney work well as an antenna?

There is an iron chimney near my house that is not used anymore. It is ~15 meters in length and ~0.5 meter in diameter. How good will it be as an antenna for rtl-sdr?
2
votes
2answers
174 views

Distance of Received Signals

I received two UV5R plus radios a couple of years ago as a gift to use for hunting. I've never used them, but I now have time on my hands due to some medical issues so figured I'd play around with ...
5
votes
2answers
744 views

How can I calculate the 1/4-wave monopole impedance dependence on groundplane angle?

I watched this video of a very nice explanation of a simple dipole and 1/4-wave monopole. In that video they show how you can impedance match the 1/4-wave monopole by bending the 4 (virtual ground ...
3
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2answers
194 views

Antenna installation for a base station

I have a detached garage that is approximately 15 feet high. The garage is approximately 20 feet from my home I will be using a Kenwood D-710GA radio, a Grandmaster SWR Meter and a 6 foot comet GP-3 ...
2
votes
4answers
2k views

If i connect two antennas to one radio using a t connector will it work?

If I connect two antennas to one radio using a t connector will it work? If a connect 2 antennas (a mag mount + a dipole?) to the same radio with an adapter will it work normally on 2M band and will ...
1
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2answers
99 views

Is a “shorted” coax feedline ok for a G5RV type antenna?

I have "inherited" what I believe to be a G5RV antenna with two 51 foot wire centerfed radiators. If I remember correctly from measuring 2 months ago, there is about 31 feet of 450 ohm ladderline ...
0
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2answers
221 views

How to design a meander antenna for 2 meter band?

How should I start if I want to design a compact antenna for 2 meter band using the principle of meander antenna? I noticed meander antennas are frequently used in mobile devices and notebooks for 2.4 ...
1
vote
1answer
48 views

Could I run a Zepp antenna from a telegraph pole underneath a mains cable?

I'm new to the forum, and I've been advised that this is a good place to get experienced opinion. I lived in a three storey terraced house in Mid Wales. It is terraced on three sides with the house on ...
4
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5answers
186 views

Coax cable as antenna for 5 watt handy

For a normal 5 watt handy working in VHF or UHF freq with 50 ohm antenna , is it possible to use a same length coax cable instead of a stub antenna, so as to work like a crude antenna. Will this only ...
1
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4answers
1k views

Turn 75 Ω TV “Rabbit Ears” with a balun into a 50 Ω dipole antenna

I got myself a TV "Rabbit Ears" module originally for a TV. It came with a small length of coax, permanently attached to the antenna foot, and a Belling-Lee connector on the other end. My idea was to ...
1
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3answers
2k views

Slot antenna for 2 meter mobile

My primary vehicle is a Smart car, with a roof that's a piece of plastic(100% moon roof). Not the most awesome of cars to use for grounds. I'm building a bumper mounted antenna tower, EMT with some ...
3
votes
2answers
259 views

Not-too-distant saltwater ground

Problem I'm planning on mounting a vertical HF multiband antenna on the edge of my roof. Due to the presence of a paved walkway and some other similar property constraints, I have no room for ...
6
votes
2answers
184 views

Communications : Ground wave propagation

I was studying ground wave propagation, my book writes the lines about it without explaining it. I really do not know any explanation for these queries coming in my mind. I've Googled it, and you will ...
3
votes
2answers
305 views

Simple antenna for an old Grundig Satellit 800

I just got my technician license, and I'm just fooling around a bit on the Grundig. I'm trying to pull in WWV from NJ, so 1st, is that possible with the radio whip? I've tried the built-in whip on 5,...
2
votes
2answers
510 views

How to determine the minimum distance between ham and TV antennas

I'm planning on putting a quarter wave ground plane antenna in my attic for use with 2m/70cm. In order to keep the feed line short, it needs to be near my TV antenna. Is there a rule of thumb for ...
3
votes
2answers
222 views

What is the easiest way to eliminate a beam antenna's backward radiation (rear lobe)?

I tried a metallic reflector which works well in terms of radiation, but considerably degrades the return loss and adds more complexity to the design.
1
vote
1answer
168 views

Intermittent High SWR

Using a Cushcraft MA5B beam, when I apply high power from an amplifier, the SWR will go up and down intermittently. Something is breaking down at high power (200-500 W). I have a new coax feedline, ...
5
votes
1answer
294 views

HF/VHF antenna for high altitude balloon

I'm working on the design of a dual band transmitter for use on a high altitude balloon. I'll be transmitting on 2 meters and 20 meters (APRS and WSPR) with about 50 mW. To keep the weight to an ...
6
votes
2answers
4k 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 ...
8
votes
1answer
212 views

SWR Measured at the Transmitter versus SWR at the Antenna

It is fairly well understood that due to transmission line losses, the SWR as measured at the transmitter will be less than the SWR at the antenna. Some of the new antenna analyzers and some vector ...
0
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1answer
347 views

Gain in long wire antennas

DARA (you know, Hamvention) TNG is looking for projects. Thursday, I will be proposing building and characterizing a vertically-polarized 1 wavelength on a side reentrant rhombic. Since in doing the ...
1
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0answers
75 views

Can a radio antenna damage a phone? [closed]

I am currently attending a radio technology course. We continuously work on radio sets that are sometimes used as manpacks by the Army. In order to learn how to operate them we work in close proximity ...
7
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6answers
709 views

Can I talk 2 Meter VHF across the United States

Can I talk on 2 meters from the east coast to the west coast without using repeaters?
1
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2answers
238 views

What is the optimal antenna for a high altitude weather balloon?

I was thinking of creating a 2.4 GHz WiFi wireless link with a directional, circular polarized antenna but I am not sure if that would work for such a long distance. The antenna cant weigh more than 1 ...
5
votes
4answers
361 views

TV strong station has no signal when coax is connected

Right, not directly ham radio related, but this puzzles my ham brain. I have several TVs connected to a distribution amp connected to an outside antenna. All but one work fine, and the one won't ...
0
votes
2answers
67 views

Does adding just an antenna adapter to a 3G modem add to it reception power?

I am looking to increase the 3G GSM reception of my mobile hotspot device by adding an antenna adapter I can attach to RS-9 port in the device. It's a simple pigtail adapter, the other end of which is ...
4
votes
1answer
691 views

Antenna, input and ground bonding

I'm new to this and am in need of guidance. I am mounting a multi-band antenna on a 50 foot tall 1 1/4" galvanized mast. I plan to drive a ground rod at the base of the antenna and bond the mast to ...
2
votes
3answers
136 views

Which antenna would you use?

I'm starting to study RF propagation at college, and I'm thinking about what antenna I should choose for this scenario: The distance between the transmitter and receiver is just 700 meters, and the ...
3
votes
2answers
591 views

proximity of rain gutter to dipole antenna

I am a new ham and wish to mount a center-fed G5RV dipole antenna under the eaves of my house, where I have a 78' clear run available two stories above ground. The problem is a metal rain gutter which ...
8
votes
5answers
5k views

Aluminum vs copper antenna element lengths

Does the particular metal used in antenna elements make any difference in element length or spacing, i.e. 1/2" aluminum tube vs 1/2" copper tube? I know that length and diameter have an effect on ...
5
votes
2answers
475 views

How to adapt commercial VHF yagi for 2 meter amateur use?

I recently acquired a Decibel 3-element VHF Yagi that was formerly in commercial service. I connected my MFJ-259B antenna analyzer to the antenna and found its minimum SWR at 155 MHz. I have not ...
-2
votes
1answer
239 views

Is it right for Amateur Radio operators to hide their antennas? [closed]

Is it right for us hams to hide our antennas? And should we tell our neighbors that we are a ham?
2
votes
2answers
81 views

Antenna Q vs pattern shape

Is there any reason to think that changing the Q of an antenna would affect the directional pattern, assuming that is the only variable that changes? Restricting to values of Q say less than 1000. ...
2
votes
3answers
118 views

Could 8' Marine whip antennas operate on much higher frequencies?

I have backgrounds on electrical communications, but know little about EM/RF. I would like to install outdoor antennas for experiments (receive only; I do not hold licenses, although I do intend to ...
0
votes
3answers
356 views

Total cancellation in corporate feed network for patch antenna

I'm trying to build an array of patch antennas in order to receive a GPS signal. The idea is to build 4 patches and connect them with a corporate feed network. An example of corporate feed is this one....
2
votes
3answers
2k views

Feeding a dual-band UHF and VHF Yagi antenna

I just built a UHF Yagi antenna for my HT, and I was thinking about adding VHF elements. If I do, could I just connect the coax directly to both sets of elements without a diplexer?
1
vote
3answers
224 views

Would the antenna described work?

For reception of amateur radio satellites, turnstile antennas (consisting of two crossed dipoles fed out-of-phase) are often used. I've recently had an idea - what if two half-wavelength dipoles are ...
0
votes
2answers
457 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 ...
1
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1answer
80 views

Resistance of antenna dipoles

A quick question: Is it a disaster if the two legs of a v-dipole antenna are different resistances? Thanks.
2
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2answers
2k views

best antenna for Baofeng

My wife is a teacher at a school about 15 miles from our home. My growing concern about a possible EMP event (natural or man-made) led me to buy a pair of Baofeng UV-5RV2+ radios in the hopes of ...
5
votes
4answers
712 views

What might this tower be used for?

This tower is located on the campus of my wife's employer. She's asked around but no one seems to know the purpose of it. Does anyone have any idea what this may be used for? Edited to add ...
3
votes
2answers
320 views

Noticeable difference between trunk and roof mount?

Between trunk-mounting and roof-mounting a 2m/70cm antenna, both as through-hole NMO mounts, is there really that big a difference performance-wise? I mean, I know roof mounting is better, but let's ...
5
votes
2answers
4k views

Can I use a CB antenna with a ham radio?

I just passed General and purchased a FT-450D with an internal antenna tuner. While my ultimate plan is to use a G5RV, it will be a while before I can get it up. What modifications would I need to ...
3
votes
2answers
159 views

Good Coating for a Radome

My club has a well used Motorola branded StationMaster UHF repeater antenna that needs to be sanded and recoated. Besides the surface, the antenna is in very good working order so we're not ...
6
votes
1answer
890 views

RX antenna and RTL SDR with upconverter ..How to hear something?

I mounted a small RX antenna (mini whip, bought from eBay) (on 10-th floor) and I want to try to listen to something. I bought a RTL-SDR with Upconverter which supports HF. RX antenna's operating ...
4
votes
3answers
332 views

2m Biquad - Why not?

I'm thinking about putting together an Echolink link node on my local repeater frequency so I can participate in the weekly net when out of town. This seems straightforward as it's simply: Being in ...
4
votes
2answers
921 views

My Baofeng UV-5RV2+ will receive a signal with rubber duck antenna but not with a new Nagoya

I bought my self a Baofeng UV-5RV2+ as an inexpensive way to introduce myself to the world of ham radio. With all of the stock components everything has been working fine. I wanted to try to increase ...
4
votes
3answers
153 views

Substitute for Dacron rope in antennas

I am building an antenna that specifies the use of Dacron rope to help support the spreaders, but that is not readily available in Trinidad and Tobago. What will be a good replacement with regards to ...