Questions tagged [antenna-system]
The system composed of an antenna and a feed line, and possibly also an RF ground connection, antenna tuner, balun, phasing device, et cetera.
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What is an antenna tuner? Why bother with resonant antennas in the first place?
There are a lot of antenna tuners on the market that have various capabilities in terms of how they can allow random radiators to work with our transceivers.
What exactly do they do? My ...
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Measuring actual feedpoint impedance for a given frequency
Background
I'm attempting to tune an antenna with my NanoVNAv2.
I calibrated it using the included open/short/(50-ohm)load standards by screwing them directly onto the NanoVNA one by one and running ...
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How did hams manage to tune their antennas before VSWR meters?
In the early 20th century --back when the hobby was still new-- before VSWR meters and antenna analyzers were invented, how did radio operators know whether they were tuned for maximum power out?
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Connect two receiving antennas to the same radio
I have built a 1090 MHz ADS-B antenna roughly following some video instructions. It appears to work reasonably.
However, because of how it is placed, it captures signals for more or less a half of ...
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Will a HF beam antenna on rooftop building interfere with other antennas there
I am moving into an apartment on the top floor of a building and I intend to install a HF beam antenna for 20 to 10 meters, on the rooftop of the building.
I notice that there are already some ...
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How does a higher antenna reduce rain static on a lower antenna?
I have operated at several stations - including my own - where a 40m beam is stacked above a tribander. During a rain storm, there is so much QRN on the 40m beam that the band is unusable, but the ...
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Does Coax Limit the Maximum SWR a Transmitter 'Sees'?
A recent discussion about SWR led to the assertion that a length of coax cable will ultimately limit the SWR to which the transmitter will be exposed.
By experimenting with an SWR calculation tool ...
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What are some ways to ground a transmitter+antenna in an enclosed attic?
If I want to minimize "RF in the shack" and lightning hazard, what some good ways to ground a transmitter and indoor antenna in a top floor room or attic with no exterior access? (say a multi-story ...
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Is it practical to use a slug-tuned variable inductor in an antenna matcher (aka "antenna tuner")?
I will soon need an antenna impedance match (aka "antenna tuner"), because I'll initially only have a single antenna for my HF rig (needs to cover 80m, 40m, 20m, 15m, and 10m). Obviously, in order to ...
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Passively reducing ground loss?
Would a disconnected wire or conductive mat below a low height antenna reduce ground losses?
A tuned length of wire under a wire antenna might be suitable for NVIS gain. But would a bunch of space ...
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Why do we distinguish between balanced and unbalanced?
I hear all the time, "you need a balun between your balanced dipole and unbalanced coax to stop the common-mode current" when it seems the proper advice is "you need something to stop common-mode ...
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Two antennas on different sides of a building
I live in the 4th floor of a building with one side facing south and the other north. I am able to use my 2M mobile base transceiver with a mobile magnet mount antenna placed just outside the window. ...
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If receive performance doesn't depend on SWR, then how can I tune my manual HF antenna tuner by band noise?
The popular question "What is the relationship between SWR and receive performance?" asks if a receiver with a well-matched antenna (low SWR) beats a receiver with a poorly-matched antenna, ...
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Lightning strikes nearby and coaxial cable
A direct hit on my home by lightning is very, very unlikely. However, many lightning strikes that hit Earth nearby are by far the main hazard for ham radio gear (in my opinion, after 60 years in the ...
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RFID extension cable
I am trying to build an extension cable to relay an RFID signal (125kHz) to various distances (2,5,10m). I am using 2 identical antennas at the two ends of a 75Ohm coax cable, and I also put 2 ...
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How does the Maximum Power Transfer Theorem relate to RF power amplifiers?
The Maximum Power Transfer Theorem says that maximum power transfer occurs when the source impedance equals the load impedance, when the power transferred to the load is 50%, the other 50% being ...
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Why is outer coax usually grounded?
I'm building a simple ground plane antenna for VHF, and I'm doing some research on grounding in case I want to permanently install it. I keep hearing that the ground rod is connected to the outer coax ...
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What would be the easiest and most cost effective ground system for a startup UHF/VHF station
I just passed both my Technician and General Class license this past weekend, and am now contemplating my first station. To get my feet wet I'm planning on getting a Yaesu FT-7900R Dual band Radio ...
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Two devices + one antenna
What I have:
GSM 900 repeater
900 - 2400 MHz MIMO antenna 2xSMA
MIMO 4G Router works with 1800 MHz LTE
Is it a good idea to connect GSM repeater via SMA splitter to one of the antenna cables? Will ...
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What is the maximum and minimum of antenna gap of dipole antenna?
Consider the picture below is design of half wave length (λ) dipole antenna. I read some explanations saying that it is the best design to get the optimum transmit power. Half wave length (λ) is from ...
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Is this antenna "system" really work? [closed]
I posted yesterday asking how can I have signal inside my house which my house is obstructed by a hill from direct signal from the cellular's operator' Base Transceiver System (BTS). The schema of the ...
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How to best ditch the counterpoise of a random wire antenna?
The "ground" has several effects on antennas, most of them negative (see e.g. Why does an HF "monopole" need dozens and dozens of radials while a VHF/UHF "ground plane" ...
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Is there a proper way to connect multiple radios via coaxial cable so they can be tested without going over the air?
Let me state up front that I am not an RF engineer, but I do have a EE background.
I'm working with a group that has a collection of radios, VHF and UHF (military) that is licensed to use a VHF and ...
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Serial matching stub combined with RF choke
If I use RG6 coaxial cable in odd multiples of 1/4 wavelength as a serial matching stub, can I also use it, without modifying the length, as a coiled RF choke balun at the antenna feed point?
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LTE (4G) - Is two (or multiple) antennas better than one?
I have two antennas. A "multiband" (1710~2170 Mhz, 22 dBi)...
...and a "fullband" (700~2600 MHz, 15dBi)...
Taking into account that my modem (router) is "fullband" and ...
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Understanding RG6-75 ohm Cable Impedance
Here is my measurement to a piece of RG6 cable. It is around 30cm cable. On the shield is written COAXIAL CABLE 5C-2V 75 ohm. From my measurement I got data as below:
From that table, we can see that ...
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