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13 votes
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What is an antenna tuner? Why bother with resonant antennas in the first place?

And if it is possible to use a tuner to make a transmitter feed power into a coat hanger then why do we worry about making resonant antennas in the first place? In a word - efficiency. Consider that ...
Glenn W9IQ's user avatar
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10 votes

What is an antenna tuner? Why bother with resonant antennas in the first place?

My understanding is that they can neutralize the imbalance between inductive and capacitive reactance so the transceiver can couple the most power out (or in) even though an antenna might not be ...
Phil Frost - W8II's user avatar
10 votes
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Does an antenna tuner remove standing waves from a transmission line?

An antenna matching network (aka "tuner") does not affect the conditions of the load (antenna) or the transmission line between the load and the matching network. The matching network transforms the ...
Brian K1LI's user avatar
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9 votes
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Tuner at antenna side versus transmitter?

There are a lot of topics in this question, so let's take them one at a time. I figure the transmitter has a 50-ohm pure resistive output Not necessarily. You're probably arriving at this conclusion ...
Phil Frost - W8II's user avatar
9 votes
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Does a halfwave (or multiple) length of coax duplicate the load impedance of one end at the other end?

I have been told that 50 ohm coax is 50 ohm at both ends, and 50 ohms all along its length, and it is 50 ohms that is presented to anything to which it is connected, and the length of it does not ...
hobbs - KC2G's user avatar
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7 votes
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How do I set up my radio for an antenna tuner?

Your TS430S has a solid state final and no internal antenna tuner. As such it is designed to work into a 50 ohm load at all times. This means you can disregard this note in your antenna tuner manual. ...
Glenn W9IQ's user avatar
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7 votes
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HF Vertical antenna with no radial and loading coil but only ATU for 80m to 10m in a boat

On boats the traditional solution is to use the backstay as the radiator, with an insulator near the top, another near the bottom, and an insulated wire running to the tuner. The water serves as the ...
tomnexus's user avatar
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6 votes
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What types of materials increase the inductance of a coil when inserted inside it?

Any material with a relative permeability greater than 1 will increase inductance when inserted into a coil. Note that permeability is a complex number and frequency dependent. The imaginary part of ...
Phil Frost - W8II's user avatar
6 votes
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Estimating SWR based on multiples of resonant length

Very high. Harmonics work the other way around — antennas can be useful on higher bands than the design band, but almost never lower bands. A dipole cut for 40m might be good on 15m. An end-fed or a ...
hobbs - KC2G's user avatar
  • 12.6k
6 votes

Reasons for an antenna tuner at the transmitter other than transmitter protection?

Just because the finals don't go up in smoke when driving a mismatched load, doesn't mean they're working well. They will probably deliver less power to the antenna than they would in a matched ...
hobbs - KC2G's user avatar
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5 votes
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Can anyone tell me how to make a 35 m long wire antenna work on 80, 40, 20, 15 and 10 metres?

I suggest you feed it in the center with open-wire (ladder) line and a balanced antenna tuner. (I have done that for many years). With the right tuner, you can obtain a near-perfect match anywhere on ...
Mike Waters's user avatar
  • 8,081
5 votes

Benefit to remote antenna tuner for end-fed non-resonant antenna?

The benefit of placing a tuner at the antenna (rather than at the transmitter) in any circumstance is a reduction in the SWR on the coax. This results in a reduction of losses. There's a bit of myth ...
Phil Frost - W8II's user avatar
5 votes
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Two Antenna Tuners in Series

A simple tuner might be just a capacitor and an inductor: simulate this circuit – Schematic created using CircuitLab For more flexibility, many tuners add a 2nd capacitor to make a pi network: ...
Phil Frost - W8II's user avatar
5 votes
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What is the actual loss in a feed line with high SWR?

Assuming no tuner losses, and assuming uniform loss throughout the line (which isn't true in practice, yet can be a practical simplifying assumption, more below), feedline losses in decibels are: $$ -...
Phil Frost - W8II's user avatar
5 votes

Antenna tuner at the transceiver output confusion

Having a transmatch (antenna tuner) at the feed point of the antenna can be an excellent way to solve the problem of a mismatched antenna; an antenna system with the transmatch at the feed point of ...
rclocher3's user avatar
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5 votes
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Using NanoVNA to tune antenna

Jesse Knott, I am not sure by what you mean when you say you "see attenuation dips" on your Nano-VNA, unless you are talking about the LogMag function. For your purposes I'd do your ...
Lou-in-USA's user avatar
5 votes
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generic antenna tuner term: impedance matching vs real tuner

Whether for an inductive antenna, like a loop, or a capacitive type antenna, an antenna tuner is correctly named, because it does tune an antenna, when used at the antenna feed-point. The problem is ...
Louis Seaman's user avatar
  • 1,127
5 votes

generic antenna tuner term: impedance matching vs real tuner

is the above correct ? Please explain. No. In both cases you're adding one or more reactive elements to the radiating element in order to get a better impedance match and improve power transfer to ...
hobbs - KC2G's user avatar
  • 12.6k
4 votes
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Will an Internal Antenna Tuner work with an external HF amplifier?

Yes, you'll need an external tuner, unless your antenna is already matched sufficiently well to 50 ohms. The objective of the tuner is to transform the impedance seen by some signal source, like your ...
Phil Frost - W8II's user avatar
4 votes

Using an HF antenna for VHF scanning

There are many problems here, only one of which has to do with impedance: Your antenna is (I assume) horizontally polarized whereas most VHF signals you might scan for (particularly ones where one ...
Kevin Reid AG6YO's user avatar
  • 24.7k
4 votes

Is ladder line necessary when using a non-resonant dipole through a tuner?

This can indeed be a fine setup. With a suitably low-loss feedline, and a good tuner, just about anything can be made to function as an effective antenna. There are two factors that determine the ...
Phil Frost - W8II's user avatar
4 votes

Antenna tuner design

So, yes, to tune a resonant antenna, you'll need an adjustable capacitor or inductor. You'd usually go the capacitor route, since adjustable caps are smaller, cheaper, and more exact, usually. Bonus: ...
Marcus Müller's user avatar
4 votes
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Do I need an 9:1 UNUN for a half-wave end fed?

An end fed, 1/2 wavelength antenna will have a relatively high impedance of 5k ohms or more. So a 9:1, or greater, ratio of balun may reduce the impedance sufficiently to help your tuner get a match ...
Glenn W9IQ's user avatar
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4 votes
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What dielectric strength is required for a variable capacitors in a 100W T-network antenna tuner?

I made a NEC model of an antenna with the dimensions of your "long wire" on 14.2MHz, found the values of C1, L1 and C2 that produce a 50$\Omega$ match and simulated the network to observe the voltages ...
Brian K1LI's user avatar
  • 7,878
4 votes

What types of materials increase the inductance of a coil when inserted inside it?

TL;DR: It's NOT mild steel, brass, or aluminum. I connected two different inductors to an antenna analyzer, and all of the above materials decreased the inductance as they were inserted. The larger ...
Mike Waters's user avatar
  • 8,081
4 votes

Ideal Doublet Size 160-10 Meters

A single antenna that functions over such a wide band will necessarily be less than ideal. Compromises must be made to achieve such wideband performance. The antenna will have to be at least big ...
Phil Frost - W8II's user avatar
4 votes
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Do I always need a tuner at both ends of the transmission line or is that only for certain types of antennas/circumstances?

It is not normal to have and use tuners on both ends of a feed line. The purpose of an antenna tuner is to provide an adjustable impedance transformation. The reason we want that transformation is so ...
Kevin Reid AG6YO's user avatar
  • 24.7k
4 votes
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What happens to the signal level if the antenna has high SWR?

Let's say the antenna impedance on a given frequency is 100 Ohm, the feedline is lossless 50 Ohm, the transceiver input impedance is 50 Ohm. Between the antenna feed point and the feedline SWR = 2, 11%...
Phil Frost - W8II's user avatar
4 votes

SWR erratic based on time of day

If it acts like a loose connection, it probably is one, just not an obvious one. If it fluctuates from day to day, especially with a pattern, it could be water intrusion. If it works worse on hot ...
user10489's user avatar
  • 6,533
4 votes

Tuner at antenna side versus transmitter?

To make a long story short, if you are using 50 ohm coax with a 50 ohm radio, putting the tuner at the antenna is higher efficiency because it reduces losses in the coax caused by high SWR. However, ...
user10489's user avatar
  • 6,533

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