Talk:Antenna tuner

Inductor and capacitor need to be swapped from the cited image http://en.wikipedia.org/wiki/File:Basicnetworkatu.svg . Diagrams further down in the article, specifically the equivalent circuit diagrams, are correct. Furthermore, external references such as http://home.sandiego.edu/~ekim/e194rfs01/jwmatcher/matcher2.html and http://leleivre.com/rf_lcmatch.html agree with the latter article diagrams. — Preceding unsigned comment added by 76.104.2.80 (talk) 21:09, 8 September 2012 (UTC)

Here are the formulae copied and pasted from the article...

XL = {(Rsource+jXsource)([Rsource+jXsource]-[Rload+jXload])}0.5

and

XC = (Rload+jXload){(Rsource+jXsource)/([Rload+jXload]−[Rsource+jXsource]}0.5

In the Xc formula, the parantheses are unpaired. I have had to guess what the real meaning is. Here are my interpretation in Excel: (is this right?) Rsource = b2 jXsource= b3 Rload = b4 jXload = b5

XL = SQRT(((B2+C2)^2)-(B4+B5)) XC = =(B4+B5) * SQRT((B2+B3)/((B4+B5)-(B2+B3))) the square root is taken across that entire term. (?)

Also, if the sum b2+b3 is negative, then there is an error (root of a negative number). This can happen if the jXsource is capacitive and large. Or an error can arise if b2+b3 is larger than b4+b5. duh. Baruchatta (talk) 20:31, 25 January 2008 (UTC)

This article needs some real world advice on how to use an antenna tuner. For example, all of the "how it works" examples show how to match one resistor value (1000 ohms) to another resistive value (50 ohms). BUT IF MY ANTENNA WAS RESISTIVE (RESONANT) I WOULD NOT NEED AN ANTENNA TUNER! I would like to see advice on how a reactive antenna (too short or too long, capacitive or inductive) is matched to a transmitter. Also, if an antenna is resonant at one frequency, what is its resistance and reactance at another frequency. For example, if an antenna is resonant at 5 MHz, what is its values at 3 MHz? --Baruchatta (talk) 14:50, 25 January 2008 (UTC)

This article could use some discussion about how to build an antenna tuner. It might be useful in this to mention complex conjugate matches. --ssd 04:44, 21 October 2005 (UTC)

This article used to have a section on how to use an ATU, which I wrote. That has since been removed because "The section on the use of ATUs has been removed becuase [sic] WP should not be how to guides" I expect that also means they should avoid becoming how to build guides as well.

Sigh, I personally think both of these would add value to the community and should really be allowed to stay. This article is now terribly complicated with much math and very little use to someone who might actually want to find out any practical information on ATUs. For the record I think the math section is important as well. But not more than how you may typically operate one.

J3gum 05:46, 12 March 2007 (UTC)

I agree that the tuner article needs more info, the author should look at the literature

http://fermi.la.asu.edu/w9cf/tuner/tuner.html

and look at the mathematics in dispute.

I have added some comments about the PI configuration , which is better then the T configuration. Missing parts are :show matching in the Smith diagram and comments about values and voltage/current handling needs of the components. The "Single side band" Collins book shows the real and imaginary Z values of a whip antenna and some thoughts about the need.

Ulrich L. Rohde N1UL , Jan 2009 —Preceding unsigned comment added by 67.84.179.142 (talk) 22:49, 18 January 2009 (UTC)

I had added that while modern solid state power stages do not like an SWR above 1.5, in reality an antanna VSWR of 2 means 11 % of power is refelcted, 11 Watts out of 100 supplied, 89 Watt send forward in the antenna. Tube amplifiers using the Collins filter could easily tune this out. I hope this sataement does not get removed again. Ulrich L. Rohde, N1UL —Preceding unsigned comment added by 67.84.179.142 (talk) 02:27, 17 February 2009 (UTC)

Here's the likely reason it was remove (and I didn't do it, so I'm just guessing). VSWR (any level) does not cause any line loss. Reflected power is not lost. The reflection will be re-reflected by the source. The only loss that will occur is the additional trips back and forth over the lossy transmission line. If the line is of relatively high quality (low loss) the useable VSWR can be relatively high. J3gum (talk) 03:57, 24 September 2009 (UTC)

In the calculations complex numbers are changed into non-complex numbers.

X_L = j 217.94 Ohms

But later

X_L = 2πfL

L = X_L/(2πf) = 1.239 μH

is incorrect, because there is no "j" in the formula:

L = X_L/(2πf) = j 1.239 μH

Z=R+jX = j*j 217.94 Ohms = - 217.94 Ohms

I think this article is much better than it was a few months ago, if not, I have wasted a lot of time. Is the C quality rating something that gets re-evaluated from time to time? Also, I can't understand why this topic, with over 100 visits a day and lots of interest in the ham community is considered of the same importance as Antarctic call signs and other low importance designated topics. Does anyone know if these ratings are reviewed and if so how it happens? JNRSTANLEY (talk) 21:04, 23 October 2014 (UTC)

I am not able to find any references that describe "backlash current". Is this another way to describe reflected power? If we are to use this term in the article, I think people need to know what it means, otherwise use more commonly understood terms. JNRSTANLEY (talk) 13:48, 3 April 2018 (UTC)

I agree. I feel this term should not be used, as you say the accepted terminology in radio is "reflected power". Edited introduction to remove this term and improve clarity. --Chetvorno^TALK 19:08, 3 April 2018 (UTC)

The article seems to be much too big for a single encyclopedia entry. Perhaps it should be split into several smaller articles.107.242.121.7 (talk) 03:43, 16 October 2019 (UTC)