SWR indicators should be used as a tune up tool. The reflection indicated can be easily tuned using a "trans match". There is no reason to believe SWR is any indication of a poor radiating antenna any more than it should be used to indicate feed line losses.

The answers...29 of them are TRUE, only one of the questions is FALSE. Do you know which one?

  There you have it. The explanations, all the references and editors notes (tips). You can follow along with each question and maybe learn something about SWR that you never realized. You will also understand why the ANTENNA TUNER is a more important device today than it was 50 years ago. There is a million ways to use SWR information. But above all don't consider it the "end to all" when you build that antenna. MATH is still the single most important tool you have in your radio room. The second will be your tape line.

Explanation and references:
(1) From an SWR reading, reflected power does not represent lost power beyond cable attenuation.
True: The SWR indicator, no matter how simple or extravagant, reads the FORWARD power to the antenna and the REFLECTED power returning from the load. It does not read the currents, simply the voltage. There are RF type current meters, but the SWR bridge is not such a device.
  In a loss-less feed line no power can be lost due to REFLECTION. In coax, attenuation is the power loss factor. There are devices that can read power loss along a specific length of coax, but at HF frequencies and the lengths common to Ham Radio installations, these losses are insignificant. It should be noted that at VHF and UHF, certain feed line does have significant loss, but for HF bands these losses, for all practical purposes, are not detectable.
  In the statement "does not represent lost power" is not a trick component. The SWR bridge simply cannot detect these attenuated losses.
  It should be understood that SWR "standing wave ratio" is very much like a wave incident in a standing pool of water. Drop a stone in the absolute middle and waves form toward the shore. these waves are "reflected" back to the point of origin and return to the shore again to be reflected. Assume water turbulence as the attenuation of these waves. The more turbulence, the more these waves are attenuated. Open feed line has less turbulence than coaxial line; but our pool is big enough that this turbulence does not effect the wave...UHF would be a much smaller pool and any turbulence at all will effect the "re-reflected wave" as it travels back from shore to the point of origin.
Reference: The ARRL handbook, any recent edition since 1970.

(2) Reflected power does not flow back into the transmitter or the tuning device and it does not cause damage to the components there in.
True: Damage that is blamed on high SWR is simply not true. There are many articles written that make these claims. There is even "false advertising" that makes claim regarding a product and product warranty. This damage simply cannot happen due to HIGH SWR.
  Such damage rendered to over heated final amplifier tubes, comes not from "reflected" power but from "poor loading" techniques, mistuned (reactive) final stages or over coupling. The trick when using a tube type amplifier, one should tune for maximum "output" and not just the "dip and load" sequence we have been taught. The SWR bridge is a tuning indicator in the FORWARD meter position. In fact the "transmitter" (tube or solid state) does not see SWR at all. It only sees the impedance. ALL IMPEDANCES ARE MATCHABLE...this must be understood. In one way or another we can match these impedances and transfer 100% of the power (less the attenuation) to the radiator.
Reference: The ARRL handbook, any recent edition since 1970 and the ARRL antenna handbook since first print.

(3) Any effort to lower an SWR of 2:1, on a coaxial line, is completely wasted from the standpoint of significant increase in power transfer.
True: Basically, any attempt would yield a result very similar to using no. 6 wire to transfer energy to a flashlight lamp. The effort yields little or nothing in respect to an increase current transfer.
Reference: Reflections, chapter 1 illustration 1.1

(4) An SWR reading of 1:1 is not proof of a good quality antenna system or any indication that the system is radiating properly
True: On the contrary, lower than normal SWR values exhibited over an extended range of frequencies by a straight dipole or vertical "over ground" is a sure sign of system problems. These undesired readings come from lost load resistance, such as found in cold solder connections, poor mechanical joints, bad grounds and poor physical cable conditions (water or contamination under the jacket skin). SWR is an indication that all is well and without it (extremely low SWR over a wide range of frequencies) there is a problem.
  A good example for questions "3" and "4" would be in the case of a "quarter wave" vertical over ground that has 50 radials under it to effectively create an "impedance" of 35 ohms. That termination to the radiator will yield a 1.6:1 SWR reading when fed with 50 ohm coax. If enough radials are removed to lower the ground resistance of the radials to 18 ohm the SWR will be a flat 1:1 and all would be perfect...NO, that is not true. The SWR went down but the effective power is being divided between the 32 ohm radiator resistance and an 18 ohm ground resistance. As a result, the effective radial tuning did not increase radiation but actually hindered it by radiating power into the ground. This will certainly raise interest with earth worms, but it will not render an effective radiator. Commercial broadcast antenna systems are, by law, required to have a minimum of 90 radials under the tower system. This eliminates the "ground warming" effect described above. The Amateur Radio system should have at least 25 radials under the ground mounted vertical in order to be effective.
  If the vertical SWR is effectively less when transmit frequency is adjusted away from the calculated resonant point, chances are you do not have enough radials under the antenna. Moving the frequency away from adjusted frequency should yield an SWR increase. If tuning higher or lower yields a LOWER SWR you have conclusive proof that the radial system is not effective.

(5) Any antenna RADIATING element need not be self-resonant for full "resonant" current flow, and the feed line need not be a particular length, and termination point of radiator and feed line needs not a "perfect match"
True: A substantial mismatch at the feed point of the feed line does not prevent the radiator from absorbing all the power available at that junction.
Reference: W1DF, "The Why's of Transmission Lines", QST Jan. Feb. Mar. 1965 (three part lecture).

(6) If a suitable "matching network" (tuner) cancels all reactance rendered in a non-resonant radiator, fed by a  random length feed-line that is mismatched to said radiator, the antenna system resonant.
True: The "tuner" ("T" network. "Pi" network or "L" network) effectively cancels the mis-match by tuning out the reactance in the antenna system. Therefore maximum current flows into the radiator and all power available at the radiator is absorbed.
  The "matching device" (ATU) removes the mismatch (reactance) that effectively lowers the output of modern solid state radios. The Hybrid radios of the 70's that are still in use today, effectively tune out the antenna reactance within the "Pi Network" of the output tank circuit. The SWR is not important because the reflected waves returning from the antenna system are simply re-reflected back to the radiator. In a low-loss feed line system, less power is lost due to attenuation, not SWR. (NOTE: Again at HF frequencies these losses are almost meaningless.)

(7) The majority of AM BROADCAST tower radiators operating between 540 KHz and 1600 KHz are at heights which mathematically are not resonant at the frequency used.
True: A perfect example would be a broadcast station at 1000 KHz or 299.8 meters. The antenna would be over 900 feet high in order to be a full wave resonant antenna. Most Commercial Broadcast antennas are quarter wave or less. many are not resonant at all on the broadcast frequency. Proper coupling and "matching devices" are used to effectively couple the radiator. These systems are based upon one single transmit frequency and are unlike amateur use where the antenna must "compromise" for multiple frequencies of operation, both transmit and receive.

(8) The SWR on the transmission line between the radiator and any matching device at the feed line input, is determined by the mismatch at the "load" and cannot be "changed" by the matching device.
True: This is what you hear on the air..."Why should you use a tuner(?), it does not have any positive effect on the antenna." Yes that is true, but nothing else you do will change the mismatch. The tuner is an aid to removing the reactance (created by the mismatch) of the antenna system and therefore it does have an active, positive effect on the antenna. Most operators believe "matching devices" effectively "fool the radio into thinking it is looking at a perfect SWR". Now that is no further from the truth than the the previous statement is from a lie. If a suitable "matching device" cancels reactance, then the mismatch is absent and all the power is absorbed at the load. The true statement should be..."Lower SWR obtained by using a matching device indicates only the mismatch remaining between the input impedance of the network and the impedance of the line from the transmitter."
  To rephrase this, the SWR indicator is placed between the "matching device" and the transmitter. The transmitter would see the lower SWR at the input to the device, BUT ONLY after the reactance is properly tuned out. If another SWR indicator is placed behind the tuner it will see no change in the mismatch, no matter how perfectly the SWR is indicated. But, because the reactance has been tuned out the REFLECTED incidence is not a LOSS it is re-reflected back to the load and absorbed in the radiator. (NOTE: See question number 2)

(9) Proper adjustment of a "matching device" for maximum line current creates a "perfect mirror" of termination for the reflected wave incident.
True: Tuning the device creates the "perfect mirror" terminator for the reflected wave. This causes the the REFLECTED WAVE to be re-reflected, on arrival at the input end of the line. The tuner provides "proper reactance" to cancel the "equal but opposite reactance" between the source and the reflected wave. This causes the REFLECTED wave to be added in phase with the source wave to render the total incident, or FORWARD POWER...which is the sum of the source and the REFLECTED power.
  That may be hard to swallow, but like the perfect wave in the pool of water, when it is reflected from the shore back to the point of origin, it is again added to the source of that wave, and re-reflected back to shore as an incident wave.
The RE-REFLECTION then becomes part of the FORWARD wave. Only loss encountered along the way will be from liquid turbulence in the pool (attenuation in the line). As you can easily see, mismatch is then determined by one of two possibilities: The shore line is not a perfect circle and all reflected waves are distorted (the antenna is not constructed properly), or the impact of the wave generator is located "off center" (off resonance frequency) and generates a FORWARD wave that does not reach the shore equally (out of phase), on all sides (the radiator is not asymmetrical). If the feed-line is known to be in good electrical order, the feed line can in no way be part of the mismatch issue.
   From what you have learned so far...does the radiator have to be perfect resonance in order to be the perfect radiator? The answer is NO, but good system design where currents are equal and do not cancel each other is certain to be more effective than one that is not. But again, this has nothing to do with SWR.

(10) Total "return of reflection" of any amount of reflected power from the radiator back to the input (caused by feed line mismatch) is the reason such reflected power is not dissipated at the transmitter.
True: The re-reflected power is not dissipated as heat in the transmitter or the matching device, but instead is conserved, rather than lost. The only LOSS is in the "attenuation" of the coaxial line. And again...this is insignificant at HF frequencies.

(11) A good antenna system including a well designed "matching device" feeding an "open wire line" into a 130 foot center-fed dipole at 50 feet does not radiate significantly more power on 75 meters than does an 80 foot dipole at the same height fed with the same power.
True: Open wire feeder has the least amount of attenuation (loss) of any type feed line at HF frequencies. The same can be held true at VHF frequencies as long as the open line has little little or no turns beyond 20 to 30 degrees.
Reference: W1DF, "The Why's of Transmission Lines", W1DX "My Feedline Tunes My Antenna"; QST March 1956, W1ICP "A Versatile Transmatch"; QST July 1965.

(12) A self resonant dipole fed with RG-8 or RG-11 cut for 3750 KHz does not, at that frequency, radiate more than it does at 3525 or 3985 KHz.
True: Of course the opposite is true also; however it should be noted that feed line length can make a difference if the length is longer than 150 feet and if the feed line is dependent on a high attenuation loss coax.

(13) A 3750 KHz dipole fed with any length of 50 ohm coax and having an SWR of 1:1 will yield an SWR of 6:1 at 3500 KHz and close to 5:1 at 4000 Khz thereby "using" the coax as a tuned feeder, with no significant loss across the entire band.
True: Plain and simple truth. Again we respond that the FEED LINE has little if anything to do with impedance mismatch or effective radiated power in the radiator.
(Note: It is possible to tune a feed line using various lengths of coax at different values, but this does not make the radiator any more efficient at one end of the band than the other. Using various length 75 ohm coax in line with a 50 ohm feed line does not effectively remove reactance from the radiator.)

(14) With the use of a "transmatch" at the line input, proper coupling between the transmitter and the tuned-coax feeder (of any length) can be maintained over the entire 80 meter band
True: Refer to the previous question and note that the "transmatch" (matching device) is used to remove reactance in the system. This cannot be done by the coax feeder alone. A simple "L" network of an inductor and a variable capacitor will work just as well as any of the "exotic" feed line devices on the market today.

(15) When using a DIPOLE antenna above ground, changing the height above ground or lowering the ends of the DIPOLE in order to increase or decrease radiator impedance has an insignificant effect on power absorption by the antenna.
True: This should be a no brainer...I hope you did not miss this one.

   I may be repeating myself, but sometimes that does not hurt when trying to emphasize one's position. Resonance is, by all basic function, a factor of math. Real world formulas are there for a reason. There is no secret medicine you have to take to understand "486 divided by frequency in megahertz". The result should not be questioned; if you build your new dipole to those specifications, the antenna should be resonant at that frequency. If the SWR is not a perfect match, any attempt to make it perfect will not increase efficiency at the original frequency applied.

(16) A 50 ohm tuned feed line at 3999 KHz can handle 700 watts of CW power within SWR readings of 5:1. However, SSB input power at this frequency can increase ratings to up to 2000 watts. A 100 foot feed of RG8 with a 5:1 SWR has an attenuation loss of .78DB (or .46DB due to SWR) which is meaningless in terms of a broadcast signal level.
True: At these frequencies you have a lot more to worry about when it comes to signal loss. The entire 75/80 meter band can be covered very nicely if design your antenna around 3750 KHz. and use a dependable matching device.

(17) If the length of feed line is critical in order to obtain the proper match, the identical matching impedance can be obtained using any length of feed line by simply adding a "matching network".
True: You do not need to perform surgery on an antenna if the length of feed line you use is critical. The matching transformer (2:1 Balun) will help "match" a 50 ohm line to a 100 impedance. You should be aware that the SWR results shown may not reflect a perfect match at resonance. A simple matching device can be made from any two components made up of two inductors, capacitors or one of each.
Reference: P.H. Smith ~ Electronic Application of the Smith Chart, R. Leo W7LR ~ An Impedance Matching Method. QST April 1959.

(18) High SWR in a coaxial feed line caused by severe mis-match at the load, does not produce antenna currents on the feed line and it does not cause the feed line to radiate.
True: Nothing more to understand the statement is true.
Reference: The ARRL Antenna Hand Book - 10th addition 1964.

(19) High SWR in a open wire feed line at HF frequencies, caused by load mismatch does not produce currents nor does it cause the feed line to radiate
True: This is also true at VHF frequencies if sharp bends are avoided. It should be noted that the line should be balanced; equally in length one leg of the line to the other and separators should also be equally spread apart.
   Most "twin lead" made today (450 ohm) is balanced and can be purchased as solid or stranded wire in gauges 12 to 16 Ga.

(20) Both types of feed line may radiate, although not significantly, caused by re-radiation of energy "coupled" into the feed line from an asymmetrical positioning of said feed line to the radiator.
True: The important factor is asymmetrical position of the feed line to the radiator. Off center termination point to the radiator can cause a limited amount of radiation.
Reference: J.J. Schultz W4FA ~ The Broad Band Balun" - CQ Aug. 1968.
  
   The use of OCF dipoles (Windom) has increased recently. These antennas are susceptible to RF presence on the broadcast signal. While this is only my opinion, I personally refrain from using such antennas if at all possible.

(21)  SWR indicator need not be placed at the junction of the feed line to the radiator in order to obtain a more accurate reading.
True: In fact the SWR indicator may be placed anywhere along the feed line. It should be noted that if a low SWR reading is dependent on where the indicating device is placed along the line, chances are you have feed line issues or termination problems at the radiator. Feed line issues could be water in the coax or a crack in the insulation. The SWR device should be used as a "primary" tune up device and not a primary "reflected power" device.

(22) The SWR in a feed line cannot be changed, adjusted or controlled in any manner by varying the length of said feed line.
True: This is a fact. Adding different lengths of various coax to the feed point may lower the SWR but it does not substantially increase radiation or lower reflected power. Before going to great lengths to make these adjustments, add a matching device ahead of the feed line and tune out the reactance.
Reference: L.G. McCoy W1ICP ~ "Antennas and Transmatch" QST Oct. 1964.

(23) If the SWR bridge indicator reading changes significantly when moved a few feet along the feed line it indicates "antenna current" is on the outside of the coax or the device is unreliable, or both.
True: If you place an SWR device directly behind the exciter and render one value that is incorrect compared to one placed directly behind the amplifier, neither of the indications are reliable. Placing the SWR indicator 1/4 wave along the feed line should result in the same indication at the input or at the termination point. The SWR bridge does not indicate (it cannot) loss from feed line attenuation.
Reference: The ARRL Antenna Hand Book - 10th addition 1964.

   Note: Testing your SWR device requires a "dummy load" of 50 OHM. You should first install the bridge as indicated by the manufacturer. Tune for 1:1 on the device in the REVERSE position and then simply reverse the feed line connections to the bridge. The SWR should be the same when read in the FORWARD position. If not, the indicator is in need of repair.

(24) Any reactance added to a resonant load (purely resistive) in order to compensate SWR readings will only make reflected matter worse, not better.
True: It has been taught and in most part, understood that the lowest SWR will only occur at radiator resonance. This can be no further from the truth. This is because SWR is an indication of the FEED LINE and not a true reading of the resonance of the radiator. These factors are totally independent of each other. Any SWR indication that the antenna is at resonance is rare and any measurements that contradict this indicates an error on the part of that measurement device. Simple terms...an SWR reading of 1:1 does not mean the antenna is at resonance.

(25) Of all common known types of DIPOLE antennas, including folded, fan, trap, coaxial or a combination of such, does not radiate more field (pattern) than another providing each has insignificant reactance losses while fed with the same power.
True: If it looks like a DIPOLE, tunes like a DIPOLE and radiates like a DIPOLE, it must be a DIPOLE. As long as the SWR is reasonable and reactance is at a minimum, no matter what you call a G5RV, it remains a DIPOLE. It also radiates like a DIPOLE, therefore it cannot radiate more energy than a DIPOLE.
Reference: G Grammer W1DF, "The Why's of Transmission Lines", QST Jan. Feb. Mar. 1965 (three part lecture).

(26) RG8 coax used in a HF mobile installation should have the MATCHING DEVICE located at the input to the coax in order to improve operating bandwidth.
True: Matching devices at the antenna (of a mobile installation) significantly decreases antenna radiation. This type of installation also improves over all bandwidth. This is more important today due to lack of counterpoise in most fiberglass and composite vehicle bodies. In many cases a "fake" ground system (a separate wire) run from the antenna mount returned back to the matching device can increase effects of over all radiation.

(27) Center loaded mobile antennas of equal size having no input matching device at the coax input, the best efficiency is obtained on units with the LOWEST terminal resistance, not the lowest SWR.
True: Many center loaded mobile antennas will have a high SWR. They radiate very well with or without a matching device located at the coax input. Antenna models with matching devices generate the LOWEST SWR, but they are usually wasting power in the loading coil because of a LOW "Q" in the coil or extreme capacitance, or in some cases, both.

(28) The RESONANT FREQUENCY of an antenna cannot be determined by probing the input of the feed line using a grid-dip meter or noise bridge, if that device cannot properly measure reactance.
True: Devices like the modern antenna analyzer offer a solution to the problem of antenna design because they can measure antenna reactance. They give this result in many forms, but the SWR indicator alone cannot do that. Use of a grid dip oscillator or noise bridge will generate different results with different lengths of feed line because these devices are reading TOTAL resonance. The resonant indication will change if the feed line is adjusted. If say they feed line is 1/2 wave at the same frequency as the radiator, the resonant indication will be totally different from that of either the radiator or the feed line.

(29) Placing an SWR bridge at the input to the matching device can offer the same results when placed at the output of the matching device if the unit is read in reverse.
False: The "matching device" tunes reactance from the feed line and therefore it offers a more effective load to the exciter. Any SWR indicator placed behind the tuner should read an identical SWR when the tuner is switched to bypass the network. The indication makes no difference which way the bridge is installed. The tuner simply "re-reflects" the reflected power, it does not absorb the reflection in it's network therefore the additional SWR indicator will read the same no matter how the tuner is matched or mismatched.

   For those who say the matching device is simply "faking" the exciter into believing it is a perfect match are only half true. Call it what you want, but a tuner is designed to TUNE reactance that insures full power absorption at the radiator by simple re-reflection of the standing waves.

(30) Tuning the receiver to the highest noise floor, using a matching device yields the same result as tuning the transmitter to the lowest SWR reading.
True: The RF front end is a good indicator where the transmitter should be "close" to proper tuning. What should be noted, tune to the highest "noise floor", take an "S" meter reading and then switch the tuner into "bypass". The "S" meter reading should be the same. If it is not, you are most likely not properly tuned or there is a feed line issue.

   In the early days of modern receivers, there was an "L" network attached to the first RF stage. This network was a simple "antenna tuner" and it allowed proper tuning of the receiver front end. Later these tuned circuits incorporated another stage of amplification and became known as "pre-selector". It was a simple amplified "tuner stage" that eliminated noise and cross band hash.

Ok, I hope you got something from all of this. I am trying my best to help you understand SWR. It is a very simple indication of forward and reverse voltages along the transmission line. These voltage are there for both "transmit" and "receive" The receiver cares less what it hears, but a high SWR does not offend the receiver...however a tuned ciscuit ahead of the receiver will indeed improve the signal to noise ratio. Remember that an antenna that is designed for all bands is a compromise, especially to your receiver. That should explain why a 40 meter loop does not boost the noise floor on 10 meters as well as a 10 meter loop. The 40 meter antenna is much larger, but the 10 meter loop is a tuned circuit and receives 28 MHz signals much better than one tuned for 7 MHz (this is also true in reverse).

I welcome comments regarding this questionnaire, but I suggest you obtain a copy of Reflections I or II and read the book like I did...read it several times.

W3EUT
Thanks, The RFampGUY.
I hope to gather another quiz like this one with reference to Baluns and feed point matching transformers. Why they are so important and the difference between the "voltage" type and the "current" type. This is also unknown territory for many of today's "memory made ~ multiple choice" Ham operators.

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