Antenna Tuners Don't Affect Antenna Range (

This episode Dave takes a question from the October issue of QST.
Dan, KJ7YBK, is asking if the tuner provides extra power to the antenna to increase range? Dave will go on to explain that antenna tuners do not affect range but impact the antenna in a different manner.
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[@robertmitchum2972]

EXCELLENT EXPLANATION! I was taught this very subject many many years ago by an absolute genius of a man and fellow Amateur Radio Operator K2RIW! This subject came up often, and Dick would Calmly and precisely explain the theory of operating and using a tuner again. He would always say.... There is no loss in using a Tuner/ Matchbox at all, all the power gets radiated through the antenna! Then he would explain about the loss incurred in the Coax. Unfortunately he became a Silent Key about a year ago....... How I miss his wonderful explanations on how things work.

[@SR-di1qr]

I’m starting my journey into radio systems and came across you here on KZbin. I will be going through all your videos. Thanks for sharing your knowledge 🙏

[@joewilson2258]

When using a tuner you should first reduce the power output of your radio to protect your output circuit and once you get the swr as close to 1-1 as possible then you can increase the power output of your radio without destroying the output circuitry . I learned this many years ago as a citizens band operator . Yes please have an swr meter between your radio and the tuner or the antenna a then you will know if your have a good match or not .

[@g0fvt]

Well done with the video, it is a highly misunderstood subject.

[@sionnachog894]

I thought I understood the ATU but you explained it very simply so now I REALLY understand it . Mni tnx EI9GT.

[@radioguy19510]

This might be better illustrated by a snow ball which becomes smaller each time it is thrown.

[@bruceblosser2040]

Yes your tuner will counteract whatever mismatch you have at the transceiver, but the problem with regular coax antenna lines is that the losses from high SWR go up substantially! So many people feed their antennas with ladder line, because it has much lower losses, with a high SWR! This especially applies to longer feed lines!

[@truhartwood3170]

I heard that if you connect the antenna directly to the tuner then it's highly efficient as the losses from the reflected signal are mostly in the coax. No coax = no coax losses. The signal bounces right back into the radiating element where it, you know, radiates. I'm combing videos on tuners to corroborate this. This video seems to support that notion. If so, you should put the tuner at the antenna and run whatever long run of coax you need between the tuner and the radio, not a long run of coax between the tuner and the antenna feed point.

[@danev1969]

Dave, thank you so much for answering my question. I am now in a better position to understand the mechanics of a tuner and building my HF rig going forward. 73 from Dan Evander, KJ7YBK

[@forgetyourlife]

use good coax as well rg8x minimum for HF. Cheap coax is very lossy.

[@rogerneale4319]

A great simple description of what an ATU can and can't do. 👌

[@francismcclaughry3794]

thanks Dave. Keep up the good work.

[@TheNoCodeTech]

Very helpful thanks

[@dickjohnson3343]

Thanks Dave. I finally understand the term SWR in technical terms! 73, Dick, KO4NLJ

[@Lockemeister]

David you are a wealth of knowledge. Your sharing is greatly appreciated. Wonderful youtube channel. God bless and 73!

[@fourfortyroadrunner6701]

Not sure I agree with your title. A tuner allows the radio to operate (safely for the radio) at full power, and therefore without the radio "cutting back" on power it follows that more power out might just equal "more range." A good example is something like a parallel line feed which, without a coupler is so far out of load impedance to the radio that it will hardly generate any power

[@markroles7304]

Wait I am confused, if the signal is being bounced back to the antenna because of a miss match in the network as you stated, and that then some of that reflected signal would then be radiated out on the second time around, that would mean there would be more of a signal power output compared to not having the tuner at all. So the affect to the antenna ranger would be greater.

[@andrewhuebner4935]

Thats a good thought. Remember that every time a signal passes through an impedance mismatch it losses some power. The sum of the forward and reflected signal must equal the incident signal. By the second time around the signal has gone through two impedance mismatches, so it is likely very small in comparison to the incident signal. Now add this twice reduced signal to the next forward traveling signal. It is mathematically impossible for the sum of the twice reflected signal and the forward signal to have more power than the signal that would have passed given no mismatch. The highest output power always occurs when all components of the system have matched impedance. This rule is always true.

[@BusDriverRFI]

Why don't you explain that the transmitter output impedance is actually looks like a 50 ohm resistor? It makes everything easier to understand.

[@ButtonsKing]

I must say the antenna tuner affects the power radiated by an antenna and therefore its range from my point of view. Explanation: If I have a transmitter with 100W output and an antenna + feeder with terrible SWR 6.0:1, then nearly 50W is reflected back to the transmitter and converted to heat in it; the remaining 5OW is radiated into the space. If I insert an antenna tuner and reach SWR 1.0:1, almost all 100W is radiated, resulting in a bigger range. The improvement is 3 dB in this case...

[@cliffyoung5712]

Dave. Could you please do a presentation on a transmatch affecting the recieved signals from a non resonant antenna. I have tried more than once to explain to people that one of my favorite antennas, a 43ft groundplane antenna is not deaf just because i use a transmatch to match the impedence at the transciever. In my experience the signal recieved from the non resonant vertical is perhaps a few microvolts different from one of my resonant verticals on the same frequency at the same time using a manual switch. I only use LMR400 coax so that very little of the signal turns to heat and is lost in the coax. I get a lot of flak for using non resonant antennas from some people. I use a 4 to 1 voltage balun at the base of the antenna and a 1 to 1 choke right before the shack to remove any common mode current that may occur. Say 100 microvolts hits the antenna, half of that energy is immediatly is reradiated, 50 microvolts heads through the 4 to 1 balun down the 125ft of LMR400 to the 1 to 1 choke, then 15ft of LMR400 to the transmatch, then 5 ft of LMR400 to the radio. At 14 mhz the published loss is about 1db in the coax. 50 microvolts at the reciever is roughly S9. My current favorite transmatch is the Dentron Super Super Tuner which features very robust silver plated strap wiring. Not having $150,000 dollars worth of calibrated Rhode and Swartz equipment to accurately measure the microvolts at the base of the antenna vs the microvolts at the transciever i am stuck using calculations and empirical evidence to suggest that no more than a few microvolts is lost to heat in this arrangement. If you could address this topic sometine i would appreciate it. I hear just fine and am more concerned with recieve than transmit power cause if you cant hear em. You can't work them. Thanks Cliff AG5WE

[@rbh1151]

I get that a tuner can't create power. Easy concept & simple conservation of energy law. But the power from the transmitter has to go some place. Heat or radiation. If the tuner bounces reflected power back to the antenna, why doesn't more power radiate from the antenna and thereby improve the range? You haven't mentioned phase issues. Wouldn't the feedline length have a phase contribution to the reflected & bounced back power? Thanks for these great videos!

[@francismcclaughry3794]

i have an older versa tuner. I guess u call the twines of the circle form. When I got this old tuner. the knob was loose or broke. I took it apart and fixed the knob with some J B weld. I have not used it, but I wonder if it would work if I blew the cob webs out of it. one om my new radios have the tuner built in in and the other has a m f j auto tenure on it. My question Can the old versa tuner be used on other radios. say a ten meter I really don't under stand tuners.

[@francismcclaughry3794]

so the S W R meter should be in front of the tuner?

[@billcosgrave6232]

Great explanation!!!

[@lyfandeth]

All that signal being bounced back and forth repeatedly between the antenna and the tuner? Does that cause any "tremelo" distortion or other degradation from the multiple time-delayed copies of the dignal going out? Or is that imperceptible to the ear, and the transmission?

[@forgetyourlife]

Speed of light negates any of that however cheap lossy coax will make the 2nd 3rd or 4th trip harder. It turns to heat and less radiated power.

[@francismcclaughry3794]

will they shut down if it is above the 1.6 is about that.?

[@jaysmall8780]

Thanks Dave! Good stuff!

[@glenmartin2437]

Thank you. N0QFT

[@hughbassoon]

I think modern transceivers have a safety feature where if the SWR is too high they will only transmit at reduced power so you can’t burn out your final. Is that true Dave? Good talk thanks. Hugh. Jones VE7YJ

[@pd9rd]

Yes, that is true. But make sure you know what the radio does that you own, with bad swr. Most atu within a radio will not tune above 3:1 and somewhere lower than 3:1 they will reduce power. But again, please check if that is the case with your radio. 73.

[@hughbassoon]

@@pd9rd thanks.

[@donaldshields2483]

That was a very interesting message about SWR thank you very much seven threes don. K1emw

[@kingduckford]

Is theoretical best practice to build an antenna to meet theoretical perfect resonance at a particular frequency, then get ideal impedance through coax length, capacitance, and tuning? Perfect the radiator and tune the rest, rather than length and shorten the antenna to get 50 Ohms? Or is that more "hot rodding" and attempting to push another 5 horsepower out of a 1,000 horsepower engine? Better stated, what is the gain from a near perfect radiator over a compromise radiator tuned to proper impedance? I.e. if I tune my 108" CB whip setup to 1.2:1 SWR and use it on 10 meters, and then use my 102" whip which is made for 10 meters specifically with a 1.2:1 SWR, and the impedance isn't the issue, how much better is the performance of the 102" whip over the 108" whip? I've gotten my 102" whip to get near 1:1 SWR on 20 meters with my external tuner. But, how good can it actually perform? Radio is a world of making compromises most of the time, but what is more important to compromise? In theory, is shortening the antenna to get proper impedance theoretically backwards?

[@erpece]

The best antenna is a physically tuned antenna. Second best is a electrically tuned antenna, using coils et cetera. A whip antenna for HF is usually not resonant by its length and is therefore a so called compromise antenna - even with a perfect 1:1 SWR. I wouldn't fuss too much over "hot rodding" it. There is one exception: some compromise antennas use the coax feedline as a counterpoise. In that case, a minimum of 20' or roughly 7m of coax is required.

[@kingduckford]

@@erpece High HF is a good example of how a compromise antenna can hurt performance. A 2 foot long loaded CB antenna from Walmart might be a ~2 mile antenna LOS with a legal rig, while an unloaded 108" full quarter length whip with no loading will do 10+ miles LOS in the same conditions. Proof of pudding is in the eating, and a compromise antenna can be a huge hit to performance. LOS is a decent reference because it is more controlled, and results can be measured more 1:1 and better understood. Since skywave is so dependent on conditions, I think lower HF users can lose a little bit of perspective in terms of performance. You can make great contacts with a 40 meter Hamstick, because of conditions. With poorer reception and ERP and radiation patterns, how can you tell how many contacts you AREN'T getting because of the performance loss? Without reference, it is hard to determine how that "compromise" antenna is failing. Maybe in some cases the loss in performance isn't concerning. Maybe it isn't that bad. But, I think there might be a decent amount to be gained in antenna optimization.

[@DontTreadOnMe825]

Thanks Dave - excellent video. 73 M7CCQ Ash

[@larryak0z672]

You mentioned the swr meter to be in front of the tuner. Is this really important or can it be after the tuner also? It seems to me it shouldn't matter. Thank you for the great video's.

[@fourfortyroadrunner6701]

Meter belongs between radio and tuner. You are NOT changing the SWR between tuner and antenna. All a tuner/ matchbox/ coupler does is to match the radio to the tuner so that the radio can load into a good proper load, put out full power without damage.

[@mikeb2459]

Why just ONE tuner?

[@francismcclaughry3794]

A ladder line is different. story. ?

[@paulmitchell4421]

no, it's the same story except the circuit is balanced.

[@daveN2MXX]

I seldom hear the fact that manufacturer spec coax loss is measured at 1:1 swr, and increases with higher mismatch.....the tuner at the transceiver does not reduce that loss!

[@forgetyourlife]

With a high mismatch its a total loss if the tuner isn't there. Insert the tuner and your "reducing" the loss from total to manageable loss.

[@daveN2MXX]

@@forgetyourlife i guess it depends on your definition of a "manageable loss".

[@forgetyourlife]

@@daveN2MXX in this case It depends on if you have a tuner or not. With a poor match your not getting on the air without one.

[@glenmartin2437]

Use low power when you tune otherwise you may damage your radio. NOQFT

[@kd5ozy]

checklist,check for boogers in nose before video!

[@paulmitchell4421]

what the hell is 'antenna range' ?!?!