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What effect does a tuner have at the antenna?
Dieter Kiel wrote:
The tuner doesn`t change the antenna specification, e.g. gain, impedance, or pattern. If you buy a beam antenna you will get this data, and the pattern of the antenna is most time a free room pattern. As the tuner is used to match the impedance of the radio to the line it will effect the power getting to the antenna or the signal received from the antenna if it is passed through the tuner. =========================================== Agree with the above because the matching device (tuner) is NOT 100% efficient , hence some (hopefully very little) RF power from the transmitter will be converted in heat inside the matching device. Frank GM0CSZ / KN6WH. |
What effect does a tuner have at the antenna?
A popular myth is developing that the tuner has no effect
at the antenna feedpoint and the only goal is to make the transmitter "happy". My question is: if we monitored only the forward current or forward power at the antenna feedpoint, could we still adjust the tuner? If the answer is "yes", the myth is false. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
Cecil Moore wrote: A popular myth is developing that the tuner has no effect at the antenna feedpoint and the only goal is to make the transmitter "happy". The myth is undoubtedly that the implied point of view is either popular or developing. ac6xg |
What effect does a tuner have at the antenna?
Jim Kelley wrote:
w5dxp wrote: A popular myth is developing that the tuner has no effect at the antenna feedpoint and the only goal is to make the transmitter "happy". The myth is undoubtedly that the implied point of view is either popular or developing. From QRZ.com regarding tuners: "The tuner has absolutely no effect at the antenna." From eHam.net regarding tuners: "Does nothing. The tuner as the other poster said, just makes your radio happy." -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
Oh, I think the 'myth' is fairly true as far as it goes. It just
doesn't 'go' far enough, sort of. As in; It does make the transmitter 'happy'. Since it 'sees' an impedance it likes, it decides to not hold back but put out full power. That means that more signal does reach the antenna than may have before using that tuner. Which means that the antenna can radiate more signal. Does that mean the tuner changes anything about the antenna? It's input impedance? Or just the amount of signal that gets radiated. Sort of depends on just 'where' that tuner is, doesn't it. People who do know something about how all that stuff works, do know that this whole thingy is a 'myth' of sorts. It needs Paul Harvey's, the "rest of the story", to finish it off. Then it makes sense. I seriously doubt if I busted and bubbles here, or repudiated any 'myth'. I'm devastated! - 'Doc |
What effect does a tuner have at the antenna?
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What effect does a tuner have at the antenna?
From QRZ.com regarding tuners: "The tuner has absolutely no effect at the antenna." From eHam.net regarding tuners: "Does nothing. The tuner as the other poster said, just makes your radio happy." Neither Eham nor QRZ publish official technical opinions of the staff, near as I can tell..... thus the above comments only reflect the opinions of some anonymous contributers. As we all know, regarding antenna theory there is a huge gap in the knowledge of many hams. Regarding tuners and antennas, isn't the main job of an antenna coupler ( tuner at feedpoint ) to maximize the efficient transfer of power from the feedline to the antenna? If true, then the coupler ( tuner) certainly does have an effect ! Ed K7AAT |
What effect does a tuner have at the antenna?
On Jun 4, 5:23 pm, "Ed_G" wrote:
From QRZ.com regarding tuners: "The tuner has absolutely no effect at the antenna." From eHam.net regarding tuners: "Does nothing. The tuner as the other poster said, just makes your radio happy." Neither Eham nor QRZ publish official technical opinions of the staff, near as I can tell..... thus the above comments only reflect the opinions of some anonymous contributers. As we all know, regarding antenna theory there is a huge gap in the knowledge of many hams. Regarding tuners and antennas, isn't the main job of an antenna coupler ( tuner at feedpoint ) to maximize the efficient transfer of power from the feedline to the antenna? If true, then the coupler ( tuner) certainly does have an effect ! Ed K7AAT I'd never really heard of this myth, but myself, I think the feed point is the best place for a tuner if the intent is to match the load to the feed line. As an example, if you were using 50 ohm coax, and the load was in the 1000 ohm range, you would have an overall lower system loss matching the load to the coax, rather than place the tuner at the rig and matching the load seen at the coax to the rig. With the lower loss ladder lines I suppose it becomes less critical. |
What effect does a tuner have at the antenna?
AI4QJ wrote:
One cannot operate the tuner in this configuration for maximum power transfer with either a forward-only meter or one that measure net power delivered (smmation of forward plus reflected). If we adjusted the tuner for maximum forward power at the antenna, wouldn't that mean the tuner was properly tuned for a Z0-match at the transmitter? -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
"Cecil Moore" wrote in message ... wrote: That means that more signal does reach the antenna than may have before using that tuner. Sounds like an effect that the tuner has on the antenna, huh? -- 73, Cecil http://www.w5dxp.com No, it sounds like it has an effect on the signal that is reaching the antenna. Jeff |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
The myth is undoubtedly that the implied point of view is either popular or developing. From QRZ.com regarding tuners: "The tuner has absolutely no effect at the antenna." From eHam.net regarding tuners: "Does nothing. The tuner as the other poster said, just makes your radio happy." The tuner doesn`t change the antenna specification, e.g. gain, impedance, or pattern. If you buy a beam antenna you will get this data, and the pattern of the antenna is most time a free room pattern. As the tuner is used to match the impedance of the radio to the line it will effect the power getting to the antenna or the signal received from the antenna if it is passed through the tuner. -- DK DJ4PB |
What effect does a tuner have at the antenna?
....100% efficient? The only thing I have ever had that was 100%
efficient was my 'Ex', which she pointed out to me quite often. So, using a tuner that got just a tiny bit 'warm' from it's inefficiency just wasn't/isn't that big'a deal. When it became noticeably 'warm', it was because I was trying to match something that just was not very close to reasonable. Then again, it sort of depends on the tuner you happen to be using, it's 'usable' impedance matching range, just how 'robust' the thing happens to be built, and what you are trying to do with it to start with. There are limits. How often you approach those limits sort of defines how much heat you will see, they make pretty nice coffee warmers at times ;), not the best idea in the world, but... - 'Doc And just for 'grins', for those who do not 'approve' of using a tuner, what do you think those gama, delta, and other variety of thingys on the feed point of that beam are? (if that don't stir the 'worm soup' up a little, I just haven't had enough coffee yet. I'm still warming it on the tuner.) :) |
What effect does a tuner have at the antenna?
AI4QJ wrote:
"Cecil Moore" wrote in message If we adjusted the tuner for maximum forward power at the antenna, wouldn't that mean the tuner was properly tuned for a Z0-match at the transmitter? I think it would be essentially true for today's FET transmitters that automatically limit output power when the Z0 is not matched, but not for any reason having to do with transmission line theory. Let's see what is wrong with the following reasoning: 1. Maximum power is delivered to a mismatched load when the forward power is at a maximum. 2. Maximum available power is delivered to the load when the source sees its designed-for impedance, e.g. is Z0-matched. Why wouldn't the forward power at the antenna be maximized by a Z0-match at the source while the tuner is being adjusted? -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
Dieter Kiel wrote:
As the tuner is used to match the impedance of the radio to the line it will effect the power getting to the antenna or the signal received from the antenna if it is passed through the tuner. If the power getting to the antenna is measurable, then the tuner is causing something to happen at the antenna. It is doing more than just making the transmitter happy. After all, a dummy load makes the transmitter just as happy as a tuner. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
As the tuner is used to match the impedance of the radio to the line it will effect the power getting to the antenna or the signal received from the antenna if it is passed through the tuner. If the power getting to the antenna is measurable, then the tuner is causing something to happen at the antenna. It is doing more than just making the transmitter happy. After all, a dummy load makes the transmitter just as happy as a tuner. The power at the antenna will also be measurable if you decide to bypass the tuner. If you have a good match you don`t need a tuner. But most of the transmitters don`t work correct with a high swr. Even if they would the best match will get the most power into the antenna. The tuner at the transmitter doesn`t change the impedance of the antenna. It also doesn`t change the gain or the pattern of the antenna. DK |
What effect does a tuner have at the antenna?
On Jun 4, 12:33*pm, Cecil Moore wrote:
A popular myth is developing that the tuner has no effect at the antenna feedpoint and the only goal is to make the transmitter "happy". My question is: if we monitored only the forward current or forward power at the antenna feedpoint, could we still adjust the tuner? If the answer is "yes", the myth is false. -- 73, Cecil *http://www.w5dxp.com I the early books I have that is how things were tuned up. The antenna was dirrectly tapped on to the tank coil. Adjusted for maximum antenna current. No one had heard of swr meters. Antennas worked just fine. Today the antenna tuner resonates the antenna. No antenna tuner? Then no resonanting the antenna. You have to take what the antenna gives. john w9zy |
What effect does a tuner have at the antenna?
"Cecil Moore" ha scritto nel messaggio
... A popular myth is developing that the tuner has no effect at the antenna feedpoint and the only goal is to make the transmitter "happy". My question is: if we monitored only the forward current or forward power at the antenna feedpoint, could we still adjust the tuner? If the answer is "yes", the myth is false. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
"Cecil Moore" ha scritto nel messaggio
... A popular myth is developing that the tuner has no effect at the antenna feedpoint and the only goal is to make the transmitter "happy". My question is: if we monitored only the forward current or forward power at the antenna feedpoint, could we still adjust the tuner? If the answer is "yes", the myth is false. -- 73, Cecil http://www.w5dxp.com If somebody really wrote that "the tuner has no effect at the antenna feedpoint", there are two cases: 1) either he meant to correctly say that, adjusting the tuner, the impedance seen at the antenna terminations - or any other antenna property - does not change (independently of whether the tuner is placed at the transmitter end or at the antenna end). If so, it is just a matter of bad wording, and I would be tempted to say that his english is even worse than my non-mother tongue one 2) or he has a poor understanding of transmission lines and antenna theory 73 Tony I0JX |
What effect does a tuner have at the antenna?
"Cecil Moore" wrote in message ... A popular myth is developing that the tuner has no effect at the antenna feedpoint and the only goal is to make the transmitter "happy". My question is: if we monitored only the forward current or forward power at the antenna feedpoint, could we still adjust the tuner? If the answer is "yes", the myth is false. -- 73, Cecil http://www.w5dxp.com Everyone makes more of a tuner than what it is. If all transmitters were designed to work into very wide loads the tuners would not be needed. Tubes have an impedance of around 1000 to 4000 ohms and must be matched to 50 ohm coax (usual ham antenna design) or some other combination of resistance and reactance. The transisitors must be matched from a very low value (under 10 ohms usually) to a higher impedance. Many transmitters now in use are for only 50 ohm output (fixed tuning) or a small range (maybe 3:1 for some amps) if they do have an adjustiable tuning. There are some antenna designs that fall way out of the 50 ohm design inpedance so some way must be made to match the inpedances for maximum power transfer. Take an amplifier that has a pi-L network built in. If it is adjusted for max power out , and an amp with a pi network with an external L network to match an antenna, what is the differance ? |
What effect does a tuner have at the antenna?
Antonio Vernucci wrote:
"Cecil Moore" ha scritto nel messaggio ... A popular myth is developing that the tuner has no effect at the antenna feedpoint and the only goal is to make the transmitter "happy". My question is: if we monitored only the forward current or forward power at the antenna feedpoint, could we still adjust the tuner? If the answer is "yes", the myth is false. -- 73, Cecil http://www.w5dxp.com If somebody really wrote that "the tuner has no effect at the antenna feedpoint", there are two cases: 1) either he meant to correctly say that, adjusting the tuner, the impedance seen at the antenna terminations - or any other antenna property - does not change (independently of whether the tuner is placed at the transmitter end or at the antenna end). If so, it is just a matter of bad wording, and I would be tempted to say that his english is even worse than my non-mother tongue one 2) or he has a poor understanding of transmission lines and antenna theory Yeah. This is probably the first time some random poster over at QRZ or Eham has been wrong! 8^) - 73 de Mike N3LI - |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
Dieter Kiel wrote: As the tuner is used to match the impedance of the radio to the line it will effect the power getting to the antenna or the signal received from the antenna if it is passed through the tuner. If the power getting to the antenna is measurable, then the tuner is causing something to happen at the antenna. It is doing more than just making the transmitter happy. After all, a dummy load makes the transmitter just as happy as a tuner. Cecil; An antenna tuner does not and can not and will not make any physical or electrical changes to any antenna it is attached to. It will, however, make electrical changes to an "ANTENNA SYSTEM" such that a transmitter or receiver will react to the system more efficiently. Take a dummy load that exhibits a characteristic impedance of say 75 ohms and hook it up to a transmitter that exhibits a characteristic impedance of 50 ohms. I guarantee that the transmitter won't like it as well as a dummy load that exhibits a characteristic impedance of 50 ohms. All impedances are purely resistive with no inductive component. Place a tuner in the circuit and adjust it for best conditions. The transmitter will think it is looking at 50 ohms not 75. Dave WD9BDZ |
What effect does a tuner have at the antenna?
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What effect does a tuner have at the antenna?
Michael Coslo wrote:
Yeah. This is probably the first time some random poster over at QRZ or Eham has been wrong! 8^) What is troubling is that the myth seems to be approaching 50% of the posters. If all an antenna tuner does is make the transmitter happy, it is no better than a dummy load. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
David G. Nagel wrote:
An antenna tuner does not and can not and will not make any physical or electrical changes to any antenna it is attached to. Seems to me that delivery of the maximum available power to the radiation resistance of an antenna is certainly a physical/electrical change capable, in the extreme, of melting the antenna. Consider what a 1kw amp could do to a 40m hamstick used on 75m when matched with a 1kw antenna tuner. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
"David G. Nagel" wrote in message ... wrote: For more grins, what do you think the "LOAD" and "TUNE" knobs on an older tube transmitter are? They match the output power tube impedance to the antenna system impedance. If you don't believe me mistune a tube transmitter and feel the warmth come from the finals. Have a spare in stock for when you are done. Dave WD9BDZ I think I am trying to say the same thing. One has to define where the matching system of the final amplifier stops and the antenna system starts. I look at an antenna tuner that is within a few feet of the transmitter as an extention of the matching network between the amplifier device (tube or transistor) and the load which starts with the transmission line. If the antenna tuner is actually at the antenna, then it is a matching device for the antenna and not in the scope of this discussion. Is the automatic internal antenna tuner such as in my Icom746 pro really an antenna tuner or is it just taking the place of some knobs that I could turn such as in a Heathkit sb100 ? All that is being done in either case is to match the amplifing device to whatever load is put to it. I thnk it is just a mater of what someone wants to call it at the time. |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
David G. Nagel wrote: An antenna tuner does not and can not and will not make any physical or electrical changes to any antenna it is attached to. Seems to me that delivery of the maximum available power to the radiation resistance of an antenna is certainly a physical/electrical change capable, in the extreme, of melting the antenna. Consider what a 1kw amp could do to a 40m hamstick used on 75m when matched with a 1kw antenna tuner. Cecil; How much change in physical length or diameter of wire does an antenna tuner make to an antenna? Dave |
What effect does a tuner have at the antenna?
David G. Nagel wrote:
Cecil Moore wrote: Consider what a 1kw amp could do to a 40m hamstick used on 75m when matched with a 1kw antenna tuner. How much change in physical length or diameter of wire does an antenna tuner make to an antenna? In the above example, it vaporizes the hamstick wire. IMO, that is quite a change. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
AI4QJ wrote:
You can take advantage of the "information" provided by the transmitter, with reference to its Z0 match condition, by merely observing the maximum available output power. The point is, it can be monitored *at the antenna* thus proving that a tuner does indeed have an effect at the antenna. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
Cecil Moore wrote: AI4QJ wrote: You can take advantage of the "information" provided by the transmitter, with reference to its Z0 match condition, by merely observing the maximum available output power. The point is, it can be monitored *at the antenna* thus proving that a tuner does indeed have an effect at the antenna. An effect "at" the antenna is not the same as an effect "on" the antenna. Which did you mean in your OP? Alan |
What effect does a tuner have at the antenna?
Alan Peake wrote:
An effect "at" the antenna is not the same as an effect "on" the antenna. Which did you mean in your OP? The subject line says it all - "at the antenna". -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
"it is no better than a dummy load."
Well, good. If it does it's job as well as a dummy load does it's job, then I would think it's doing a pretty good job. Wouldn't you? 'Course, they don't have the same job so I wouldn't expect one to replace the other (although, it isn't impossible). Where are you going with this Cecil? - 'Doc |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
David G. Nagel wrote: An antenna tuner does not and can not and will not make any physical or electrical changes to any antenna it is attached to. Seems to me that delivery of the maximum available power to the radiation resistance of an antenna is certainly a physical/electrical change capable, in the extreme, of melting the antenna. Consider what a 1kw amp could do to a 40m hamstick used on 75m when matched with a 1kw antenna tuner. It will do to it just what the Hamstick deserves! ;^) - 73 de Mike N3LI - |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
AI4QJ wrote: You can take advantage of the "information" provided by the transmitter, with reference to its Z0 match condition, by merely observing the maximum available output power. The point is, it can be monitored *at the antenna* thus proving that a tuner does indeed have an effect at the antenna. All canards have a kernel of truth in them. My guess is that someone observed that an antenna "tuner" would "tune" a wide variety of oddball antennas to transmitters that were looking for a particular impedance. Then to simplify matters, someone said "the transmitter doesn't care what is on the end of it, so long as it sees that 50 ohms impedance. It's a short drive from there to "the tuner has no effect on the antenna". - 73 de Mike N3LI - |
What effect does a tuner have at the antenna?
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What effect does a tuner have at the antenna?
Michael Coslo wrote:
It's a short drive from there to "the tuner has no effect on the antenna". Actually, it went farther than that: From QRZ.com regarding tuners: "The tuner has absolutely no effect at the antenna." From eHam.net regarding tuners: "Does nothing. The tuner as the other poster said, just makes your radio happy." -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
wrote: Where are you going with this Cecil? "Reflections" Again? ;^) - 73 de Mike N3LI - |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
David G. Nagel wrote: Cecil Moore wrote: Consider what a 1kw amp could do to a 40m hamstick used on 75m when matched with a 1kw antenna tuner. How much change in physical length or diameter of wire does an antenna tuner make to an antenna? In the above example, it vaporizes the hamstick wire. IMO, that is quite a change. Cecil; A "HAMSTICK" antenna has a "MAX" power rating. If you exceed this power rating you will indeed vaporize the wire. Of course this is true of ALL antenna's. Hook up a 50,000 watt transmitter to a 20 gage wire dipole and watch the copper vapor drift off in the wind. I am currently to lazy to look up the HAMSTICK power rating but you can at your leisure. Dave PS: Good to talk with you again, it's been a while. I learn from you each time, usually. |
What effect does a tuner have at the antenna?
David G. Nagel wrote:
A "HAMSTICK" antenna has a "MAX" power rating. If you exceed this power rating you will indeed vaporize the wire. The point is that if an amp is equipped with foldback, it probably cannot vaporize a severely mismatched antenna without the aid of an antenna tuner. -- 73, Cecil http://www.w5dxp.com |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
David G. Nagel wrote: A "HAMSTICK" antenna has a "MAX" power rating. If you exceed this power rating you will indeed vaporize the wire. The point is that if an amp is equipped with foldback, it probably cannot vaporize a severely mismatched antenna without the aid of an antenna tuner. Actually it will most likely vaporize the tuner first... |
What effect does a tuner have at the antenna?
Cecil Moore wrote:
Consider what a 1kw amp could do to a 40m hamstick used on 75m when matched with a 1kw antenna tuner. David: How much change in physical length or diameter of wire does an antenna tuner make to an antenna? Cecil: In the above example, it vaporizes the hamstick wire. IMO, that is quite a change. You have a tuner that vaporizes hamsticks? Craig 'Lumpy' Lemke www.n0eq.com |
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