Amplifiers in general
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I have always been under the impression the doubling of output power
will result in a power gain of 3 db. And, that 3 db gain is the least signal increase noticeable at the receiving point. KPA500 outputs 500 Watts - 1000 Watts would give an output gain of 3 db (over the KPA500) and 1500 Watts a little over 4 db gain. That being my understanding - why would I want to spend a box full of dollars for more power than my KPA500 provides? Or, is my understanding flawed? FWIW, I have run all kinds of amps in my nearly 60 years of being the on the air and have found that Watts are Watts, regardless of how you generate them (fancy, cheap, junk, or solid gold). Everyone have a super HAPPY NEW YEAR!!! Bill W2BLC K-Line (medium power HF) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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On Sat,12/31/2016 7:01 AM, Bill wrote:
> I have always been under the impression the doubling of output power > will result in a power gain of 3 db. Right. > And, that 3 db gain is the least signal increase noticeable at the > receiving point. Wrong. As an audio professional, I had to learn a lot about human perception of sound. Here are some things I've learned, both by studying what others have learned and by my own observations. 1) If some sound is all by itself (that's all that you here, no other sounds), 1 dB is the smallest change in level that most listeners will hear. 2) If some sound is surrounded by other sounds -- a single instrument in a band or orchestra, a signal in noise, a 1 dB change can be the difference between hearing it and not hearing it. When I mixed live sound for 20-40 piece orchestras (Tony Bennett, for example), correcting a balance problem usually involved slightly moving the fader for the instrument that was too loud or not loud enough. When adjusting voice paging levels in an office building, 2-3dB was the difference between not quite loud enough to get over the air conditioner noise and being to loud. A change in the frequency response of a dB or two can be the difference between sounding "right" or not. 3) If a sound is all by itself, it takes a change in level of 6-10 dB to be perceived as "twice" (or "half" as loud. But that doesn't apply to a transmitter, because we have a volume control on our radio. :) 4) Human voice levels vary widely as we talk. Variations of 20 dB are common. 5) Voice frequencies in the range of 500 - 3,000 Hz are most critical for speech intelligibility. In addition to running more power, we can get gain from improving our antenna system. A more efficient counterpoise/radial system for a vertical, feedline with lower loss, a more efficient antenna tuner, and the biggie, an antenna that better focuses its radiation at the elevation, and/or in the direction, that gets to the other station. We can use audio compression, and we can equalize our audio to transmit only the parts of our voice that provides the greatest speech intelligibility. Compression and EQ, if done well, can yield an effective 13 dB of gain! All of those dB add up with the power that we're running. Nearly all TV and radio broadcasting makes extensive use of dynamics processing to make their signal as loud as possible, and the most skilled use careful equalization on the microphones of talkers that matter. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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I'd just like to add that, averaged over a period of time, say a whole
contest, a small difference in power can have a significant effect. While a dB or so might be very hard to detect in one QSO, over a few hundred it makes a difference. On average, you get through a bit more often, more stations come back to your CQ's, and it adds up. 73, Scott K9MA -- Scott K9MA [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Bill-3
Using your same logic, why run more than a couple watts output?
It can easily be heard around the world if conditions are right. Anything more is a waste of power AND money. 73, Charlie k3ICH -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Bill Sent: Saturday, December 31, 2016 10:01 AM To: [hidden email] Subject: [Elecraft] Amplifiers in general I have always been under the impression the doubling of output power will result in a power gain of 3 db. And, that 3 db gain is the least signal increase noticeable at the receiving point. KPA500 outputs 500 Watts - 1000 Watts would give an output gain of 3 db (over the KPA500) and 1500 Watts a little over 4 db gain. That being my understanding - why would I want to spend a box full of dollars for more power than my KPA500 provides? Or, is my understanding flawed? FWIW, I have run all kinds of amps in my nearly 60 years of being the on the air and have found that Watts are Watts, regardless of how you generate them (fancy, cheap, junk, or solid gold). Everyone have a super HAPPY NEW YEAR!!! Bill W2BLC K-Line (medium power HF) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Dear OMs,
There are times when I am sure that 1 dB would make a difference on 160M. 73 Doug EI2CN -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Charlie T, K3ICH Sent: 31 December 2016 18:44 To: [hidden email] Subject: Re: [Elecraft] Amplifiers in general Using your same logic, why run more than a couple watts output? It can easily be heard around the world if conditions are right. Anything more is a waste of power AND money. 73, Charlie k3ICH -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Bill Sent: Saturday, December 31, 2016 10:01 AM To: [hidden email] Subject: [Elecraft] Amplifiers in general I have always been under the impression the doubling of output power will result in a power gain of 3 db. And, that 3 db gain is the least signal increase noticeable at the receiving point. KPA500 outputs 500 Watts - 1000 Watts would give an output gain of 3 db (over the KPA500) and 1500 Watts a little over 4 db gain. That being my understanding - why would I want to spend a box full of dollars for more power than my KPA500 provides? Or, is my understanding flawed? FWIW, I have run all kinds of amps in my nearly 60 years of being the on the air and have found that Watts are Watts, regardless of how you generate them (fancy, cheap, junk, or solid gold). Everyone have a super HAPPY NEW YEAR!!! Bill W2BLC K-Line (medium power HF) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Bill-3
An increase in power of another station is not always well perceived but the difference is there. I've heard guys turn amps on and off and you really hear no difference this is because your AGC is compensating. the difference may actually be big your just not hearing it. Sometime in a QSO have the other station increase or decrease the signal by 3db. it will not be that noticable. now turn off AGC and ask the other station do it again it will be much more evident. than with AGC on. With more than one signal present say in a pileup the different will be noticeable because the weaker signals will seem quiter when a strong signal comes in. its all relative. David Moes VE3SD ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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One can do this with the NCDXF Beacons ... they change in four 10 dB
steps, 100 W, 10 W, 1 W, and 100 mW. No sunspots right now, but you might be able to hear one or two of them on 14100. Most interesting thing I notice is, while the 100 W signal may be S6 in S2 noise, I can still hear the 100 mW signal which should be 40 dB down [~S0]. The math is sound and exact, the reality ... not so much. 73, Fred K6DGW - Sparks NV DM09dn - Northern California Contest Club - CU in the Cal QSO Party 7-8 Oct 2017 - www.cqp.org On 12/31/2016 10:58 AM, [hidden email] wrote: > Sometime in a QSO have the other station increase or decrease the > signal by 3db. it will not be that noticable. now turn off AGC and > ask the other station do it again it will be much more evident. than > with AGC on. > With more than one signal present say in a pileup the different will be > noticeable because the weaker signals will seem quiter when a strong > signal comes in. its all relative. > David Moes > VE3SD ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Please let me correct my typo: 100 mW is 30 dB down, not 40. Correct
hand, wrong finger. 100 mW should be close to S0, 2 S-units into the noise. 73, Fred K6DGW Sparks NV USA Washoe County DM09dn On 12/31/2016 11:25 AM, Fred Jensen wrote: > One can do this with the NCDXF Beacons ... they change in four 10 dB > steps, 100 W, 10 W, 1 W, and 100 mW. No sunspots right now, but you > might be able to hear one or two of them on 14100. Most interesting > thing I notice is, while the 100 W signal may be S6 in S2 noise, I can > still hear the 100 mW signal which should be 40 dB down [~S0]. The math > is sound and exact, the reality ... not so much. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by ve3dvy
David, Super point.
73, Bill K9YEQ -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of [hidden email] Sent: Saturday, December 31, 2016 12:58 PM To: [hidden email] Subject: Re: [Elecraft] Amplifiers in general An increase in power of another station is not always well perceived but the difference is there. I've heard guys turn amps on and off and you really hear no difference this is because your AGC is compensating. the difference may actually be big your just not hearing it. Sometime in a QSO have the other station increase or decrease the signal by 3db. it will not be that noticable. now turn off AGC and ask the other station do it again it will be much more evident. than with AGC on. With more than one signal present say in a pileup the different will be noticeable because the weaker signals will seem quiter when a strong signal comes in. its all relative. David Moes VE3SD ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by k6dgw
Let me posit a SWAG on why this case APPEARS to buck the math in reality....
I submit that all "noise" is not equal. I'm guessing that you can hear a radio transmission mathematically below the apparent noise level because it is "atypical" or "organized noise" as opposed to the "noise" in the S2 noise floor which is "disorganized". Obviously, there are much more correct and scientific ways of illustrating this, but it would be a LOT longer winded. :) 73, PS - Just my intuitive SWAG, btw. ______________________ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 12/31/2016 1:36 PM, Fred Jensen wrote: > Please let me correct my typo: 100 mW is 30 dB down, not 40. Correct > hand, wrong finger. 100 mW should be close to S0, 2 S-units into the > noise. > > 73, > > Fred K6DGW > Sparks NV USA > Washoe County DM09dn > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by k6dgw
Fred,
I agree with all you say but still when reading a signal in the noise on 160M believe me a dB can help in recognizing a call sign. I often think that operating on TB is some what like operating on VHF/UHF. It is certainly a struggle with noise. 73 Doug EI2CN -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Fred Jensen Sent: 31 December 2016 19:36 To: [hidden email] Subject: Re: [Elecraft] Amplifiers in general Please let me correct my typo: 100 mW is 30 dB down, not 40. Correct hand, wrong finger. 100 mW should be close to S0, 2 S-units into the noise. 73, Fred K6DGW Sparks NV USA Washoe County DM09dn On 12/31/2016 11:25 AM, Fred Jensen wrote: > One can do this with the NCDXF Beacons ... they change in four 10 dB > steps, 100 W, 10 W, 1 W, and 100 mW. No sunspots right now, but you > might be able to hear one or two of them on 14100. Most interesting > thing I notice is, while the 100 W signal may be S6 in S2 noise, I can > still hear the 100 mW signal which should be 40 dB down [~S0]. The math > is sound and exact, the reality ... not so much. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Clay Autery
I believe you're correct Clay. I think our ears/brain can integrate the
overall signal, and the noise, if more or less random, will recede into the background. The desired CW signal will then stand out. I suspect that, were you to key noise similar to the background noise and that filled the receive BW, it would disappear for a listener as soon as it's mean amplitude fell to the background level. This may also explain why, the more you talk, the less your teenager hears. 73, Fred K6DGW - Sparks NV DM09dn - Northern California Contest Club - CU in the Cal QSO Party 7-8 Oct 2017 - www.cqp.org On 12/31/2016 11:51 AM, Clay Autery wrote: > Let me posit a SWAG on why this case APPEARS to buck the math in reality.... > > I submit that all "noise" is not equal. I'm guessing that you can hear > a radio transmission mathematically below the apparent noise level > because it is "atypical" or "organized noise" as opposed to the "noise" > in the S2 noise floor which is "disorganized". > > Obviously, there are much more correct and scientific ways of > illustrating this, but it would be a LOT longer winded. :) > > 73, > > PS - Just my intuitive SWAG, btw. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Charlie T, K3ICH
That's what I was thinking.
On 12/31/2016 11:43 AM, Charlie T, K3ICH wrote: > Using your same logic, why run more than a couple watts output? > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Clay Autery
A group of about 5 of my friends and I noticed this effect at a
early 1970s Grateful Dead concert at the San Francisco Cow Palace. They were testing a new sound system which came to be called "The Wall of Sound". While the music was definitely loud, very loud, we could have a normal conversation with each other, something we had never been able to do at other concerts. We concluded that the very low harmonic and IMD distortions of the sound system made it easier to decode the (undistorted) acoustic speech. This experience makes me very interested in the level of audio distortion in amateur radio audio chains. The 10% quoted for HTs is much too much for optimum copy. Copy is better if the audio chains are hifi quality for distortion. 73 Bill AE6JV On 12/31/16 at 11:51 AM, [hidden email] (Clay Autery) wrote: >I submit that all "noise" is not equal. I'm guessing that you can hear >a radio transmission mathematically below the apparent noise level >because it is "atypical" or "organized noise" as opposed to the "noise" >in the S2 noise floor which is "disorganized". ------------------------------------------------------------------------- Bill Frantz | Re: Hardware Management Modes: | Periwinkle (408)356-8506 | If there's a mode, there's a | 16345 Englewood Ave www.pwpconsult.com | failure mode. - Jerry Leichter | Los Gatos, CA 95032 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Bill, I also experienced a very quality system at a friend's house ~ 1976
and it was amazing. A wall of speakers and beautiful volume, concert level and able to talk. Reminds me of my Dynaco A60 speakers and amp. This was the best audio at the time and I starved to save $'s to purchase this audio equipment, while stationed in Germany, from the PX. In the Signal Corp we were trained techs in audio for the passing of traffic to and fro from Korat AFB to Viet Nam and other linked stations. We learned a ton about audio and equalization and worked diligently to stay within parameters in our multiplexed signals with the best audio equipment for the military and probably anywhere. ( My experience is frozen in memory so I understand what you are writing about. ) A truly fantastic experience. Yes, I can still hear with damage done from shooting ranges, concussion grenades and 105 dB alarms at the site when parameters failed. Other than that, life now is good. 73, Bill K9YEQ -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Bill Frantz Sent: Saturday, December 31, 2016 8:30 PM To: [hidden email] Subject: Re: [Elecraft] Amplifiers in general A group of about 5 of my friends and I noticed this effect at a early 1970s Grateful Dead concert at the San Francisco Cow Palace. They were testing a new sound system which came to be called "The Wall of Sound". While the music was definitely loud, very loud, we could have a normal conversation with each other, something we had never been able to do at other concerts. We concluded that the very low harmonic and IMD distortions of the sound system made it easier to decode the (undistorted) acoustic speech. This experience makes me very interested in the level of audio distortion in amateur radio audio chains. The 10% quoted for HTs is much too much for optimum copy. Copy is better if the audio chains are hifi quality for distortion. 73 Bill AE6JV On 12/31/16 at 11:51 AM, [hidden email] (Clay Autery) wrote: >I submit that all "noise" is not equal. I'm guessing that you can hear >a radio transmission mathematically below the apparent noise level >because it is "atypical" or "organized noise" as opposed to the "noise" >in the S2 noise floor which is "disorganized". ------------------------------------------------------------------------- Bill Frantz | Re: Hardware Management Modes: | Periwinkle (408)356-8506 | If there's a mode, there's a | 16345 Englewood Ave www.pwpconsult.com | failure mode. - Jerry Leichter | Los Gatos, CA 95032 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Bill Frantz
On Sat,12/31/2016 6:29 PM, Bill Frantz wrote:
> We concluded that the very low harmonic and IMD distortions of the > sound system made it easier to decode the (undistorted) acoustic speech. That system was highly respected by auidio pros at the time. The primary reason it was so clean was that each instrument was feeding its own vertical line array. Loudspeaker arrays like that produce a narrow beam in the vertical plane, but are wide in the horizontal plane. It's like stacking antennas. That narrow beam greatly reduces reverberation, which is what made the sound easy to understand. Another advantage of that system was that if you were reasonably close, you could localize each instrument aurally as well as visually. That also makes the sound cleaner. And yes, the distortion was probably lower, but the other two reasons I noted are probably the most important. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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