Re: Topband: Impressive demonstration of one dB of signal strength improvement
Frank, Rick, I found my ".wav" files doing similar to what AB7E does. Except that his has MP3 raspy artifacts all over the place and mine doesn't. Take a listen to his and mine AB7E MP3: http://www.ab7e.com/weak_signal/0_1_2_3_4_5_6_db.mp3 N3QE WAV: Sum of morse + noise: http://n3qe.org/sum.wav Just in case you are interested, the raw noise and raw morse WAV files before mixing below: N3QE WAV: My raw noise (no morse): http://n3qe.org/noise.wav N3QE WAV: My raw morse (no noise): http://n3qe.org/morse.wav Tim N3QE On Wed, Aug 21, 2019 at 3:34 PM Tim Shoppa wrote: > Will do, Frank! > > Here's an interesting exercise: > https://www.npr.org/sections/therecord/2015/06/02/411473508/how-well-can-you-hear-audio-quality > > I just ran through it and picked the uncompressed .WAV all 6 times :-) > > One giveaway to my ears is things that were clear sharp impulses in the > originals, get muddy in compression. For example the glocks at the end of > the Neil Young sample is the easiest way to tell with that one. > > Other times, it's the lack of artifacts that helped me pick the original > .WAV. For example the Suzanne Vega samples. > > Interestingly the Suzanne Vega clip was used by developers of MP3! > > On Wed, Aug 21, 2019 at 3:15 PM wrote: > >> Hi Tim, >> >> As you're well aware, perfect is often the enemy of good enough. >> >> Please publish your files and let us all experience how much better they >> are. >> >> Thanks >> >> 73 >> Frank >> W3LPL >> >> -- >> *From: *"Tim Shoppa" >> *To: *"Richard (Rick) Karlquist" >> *Cc: *"Frank Donovan" >> *Sent: *Wednesday, August 21, 2019 6:30:20 PM >> *Subject: *Re: Topband: Impressive demonstration of one dB of signal >> strength improvement >> >> Rick, I agree, MP3 just muddies the sound of those examples. I regularly >> save my radio audio as 8kHz WAV and am happy with that. But I can tell if I >> convert it to MP3 that it is "off" and "wrong". The MP3 format's >> psychoacoustic encoding muddies the beginning and end of each dit AND does >> a horrible job when presented with lightning or impulse noise. >> >> Last time Frank and I talked about these examples, I made a completely >> independent set for my own use that was never compressed along the way. >> (.WAV uncompressed format). Will dig up at home. >> >> Tim N3QE >> >> >> >> >> On Wed, Aug 21, 2019 at 12:54 PM Richard (Rick) Karlquist < >> rich...@karlquist.com> wrote: >> >>> On 8/21/2019 8:16 AM, donov...@starpower.net wrote: >>> > These recordings are an impressive demonstration of the benefit of >>> > one dB of signal strength improvement in a weak signal situation. >>> > >>> > >>> > Click on the links on this website: >>> > >>> > >>> > >>> > www.ab7e.com/weak_signal/mdd.html >>> > >>> > >>> > 73 >>> > Frank >>> > W3LPL >>> >>> It seems to me that converting the files to .mp3 >>> muddies the water. Dave comments that 32 kHz >>> is "decent fidelity". It certainly isn't (IMHO) >>> decent fidelity for music. I don't know about >>> noisy CW. The .mp3 format was optimized >>> for music or possibly high S/N voice, but not CW >>> buried in noise. The operational principle of >>> mp3 (or any lossy compression) is "noise gating". >>> For all I know, the abrupt change at low S/N may >>> be an artifact of the compression. >>> >>> I don't understand the comment about "all audio files >>> were converted to .mp3 format and mixed ..." AFAIK, >>> mixing should be done before any compression. >>> >>> Using "band noise" also muddies the water. It would >>> have been better to use the proverbial Additive >>> White Gaussian Noise (AWGN), to get reproducible results. >>> Dave comments that "spikey" noise is another hard to >>> quantify condition. I have noticed anecdotally that >>> 160 meters tends to have spikey noise vs AWGN on say >>> 20 meters. This results in clearly audible signals that >>> can't be copied by ear on 160 meters, whereas on 20 >>> meters, I seem to be able to get solid copy on signals >>> that are just barely detectable. This is a poorly understood >>> phenomenon. >>> >>> Another issue with reproducibility is the audio bandwidth. >>> The brain tends to be able to provide some audio filtering >>> of its own. IOW, I believe that you will find that >>> a 250 Hz bandwidth will give less than a 3 dB advantage >>> vs 500 Hz for the threshold of copy. At narrow bandwidths, >>> ringing becomes an issue. Typical brick wall filters in SDR's >>> may or may not be optimum for copying a CW in noise >>> (and in the absence of QRM). My Flex 6700 uses a >>> gazillion poles "because they can" :-) >>> >>> Rick N6RK >>> _ >>> Searchable Archives: http://www.contesting.com/_topband - Topband >>> Reflector >>> >> >> _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Impressive demonstration of one dB of signal strength improvement
On 8/21/2019 8:16 AM, donov...@starpower.net wrote: These recordings are an impressive demonstration of the benefit of one dB of signal strength improvement in a weak signal situation. Click on the links on this website: www.ab7e.com/weak_signal/mdd.html 73 Frank W3LPL It seems to me that converting the files to .mp3 muddies the water. Dave comments that 32 kHz is "decent fidelity". It certainly isn't (IMHO) decent fidelity for music. I don't know about noisy CW. The .mp3 format was optimized for music or possibly high S/N voice, but not CW buried in noise. The operational principle of mp3 (or any lossy compression) is "noise gating". For all I know, the abrupt change at low S/N may be an artifact of the compression. I don't understand the comment about "all audio files were converted to .mp3 format and mixed ..." AFAIK, mixing should be done before any compression. Using "band noise" also muddies the water. It would have been better to use the proverbial Additive White Gaussian Noise (AWGN), to get reproducible results. Dave comments that "spikey" noise is another hard to quantify condition. I have noticed anecdotally that 160 meters tends to have spikey noise vs AWGN on say 20 meters. This results in clearly audible signals that can't be copied by ear on 160 meters, whereas on 20 meters, I seem to be able to get solid copy on signals that are just barely detectable. This is a poorly understood phenomenon. Another issue with reproducibility is the audio bandwidth. The brain tends to be able to provide some audio filtering of its own. IOW, I believe that you will find that a 250 Hz bandwidth will give less than a 3 dB advantage vs 500 Hz for the threshold of copy. At narrow bandwidths, ringing becomes an issue. Typical brick wall filters in SDR's may or may not be optimum for copying a CW in noise (and in the absence of QRM). My Flex 6700 uses a gazillion poles "because they can" :-) Rick N6RK _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Impressive demonstration of one dB of signal strength improvement
Martin the article Part 1 starts in Sept 1966 and there are a number of articles after that, up to Part 4, and even another article in 1980 and 1981, but I had to log into ARRL to be able to search and read those. I have no idea if they are available from some other source. 73 Merv K9FD What QST? Would be a copy available? 73, Martin, OK1RR Dne 21. 08. 19 v 18:24 K9FD napsal(a): An excellent article is in an old QST called "station design for DX" It mentions that 1 DB improvement in the station will provide a whole new layer of DX signals. Very true. In the average station you can easily find several DB that can be gained. If your into DX think of all your missing. I always have to laugh when the statement is made "I can work all I can hear" that says it all, its what your not hearing is the problem. 73 Merv K9FD These recordings are an impressive demonstration of the benefit of one dB of signal strength improvement in a weak signal situation. Click on the links on this website: www.ab7e.com/weak_signal/mdd.html 73 Frank W3LPL - Original Message - From: "David Gilbert" To: elecr...@mailman.qth.net Sent: Wednesday, August 21, 2019 7:02:21 AM Subject: Re: [Elecraft] KPA500 Coax size requirements That's not a universally true statement. Several years ago I was trying to decide which antenna to buy, and my choice came down to two antennas that were 2 db apart. I created some audio files by recording typical band noise and then overlaying them with recorded CW messages at various strengths. The difference between 1 dB above the noise level and 2 dB above the noise level can make the difference between no copy and copy. The files and testing methodology can be found here: http://www.ab7e.com/weak_signal/mdd.html If you're ragchewing it doesn't matter, but if you're trying to make a contact and your signal is at the level of the mud it does. 73, Dave AB7E On 8/20/2019 9:18 PM, Jim Danehy wrote: ONE DB loss is the LEAST DETECTABLE amount a human can detect. Hardly if not impossible to notice. Jim W9VNE/VA3VNE _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Impressive demonstration of one dB of signal strength improvement
Good Morning/Afternoon/Evening All, I believe this references the original W3AFM series of QST articles in 1966? If so ... try this link please: http://www.rfcafe.com/references/qst/station-design-dx-september-1966-qst.htm 73 de Billy, AA4NU > > On August 21, 2019 at 11:38 AM K9FD wrote: > > > > Martin I am sorry I do not know when that article was published, I have > > moved QTH and > > gave away all my old QSTs. Will try and find it in the on-line > > archives, but think you have > > to be a member to read those archives. Perhaps someone knows where > > else it could be > > found. > > 73 Merv k9FD > > > > > What QST? Would be a copy available? > > > > > > 73, > > > Martin, OK1RR > > > > > > Dne 21. 08. 19 v 18:24 K9FD napsal(a): > > >> An excellent article is in an old QST called "station design for DX" > > >> It mentions that 1 DB improvement in the station will provide a whole > > >> new layer of DX signals. Very true. > > >> > > >> In the average station you can easily find several DB that can be > > >> gained. > > >> If your into DX think of all your missing. > > >> > > >> I always have to laugh when the statement is made "I can work all I > > >> can hear" > > >> > > >> that says it all, its what your not hearing is the problem. > > >> > > >> 73 Merv K9FD > > >> > > >>> These recordings are an impressive demonstration of the benefit of > > >>> one dB of signal strength improvement in a weak signal situation. > > >>> > > >>> > > >>> Click on the links on this website: > > >>> > > >>> > > >>> > > >>> www.ab7e.com/weak_signal/mdd.html > > >>> > > >>> > > >>> 73 > > >>> Frank > > >>> W3LPL > > >>> > > >>> > > >>> - Original Message - > > >>> > > >>> From: "David Gilbert" > > >>> To: elecr...@mailman.qth.net > > >>> Sent: Wednesday, August 21, 2019 7:02:21 AM > > >>> Subject: Re: [Elecraft] KPA500 Coax size requirements > > >>> > > >>> > > >>> That's not a universally true statement. > > >>> > > >>> Several years ago I was trying to decide which antenna to buy, and my > > >>> choice came down to two antennas that were 2 db apart. I created some > > >>> audio files by recording typical band noise and then overlaying them > > >>> with recorded CW messages at various strengths. The difference between > > >>> 1 dB above the noise level and 2 dB above the noise level can make the > > >>> difference between no copy and copy. The files and testing methodology > > >>> can be found here: > > >>> > > >>> http://www.ab7e.com/weak_signal/mdd.html > > >>> > > >>> If you're ragchewing it doesn't matter, but if you're trying to make a > > >>> contact and your signal is at the level of the mud it does. > > >>> > > >>> 73, > > >>> Dave AB7E > > >>> > > >>> On 8/20/2019 9:18 PM, Jim Danehy wrote: > > ONE DB loss is the LEAST DETECTABLE amount a human can detect. > > Hardly if not impossible to notice. > > > > Jim > > W9VNE/VA3VNE > > >>> _ > > >>> Searchable Archives: http://www.contesting.com/_topband - Topband > > >>> Reflector > > >> > > >> _ > > >> Searchable Archives: http://www.contesting.com/_topband - Topband > > >> Reflector > > > > > > _ > > > Searchable Archives: http://www.contesting.com/_topband - Topband > > > Reflector > > > > _ > > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Impressive demonstration of one dB of signal strength improvement
Martin I am sorry I do not know when that article was published, I have moved QTH and gave away all my old QSTs. Will try and find it in the on-line archives, but think you have to be a member to read those archives. Perhaps someone knows where else it could be found. 73 Merv k9FD What QST? Would be a copy available? 73, Martin, OK1RR Dne 21. 08. 19 v 18:24 K9FD napsal(a): An excellent article is in an old QST called "station design for DX" It mentions that 1 DB improvement in the station will provide a whole new layer of DX signals. Very true. In the average station you can easily find several DB that can be gained. If your into DX think of all your missing. I always have to laugh when the statement is made "I can work all I can hear" that says it all, its what your not hearing is the problem. 73 Merv K9FD These recordings are an impressive demonstration of the benefit of one dB of signal strength improvement in a weak signal situation. Click on the links on this website: www.ab7e.com/weak_signal/mdd.html 73 Frank W3LPL - Original Message - From: "David Gilbert" To: elecr...@mailman.qth.net Sent: Wednesday, August 21, 2019 7:02:21 AM Subject: Re: [Elecraft] KPA500 Coax size requirements That's not a universally true statement. Several years ago I was trying to decide which antenna to buy, and my choice came down to two antennas that were 2 db apart. I created some audio files by recording typical band noise and then overlaying them with recorded CW messages at various strengths. The difference between 1 dB above the noise level and 2 dB above the noise level can make the difference between no copy and copy. The files and testing methodology can be found here: http://www.ab7e.com/weak_signal/mdd.html If you're ragchewing it doesn't matter, but if you're trying to make a contact and your signal is at the level of the mud it does. 73, Dave AB7E On 8/20/2019 9:18 PM, Jim Danehy wrote: ONE DB loss is the LEAST DETECTABLE amount a human can detect. Hardly if not impossible to notice. Jim W9VNE/VA3VNE _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Impressive demonstration of one dB of signal strength improvement
What QST? Would be a copy available? 73, Martin, OK1RR Dne 21. 08. 19 v 18:24 K9FD napsal(a): An excellent article is in an old QST called "station design for DX" It mentions that 1 DB improvement in the station will provide a whole new layer of DX signals. Very true. In the average station you can easily find several DB that can be gained. If your into DX think of all your missing. I always have to laugh when the statement is made "I can work all I can hear" that says it all, its what your not hearing is the problem. 73 Merv K9FD These recordings are an impressive demonstration of the benefit of one dB of signal strength improvement in a weak signal situation. Click on the links on this website: www.ab7e.com/weak_signal/mdd.html 73 Frank W3LPL - Original Message - From: "David Gilbert" To: elecr...@mailman.qth.net Sent: Wednesday, August 21, 2019 7:02:21 AM Subject: Re: [Elecraft] KPA500 Coax size requirements That's not a universally true statement. Several years ago I was trying to decide which antenna to buy, and my choice came down to two antennas that were 2 db apart. I created some audio files by recording typical band noise and then overlaying them with recorded CW messages at various strengths. The difference between 1 dB above the noise level and 2 dB above the noise level can make the difference between no copy and copy. The files and testing methodology can be found here: http://www.ab7e.com/weak_signal/mdd.html If you're ragchewing it doesn't matter, but if you're trying to make a contact and your signal is at the level of the mud it does. 73, Dave AB7E On 8/20/2019 9:18 PM, Jim Danehy wrote: ONE DB loss is the LEAST DETECTABLE amount a human can detect. Hardly if not impossible to notice. Jim W9VNE/VA3VNE _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Impressive demonstration of one dB of signal strength improvement
An excellent article is in an old QST called "station design for DX" It mentions that 1 DB improvement in the station will provide a whole new layer of DX signals. Very true. In the average station you can easily find several DB that can be gained. If your into DX think of all your missing. I always have to laugh when the statement is made "I can work all I can hear" that says it all, its what your not hearing is the problem. 73 Merv K9FD These recordings are an impressive demonstration of the benefit of one dB of signal strength improvement in a weak signal situation. Click on the links on this website: www.ab7e.com/weak_signal/mdd.html 73 Frank W3LPL - Original Message - From: "David Gilbert" To: elecr...@mailman.qth.net Sent: Wednesday, August 21, 2019 7:02:21 AM Subject: Re: [Elecraft] KPA500 Coax size requirements That's not a universally true statement. Several years ago I was trying to decide which antenna to buy, and my choice came down to two antennas that were 2 db apart. I created some audio files by recording typical band noise and then overlaying them with recorded CW messages at various strengths. The difference between 1 dB above the noise level and 2 dB above the noise level can make the difference between no copy and copy. The files and testing methodology can be found here: http://www.ab7e.com/weak_signal/mdd.html If you're ragchewing it doesn't matter, but if you're trying to make a contact and your signal is at the level of the mud it does. 73, Dave AB7E On 8/20/2019 9:18 PM, Jim Danehy wrote: ONE DB loss is the LEAST DETECTABLE amount a human can detect. Hardly if not impossible to notice. Jim W9VNE/VA3VNE _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Impressive demonstration of one dB of signal strength improvement
These recordings are an impressive demonstration of the benefit of one dB of signal strength improvement in a weak signal situation. Click on the links on this website: www.ab7e.com/weak_signal/mdd.html 73 Frank W3LPL - Original Message - From: "David Gilbert" To: elecr...@mailman.qth.net Sent: Wednesday, August 21, 2019 7:02:21 AM Subject: Re: [Elecraft] KPA500 Coax size requirements That's not a universally true statement. Several years ago I was trying to decide which antenna to buy, and my choice came down to two antennas that were 2 db apart. I created some audio files by recording typical band noise and then overlaying them with recorded CW messages at various strengths. The difference between 1 dB above the noise level and 2 dB above the noise level can make the difference between no copy and copy. The files and testing methodology can be found here: http://www.ab7e.com/weak_signal/mdd.html If you're ragchewing it doesn't matter, but if you're trying to make a contact and your signal is at the level of the mud it does. 73, Dave AB7E On 8/20/2019 9:18 PM, Jim Danehy wrote: > ONE DB loss is the LEAST DETECTABLE amount a human can detect. Hardly if not > impossible to notice. > > Jim > W9VNE/VA3VNE _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
