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At 10/24/2022 06:59 PM, you wrote: When I first saw the question, I scratched my head and went on to other things. It looked wierd. Then I remembered why.
If you are actually going to feed audio up to 6 khz. to the modulator, where does it actually go after that???
Even if you reduce the deviation and the pre-emphasis to keep the bandwidth down to a normal FM channel, anyone trying
to recieve it will have to modify the reciever so it won't squelch itself out trying to recieve. Literally hundreds of 440 repeaters in this area have audio responses approaching 6 kHz, & no one has had to modify their RXs to hear them. Sounds confusing, but the typical 16kF3 reciever needs to have a 20khz bandwidth in the IF to allow for drift and to prevent
the reciever from squelching out. The back-end was made to roll off above 3khz to the speech amp and the squelch amp will
be listening for noise above that to keep the squelch closed. Much above, actually. The last squelch circuit I looked at actually responded best to noise around 10-20 kHz, so 6 kHz won't really affect it much If this is for a link radio on the 2m ham band, how were you planning to keep the bandwidth to a normal ham channel? If this is
for a ham voice repeater, everyone will have to modify their radios to use it. Nope - see above. Granted on 2 meters with 15 kHz channel spacing some modifications to the standard are needed. I find that by keeping the deviation down to, say 4.2 kHz peak, the occupied BW is sufficiently controlled without losing S/N. Also the audio has to have a flat response (aside from the usual 6 dB/octave pre-emphasis). Any extra slope that favors the high frequencies or hard clipping will shift the PSD to the high end, greatly increasing the occupied bandwidth. Bob NO6B
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Flat audio really means no de-emphasis in the RCVR being coupled to the TX with no pre-emphasis.?
Hopefully with less processing. Of course on a PM radio vs. a FM modulator means something different.?
A lot of people get the whole Pre and De-emphasis and flat audio wrong because they are plugging
different things together and picking from jumpers one way or another and finding more must be done.
There is truely much to be desired on most under-dash mobiles.? There is a lot of poor quality from
mics, poor mic technique, poor filtering and equalization out there, and crappy tinny little speakers
pointed at the floor.? It is a good idea to work on cleaning up the repeaters audio quality, but for voice
audio, it is better to concentrate on a PL notch in the RCVR and an IF filter that does not ring as with
a dedicated P25 digital station.? Perhaps 3-6 db compression and no more than that, then repeat
audio short of clipping.? The compression must be off when sweeping and comparing the input and
output equalization, but only those who work on improving their own will notice.
I still have some good condition Motrac speakers with AlNiCo magnets, but I bet not many have them anymore.?
I use them over and over again in mobile installations and around the shack for FM radios.? You can't get the
replacement speaker anymore though.? I have wondered how to re-cone them.? I have tried in vain to find
a replacement that even fits, let alone sounds as good.
After the Motrac and Micor, it seems everything after that got more and more compromised.?
Agree about HIFI SSB.? If you actually have a RCVR with a speaker that is HiFi, you find these people bass
boosting trying to make voice energy at 50 hz that it is completely unintelligible and you are left with the
impression of a 600lb hog grunting.? Also, most guys rarely generate much energy above 2400hz and even
women and little children don't either unless they want to shriek.? The only reason to go out to 3000hz is to
avoid ringing, but voice audio will rarely exceed 2800hz unless you are pushing something else besides voice.
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My point is, where is the energy above 3Khz comming from?? Unless it is background music or road noise.? The audio
spectrum from the human voice isn't there.? The idea of getting AM broadcast to 6kc was to help music reproduction.?
If the voice audio is well equalized for inteligibility, it's not a bad thing to have 50hz- 6khz but you won't likely hear anything
above 3000 and if anyone wants to do any bass boosting it will get old fast.? And there is no reason to pass the PL either.
If someone really WANTS 6kc audio, it will have to be addressed throughout the chain, and keep an eye on the spectrum
analyzer.
?
Then I looked up K6OQK and saw 147.435 in Los Angeles.? I think that one is world famous for sending the FCC packing,
and pushing the envelope well past the 7 dirty words.? Maybe when Burt was involved it wasn't that way, but it became the
attractive nuisance of the amateur community.? stories like that prevented me from even toying with the idea of putting up
a ham repeater.? I have dabbled with remotes, but keep it real low key.? I have enough trouble with commercial 2way to keep
me busy.
toggle quoted message
Show quoted text
On Tue, Oct 25, 2022 at 11:12 AM, Bob Dengler wrote:
At 10/24/2022 06:59 PM, you wrote:
When I first saw the question, I scratched my head and went on to other things. It looked wierd. Then I remembered why.
If you are actually going to feed audio up to 6 khz. to the modulator, where does it actually go after that???
Even if you reduce the deviation and the pre-emphasis to keep the bandwidth down to a normal FM channel, anyone trying
to recieve it will have to modify the reciever so it won't squelch itself out trying to recieve.
Literally hundreds of 440 repeaters in this area have audio responses approaching 6 kHz, & no one has had to modify their RXs to hear them.
Sounds confusing, but the typical 16kF3 reciever needs to have a 20khz bandwidth in the IF to allow for drift and to prevent
the reciever from squelching out. The back-end was made to roll off above 3khz to the speech amp and the squelch amp will
be listening for noise above that to keep the squelch closed.
Much above, actually. The last squelch circuit I looked at actually responded best to noise around 10-20 kHz, so 6 kHz won't really affect it much
If this is for a link radio on the 2m ham band, how were you planning to keep the bandwidth to a normal ham channel? If this is
for a ham voice repeater, everyone will have to modify their radios to use it.
Nope - see above. Granted on 2 meters with 15 kHz channel spacing some modifications to the standard are needed. I find that by keeping the deviation down to, say 4.2 kHz peak, the occupied BW is sufficiently controlled without losing S/N. Also the audio has to have a flat response (aside from the usual 6 dB/octave pre-emphasis). Any extra slope that favors the high frequencies or hard clipping will shift the PSD to the high end, greatly increasing the occupied bandwidth.
Bob NO6B
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John,
I personally do not believe in the 5 kHz in and 5 kHz out thinking.? A part of the problem is that stations with low deviation will come through with low deviation and those with high deviation can hit the transmitter's limiter too hard.? Some believe that it's the responsibility of those stations to correct their deviation, and learn to use correct mic technique. My experience in that area has proven to be: Good Luck!
Please understand, I don't mean to be talking at you, but just intellectualizing with you...
To my way of thinking, a repeater is not a piece of test equipment to be used as a deviation tester.? It's a contraption to improve / enable communications.? Proper processing also protects the transmitter and adjacent channel spectrum in a less destructive way.? Anything I can do to make it simple, reliable, and pleasant, is a plus.? That's why I have always used appropriate audio processing on my repeaters.? I've gotten arguments from the unwashed telling me that it brings up the noise on the incoming signal. Well, yes, that's true, but you're going to have to turn up the volume at the user's end if you want to hear those stations anyway.? When you do that you are not only bringing up the noise heard by the repeater, but also any noise between and the repeater.? Having to turn the volume up and down while listening to a repeater gets tiring after a while.
For what it's worth,
Burt, K6OQK
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? My point is, where is the energy above 3Khz comming from?? Unless it is background music or road noise.? ? Sibilance. The hand mics with many Yaesu VHF/UHF mobiles, and their newer HT’s, have quite a bit above 3K, I’m going to say up to about 4.6 or 4.7. ? I love the sound of repeaters that let some of that through, although not too much… not as much as you hear on simplex. But similar… ?
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jb,
I want to assure you that WA6TDD was not that way when I ran it.? Once it started to turn in that direction I tried my best to clean it up.? When that failed I took it off the air and others picked it up.? I will not be a part of that kind of operation.? Please do not associate me with the .435 operation.
Burt, K6OQK
toggle quoted message
Show quoted text
On Tue, Oct 25, 2022 at 01:32 PM, jb wrote:
Then I looked up K6OQK and saw 147.435 in Los Angeles.? I think that one is world famous for sending the FCC packing, and pushing the envelope well past the 7 dirty words.? Maybe when Burt was involved it wasn't that way, but it became the attractive nuisance of the amateur community.? stories like that prevented me from even toying with the idea of putting up a ham repeater.? I have dabbled with remotes, but keep it real low key.? I have enough trouble with commercial 2way to keep me busy.
|
Mt Wilson's rep lasts a long time!
At 01:53 PM 10/25/2022, you wrote:
toggle quoted message
Show quoted text
jb,
I want to assure you that WA6TDD was not that way when I ran it.?
Once it started to turn in that direction I tried my best to clean it
up.? When that failed I got rid of it.? I will not be a part of
that kind of operation.? Please do not associate me with the .435
operation.
Burt, K6OQK
On Tue, Oct 25, 2022 at 01:32 PM, jb wrote:
- Then I looked up K6OQK and saw 147.435 in Los Angeles.? I think
that one is world famous for sending the FCC packing, and pushing the
envelope well past the 7 dirty words.? Maybe when Burt was involved
it wasn't that way, but it became the attractive nuisance of the amateur
community.? stories like that prevented me from even toying with the
idea of putting up a ham repeater.? I have dabbled with remotes, but
keep it real low key.? I have enough trouble with commercial 2way to
keep me busy.
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Makers of repeater controllers and accessories
Phone: (503) 678 6182
Authorized Dealers for Kenwood and Telewave.
We offer complete turn-key repeater packages!
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Yes, Burt, I also agree with that concept because it is better in those circumstances of low initial audio and to me it also makes sense to increase intelligibility when you are receiving noise on the repeater.? It does usually reduce the highs from them being selectively clipped, so the question is how do you boost the highs back when the clipping is done on pre-emphasized audio as defined by the same voltage at the clipper when the input frequency is swept from lowest to highest frequency at the same input deviation? By adding high frequency boost after the clipper, and then more low pass filtering?
To my thinking, the advantage from no repeater compression or clipping is when you want to repeat a repeat times X in analog so as to not keeping adding background noise or distortion each time. Guess that is one big advantage of digital repeaters?
John
On 10/25/2022 4:47 PM Burt K6OQK <biwa@...> wrote:
John,
I personally do not believe in the 5 kHz in and 5 kHz out thinking.? A part of the problem is that stations with low deviation will come through with low deviation and those with high deviation can hit the transmitter's limiter too hard.? Some believe that it's the responsibility of those stations to correct their deviation, and learn to use correct mic technique. My experience in that area has proven to be: Good Luck!
Please understand, I don't mean to be talking at you, but just intellectualizing with you...
To my way of thinking, a repeater is not a piece of test equipment to be used as a deviation tester.? It's a contraption to improve / enable communications.? Proper processing also protects the transmitter and adjacent channel spectrum in a less destructive way.? Anything I can do to make it simple, reliable, and pleasant, is a plus.? That's why I have always used appropriate audio processing on my repeaters.? I've gotten arguments from the unwashed telling me that it brings up the noise on the incoming signal. Well, yes, that's true, but you're going to have to turn up the volume at the user's end if you want to hear those stations anyway.? When you do that you are not only bringing up the noise heard by the repeater, but also any noise between and the repeater.? Having to turn the volume up and down while listening to a repeater gets tiring after a while.
For what it's worth,
Burt, K6OQK
|
---------- Original Message ----------
From: John <jhaserick84@...>
Date: 10/25/2022 8:38 PM
Subject: Re: [repeater-builder] QUANTAR VHF Audio Interface...
Yes, Burt, I also agree with that concept because it is better in those circumstances of low initial audio and to me it also makes sense to increase intelligibility when you are receiving noise on the repeater.? It does usually reduce the highs from them being selectively clipped, so the question is how do you boost the highs back when the clipping is done on pre-emphasized audio where flat audio is defined by the same voltage at the clipper when the input frequency is swept from lowest to highest frequency at the same input deviation? By adding high frequency boost after the clipper, and then more low pass filtering? Possibly easier and better to just eliminate the pre-emphasis components before the clipper, and add comparable pre-emphasis after the clipper so a little audio compression without reducing highs and still the same low pass roll-off. There must be a way to configure Kevin's clipper /filter to achieve this result.
To my thinking, the advantage from having no repeater compression or clipping is when you want to repeat a repeat times X in analog so as to not keeping adding background noise or distortion each time, at least on the link radios if a quiet link path. Guess that is one big advantage of digital repeaters?
John
On 10/25/2022 4:47 PM Burt K6OQK <biwa@...> wrote:
John,
I personally do not believe in the 5 kHz in and 5 kHz out thinking.? A part of the problem is that stations with low deviation will come through with low deviation and those with high deviation can hit the transmitter's limiter too hard.? Some believe that it's the responsibility of those stations to correct their deviation, and learn to use correct mic technique. My experience in that area has proven to be: Good Luck!
Please understand, I don't mean to be talking at you, but just intellectualizing with you...
To my way of thinking, a repeater is not a piece of test equipment to be used as a deviation tester.? It's a contraption to improve / enable communications.? Proper processing also protects the transmitter and adjacent channel spectrum in a less destructive way.? Anything I can do to make it simple, reliable, and pleasant, is a plus.? That's why I have always used appropriate audio processing on my repeaters.? I've gotten arguments from the unwashed telling me that it brings up the noise on the incoming signal. Well, yes, that's true, but you're going to have to turn up the volume at the user's end if you want to hear those stations anyway.? When you do that you are not only bringing up the noise heard by the repeater, but also any noise between and the repeater.? Having to turn the volume up and down while listening to a repeater gets tiring after a while.
For what it's worth,
Burt, K6OQK
|
Just a note from the gallery here -? but to me it seems that some are confusing frequency deviation and frequency response in this thread.? Both are important for their own reasons, both are measured in Hz/kHz, and both impact audio quality but they are most definitely not the same thing and an increase in frequency response does not (necessarily) mean an increase in frequency deviation (though there will often be some difference since additional audio energy is added to the signal).
As far as frequency response goes the Quantar 25-pair connector contains wideband RX and TX connections that are suitable for most applications for Data and unfiltered voice.? Personally I find that the best performance for voice is to use the internal controller for all audio routing.? If you must connect an external controller for control and voice announcements don't use it as the repeat audio path.? The voice announcements?can be recorded?from the receiver and transmitted from the wireline/flat audio in and given lower priority than the internal repeat function - so they will be overridden when there is an active QSO - and the internal CW ID can keep things legal.? I see no purpose in trying to make a "Hi-Fi" repeater when half of the users are using Baofengs and 99.9% of the other radios are using speakers and mics that won't benefit anyway - or it can often make it sound worse with the wide range.? The range below 300 Hz is filtered on pretty much all transceivers on receive or you would hear PL tones consistently - and above 3K you are just going to get more pronounced noise for which the pre-emphasis/de-emphasis is unlikely to help.? Having the frequency response set too wide can also impact deviation controls since proximity effect and similar things related to the additional ranges can become an issue when they were not previously.? A frequency response of 300-3000 KHz will produce optimal speech intelligibility for communications in the majority of situations.? If needed, the Quantar also allows you to disable Pre-Emphasis, De-Emphasis, and Hi-Pass filters from WinRSS which, "in essence, provides a flat audio path through the station" per the WinRSS help file.
As far as frequency deviation goes, that directly impacts the audio dynamic range.? While it can be beneficial in some instances to use an expander or compander function to bring up low-level signals, the down-side of this is the significant increase in noise and decrease in dynamic range (the difference in magnitude from the lowest-level sound to the highest-level sound).? Decreasing dynamic range can severely impact both voice intelligibility and perceived audio quality.? When using the internal controller for audio routing you can utilize the "Analog Repeater Boost" function to increase the level of stations, but keep in mind that this will effectively decrease your overall audio dynamic range by about 20% as it will push louder stations into the deviation limiter.? Below is what the RSS Manual has to say about this function: Toggle between ENABLED and DISABLED by pressing the Up/Down Arrow keys.
When ENABLED (default state), an incoming 40% rated system deviation
signal will be boosted to 60% rated system deviation for re-transmission.
For example, in a 5KHz maximum deviation channel, a signal coming in at
2 KHz deviation will be transmitted at 3 KHz deviation.
When DISABLED, the transmitted signal will be at the same deviation as
the incoming signal.
Default setting is DISABLED. ?A more aggressive Audio Dynamic Range control in the Quantar is called "Hear Clear".? It is an aggressive compander which, in my experience, makes the audio sound absolutely terrible and far less intelligible.
I run all of my Quantars with pre-emphasis and de-emphasis disabled (since I have no need for audio inputs/outputs at the site, and therefore no need for de-emphasized inputs/outputs), with repeater boost turned off, hear clear turned off, and with the deviation limit set at 98% (to ensure I stay within 5 KHz Deviation).? All of my repeaters sound excellent to me and many have complemented the audio compared to the many other repeaters in the area.? If someone has low audio coming into the repeater then it is on them to resolve their issue and the other users are generally quick to report the issue to those users.? If they are too hot the deviation limiter will take care of keeping me in compliance even though they may get clipped a bit,?often also resulting in reports to those stations of their poor audio quality.
I feel there are far more important things to be spending money and time on than trying to create a Hi-Fi repeater - like bringing new Hams into the hobby - and teaching some of them to be the next generation of technicians to maintain this equipment,?but to each their own.? I believe in the KISS principle most of the time - why take an excellent, highly Engineered repeater such as a Quantar and try to reinvent the wheel with it when it does exceedingly well as-is.? Quantars have so many options as-is with all of the inputs/outputs/wildcards, etc that you can do pretty much anything you could ever want with this platform without adding piles of external controllers, processors, filters, etc.
Most (but not all) external controllers with audio delays tend to decrease both frequency response and dynamic range due to limitations in the delay circuitry.? This is one of the primary reasons I always avoid using an external controller for the repeater audio path, in addition to coloration (changes in frequency response) that can be caused by impedance mismatches and other parts of the audio circuits of the external controllers.? The internal Quantar repeat audio path is designed such that the signal (within the 300-3000 Hz pass-band) at the Gozinta matches the signal at the Gozouta (technical terms) so long as the audio settings are left at default.? Since the Quantar has a built-in community tone panel you can use a non-repeated PL/DPL for control tones, completely eliminating the need for an audio delay while still delivering the control codes to your controller - which can control the Quantar via contact closures on the 25-Pair connector. Daniel Woodie, CETsr KC8ZUM
M: +1.513.478.9844
H: +1.513.231.1101 ? ? ? ? ? ? ? ? ?  
Yes, Burt, I also agree with that concept because it is better in those circumstances of low initial audio and to me it also makes sense to increase intelligibility when you are receiving noise on the repeater.? It does usually reduce the highs from them being selectively clipped, so the question is how do you boost the highs back when the clipping is done on pre-emphasized audio as defined by the same voltage at the clipper when the input frequency is swept from lowest to highest frequency at the same input deviation? By adding high frequency boost after the clipper, and then more low pass filtering?
To my thinking, the advantage from no repeater compression or clipping is when you want to repeat a repeat times X in analog so as to not keeping adding background noise or distortion each time. Guess that is one big advantage of digital repeaters?
John
On 10/25/2022 4:47 PM Burt K6OQK < biwa@...> wrote:
John,
I personally do not believe in the 5 kHz in and 5 kHz out thinking.? A part of the problem is that stations with low deviation will come through with low deviation and those with high deviation can hit the transmitter's limiter too hard.? Some believe that it's the responsibility of those stations to correct their deviation, and learn to use correct mic technique. My experience in that area has proven to be: Good Luck!
Please understand, I don't mean to be talking at you, but just intellectualizing with you...
To my way of thinking, a repeater is not a piece of test equipment to be used as a deviation tester.? It's a contraption to improve / enable communications.? Proper processing also protects the transmitter and adjacent channel spectrum in a less destructive way.? Anything I can do to make it simple, reliable, and pleasant, is a plus.? That's why I have always used appropriate audio processing on my repeaters.? I've gotten arguments from the unwashed telling me that it brings up the noise on the incoming signal. Well, yes, that's true, but you're going to have to turn up the volume at the user's end if you want to hear those stations anyway.? When you do that you are not only bringing up the noise heard by the repeater, but also any noise between and the repeater.? Having to turn the volume up and down while listening to a repeater gets tiring after a while.
For what it's worth,
Burt, K6OQK
|
On 10/25/2022 10:36 PM, Dan Woodie
wrote:
-------------------BIG snip
----------------------------
I feel there are far more important things to be spending
money and time on than trying to create a Hi-Fi repeater
------------------------BIG snip ---------------------
Daniel Woodie, CETsr
KC8ZUM
But that's one of the reasons this group
exists - not most of the other things you wrote about.? Keep that
in mind when replying to this group.? We're about highly technical
stuff here.
And - just because some of the radios that users use are junk -
doesn't mean we should be building repeaters that have substandard
frequency response.?
I can also hear the difference between a properly built repeater
and a stock "300Hz - 3kHz" one.? You want to hear a thing of
beauty - listen to one of the WN3A built machines.? Observation of
wider audio frequency response and properly built and set
processing will change your opinion.
Kevin W3KKC
|
Kevin,
I do agree with you?that this group can be about going outside of what is normally done with repeaters and improving on them - so in that respect maybe my comment was a bit off the mark.??
I will disagree with your inference that Quantar has "substandard frequency response".? Which standard are you comparing it to?? I would suggest that Quantar and other repeaters of similar performance ARE the industry standard.? I believe what the goal of this post was - and what you prefer - would be considered a "superior frequency response" while Quantar would match or exceed "Standard frequency response".? I understand the goal here - the question is what has to be given up to achieve it and is it worth it.? I worked in pro audio (install/recording/touring) for many years so I also appreciate quality audio - but it also has to be practical and not cause other technical and functional issues in the process.
If I get some time this week, since I have the test equipment to do it, I might setup a Quantar on the bench and do some tests to see what the actual frequency response is through the internal repeat audio path - and then change some of the settings to see how they impact it.? I will use Pink Noise as a baseline, below the deviation limiter threshold -? then I can play some high-quality/wide range voice through to see the actual impact on the intelligibility and quality.? I will probably use my HP 8924C and Ivie IE-30A/IE-20P to perform the testing.? The HP 8924C has the ability to turn off the pre-emphasis/de-emphasis and both low and high-pass filters so it is ideal for the task and will likely?outperform any available transceiver in regards to modulating a "flat" response.? I am curious how the Quantar will perform.
Thanks, Daniel Woodie, CETsr KC8ZUM
M: +1.513.478.9844
H: +1.513.231.1101 ? ? ? ? ? ? ? ? ?
On Tue, Oct 25, 2022 at 11:07 PM Kevin Custer < kuggie@...> wrote:
On 10/25/2022 10:36 PM, Dan Woodie
wrote:
-------------------BIG snip
----------------------------
I feel there are far more important things to be spending
money and time on than trying to create a Hi-Fi repeater
------------------------BIG snip ---------------------
Daniel Woodie, CETsr
KC8ZUM
But that's one of the reasons this group
exists - not most of the other things you wrote about.? Keep that
in mind when replying to this group.? We're about highly technical
stuff here.
And - just because some of the radios that users use are junk -
doesn't mean we should be building repeaters that have substandard
frequency response.?
I can also hear the difference between a properly built repeater
and a stock "300Hz - 3kHz" one.? You want to hear a thing of
beauty - listen to one of the WN3A built machines.? Observation of
wider audio frequency response and properly built and set
processing will change your opinion.
Kevin W3KKC
|
Kevin,
Thank you for your comments.? I agree on all points 100%.? One thing you said that is especially true that I also tried to get across earlier...
I can also hear the difference between a properly built repeater and a stock "300Hz - 3kHz" one.? You want to hear a thing of beauty - listen to one of the WN3A built machines.? Observation of wider audio frequency response and properly built and set processing will change your opinion.
Thank you for your comments.
Burt, K6OQK
|
Here is some additional good reading on the subject of FM Transmitter frequency response and some reasons it is limited in most FM transmitters - from Repeater-Builder no less:
I guess as long as you can extend the frequency response without violating Part 97.307, in particular Part 97.307(b), then I guess all is good.??
My concern would be that the splatter filter is there for a good reason - and it is what generally limits the response of the transmitter - so by forcing more bandwidth through the transmitter I would expect the chances of splatter to be higher.? The very low frequencies would be my main concern as they contain the most audio power and are most likely to be impacted by proximity effect.
I will leave it at that until I do some testing - and look at the spectral purity while doing so. Daniel Woodie, CETsr KC8ZUM
M: +1.513.478.9844
H: +1.513.231.1101 ? ? ? ? ? ? ? ? ?
On Tue, Oct 25, 2022 at 11:07 PM Kevin Custer < kuggie@...> wrote:
On 10/25/2022 10:36 PM, Dan Woodie
wrote:
-------------------BIG snip
----------------------------
I feel there are far more important things to be spending
money and time on than trying to create a Hi-Fi repeater
------------------------BIG snip ---------------------
Daniel Woodie, CETsr
KC8ZUM
But that's one of the reasons this group
exists - not most of the other things you wrote about.? Keep that
in mind when replying to this group.? We're about highly technical
stuff here.
And - just because some of the radios that users use are junk -
doesn't mean we should be building repeaters that have substandard
frequency response.?
I can also hear the difference between a properly built repeater
and a stock "300Hz - 3kHz" one.? You want to hear a thing of
beauty - listen to one of the WN3A built machines.? Observation of
wider audio frequency response and properly built and set
processing will change your opinion.
Kevin W3KKC
|
At 10/25/2022 01:32 PM, you wrote: My point is, where is the energy above 3Khz comming from? Unless it is background music or road noise. The audio
spectrum from the human voice isn't there. You must not have a tongue or teeth; my sympathies. The idea of getting AM broadcast to 6kc was to help music reproduction.
If the voice audio is well equalized for inteligibility, it's not a bad thing to have 50hz- 6khz but you won't likely hear anything
above 3000 and if anyone wants to do any bass boosting it will get old fast. "Bass boosting"? No one has mentioned that; what does that have to do with this discussion? And there is no reason to pass the PL either. Why not? If someone really WANTS 6kc audio, it will have to be addressed throughout the chain, and keep an eye on the spectrum
analyzer. Why? I'm sorry but this is borderline nonsense. Just what is to be "addressed throughout the chain"? Then I looked up K6OQK and saw 147.435 in Los Angeles. I think that one is world famous for sending the FCC packing,
and pushing the envelope well past the 7 dirty words. Maybe when Burt was involved it wasn't that way, but it became the
attractive nuisance of the amateur community. ...and what the hell does that have to do with the subject? Bob NO6B
|
Dan,
I'm glad you realize that you are going off far into the weeds.
I don't disagree that many stock repeaters have "industry
standard" frequency response - but for some of us - we want more.?
This is no different than buying a stock vehicle and modifying it
for our needs.? Whether that be performance or whatever.
As far as standards to compare to - until you become familiar and
ultimately used to better audio - you don't want to go back to
industry standard.? At that point - industry standard audio is
substandard.? As hams - we're afforded the ability to stretch the
frequency response - commercial applications, that's not allowed.?
What you seem to be missing is goals in amateur radio can be
different - and that's okay.
And - I'm not talking about some hack job by ramming discriminator
audio into a FM modulator without any protection.? There are
products that are "out there" that allow you to do it right, and
protect your neighbors.? Some bands allow you to stretch the
bandwidth farther than others because of channel utilization and
separation.? These are topics that have been debated for 30 years
on various Internet groups/lists/etc.
Kevin
On 10/25/2022 11:42 PM, Dan Woodie wrote:
toggle quoted message
Show quoted text
Kevin,
I do agree with you?that this group can be about going
outside of what is normally done with repeaters and improving
on them - so in that respect maybe my comment was a bit off
the mark.??
I will disagree with your inference that Quantar has
"substandard frequency response".? Which standard are you
comparing it to?? I would suggest that Quantar and other
repeaters of similar performance ARE the industry standard.? I
believe what the goal of this post was - and what you prefer -
would be considered a "superior frequency response" while
Quantar would match or exceed "Standard frequency response".?
I understand the goal here - the question is what has to be
given up to achieve it and is it worth it.? I worked in pro
audio (install/recording/touring) for many years so I also
appreciate quality audio - but it also has to be practical and
not cause other technical and functional issues in the
process.
If I get some time this week, since I have the test
equipment to do it, I might setup a Quantar on the bench and
do some tests to see what the actual frequency response is
through the internal repeat audio path - and then change some
of the settings to see how they impact it.? I will use Pink
Noise as a baseline, below the deviation limiter threshold -?
then I can play some high-quality/wide range voice through to
see the actual impact on the intelligibility and quality.? I
will probably use my HP 8924C and Ivie IE-30A/IE-20P to
perform the testing.? The HP 8924C has the ability to turn off
the pre-emphasis/de-emphasis and both low and high-pass
filters so it is ideal for the task and will likely?outperform
any available transceiver in regards to modulating a "flat"
response.? I am curious how the Quantar will perform.
Thanks,
Daniel Woodie, CETsr
KC8ZUM
|
"
until you become familiar and
ultimately used to better audio - you don't want to go back to
industry standard. "
Amen to that.
This is also why some people actually think that YSF or other digital sounds better than analog audio.?? Because the "normal" analog they are comparing to is the average sounding repeater.?? And most don't actually do even 300-3000, many start the rolloff at 2000, and also don't start passing well until about 500.?? If you compare YSF vs simplex, well, simplex sounds better hands down.? (And use a good analog radio). ? So if you can get a repeater so there is no distinguishable difference between input and output audio, you have it as good as simplex.???
Andy WJ9J
On Wed, Oct 26, 2022 at 8:21 AM Kevin Custer < kuggie@...> wrote:
Dan,
I'm glad you realize that you are going off far into the weeds.
I don't disagree that many stock repeaters have "industry
standard" frequency response - but for some of us - we want more.?
This is no different than buying a stock vehicle and modifying it
for our needs.? Whether that be performance or whatever.
As far as standards to compare to - until you become familiar and
ultimately used to better audio - you don't want to go back to
industry standard.? At that point - industry standard audio is
substandard.? As hams - we're afforded the ability to stretch the
frequency response - commercial applications, that's not allowed.?
What you seem to be missing is goals in amateur radio can be
different - and that's okay.
And - I'm not talking about some hack job by ramming discriminator
audio into a FM modulator without any protection.? There are
products that are "out there" that allow you to do it right, and
protect your neighbors.? Some bands allow you to stretch the
bandwidth farther than others because of channel utilization and
separation.? These are topics that have been debated for 30 years
on various Internet groups/lists/etc.
Kevin
On 10/25/2022 11:42 PM, Dan Woodie wrote:
Kevin,
I do agree with you?that this group can be about going
outside of what is normally done with repeaters and improving
on them - so in that respect maybe my comment was a bit off
the mark.??
I will disagree with your inference that Quantar has
"substandard frequency response".? Which standard are you
comparing it to?? I would suggest that Quantar and other
repeaters of similar performance ARE the industry standard.? I
believe what the goal of this post was - and what you prefer -
would be considered a "superior frequency response" while
Quantar would match or exceed "Standard frequency response".?
I understand the goal here - the question is what has to be
given up to achieve it and is it worth it.? I worked in pro
audio (install/recording/touring) for many years so I also
appreciate quality audio - but it also has to be practical and
not cause other technical and functional issues in the
process.
If I get some time this week, since I have the test
equipment to do it, I might setup a Quantar on the bench and
do some tests to see what the actual frequency response is
through the internal repeat audio path - and then change some
of the settings to see how they impact it.? I will use Pink
Noise as a baseline, below the deviation limiter threshold -?
then I can play some high-quality/wide range voice through to
see the actual impact on the intelligibility and quality.? I
will probably use my HP 8924C and Ivie IE-30A/IE-20P to
perform the testing.? The HP 8924C has the ability to turn off
the pre-emphasis/de-emphasis and both low and high-pass
filters so it is ideal for the task and will likely?outperform
any available transceiver in regards to modulating a "flat"
response.? I am curious how the Quantar will perform.
Thanks,
Daniel Woodie, CETsr
KC8ZUM
|
All my repeaters , regardless of using flat or non flat audio sound like simplex...I'm a sticker when it comes to audio...too many years in broadcast engineering I guess lol...it's not hard to do either...but too many don't take the time to do it right..I've heard commercial repeaters sound like garbage...and then there's the ham rptrs, using commercial equipment, set to narrow band yet the users are all wide band....ugh ..one KW TKR750 I know of is set to NB because the wideband filter died...easy to replace but the trustee was too lazy and put the rptr in NB mode....that's just stupid
Chris WB5ITT?
On Wed, Oct 26, 2022, 8:02 AM wj9jrg < wj9jrg@...> wrote: "
until you become familiar and
ultimately used to better audio - you don't want to go back to
industry standard. "
Amen to that.
This is also why some people actually think that YSF or other digital sounds better than analog audio.?? Because the "normal" analog they are comparing to is the average sounding repeater.?? And most don't actually do even 300-3000, many start the rolloff at 2000, and also don't start passing well until about 500.?? If you compare YSF vs simplex, well, simplex sounds better hands down.? (And use a good analog radio). ? So if you can get a repeater so there is no distinguishable difference between input and output audio, you have it as good as simplex.???
Andy WJ9J
On Wed, Oct 26, 2022 at 8:21 AM Kevin Custer < kuggie@...> wrote:
Dan,
I'm glad you realize that you are going off far into the weeds.
I don't disagree that many stock repeaters have "industry
standard" frequency response - but for some of us - we want more.?
This is no different than buying a stock vehicle and modifying it
for our needs.? Whether that be performance or whatever.
As far as standards to compare to - until you become familiar and
ultimately used to better audio - you don't want to go back to
industry standard.? At that point - industry standard audio is
substandard.? As hams - we're afforded the ability to stretch the
frequency response - commercial applications, that's not allowed.?
What you seem to be missing is goals in amateur radio can be
different - and that's okay.
And - I'm not talking about some hack job by ramming discriminator
audio into a FM modulator without any protection.? There are
products that are "out there" that allow you to do it right, and
protect your neighbors.? Some bands allow you to stretch the
bandwidth farther than others because of channel utilization and
separation.? These are topics that have been debated for 30 years
on various Internet groups/lists/etc.
Kevin
On 10/25/2022 11:42 PM, Dan Woodie wrote:
Kevin,
I do agree with you?that this group can be about going
outside of what is normally done with repeaters and improving
on them - so in that respect maybe my comment was a bit off
the mark.??
I will disagree with your inference that Quantar has
"substandard frequency response".? Which standard are you
comparing it to?? I would suggest that Quantar and other
repeaters of similar performance ARE the industry standard.? I
believe what the goal of this post was - and what you prefer -
would be considered a "superior frequency response" while
Quantar would match or exceed "Standard frequency response".?
I understand the goal here - the question is what has to be
given up to achieve it and is it worth it.? I worked in pro
audio (install/recording/touring) for many years so I also
appreciate quality audio - but it also has to be practical and
not cause other technical and functional issues in the
process.
If I get some time this week, since I have the test
equipment to do it, I might setup a Quantar on the bench and
do some tests to see what the actual frequency response is
through the internal repeat audio path - and then change some
of the settings to see how they impact it.? I will use Pink
Noise as a baseline, below the deviation limiter threshold -?
then I can play some high-quality/wide range voice through to
see the actual impact on the intelligibility and quality.? I
will probably use my HP 8924C and Ivie IE-30A/IE-20P to
perform the testing.? The HP 8924C has the ability to turn off
the pre-emphasis/de-emphasis and both low and high-pass
filters so it is ideal for the task and will likely?outperform
any available transceiver in regards to modulating a "flat"
response.? I am curious how the Quantar will perform.
Thanks,
Daniel Woodie, CETsr
KC8ZUM
|
The input is direct coupled. No transformers involved since the
input passes down to 5 Hz.
73, Jim W7RY
On 10/25/2022 10:20 AM, Burt K6OQK
wrote:
Jim,
Thanks for your reply, and no, for some reason I did not see it
earlier.? Are pins 9 & 34 a balanced pair?? How are they
coupled in so as to have wide band audio? Electronically balanced,
transformer, or each and unbalanced input?? I had seen those on
another sheet and wasn't sure if they were data only and not
capable of passing analog audio.
Thanks,
Burt, K6OQK
Then you did not see my reply.
The general transmit input is uses for simulcast. It passes DC
to 10 KHz with no issues.
Connector 17, (50 pin telco)Pins 9 and 34
--
Thanks and 73, Jim W7RY
|
STOP hijacking threads please.
Jim W7RY
On 10/25/2022 8:46 PM, John wrote:
---------- Original Message ----------
Date: 10/25/2022 8:38 PM
Subject: Re: [repeater-builder] QUANTAR VHF Audio
Interface...
Yes, Burt, I also agree with
that concept because it is better in those circumstances of
low initial audio and to me it also makes sense to increase
intelligibility when you are receiving noise on the
repeater.? It does usually reduce the highs from them being
selectively clipped, so the question is how do you boost the
highs back when the clipping is done on pre-emphasized audio
where flat audio is defined by the same voltage at the
clipper when the input frequency is swept from lowest to
highest frequency at the same input deviation? By adding
high frequency boost after the clipper, and then more low
pass filtering? Possibly easier and better to just eliminate
the pre-emphasis components before the clipper, and add
comparable pre-emphasis after the clipper so a little audio
compression without reducing highs and still the same low
pass roll-off. There must be a way to configure Kevin's
clipper /filter to achieve this result.
To my
thinking, the advantage from having no repeater compression
or clipping is when you want to repeat a repeat times X in
analog so as to not keeping adding background noise or
distortion each time, at least on the link radios if a quiet
link path. Guess that is one big advantage of digital
repeaters?
John
On 10/25/2022 4:47 PM Burt K6OQK <biwa@...>
wrote:
John,
I personally do not believe in the 5 kHz in and 5 kHz out
thinking.? A part of the problem is that stations with low
deviation will come through with low deviation and those with
high deviation can hit the transmitter's limiter too hard.?
Some believe that it's the responsibility of those stations to
correct their deviation, and learn to use correct mic
technique. My experience in that area has proven to be: Good
Luck!
Please understand, I don't mean to be talking at you, but just
intellectualizing with you...
To my way of thinking, a repeater is not a piece of test
equipment to be used as a deviation tester.? It's a
contraption to improve / enable communications.? Proper
processing also protects the transmitter and adjacent channel
spectrum in a less destructive way.? Anything I can do to make
it simple, reliable, and pleasant, is a plus.? That's why I
have always used appropriate audio processing on my
repeaters.? I've gotten arguments from the unwashed telling me
that it brings up the noise on the incoming signal. Well, yes,
that's true, but you're going to have to turn up the volume at
the user's end if you want to hear those stations anyway.?
When you do that you are not only bringing up the noise heard
by the repeater, but also any noise between and the
repeater.? Having to turn the volume up and down while
listening to a repeater gets tiring after a while.
For what it's worth,
Burt, K6OQK
--
Thanks and 73, Jim W7RY
|
Burt K6OQK
Ken Arck AH6LE
Kevin Custer
Chris Boone WB5ITT