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N5WRX
05-07-2008, 02:55 PM
I know the FCC rules do not provide a fixed bandwidth limit for SSB signals on the ham bands but I would think 4K or more of SSB would qualify as excessive.

The new Flex 5000 Radio will allow a very wide transmit bandwidth and it seems there are a few hams on 3.930 that feel their need for broadcast quality audio justifys a 4K+ SSB bandwidth.
With the visual monitoring features of the Flex Radio there is no excuse to NOT know the bandwidth you are transmitting as you must set it in a menu box and can see it on the display console when you transmit.

As a listener using a Flex 5000 it is just as easy to see the transmitted bandwidth of any transmitting station.

I can only assume they are aware that they are excessively wide and want it that way regardless of what the FCC rules say.

KC4RAN
05-07-2008, 02:57 PM
"ESSB" is the term you're looking for...

N8YX
05-07-2008, 02:58 PM
Oh gawd, here it goes AGAIN... :rolleyes:

N2RJ
05-07-2008, 02:59 PM
If you're running that much bandwidth, just do AM, and please, don't do it in a crowded band.

N5WRX
05-07-2008, 03:14 PM
"ESSB" is the term you're looking for...

What ....?
So we can now spread out if we call it a different mode?
What a concept.
So I can transmit in expanded double sideband and take up 10K of bandwidth?

Cool

We all NEED to sound like Imus in the Morning ... dont we?

KB3LAZ
05-07-2008, 03:20 PM
I personally Use 3k for transmit and receive, but I hear a lot of guys and gals use around 6k wide. They sound quite good actually, but each to their own I guess.

W3WN
05-07-2008, 03:45 PM
I know the FCC rules do not provide a fixed bandwidth limit for SSB signals on the ham bands but I would think 4K or more of SSB would qualify as excessive.

The new Flex 5000 Radio will allow a very wide transmit bandwidth and it seems there are a few hams on 3.930 that feel their need for broadcast quality audio justifys a 4K+ SSB bandwidth.
With the visual monitoring features of the Flex Radio there is no excuse to NOT know the bandwidth you are transmitting as you must set it in a menu box and can see it on the display console when you transmit.

As a listener using a Flex 5000 it is just as easy to see the transmitted bandwidth of any transmitting station.

I can only assume they are aware that they are excessively wide and want it that way regardless of what the FCC rules say.

Oh lordy, here we go again.

Look... for communications quality speech, an ~3 kHz bandwith is sufficient for most operators. That is the reason that most AM signals have a 6 kHz bandwith and most SSB signals have a 3 kHz bandwith. On most SSB rigs, the bandwith is set by filtering; if you run into someone running a Phased SSB rig (such as a Hallicrafters HT-37) their bandwith might be wider because it's not cut down in the filters.

There is or was a group a few years who were experimenting with what they were calling "Enhanced SSB." Their argument was that they were trying to improve the quality of transmitted speech -- think "high fidelity" -- by widening the SSB bandwith. Now personally, I don't see the point, but regardless of my opinion, there they were.

From what I recall, most of the ESSB experimentation was going on in the upper parts of the 10 and 17 meter phone bands, where the experimenters had hoped to operate unmolested.

However, as was inevitable, other amateurs came across the ESSB experiments, and complaints (valid or not) of interference and distorted signals soon followed.

I do not know the status, if any, of ESSB today. My understanding is that after the big ruckus a few years ago, many of the ESSB crowd moved on to other things or laid low.

So... the Flex 5000 can do a wider transmitted bandwith than 3 kHz? That's nice. Do you have to use it? No. If you're not happy with it, don't use it.

If you want to experiment with ESSB (and risk arousing the wrath of the sleeping anti-ESSB luddites) be my guest. Good luck, duck often, and thanks for all the fish.

73

WB2WIK
05-07-2008, 04:20 PM
I've joined the "who cares?" side of this, long ago.

Let 'em try it during a contest and see if they can work anybody.

Life's too short to worry about what others do. I don't get road rage, and I'm surely not going to get "band" rage.

Personally, I just don't answer the "wide banders."

WB2WIK/6

K3MSB
05-07-2008, 04:26 PM
don't do it in a crowded band.

Exactly. If the band's sparsely populated, who cares if you're running wide AM or SSB?

If the band's crowded, be courteous and tighten it up.

KC4RAN
05-07-2008, 04:43 PM
What ....?
So we can now spread out if we call it a different mode?
What a concept.
So I can transmit in expanded double sideband and take up 10K of bandwidth?

Cool

We all NEED to sound like Imus in the Morning ... dont we?
I wasn't attempting to justify it. I was informing you of what 'those that do it' call what they do.

Geez...

N8YX
05-07-2008, 04:44 PM
We all NEED to sound like Imus in the Morning ... dont we?

How's that - half in the bag? :p

N5WRX
05-07-2008, 04:48 PM
I guess I need to work on my apathy or my "I dont care what others do" attitude.

Wide modes, out of band, pirate call, bad language, trash signal, 5K of power ....
who cares!

N5WRX
05-07-2008, 04:53 PM
How's that - half in the bag? :p

He He ... good one!

KJ3N
05-07-2008, 05:07 PM
We all NEED to sound like Imus in the Morning ... dont we?
How's that - half in the bag? :p

Obviously, you've listened to 75m AM. Some of those guys sound like it's a "3 martini minimum" crowd. ;)

N8YX
05-07-2008, 05:09 PM
Obviously, you've listened to 75m AM. Some of those guys sound like it's a "3 martini minimum" crowd. ;)

That, and no jacket required...:eek:

AI4EP
05-07-2008, 05:13 PM
no shirt / shoes / brains required either......


just talk like you did on the ol' cb.

WD0CT
05-07-2008, 06:00 PM
ESSB - Double feature now showing on eham and qrz.

K4KYV
05-07-2008, 06:31 PM
I think the FCC just spoke on this issue:


The present rules allow amateur stations to transmit PSK data emissions subject to the conditions that the station transmission shall occupy no more bandwidth than necessary for the information rate and emission type being transmitted, and that emissions resulting from modulation must be confined to the band or segment available to the control operator. We believe that these rules provide amateur service licensees the flexibility to develop new technologies within the spectrum authorized for the various classes of licensees, while protecting other users of the spectrum from harmful interference. We also believe that imposing a maximum bandwidth limitation on data emissions would result in a loss of flexibility to develop and improve technologies as licensees’ operating interests change, new technologies are incorporated, and frequency bands are reallocated. Additionally, we believe that amending the amateur service rules to limit the ability of amateur stations to experiment with various communications technologies or otherwise impeding their ability to advance the radio art would be inconsistent with the definition and purpose of the amateur service. Moreover, we do not believe that changing the rules to prohibit a communications technology currently in use is in the public interest.

http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-08-1082A1.pdf

QRZ.com Thread on the subject (http://forums.qrz.com/showthread.php?t=162099)

We rarely have those "congested band conditions" in recent years except perhaps during contests, and contests should not be regarded as normal operating conditions. Even on 75m on weekend nights they seem to roll up the sidewalks shortly after sundown. I wonder what ever happened to the nocturnal emissions crowd of years past.

Just as we adjust our receiver selectivity in accordance with QRM conditions and the degree of congestion, it would be good amateur practice to likewise adjust transmitted bandwidth. If there is sparse activity on the band, there is absolutely nothing wrong with running hi-fi AM or SSB with a total bandwidth of 15 kHz or more if one so desired, but that bandwidth should be due only to the frequency range of the transmitted audio and not include spurious distortion products, aka "splatter". If there is plenty of room on the band, and your favourite frequency is already occupied by an ESSB or AM QSO in progress, just QSY to a clear spot. Too bad if someone has beat you to your self-proclaimed "private channel" that you have transmitted on every night for the past 30 years. That is what your VFO is for. Few hams are limited to crystal control these days.

But under crowded conditions, few listeners are going to hear modulation frequencies that extend out beyond about 3000 Hz because their receiver, adjusted to narrow selectivity, will filter them out, so there is no point in transmitting "hi-fi" audio even if you are unconcerned about interfering with adjacent channel QSO's.

Many of the new software-defined radios offer just that kind of flexibility in receiver selectivity and transmitting bandwidth.

AG3Y
05-07-2008, 06:32 PM
Let me give you an example of "poor engineering practice" that is NOT ILLEGAL , but poor,none-the-less.

Suppose you ran SSB thorough a filter that was less than 1Khz wide. You would certainly not be using excessive bandwidth, and could use the excuse that you were trying to avoid "hogging the band". But almost no one would be able to understand your muffled, constricted audio! Is that "good engineering practice" on the ham bands?

Now, go the other way. You are using 6Khz of bandwidth to transmit your ESSB signal. A very small minority of ham radio operators could actually hear your entire bandpass because the vast majority of SSB radios filter out almost everything except 300-3000 or so hz ! It is even possible that you are not splattering all up and down the band, but no one can operate within 6Khz of your supressed carrier frequency without infringing on your ESSB signal. Is that good or poor engineering practice ? ? ?

Talk about that for a while. I will be avidly reading the discussion.

73, Jim

K9KXQ
05-07-2008, 06:33 PM
ESSB - Double feature now showing on eham and qrz.

Pitiful ain't it, wonder just how many of these guys complaining run one of the Heil mics, or the w2ihy EQ ? OK gentlemen, go back to your hand mic and you can send me all of the w2ihy EQ's and Heil mics, I would be more than happy to except them, shucks I'll even offer up the shipping expense...

kxq

N8YX
05-07-2008, 06:33 PM
Many of the new software-defined radios offer just that kind of flexibility in receiver selectivity and transmitting bandwidth.

Now if we can just get their owners to USE those features in the most constructive manner for all...

K4KYV
05-07-2008, 07:03 PM
You are using 6Khz of bandwidth to transmit your ESSB signal. A very small minority of ham radio operators could actually hear your entire bandpass because the vast majority of SSB radios filter out almost everything except 300-3000 or so hz ! It is even possible that you are not splattering all up and down the band, but no one can operate within 6Khz of your supressed carrier frequency without infringing on your ESSB signal. Is that good or poor engineering practice ? ? ?

It wouldn't necessarily be poor engineering practice if there happens to be plenty of unoccupied spectrum on both sides of your transmit frequency. But if the band is so congested that there are few clear spots to operate, it would be better operating and engineering practice to narrow the signal down a bit.

W3OZ
05-07-2008, 09:46 PM
Let me give you an example of "poor engineering practice" that is NOT ILLEGAL , but poor,none-the-less.

Suppose you ran SSB thorough a filter that was less than 1Khz wide. You would certainly not be using excessive bandwidth, and could use the excuse that you were trying to avoid "hogging the band". But almost no one would be able to understand your muffled, constricted audio! Is that "good engineering practice" on the ham bands?

Now, go the other way. You are using 6Khz of bandwidth to transmit your ESSB signal. A very small minority of ham radio operators could actually hear your entire bandpass because the vast majority of SSB radios filter out almost everything except 300-3000 or so hz ! It is even possible that you are not splattering all up and down the band, but no one can operate within 6Khz of your supressed carrier frequency without infringing on your ESSB signal. Is that good or poor engineering practice ? ? ?

Talk about that for a while. I will be avidly reading the discussion.

73, Jim

You are one of the few who even though I don’t think you take part in ESSB really seems to get the point.

I can do ESSB, I have a Kenwood 850 and modified DSP-100. I can go out past 6K. I very very rarely do so for my own reasons. I run an Icom Pro III stock with just a couple of boxes to smooth it a little and limit the fan noise and other background noses in the shack. No bass boosts at all below 100HZ. To true ESSB guys it sounds like crap.

What I am going to say next is considered heresy by my fellow audio enthusiasts. What you said about the bandpass is very true. If you try to get good audio through a too thin filter it will sound bad, but if you are wide, much more than about 3.5Khz you sound bad to MOST hams. I would challenge any of my friends to come over to my shack and listen to a 6 Khz ESSB signal on a unmodified Yaesu 1000D rig and say it sound good. No matter what you do it is going to sound poor. I have been in shacks with other hams who have like rigs, they have no agenda no built in dislike for ESSB, but really they have no way of listening to the transmitted signal with their current rigs. It sounds poor to them and I have had to agree reluctantly.

Yes there are pockets of guys having fun running ESSB. Apparently most of the guys I used to talk to have gone to 75 meters in the evenings. I can not address what goes on there as I do not listen. But on 20 meter, I can tell you that around 14.178 which used to be the ESSB watering hole, there is only a few of us and we are all running skinny.

Most of the ESSB guys think we suck and really we do in comparison to what true ESSB is. But we are at least trying to be good citizens on the bands especially 20 meters. But as hard as we try others just can’t help to interfere with our QSOs.

I know my transmitted signal and the amount of frequency I am taking. I run a spectrum analyzer most of the time and have others monitor me as well. My mic gain, ALC, and drive to my amp are within spec, for the Pro III. Again no bass boosting or special EQing other than taking the peeks and valleys out of the signal and reducing fan noise. I do run the Pro III in the wide mode as was designed by the Icom engineers that is about 100Hz to 2.9Khz. Far less than 3Khz and not that much more than the 2.7Khz a lot of you guys run all the time. But still guys come by, don’t identify and make nasty comments. WHY???? Maybe you are just naturally nasty I do not know.

The problem as I see it is that like everyone else we hams get kind of used to having things as they were and as much as we pretend we are forward looking folks we are really not. Yes I still like the smell and glow of the old tube stuff. I used to run AM in the good old days. Late 50s early 60s. Thought those damn SSB guys were full of it. But today I find myself doing it along with CW. I really want to sound somewhat like we did in the AM days but not take up so much space. That is the reason I work in enhanced audio EA not ESSB.

We got real used to hearing SSB in the early days and got accustomed to the sound. We all think that is the normal SSB sound, good clean, clear as it should be. We are all happy right? No we are not all happy obviously. Some of us think we can do better and are trying to do so, but some will not even entertain the thought. They put out generalizations and exaggerations and do what ever they can to get others all upset just so that they do not have to say something like well maybe those guys have a point, or maybe I am wrong.

Done correctly, EA or ESSB does not splatter. Done correctly EA can work as much DX as 1.8Khz DX audio. Guys I am on top of the ARRL Honor Roll, I have worked them all. I have done it with skinny audio and EA audio, when conditions are right it does not matter. I will give you the fact that audio that is higher in pitch like a female voice will get through faster in pile up than lower or more male pitched audio.

I will also say, and this makes the audio guys mad at me, that most, not all but most of the audio guys are not DXers, they have no idea what it is about. Oh ya they are in the East Coast and work Europe, or West Coast and get into the Orient, but all DXers know that is not working a large pileup with an upside down split. So ESSBers have some respect for others as well.

Ok I am done. From my past experience posting things on places like this, nobody reads them they just get the drift and start to slam me anyway without trying to understand what I am saying. I don’t really expect this to be any different, but was just wishing that I could build some understanding between apparently two groups who do not want to like each other for some reason…AMEN

G0GQK
05-07-2008, 09:51 PM
Sounds like those characters who use the frequencies intended for PSK31 and then start pumping out some unknown wide digital mode on top of narrow band PSK operators. When somebody mentions it they give out the crap about digital modes are all narrow band and they get all..... well, nasty about the fact its mentioned. Thoughtless and, so who cares !

G0GQK

AI4EP
05-07-2008, 10:39 PM
if you didnt have such excellant recievers, you would not be hearing all those signals that you can complain about...!!

or did I say it all wrong ?

hee hee hee :)

KE6KA
05-08-2008, 07:03 AM
I think the FCC just spoke on this issue:



http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-08-1082A1.pdf

QRZ.com Thread on the subject (http://forums.qrz.com/showthread.php?t=162099)


Just as we adjust our receiver selectivity in accordance with QRM conditions and the degree of congestion, it would be good amateur practice to likewise adjust transmitted bandwidth. If there is sparse activity on the band, there is absolutely nothing wrong with running hi-fi AM or SSB with a total bandwidth of 15 kHz or more if one so desired,

If you want to broadcast hi-fi audio, get a commercial broadcasting license. Knowingly using 15Khz of bandwidth, which is five times the bandwidth needed on SSB, is nothing short of total disregard for others.

Yes, we all noticed you didn't bold the data part of that quote. Phone and data are not the same thing.

K4KYV
05-08-2008, 07:50 AM
If you want to broadcast hi-fi audio, get a commercial broadcasting license. Knowingly using 15Khz of bandwidth, which is five times the bandwidth needed on SSB, is nothing short of total disregard for others.

Yes, we all noticed you didn't bold the data part of that quote. Phone and data are not the same thing.

Agreed, hi-fi audio wouldn't be appropriate during periods of heavy band usage, but how is this a case of "disregard for others", if you listen before transmitting and find 10's of kiloHertz of unoccupied frequency space on both sides of the frequency, for example on 75 or 160 during the day or the wee hours of the morning? If "others" want to use the band under those conditions, they have plenty of vacant frequencies outside your passband to choose from.

The data part wasn't bolded because, while the FCC's order was referring to a specific case regarding data transmission, the underlying principles stated in their Order regarding bandwidth apply equally well to all modes. What does phone vs data have to do with it?

AG3Y
05-08-2008, 02:16 PM
"Just as we adjust our receiver selectivity in accordance with QRM conditions and the degree of congestion, it would be good amateur practice to likewise adjust transmitted bandwidth. If there is sparse activity on the band, there is absolutely nothing wrong with running hi-fi AM or SSB with a total bandwidth of 15 kHz or more if one so desired,"

OH ? ? ? If that is the case, than how come FM is only allowed on 10 meters, and not lower in frequency, and how come even on that band, the modulation index is limited to 1 ? ? ? It seems that the FCC IS CONCERNED about limiting bandwidth to "communications quality"

And how come data is limited to 300 baud on the HF bands, and the spacing between mark and space is limited, as well . How come ? ? ?

" Inquiring minds want to know ! ! ! "

WA0LYK
05-08-2008, 02:40 PM
"Just as we adjust our receiver selectivity in accordance with QRM conditions and the degree of congestion, it would be good amateur practice to likewise adjust transmitted bandwidth. If there is sparse activity on the band, there is absolutely nothing wrong with running hi-fi AM or SSB with a total bandwidth of 15 kHz or more if one so desired,"

OH ? ? ? If that is the case, than how come FM is only allowed on 10 meters, and not lower in frequency, and how come even on that band, the modulation index is limited to 1 ? ? ? It seems that the FCC IS CONCERNED about limiting bandwidth to "communications quality"

And how come data is limited to 300 baud on the HF bands, and the spacing between mark and space is limited, as well . How come ? ? ?

" Inquiring minds want to know ! ! ! "

There are a couple of reasons. One, the fcc did not want fm to become a "standard" with modulation indexes greater than 1 on hf. Remember, with fm, both the receiver and transmitter much match. This would mean that a "standard" would end up evolving and could be much wider than other types of emissions, even when the bands were crowded. Two, the creation of additional heterodynes besides those from AM would be a possibility. I suspect the fcc did not want to encourage other types of constant carrier emissions on hf phone segments.

With the recent fcc ruling on N5RFX's petition and a slightly earlier one declining to specify exact limits on phone, the fcc has made it pretty plain that they are not going to apply bandwidth limits on emissions.

I suspect before too many more months, we will begin to see multi-tone data modes of 5, 10, or 20 kHz utilizing some of the software defined radios. Yes, they will have to limit the shifts of each tone to 1000 Hz and limit the baud rate of each tone to 300 baud but when you can use 100 tones spread over 10 kHz, who cares?

Jim
WA0LYK

AG3Y
05-08-2008, 02:53 PM
Jim, FM does not create "hetrodynes", which are basically an AM mixing process, but does have a characteristic called "capture effect". If one station is as little as 3dB stronger than another, that station will completely take over a frequency and supress the other station into non-audibility ! That is one of the major reasons that aircraft communications are still using good old AM modulation! A weak signal, perhaps calling a "Mayday" can still be heard through the other traffic on a frequency !

I don't understand what you mean by "match". An FM receiver can detect any deviation up to that which is no longer linear in the bandpass of the IF/detector chain. Thus, a commercial broadcast FM receiver might have a linear bandpass of 100Khz, but be able to detect a very soft passage of a classical music selection that is modulating the transmitter at no more than 5Khz deviation, and present it nearly perfectly! I am sure that that illustration can be applied to communications receivers, as well. So what do you mean by "matched" ?

Your illustration of "100 tones spread over 10Khz" does cause reason for concern. However, since MT63 - 1000 seems to be allowed in the U.S. but 2000 does not, there seems to be some restraint written into the rules and regs, yet. I am seeking hard to find someone who can give me specifics on where these standards are to be found. So far, no one has actually cited me "chapter and verse" outside of the ones that we have been seeing for years, now. No changes that I know of !

73, Jim

K9STH
05-08-2008, 03:28 PM
Jim:

FM IS permitted on all amateur radio frequencies on which phone operation is allowed except for the 60 meter band which is limited to USB only. Above 29.0 MHz the modulation index CAN exceed 1. In fact, the vast majority of FM operation in the 10-meter band (generally in the 29.5 MHz to 29.7 MHz range and around 29.300 MHz) operates using +/- 5 kHz deviation. When the usual maximum modulating frequency is 3000 Hz (3 kHz) this means a modulation index of 1.6667.

Below 29.0 MHz the modulation index is limited to a maximum of 1. That means with the usual maximum modulation frequency of 3000 Hz this means that the deviation cannot exceed +/- 3 kHz. Many "modern" HF transceivers have a "narrow" deviation position which limits the deviation to +/- 2.5 kHz which results in a modulation index of 0.8333 which is well within the modulation index limitations for HF operation.

Frequency modulation (FM) and phase modulation (PM), which produces a similar mode as FM, are completely legal on HF where phone operation is allowed except for the 60 meter band. FCC regulations specify that any "angle modulation" (this means FM or PM) operations below 29.0 MHz cannot have a modulation index greater than 1. Many amateur radio operators believe that using FM (or PM) below 29.0 MHz is illegal. This is just not true. However, there is very little FM/PM operation below 29.0 MHz but using those modes is completely legal except for the 60 meter band.

From the later half of the 1940s through the 1950s there was a considerable amount of FM activity on HF using a maximum deviation of +/- 3 kHz. This was known as NBFM and quite a few commercially built amateur radio transmitters had NBFM capabilities. A good number of the "top end" amateur radio receivers had optional NBFM adapters available. I have one such adapter in my Collins 75A-3 receiver. But, NBFM can be received on any AM receiver by using "slope detection" (tuning to the side of the frequency so that only one of the sidebands is received. Also, it is possible to receive a NBFM signal using a product detector (used for "normal" SSB reception).

I have been "tempted" to try VNBFM (very narrowband FM) with deviations well under +/- 1 kHz deviation. This would help considerably with the apparent gain of the signal due to the reduction in bandwidth. Of course this would require considerably more "audio recovery" (the amount of gain required for satisfactory reception) and a narrow bandwidth in the receiver. My Collins 75A-3 has both the FM detector and the capability of reducing the bandwidth to well under 1 kHz and therefore should work fine. Now the audio gain will have to be run considerably higher than for "normal" operation but there is definitely "gain to spare" in the receiver.

Glen, K9STH

AG3Y
05-08-2008, 03:35 PM
I completely missed that Glen! I was wrong, and thanks for pointing that out !

Thanks for the history lesson and the clarification . I learned something today !

( not that I'm going to go out and do FM on the HF bands any time soon ! )

;) :)

AB0WR
05-08-2008, 03:36 PM
Jim, FM does not create "hetrodynes", which are basically an AM mixing process, but does have a characteristic called "capture effect". If one station is as little as 3dB stronger than another, that station will completely take over a frequency and supress the other station into non-audibility ! That is one of the major reasons that aircraft communications are still using good old AM modulation! A weak signal, perhaps calling a "Mayday" can still be heard through the other traffic on a frequency !

I don't understand what you mean by "match". An FM receiver can detect any deviation up to that which is no longer linear in the bandpass of the IF/detector chain. Thus, a commercial broadcast FM receiver might have a linear bandpass of 100Khz, but be able to detect a very soft passage of a classical music selection that is modulating the transmitter at no more than 5Khz deviation, and present it nearly perfectly! I am sure that that illustration can be applied to communications receivers, as well. So what do you mean by "matched" ?

Your illustration of "100 tones spread over 10Khz" does cause reason for concern. However, since MT63 - 1000 seems to be allowed in the U.S. but 2000 does not, there seems to be some restraint written into the rules and regs, yet. I am seeking hard to find someone who can give me specifics on where these standards are to be found. So far, no one has actually cited me "chapter and verse" outside of the ones that we have been seeing for years, now. No changes that I know of !

73, Jim

Try using a 2.5khz FM transmitter on a receiver designed for 5khz or even 15khz versus one designed for 2.5khz. What will the result be? (yes, it will detected, but what will the actual output be?)

There is nothing limiting 2khz mt63 on the ham bands except the attitude of cooperation among hams to not use bandwidth unnecessarily.

20khz OFDM signals will use 20khz regardless of the information rate being passed. If you are using it for anything resembling human interaction the OFDM will be passing idle data most of the time.

This is cooperating with other hams to make the best use of the ham bands?

Those that want the broader signals, almost without exception, want it for computer-to-computer communication (e.g. internet gateways) and not for control operator-to-control operator communication. These hams have no regard for other operators wanting to use the spectrum for intercommunication between control operators which is what the definition of the service is.

I can only hope that the FCC *truly* meant their decision to be a shot across the bow of this segment of the ham population. It will probably go by totally unheeded, however.

tim ab0wr

AG3Y
05-08-2008, 03:42 PM
As Glen points out in his post, it is possible to increase the audio gain and still find a low deviation signal to be perfectly audible and understandable.

Also, since narrow FM can be detected using slope detection, it would not be impossible to listen to it using a conventional AM receiver. However, without the limiters and high gain IF stages built into a standard FM receiver, static crashes and other QRM/N would probably be very high, verging on intolerable to cope with!

K9STH
05-08-2008, 03:58 PM
3Y:

FM signals can definitely create heterodynes if the signal strengths are fairly close to the same. Now "capture" is a different phenonomen and if a weaker signal is being received it takes a much stronger signal to overcome the weaker signal and "take over".

What happens when the deviation of the transmitter is greater than the receiver bandpass is that the signal "chops out". That is the modulation completely disappears because the signal is outside of the frequency range of the signal.



WR:

When the deviation of the transmitted signal is considerably less than the bandwidth of the receiver there are two things that happen. First of all the signal to noise ratio of the signal is degraded. The second is that the audio recovery is not as good and it will require more audio gain in the receiver to produce a satisfactory level in the speaker.

This was very apparent in the commercial two-way FM arena when, in 1957, lowband and highband were "narrowbanded" (the deviation dropped from +/- 15 kHz to +/- 5 kHz - "drop dead" date of 1962 except for public safety where the "drop dead" date was in 1967 by which time all transmitters had to fully meet the "narrowband" requirements - the first thing done was that the deviation controls had to be immediately set to +/- 5 kHz deviation). The receivers were still quite usable but the volume controls had to be run at a considerably higher level. Of course there was more interference from adjacent channels because the wider bandpass filters did not eliminate the signals that were now 30 kHz away and not 60 kHz away (on highband) and 20 kHz away and not 40 kHz away on lowband.

On a clear frequency the main thing that you will notice when running +/- 5 kHz deviation or even +/- 2.5 kHz deviation using a receiver designed for +/- 15 kHz deviation is that the apparent volume of the received signal will be noticeably less than when the bandwidth of the receiver is closer matched to the deviation. For example, you can receive a 2-meter FM repeater on a receiver designed for FM broadcast (either by retuning the receiver or through use of a converter) without any problems if there are no other signals within the passband (which will produce multiple audio signals). However, the volume control is going to have to be run at a higher level to compensate for the lack of audio recovery in the receiver.

Glen, K9STH

AB0WR
05-08-2008, 04:04 PM
As Glen points out in his post, it is possible to increase the audio gain and still find a low deviation signal to be perfectly audible and understandable.

Also, since narrow FM can be detected using slope detection, it would not be impossible to listen to it using a conventional AM receiver. However, without the limiters and high gain IF stages built into a standard FM receiver, static crashes and other QRM/N would probably be very high, verging on intolerable to cope with!

Go back and read what LYK said again. Having to continually adjust volume as different stations speak (perhaps even having distortion at high audio amp gain levels) helps *drive* the development of a standard, it doesn't hinder it.

If the deviation of the transmitters and receivers don't match then there *is* a drive to standardize them in order to maximize operating convenience. The FCC seems to have seen fit to pre-establish what that standard would be on HF.

As far as heterodynes being caused by FM, this isn't an issue of capture effect between two FM stations. It's an issue of another carrier-based mode on the bands. An AM station and an FM station operating close together will cause a heterodyne signal in an AM or SSB receiver even if it doesn't in the two FM receivers. Strong AM signals can also interfere with the reception of FM signals that are not causing full limiting in the FM receiver. While the heterodyne issue may not have been a consideration of the FCC it could just as easily have been too.

tim ab0wr

AB0WR
05-08-2008, 04:08 PM
Glen,

Thank you.. The operating inconvenience of different deviations would have generated a drive toward a standard just like LYK pointed out. The FCC just set a rule as to what that standard would be on HF.

tim ab0wr

AG3Y
05-08-2008, 04:08 PM
I was basing my response about hetrodynes on what I hear on 2 meter FM when two stations "double" either on a repeater input, or when running simplex. In almost every case, one station completely dominates the frequency, and a very low level "squawk" may or may not be heard waaaay in the background. Compare this to when two AM signals try to transmit on the same frequency. Usually, if not always, a very loud whistle will be heard as a result, and the effect is very disconcerting!

Also, in my experience, a signal that is deviating much higher than a receiver's bandwidth will not necessarily "chop out" and completely disappear, but will rather, have a very distorted characteristic, much like a line level audio signal being fed into a mic preamp sounds ! Terrible !

N5RFX
05-08-2008, 04:33 PM
The operating inconvenience of different deviations would have generated a drive toward a standard just like LYK pointed out. The FCC just set a rule as to what that standard would be on HF.

But they didn't set a maximum deviation, they set a modulation index. Since the modulation index is the maximum deviation/maximum audio frequency there can still be differing deviations depending on what is the maximum audio frequency. If there had been a maximum modulating frequency specified, then I would agree that setting the modulation index at 1 would set the maximum deviation. I believe that the assumption was that the maximum modulation frequency should be 3 kHz and that would set the maximum deviation to 3 kHz. But I am hearing that there are no maximum modulating frequencies in Amateur radio, so I am not sure what specifying a modulation index accomplishes.

73,
Mark N5RFX

KD6NIG
05-08-2008, 04:35 PM
I was basing my response about hetrodynes on what I hear on 2 meter FM when two stations "double" either on a repeater input, or when running simplex. In almost every case, one station completely dominates the frequency, and a very low level "squawk" may or may not be heard waaaay in the background. Compare this to when two AM signals try to transmit on the same frequency. Usually, if not always, a very loud whistle will be heard as a result, and the effect is very disconcerting!

Also, in my experience, a signal that is deviating much higher than a receiver's bandwidth will not necessarily "chop out" and completely disappear, but will rather, have a very distorted characteristic, much like a line level audio signal being fed into a mic preamp sounds ! Terrible !

Totally off topic, but I've noticed on the local police frequencies here that when there is an urgent call and a few mobiles chime in, one of them doesn't beat the others anymore-it just seems to be a total scramble. Nobody makes it unless one is MUCH stronger than the others.

I wonder if its the frequency (460 mhz, roughly) or other factors, because usually when people double on 2m, someone usually wins.

AG3Y
05-08-2008, 04:48 PM
Sorry for being off topic, but to answer your question, Joshua, that depends on the "capture ratio" of the RF receiver being used. On the Commercial Broadcast bands, the capture radio can approach as little as 3dB because of the excellent limiters and high gain IF stages in hi end FM tuners. ( maybe not so much today as back in the "golden age" of Hi Fi with units such as the original Fisher, Harmon Kardin, Scott, etc. ) Glen is more than likely right. With a typical narrowFM unit that would be popular on the 2 meter FM band, the capture ratio is probably closer to 10dB.

Now back to the "regularly scheduled" discussion, already in progress.

73, Jim

K9STH
05-08-2008, 07:57 PM
NIG:

The "scramble" on 460 MHz is more probable due to the fact that most of the units are identical in power and identical in the type of antenna used. Therefore, the relative signal strength is relatively the same and therefore no one signal has a sufficient signal strength to actually "capture" the receiver.


3Y:

When you hear distortion instead of "chopping out" that is normally a function of the "skirts" of the bandpass filter used in the receiver. The poorer the skirts the more likely you are to get distortion. With a filter with excellent characteristics (like the old Motorola "Permakay" filters) it is almost unheard-of to get distortion and not "chopping out". Filters like the Motorola TU540S "Permakay" have a very narrow bandpass and the "skirts" are measured in like 120 dB "down" versus 6 dB and 60 dB like most filters used in amateur radio equipment. In fact, many receivers have filters that are rated at 6 dB and 20 dB points or 6 dB and 40 dB points.

With "decent" filter characteristics an FM signal wider than the bandpass will "chop out" and not distort. Unfortunately, almost all consumer radios as well as most amateur radio units and many of the "lower lines" of commercial two-way radios definitely "skimp" on the quality of the i.f. filters used in the receivers.

Glen, K9STH

K4AX
05-08-2008, 07:59 PM
Here are over the air recordings of some horrible sounding essb audio... :rolleyes:

http://www.nu9n.com/mp3.html

AG3Y
05-08-2008, 09:02 PM
Well, bfd, as a retired audio engineer, I believe I can tell what is good audio, and what is NOT.

I listened to several samples on the web page cited above, and most of what I heard had evidence of severe frequency response altering. In the wider bandwidths, on several samples the treble started to "screeching" , and in almost every sample that I listened to, the bass was so jacked up that I had an urgent temptation to grab the bass control on my hi fi system and BACK IT OFF !

I cannot understand WHY so many ESSB operators think that they should all sound like Howard Stern ! That is NOT the way the natural human voice sounds, and it should NOT be the way that it comes across over the air.

Years ago, when I was in Commerical Broadcasting, the criteria for a good sounding announcer was NOT how he sounded through a set of 15 inch woofers! Rather, it was how good he sounded on a typical "All American 5" with its 4 inch speaker in an open back cabinet. A smooth baritone voice was much to be preferred to one that groveled in the basement ! If you don't believe me, listen to many recordings of Milton Cross, who hosted the weekly Metropolitan Opera Broadcasts over NBC for years and years !

John Derimus ( sp ? ) who hosted the "All Night Meister Brau Showcase" out of Chicago for years and years, had a deeper bass voice, but never did anything in the way of equalization to emphasize it. He sounded absolutely FABULOUS over the typical "AA5" !

These professional announcers, and many others like them, became famous, not because their voices could rattle the floorboards, but because of what they had to say, and how they said it!

That still should be the top criteria in communications, even today.

73, Jim

AB0WR
05-08-2008, 09:32 PM
Here are over the air recordings of some horrible sounding essb audio... :rolleyes:

http://www.nu9n.com/mp3.html

First off, I have a suspicion that whoever recorded these needs to check his equipment. A spectrum scan with CoolEdit Pro shows that *all* of the recordings have huge frequency spikes at 94hz, 168hz, and around 300hz (I don't remember the exact frequency) and a big hole at about 416hz and they are exactly the same in each of the recordings. I just have my doubts that each and every voice that was recorded has exactly the same harmonic content at these frequencies.

Second, some of these sound "not so good" and some sound very good. The recordings run the gamut. They don't *all* sound bad and therefore these cannot be used as a blanket condemnation of essb.

From an intelligibility point of vew there are several that sounded very good. When looked at with Cool Edit pro they all had preemphasis being applied above 2khz. While these may not sound "natural" I would expect them to be much more usable as the SNR drops. That isn't bad either.

If I'm passing traffic on an emergency net and a 3.5khz bandwidth with pre-emphasized treble will make me understood -- that's a good thing in my book!

tim ab0wr

K4KYV
05-08-2008, 09:42 PM
If that is the case, than how come FM is only allowed on 10 meters, and not lower in frequency, and how come even on that band, the modulation index is limited to 1 ? ? ?

FM is allowed on all phone bands, from 160 to microwave. The modulation index limit of 1 applies only below 29.0 mHz.

From Part 97


Wavelength......Frequencies.......Emission types............authorized Standards
band

160 m..............Entire band .......Phone, image..............(1), (2)
75 m................Entire band........Phone, image..............(1), (2).
40 m...........7.125–7.300 MHz.....Phone, image..............(1), (2).
20 m...........14.15–14.35 MHz.....Phone, image..............(1), (2).
17 m...........18.110–18.168 MHz..Phone, image..............(1), (2).
15 m...........21.20–21.45 MHz.....Phone, image..............(1), (2).
12 m...........24.93–24.99 MHz.....Phone, image..............(1), (2).
10 m...........28.3–28.5 MHz........Phone, image..............(1), (2), (10).
10 m...........28.5–29.0 MHz........Phone, image..............(1), (2)
10 m...........29.0–29.7 MHz........Phone, image..............(2).

(1) No angle-modulated emission may
have a modulation index greater than 1
at the highest modulation frequency.
(2) No non-phone emission shall exceed
the bandwidth of a communications
quality phone emission of the
same modulation type. The total bandwidth
of an independent sideband emission
(having B as the first symbol), or
a multiplexed image and phone emission,
shall not exceed that of a communications
quality A3E emission.

AG3Y
05-08-2008, 09:43 PM
"these are stations that I have had receiver access to, that sound better than the typical audio associated with SSB."

This quote from the web page cited, shows that the author of the page has every intention of showing that ESSB sounds BETTER than standard SSB. I believe, as Tim agrees, that the samples "run the gamut", and I certainly don't agree with the author of the page that he has proven that ESSB sounds better than standard SSB.

73, Jim


Edit: Concerning the FM modulation index. I was wrong about that, Glen corrected me, and I thanked him for that correction. It was too late for me to delete the content of that post. No one is PERFECT !

AI4EP
05-09-2008, 12:36 AM
...but you have to be absolutely PERFECT when you make a post, or folks will come out of the woodwork to notice your tiny error.

You will hear from folks whose sole mission in life is to harass, intimidate and aggravate you about the trivilest of matters.

Go ahead and make one and see........!!!! :)

AG3Y
05-09-2008, 01:13 AM
Doggone it, EP, how come you are always SOOOOO RIGHT ! ! !


:eek: :o ;) :)

WA0LYK
05-09-2008, 02:09 AM
I was basing my response about hetrodynes on what I hear on 2 meter FM when two stations "double" either on a repeater input, or when running simplex. In almost every case, one station completely dominates the frequency, and a very low level "squawk" may or may not be heard waaaay in the background. Compare this to when two AM signals try to transmit on the same frequency. Usually, if not always, a very loud whistle will be heard as a result, and the effect is very disconcerting!

Also, in my experience, a signal that is deviating much higher than a receiver's bandwidth will not necessarily "chop out" and completely disappear, but will rather, have a very distorted characteristic, much like a line level audio signal being fed into a mic preamp sounds ! Terrible !

My mention of hetrodynes was alluding to what would happen in a mixed mode band of fm, am, and ssb. Since fm is a constant carrier mode, it will create hetrodynes when operating am or ssb (or cw).

Jim
WA0LYK

AG3Y
05-09-2008, 02:56 AM
True, and if the FM carrier is being modulated, due to the repeating sidebands ( see a Frequency Domain graph of a modulated FM carrier to see what I mean ! ) those hetrodynes would certainly be a scrambled mess !

73, Jim

WD0CT
05-09-2008, 04:37 AM
I found this on the eham essb thread and thought it quite good even though I don't agree withe calling frequency part:

You naysayers have missed the point of Don's article. He is arguing for amateurs to educate themselves about ssb audio, to learn about what is most effective and what is not. Don wrote:

"The point of this article: adjusting our SSB audio so it is the most efficient it can be to communicate the way we want to communicate without interfering with the other guy's right to communicate the way he wants to. That is sort of the Golden Rule of On-air SSB Audio."

From the many comments posted it is obvious that the topic of 'Effective Audio' is a mystery to these scoffers. Instead of looking at the worst examples of 'experimental audio', why not pay attention to the many excellent sounding ESSB signals?

Some observations might clear up your confusion as to what ESSB actually is. The acronym 'ESSB' stands for Extended SSB and was defined and published by John, NU9N about 5 years ago. It refers to ssb signals whose high frequencies extend beyond 3.1kHz and whose low frequencies extend down to 100Hz.

2.8kHz wide ssb with over-powering bass frequencies is NOT ESSB! Infortunately, most hams immediately assume this is so and therefore brand all bass heavy ssb signals as 'ESSB'. Wrong!

There are essentially two groups of ESSB audiophiles. One group wants the majority of ssb operators to receive them correctly, so they keep their bandwidth below 3.6kHz. They CAN accurately be received on most ssb transceivers. The other group works with wider bandwidths from about 4.5kHz to 6kHz. They can only be correctly demodulated on an SSB receiver capable of 4.5kHz and wider bandwidth. They are seeking an AM Alternative mode, not a replacement for conventional bw ssb! So many foolish arguments could have been avoided if that concept was made clear! Both modes have their supporters and indeed many users of one mode use the other.

The compatible 3.0 to 3.6kHz wide ESSB is usually transmitted with a balanced frequency spectrum, whose low and high frequency limits cut of sharply - without splatter and objectionable IMD products. This is what should be considered examples of good ESSB. Furthermore, nearly every ESSB operator transmits at 1/3 to 1/2 the full power of their transceiver, thereby reducing 3rd and 5th order IMD by 15 to 25dB! So please, naysayers - give ESSB users the same credit you allow yourselves.

The wider ESSB signals are not compatible to conventional ssb and much on the air GRIEF could have been avoided if calling frequencies for ESSB was set aside as we have for AM. 6kHz wide ESSB should be considered an alternative to AM. 6kHz ESSB can do the job much better, offering TWICE the audio fidelity and no troublesome carrier. In addition 6kHz ESSB has excellent intelligibility even just a few dB above the noise floor. But you naysayers don't know about that, do you?

How ridiculous it is to criticize ESSB signals as being 'too wide' when others are running 2kw+ SSB for no other reason then to sound LOUD. Until our transmitters all run Class-A, kW class signals will ALWAYS have more occupied bw then 100w signals, because a transmitter's bandpass slopes are not rectangular. IMD products pad out the signal so at 30dB down and more many RF clipper driven transmitter's are MUCH wider than 3kHz. The worst offenders are contesters and DX'ers in battle. Add a high gain antenna and that compounds the problem. So who's kidding who?

I believe the best thing we can do is stop fighting amongst ourselves. Audio is more important then most hams realize. The military and air traffic controllers have been using wider bandwidth voice channels for some time. Instead of criticizing ESSB experimenters, why don't you naysayers find out what the advantages of using wider speech bandwidth are?

WA3VJB
05-09-2008, 09:42 AM
I always trust NASA.

They envy, so much, the pinched and narrow audio of certain ham radio operators that they emulate it for the space shuttle.

Sometimes you can't even understand them, it's so "efficient," but being audible is less important than presenting excellent examples of distortion and that "sweet spot" of audio at 2000 hz.

Ear bleed, anyone? Crank it up !

K9STH
05-09-2008, 01:53 PM
KYV:

You made the same mistake as most people make about where FM is allowed. It is NOT allowed in the 60 meter band where only USB is allowed.

Glen, K9STH

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