Bandwidth Recommendations

[Pete, WA2CWA]

For those that don't read the ARRL section of the forum:

ARRL Executive Committee Readies Bandwidth Recommendations[/color][/b]

For all the info, go here:
http://amfone.net/phpBB2/viewtopic.php?t=4462

[W8ER]

Whelp (to borrow a phrase) I see that they got the 160 meter band right!

What's interesting is that Sumner admits "using the FCC rules to subdivide the amateur HF bands is the wrong approach. The FCC rules are too static and too difficult to change". His words! and yet the very basis of the proposal is to subdivide the amateur bands.

Talk about inconsistency!




--Larry W8ER[/b]

[W1QWT]

I hope I am not rehashing something already beat to death but I was concerned about this bandwidth proposal and I'm having trouble understanding something.
I am heavily involved with the original equipment on the USS Salem. I also run the annual Museum Ship Radio event and try and encourage all the museum ships to operate thier ships original equipment on AM.
I am concerned whether this old WW2 equipment will meet the requirements. The FCC defines bandwidth as the - 26 dB points and the league is proposing allowing AM to have 9 KHz bandwidth.
The RF generation part of this old equipment might have, for instance, a two pole filter driving the final and a 3 pole filter on the final output. I guess that is ok but I don't remember seeing anything more than a one or two pole RC filter on the audio. (6 dB/octave vs 12 dB/octave)

Has anybody ever measured the bandwidth of some older commercial or military transmitters for the 1940's or 1950's vintage?

I would hate to have to tear into these rigs. But ofcourse they already sound constricted so maybe the carbonium microphonium already limits the frequency response. AM I all wet?

[WD8BIL]

Has anybody ever measured the bandwidth of some older commercial or military transmitters for the 1940's or 1950's vintage?

Q,
The Viking 1 was bulit as a kit in1950.
The Viking 2 is maybe, 1954
Checkout the scans on my webpage.

www.wd8bil.com

[WB3JOK]

THERE IS NO "H" IN "WELP"

The "H" is silent, like the "Q" in "Billiards" or the "P" in "Swimming" :lol:

[W8ER]

THERE IS NO "H" IN "WELP"    :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  :lol:

WHELP was correct!

Jack spelt it wrong in the first place!


--Larry w8er

[Tom WA3KLR]

Hi Q,

Jocularity aside, I participated in a Technical thread on measured AM transmitted bandwidth last August and September.  Unfortunately that thread and most all others on this bulletin board were lost a few months ago.

I was trying to come up with a spectrum analyzer standard measurement procedure.  There was very little participation/response to submit data on their AM transmitters; just Bud WD8BIL and myself as I recall.

The procedure I came up with was to use 300 Hertz resolution bandwidth, set video bandwidth to maximum (per Bud), set the analyzer display for peak hold, read the “Rainbow passage” which contains all English sounds, for at least 2 minutes.

I have 4 AM transmitters here and use no external speech processing.
This was the results; BW @ -26dBc.:

Icom  IC-706         6.2 kHz.
Kenwood TS-430    6.7 kHz.
Johnson Viking II   7.4 kHz.
Collins 32V-3         7.5 kHz.

(Note that the Icom and Kenwood rigs pass their modulator signal through a crystal filter.)

I went into this study with the preconception that the new specification might be difficult to meet.  So I was somewhat surprised at the results.  Bare in mind that this is just my voice and no external processors were used.  

I have observed however some amateur signals over the air that were probably greater than or equal to 14 kHz wide at -26 dBc.   These observations are with my Drake R-7 receiver, not my HP spectrum analyzer.

In my experience I have never found a correlation between the quality of audio heard on channel and the total bandwidth, surprisingly!  Some really hyellowy signals that you’d think must definitely be spattering were not.  And some very good sounding signals are much wider than the impending rule.  (In my opinion, the most consistently very good sounding AM signal and yet always very clean and narrowest bandwidth is of Bob, K1KBW.)

When the announcement of the impending rule came out and I posted my results here and there was no outcry.  So I presume people are largely content with the situation.  Of course this is based solely on the response, or lack of, to my postings last September.  But people are not obligated to response to this forum. They may have written their opinions to the FCC and/or ARRL hopefully.

I don’t have any knowledge or experience with the big WWII behemoths.  But my guess is if you are using the transmitter in the original configuration with the mic right into the audio and the modulator has no technical problems, you should be o.k.

[W1RFI]

After the results of my last post here on the topic of bandwidth, I should know better, but I have to at least point out a few technical points.

The rules do not say to measure the -26 dB points. Occupied bandwidth is defined as the bandwidth outside of which the mean power of the emissions is 26 dB less than the mean power of the emission.  To calculate the occupied bandwidth, one must compare the total power in the emission with the total power outside of the occupied channel and when you find the bandwidth at which the sum of the power outside the bandwidth is 26 dB less than the total power, that is the occupied bandwidth.  From what little I started to do before deciding that I was much better off not being interested in bandwidth, this would usually occur at about -23 dB or so from the peak of the emissions in the channel.

This is complicated, however, by the "mean-power" issue.  That has a precise definition, but there is still a question about the time period over which the mean power should be determined.  In general, I believe that amateurs should take the least restrictive interpretation of FCC rules.  This would mean that the mean power should be determined over the total time of a transmission. In that case, for SSB signals, the majority of the energy is found in the lower-frequency components. The higher frequency components occur infrequently, so their mean power is less.

A technique that uses "peak hold" is NOT looking at the mean power of an emission, but the peak power. OTOH, I have seen a developing ITU-R standard draft that requires that peak hold be used. This is not fully compatible with the FCC definitions of occupied bandwidth by my interpretation of the rules.   Peak hold would measure the mean power over a short time period. I have no idea how this will shake out in the long run.

AM, btw, has a natural advantage in terms of mean power and occupied bandwidth.  That carrier is 3 dB higher than the modulation product peaks, and its mean power and peak-envelope power are the same, so that really does make a big difference in terms of measuring mean power occupied bandwidth if measured over the entire period of a typical transmission.
 
To test rigs, the easiest way I could think of that hams could do would be to heterodyne a transmitted signal down in frequency to LF, typically 5 kHz of so, so it could be analyzed with a sound card. I then started a piece of Visual Basic software with an FFT to analyze about 10 seconds of trasmitted audio. The software then calculates occupied bandwidth to find the bandwidth outside of which the power is 26 dB less than the total power.  At this point, the software is unfinished and I don't expect to do any more work on bandwidth issues unless our DC technical guys need me to do something specific.  

For a number of reasons, this really is my last and only post on the subject. I don't want to be part of the firestorm that some are creating over this issue, or the lashing out that seems to occur any time I post on this topic. But I did want to explain the difference between -26 dBc and the actual definition of occupied bandwidth. You are on the right track in making bandwidth measurements.

Ed Hare, W1RFI

[w3jn]

Thanks for the post, Ed.  I *hope* nobody here is dumb enough to shoot the messenger.

This measurement is complex enough that many late-model spectum analyzers have an automatic bandwidth-power measurement.

Which underscores how miserably this effort by the ARRL will fail in the real world.  Most hams can't even understand  the relationship between modulation mode, modulation frequency, bandwidth, and power.  All it's gonna do is generate bitter complaints to the FCC about someone running too much bandwidth.

Grrr.....

73 John

[k4kyv]

Most hams can't even understand  the relationship between modulation mode, modulation frequency, bandwidth, and power.  All it's gonna do is generate bitter complaints to the FCC about someone running too much bandwidth.

Kinda like the PEP power rule.  If you took a poll of active licensed hams, wonder what percentage would be able to correctly describe what PEP is, and its relationship to emission mode and the actual transmit power?

I suspect most hams just stick in a wattmeter (often a miserable cheap one) inline and swear by what it reads in the "peak power" mode, without considering such things as SWR and load mismatch.  Kids in school often do the same thing with calculators.  They punch in a bunch of numbers, and swear by the result that pops up on the display, regardless of how absurd their "answer" may be.

If the bandwidth rule is adopted, sooner or later someone will market a "bandwidth meter", some kind of cheap pseudo spectrum analyser that (allegedly) displays the signal bandwidth on a numerical display.  Maybe it'll even have a peak and average mode.

It is difficult, if not impossible, to accurately measure occupied bandwidth per Ed's definition over a distance via skywave propagation, due to the noise and fading.  Like power measurements, it must be done at the actual transmitter site.

Ed, thanks for clarifying the definition.  It makes sense.  I have always thought of it as how far you tuned through a signal until the signal level reads 26 dB down from the point of maximum signal amplitude (in the case of AM, the carrier), but I can see how ambiguous that definition would be.

[WD8BIL]

Hi Ed... good to see ya again.

A while back Bill KD0HG posted the criteria for AM broadcast measurements. IIRC the analyzer was to be on peak hold for 10 minutes.

Bill..... can you repost that please

[W8ER]

Hi Ed .. thanks for the information on bandwidth.

I look at your elegant explanation and am reminded of the QSO I heard on 3865 SSB several months ago where a guy running legal limit with a big Ameritron and an Icom was trying to figure out how to tell which was the positive terminal on the coil of a 12 VDC relay.

John .. are you looking at your crystal ball again:  

Most hams can't even understand the relationship between modulation mode, modulation frequency, bandwidth, and power. All it's gonna do is generate bitter complaints to the FCC about someone running too much bandwidth.

--Larry W8ER

[w3jn]

Larry, what can I say?  I'm just clairvoyant, I tell ya! :badgrin:

[Steve - WB3HUZ]

For broadcast, the FCC has a spectral emission mask. The mask is nothing more than limits on radiation referenced to the carrier. I don't see why the FCC couldn't develop mode appropriate masks to meet the mean power requirements Ed detailed above.

With the mask, making a bandwidth measurement is easy. Just take a spectrum shot with the appropriate times and bandwidth. Then overlay the mask. If all emissions are within (less than) the mask, everything is FB. If not, then there is a problem.


Below is the mask for FM broadcast.





And this is a mask for SSB derived from 47 CFR 2.989 (c)(4), FCC type acceptance.

[Jack-KA3ZLR-]

I'm Always Glad when Ed comes in, It Brings out the best on the Board here and the Technical Conversations are Always first Rate.

[k4kyv]

I don't see why the FCC couldn't develop mode appropriate masks to meet the mean power requirements Ed detailed above.

With the mask, making a bandwidth measurement is easy. Just take a spectrum shot with the appropriate times and bandwidth. Then overlay the mask. If all emissions are within (less than) the mask, everything is FB. If not, then there is a problem.

Well, since they claimed they were unable to come up with a mode appropriate power rule, could you expect them to come up with a with a mode appropriate bandwidth mask?

At best, they would come up with some one-size-fits-all approach like the p.e.p. power limit rule or  the Docket 20777 bandwidth proposal.

[W8ER]

Steve and Don,

There are two problems that I see:

1. The level of technical expertise necessary to understand the method by which we are to measure bandwidth and the necessary equipment is out of the reach of most amateurs, both financially and operationally. It simply is expecting too much. If you say .. phone starts here and CW starts here .. well that's a no brainer and that's what you can expect from the average ham today. Notice I said average ham and not AM'er!  :roll:

2. The FCC itself is unsure of the measurement and role it plays and this proposal isn't going to help that. Take for instance the Advisory Notices that were issued to the ESSB boys and the later stand that the FCC took on specificity of bandwidth rules. How much more contractdictory can the situation be?

Sumner ARRL CEO said:

Sumner points out that amateurs would not have to be able to measure the bandwidth of their signals. "The proposed bandwidths are more than sufficient for 'clean' signals using the traditional HF modes," he said. "Measurement would only arise as a potential problem for those who try to push the edge of the envelope."

The ARRL article from which that quote was taken is published on their web site. I can only ask, what would happen if the speed limits on todays roads were treated the same way?  That is:

Larry W8ER proposes:

W8ER points out that drivers would not have to be able to measure the speed of their vehicles. "The proposed speeds are more than sufficient for 'safe' vehicles using the traditional US highways," he said. "Measurement would only arise as a potential problem for those who try to push the edge of the envelope."

This is not a "firestorm" or "lashing out" as some would have us believe! This is just plain common sense leveled at an organization whose leaders say that FCC rules in this area are not wise, as a preamble to proposing such rules!  :idea:



--Larry W8ER

[Steve - WB3HUZ]

Well, since they claimed they were unable to come up with a mode appropriate power rule, could you expect them to come up with a with a mode appropriate bandwidth mask?

Yes I could. If we expect and demand nothing, we will get nothing.

At best, they would come up with some one-size-fits-all approach like the p.e.p. power limit rule or  the Docket 20777 bandwidth proposal.

All the more reason for amateur radio to be proactive not reactive. The ARRL should develop the masks now.

[k4kyv]

Sumner ARRL CEO said:

Sumner points out that amateurs would not have to be able to measure the bandwidth of their signals. "The proposed bandwidths are more than sufficient for 'clean' signals using the traditional HF modes," he said. "Measurement would only arise as a potential problem for those who try to push the edge of the envelope."

There is a precedent for that in the power limit rule.  The amateur community expressed concern about hams being able to accurately measure PEP output power.  So the FCC deleted the former requirement that amateurs must have the means to measure power.

One of the statements in the R&O on that docket was that amateurs "have means for determining their output power other than accurate measurement."

I never was able to figure that one out.

One problem I do see for AM is that every appliance operator with a crappy-front-end receiver will be jumping in on top of AM QSO's hollering on SSB, "You're exceeding your bandwidth."  It's bad enough now with the P & M'ing we hear about "wide" signals (and yes, even "wide" carriers).  Wait till they think they have a legal basis to do so and decide it's their duty to play kilocycle cop.


Check out this:

New Bandwidth Thread on QRZ

[W1RFI]

> The ARRL article from which that quote was taken is published on their web site. I can only ask, what would happen if the speed limits on todays roads were treated the same way?

Do you feel the same way about all of the technical requirements for amateur radio that could involve measurement, or just bandwidth?

How often do you measure the spurious emissions of your station operating in-situ into its real antenna system?  

Ed Hare, W1RFI

[Jack-KA3ZLR-]

Good Morning All,

I don't know fellas, 26dB is way down, A need to define this 3kc idea of theirs is bothering me, looking at my analyzer of a ssb signal in real time here doesn't flush with this idea of theirs, i have to put in 1.5 Kc of filtering to see the bandwidth they want, using my new Yeasu FT-897D to the HP Analyzer and that won't add to any plus in intelligbility and Sounds like crap.

Now either i'm reading their requirement wrong, or my test is wrong, either way, for my test to be 26 dB Down between the 6 dB points i'm showing a narrower filter to meet this...of course now each rig is it's own animal and filtering being what it is, slope figures etc, This Not a Cool Idea...IMHO.

Now all i did was to talk into the mike and pipe off the spectral graph to the gaterway and read the signal on a couple of these freeware spectrum programs i got off of the net...

I'm probably doing something wrong here...this just doesn't add up....

[W8ER]

> The ARRL article from which that quote was taken is published on their web site. I can only ask, what would happen if the speed limits on todays roads were treated the same way?

Do you feel the same way about all of the technical requirements for amateur radio that could involve measurement, or just bandwidth?

How often do you measure the spurious emissions of your station operating in-situ into its real antenna system?  

Ed Hare, W1RFI

Ed, I would think that anything that is specified in Part 97 as having a quantity and a reasonable capability of being measured, such as frequency and power ... should be, yes. Does that mean that I think bandwidth should be measured under Part 97 (currently)? Not as long as it states "  in accordance with good amateur practice" and does not specify a specific amount!

Under the the ARRL proposal, bandwidth is going to be the deciding factor of where we can transmit! It therefore becomes critical to understand it and measure it. That's not in the cards unless MFJ comes out with a "automatic bandwidth analyzer" let's call it the lucky MFJ-777 analyzer and I'll bet it will read 5 khz one day and 2 khz the next cause even it won't know how to measure bandwidth!!!!

Let's not only talk about the hams, let's address the FCC. Here we have the enforcement division handing out Advisory Notices to ESSB guys about excessive bandwidth and then FCC division comes along and trounces the proposal to limit bandwidth, stating that traditional rules are reasonable.

It's time Ed .. make all of the band plans look just like the 160 band plan! Sumner is right, the FCC rules are too difficult to change and he's right that something need to be done to allow the hobby to keep up with technology but sub divison by bandwidth (such a obscure and difficult thing to measure) is not right.

and yes Jack, the 3 khz figure bothers me too. All of the current transceivers do that and more. the TS-870 (3100 khz), the TenTec Jupiter (3900 khz), etc etc. BUT HOW IS THAT MEASURED? and darn sure some little twit is going to come along and tell me that I am using 3002 khz of bandwidth! Jack I just don't understand the how and why of this whole thing, it doesn't make sense! Why do you think the ARRL is insisting on making such a proposal?


--Larry W8ER

[k4kyv]

From this week's ARRL LETTER


==>ARRL EXECUTIVE COMMITTEE READIES BANDWIDTH RECOMMENDATIONS

Acting on the premise that the amateur bands must flexibly and comfortably
accommodate present and future operating modes and technologies over the
long haul, the ARRL Executive Committee has reached consensus on
recommendations to the ARRL Board of Directors for a regulation-by-bandwidth
proposal. The recommendations the panel adopted April 9 in Denver will form
the basis of a draft ARRL petition to the FCC seeking to govern the usage of
amateur spectrum by emission bandwidth rather than by mode. The proposals
remain only EC recommendations at this point, and the League will file
nothing with the FCC until the ARRL Board gives its go-ahead. Five of the 15
voting Directors sit on the EC. ARRL CEO David Sumner, K1ZZ, says a key
principle underlying the League initiative is that the amateur community
must shoulder the responsibility for resolving conflicts among potentially
conflicting modes and not expect--or wait for--the FCC to impose its own
solutions.

"We are in the early stages of a dramatic shift in amateur HF operating
patterns, and it's impossible to predict where this shift may lead," Sumner
said. "The FCC rules should not stand in the way of where technology takes
us in our fulfillment of the bases and purposes of Amateur Radio." The
bandwidth initiative is aimed in part at encouraging new digital modes, but
the primary emphasis is to avoid having to write a new rule every time a new
mode bursts onto the scene. The League's proposals will establish a
framework that creates an environment for change over the next decade--and
perhaps longer, Sumner concluded. The Board will consider the draft
petition, now on the drawing board, at its July meeting.

The EC recommendations abandon efforts to have the FCC segregate digital and
analog emissions by rule. As the EC sees it, the FCC rules should simply set
out band segments in which amateurs may employ bandwidths of up to 3 kHz,
with any further subdivision left up to amateur band planning. The EC
acknowledged a need to improve band planning mechanisms for this approach to
work well, however.

"Certainly there have to be mechanisms to minimize interference between
analog and digital stations, since they cannot compatibly share the same
frequency," Sumner explained. But, he says, using FCC rules to subdivide the
HF bands is the wrong approach, in part because they're too static and too
difficult to change.

Resolving two issues that have been hanging fire, the EC's proposals would
permit semi-automatic control (ie, with a control operator at the querying
station) throughout the amateur HF bands. Sumner says that while this
carries some risk of interference, the EC believes the amateur community can
manage it more effectively through a combination of technology and
respectful operating practices. Additionally, automatic control would
continue to be permitted at bandwidths of up to 3 kHz in narrow segments of
some HF bands.

The EC made no change to its earlier recommendation that the rules continue
to permit double-sideband, full-carrier AM and independent sideband (ISB) as
specific exceptions to the 3 kHz bandwidth limit--with restrictions of 9 kHz
and 6 kHz respectively--on all bands now allowing 'phone transmissions. (In
ISB, or independent sideband, each sideband of a double-sideband signal
carries information or data independent of the other.)

FCC rules now permit RTTY and data emissions throughout the HF CW subbands.
"It is only through compliance with 'gentlemen's agreements' that RTTY and
data signals are not heard in the parts of the band that are generally used
for CW," Sumner notes. The ARRL would propose limiting bandwidth in the "CW
subbands" to 200 Hz, which also will accommodate data modes such as PSK31.
In addition, the League's proposal would set bandwidth limits of either 500
Hz or 3 kHz in the rest of the bands below 29 MHz. The proposals would not
affect 60 or 160 meters.

"The objective is not to expand the phone bands to let robot stations run
roughshod over the phone bands, or to effect any other immediate change in
amateur operating practices," Sumner emphasized. For example, while the
3-kHz bandwidth segment of the 30-meter band theoretically could accommodate
voice, this is prohibited by international band plan agreements because the
band is so narrow. Additionally, the Amateur Service is secondary on 30
meters and must protect the primary fixed service from interference.

Sumner pointed out that there now is no effective bandwidth limit on HF
digital operation. The existing 500 Hz bandwidth limit applies only to
automatically controlled stations in semi-automatic operation. Band segments
limited to 200 Hz and 500 Hz respectively provide greater protection for
narrowband operations than exists today, Sumner stressed.

Frequently Asked Questions (FAQs) on the EC recommendations are available on
the ARRL Web site
<http://www.arrl.org/announce/regulatory/bandwidth/bw-faq.html>. Direct
comments on these proposals via e-mail to <bandwidth@arrl.org>.

[Jack-KA3ZLR-]

> The ARRL article from which that quote was taken is published on their web site. I can only ask, what would happen if the speed limits on todays roads were treated the same way?

Do you feel the same way about all of the technical requirements for amateur radio that could involve measurement, or just bandwidth?

How often do you measure the spurious emissions of your station operating in-situ into its real antenna system?  

Ed Hare, W1RFI

Ed, I would think that anything that is specified in Part 97 as having a quantity and a reasonable capability of being measured, such as frequency and power ... should be, yes. Does that mean that I think bandwidth should be measured under Part 97 (currently)? Not as long as it states "  in accordance with good amateur practice" and does not specify a specific amount!

Under the the ARRL proposal, bandwidth is going to be the deciding factor of where we can transmit! It therefore becomes critical to understand it and measure it. That's not in the cards unless MFJ comes out with a "automatic bandwidth analyzer" let's call it the lucky MFJ-777 analyzer and I'll bet it will read 5 khz one day and 2 khz the next cause even it won't know how to measure bandwidth!!!!

Let's not only talk about the hams, let's address the FCC. Here we have the enforcement division handing out Advisory Notices to ESSB guys about excessive bandwidth and then FCC division comes along and trounces the proposal to limit bandwidth, stating that traditional rules are reasonable.

It's time Ed .. make all of the band plans look just like the 160 band plan! Sumner is right, the FCC rules are too difficult to change and he's right that something need to be done to allow the hobby to keep up with technology but sub divison by bandwidth (such a obscure and difficult thing to measure) is not right.

and yes Jack, the 3 khz figure bothers me too. All of the current transceivers do that and more. the TS-870 (3100 khz), the TenTec Jupiter (3900 khz), etc etc. BUT HOW IS THAT MEASURED? and darn sure some little twit is going to come along and tell me that I am using 3002 khz of bandwidth! Jack I just don't understand the how and why of this whole thing, it doesn't make sense! Why do you think the ARRL is insisting on making such a proposal?


--Larry W8ER

Hi Larry,

 Welp, Daves Idea is to source a bandwidth proposal to encourage the new  Digital modes, I'm OK with that if they stay with that...Naturally they are not, and feel the need to address all aspects in their wisdom to further their own agenda...Now here is where we have to step in and make our thoughts known...AM and ISB respectively to be addressed at 6 and 9 Kc's in general.., That's gona put some Tall ships outta buisness... i know it and you know it...Good Hi-Fi comes with a Price and some have found a common ground at 6 and 7 Kcs and some have a bandwidth exceedingly high BUT have paid attention to good Amateur practice and addressed the Asymetrical elements and actually even though bandwidth is exceeded the Splatter elements are at a minimum compared to some stock rigs with squeaky Yellowie Audio...We all Know this....getting it accross to the leaders at hand is another problem So..Dave in his Wisdom has decidedly factored this and feels the need to compare Conflicts with The Plug and Play crowd and Covered the Morse crowd covetedly,, Hi Hi,, So We this crowd here aren't getting any more room...we're are going to have to tighten up our signals..........IMO...

 Now this just being my opinion and not the Facts as of yet with the rules we have now, the meeting is up and coming so we the Free need to act on our freedom of expression and relate our thoughts to these leaders...Quite  strongly I might add....


 Like Steven says " if we expect and demand nothing..we will get nothing"

[Pete, WA2CWA]

Jack said: Naturally they are not, and feel the need to address all aspects in their wisdom to further their own agenda...Now here is where we have to step in and make our thoughts known...AM and ISB respectively to be addressed at 6 and 9 Kc's in general.., That's gona put some Tall ships outta buisness... i know it and you know it...Good Hi-Fi comes with a Price and...

Their agenda quoted below, or maybe they're going to develop a line of bandwidth measurement tools, or maybe it's some dark government conspiracy to screw all amateurs that don't embrace the new digital modes coming down the road. "Good" Hi-Fi is great on your home sound system.  Amateur Radio is not Hi-Fi heaven. If you can't sound "good" in 6, 7, or 8 KHz, you probably need to go back and review the design.

From the ARRL Letter: "We are in the early stages of a dramatic shift in amateur HF operating
patterns, and it's impossible to predict where this shift may lead," Sumner
said. "The FCC rules should not stand in the way of where technology takes
us in our fulfillment of the bases and purposes of Amateur Radio." The
bandwidth initiative is aimed in part at encouraging new digital modes, but
the primary emphasis is to avoid having to write a new rule every time a new
mode bursts onto the scene. The League's proposals will establish a
framework that creates an environment for change over the next decade--and
perhaps longer, Sumner concluded.