The AM Forum

One more indication that Johnston indeed was the instigator of 20777.

http://forums.qrz.com/showthread.php?t=208226&page=10

Don,

I have been reading the whole history of AM and the actions of Johnston and others in the past two issues of E.R.  I had no idea of all the work you and others did to protect AM.   I  was licensed back then but part of the time I was in the Army, then college and moving around so I was mostly inactive and unaware of what was going on.  I was also brainwashed by what I'll refer to collectively as the Anti-AM Officialdom and led to believe SSB was the radiotelephone way to go.  I wish to thank you for all your work to protect AM and keep it alive with the Press Exchange etc. so that I am able to enjoy it today.

73

Rob K5UJ

Thanks.

I don't know how I ever had the time to do it.  I was working full time at a high school teaching job back then, and even managed to still get in some actual ham radio operating time.  After Roger, N4IBF went SK, I carried it on single-handedly for several more years.

The main problem was that eventually the articles submitted slowed to a trickle, so instead of coming out monthly, we managed to get an issue out every few months.  By then ER had taken hold as a reliable AM-oriented monthly, and the kind of information we attempted to distribute was increasingly available on the internet, as more and more hams went on-line in the late 90's and early 00's.

A unique feature of AM P/X was camera-ready submission of articles. I have never heard of any other publication operating in that manner, but it worked for us all those years. Writers typed up and laid out their own articles and included photographs, charts and circuit diagrams, and we used the material as-is, sometimes uncorrected typos and all, to paste up a master copy of each issue, including some editorial material, and then took it to the printers.  The hard work was assembling all the issues, affixing the stamps and mailing labels and getting them to the P.O., plus keeping track of subscriptions.

But with the proliferation of personal computers and the internet, paper newsletters have become somewhat a thing of the past.  Now, if some ill-conceived, poorly thought-out docket comes out of the FCC threatening to adversely affect AM, within hours, word has spread throughout the community and the FCC receives feedback almost immediately.  The most significant recent example that I can think of was the ARRL's ill-fated bandwidth petition.

The W5YI Report ceased publication and even the ARRL LETTER has converted to online-only, by discontinuing the dead-tree edition.  Most recently, WorldRadio has gone that route.

The ER articles contain a few trivial errors in the details , but all told, he did a good job telling the story like it was.

Yeah, it's amazing how we get through things when we look back on them.  That's another sacrifice, giving up operating time. You could have blown it all off and just operated and had a good time.  The camera-ready copy process was a great idea.  It probably really speeded up the getting out of news.  I've observed that the FCC Electronic Filing system has democratized the process of filing and commenting on filings for rule making petitions.   It used to be only a few entities who could afford the costs of having a Washington firm draw up a petition, produce around 20 official copies and submit them in person in Washington, could get the ear of the FCC.  Seems like often, we'd hear about something having to do with Part 97 after the fact from those who thought they knew what was good for us more than we did.   

Now, any yahoo like me can file a comment and find out what's going on with an online search of the ECFS.  I bet there are those who are not real pleased by this because they no longer have a special pipeline to the FCC and are therefore not much more relevant than anyone else.     

We who came into AM well after this debacle owe a huge debt of gratitude to gentlemen such as Don, Dale KW1I, Bill KD0HG, and yes even Glenn Baxter as well as the others who played a part.  Were it not for their huge investment of time, and persistence in keeping the flame lit, there's no doubt that AM would be outlawed today.

Yes indeed.  And at the Midwest Hamboree this morning I picked up three handbooks, 1939, 1951 and 1957 and I've spent a few hours this afternoon reading from the days when Phone meant AM.

Another factor in the pre-internet days was that the monthly publications were incredibly slow in disseminating the news.  It took not just weeks, but months for an event to occur and news of it to make it to publication and actually arrive in the hands of the  subscriber.  By then, the comment period had already closed on many of the petitions and dockets.  Particularly in the 70's and 80's, many of the most controversial proposals were given incredibly short comment periods.  This is not to mention numerous anti-AM petitions submitted to the FCC by members of the amateur community.

The idea of a monthly AM newsletter was first realised by Howard Jack, W2NRM, with the  original Press Exchange.  The mainstream amateur radio publishers were aware of the time delay problem with monthly magazines, and several bi-weekly amateur radio newsletters appeared: H-R Reports, W5YI Report and ARRL Letter.

Many of us remember the docket-a-month era during the late 70's and early 80's.  For a long period, the FCC was releasing a seemingly never ending stream of proposals that would have radically changed some aspect of amateur radio, and "coincidentally", many of them would have adversely affected AM in some manner.

Just to mention a few: Docket 20777, the bandwidth docket that would have outlawed AM below 28 mHz.  The first "restructuring" docket during the 70's that for the first time proposed a p.e.p. power limit and limited General class to DX-100 power levels on AM.  The "plain language" docket that would have imposed a specific bandwidth limit of 7.0 kHz.  Somewhere in there was another proposal that contained a provision to impose an "interim" power limit in terms of p.e.p. input power. And of course, there was the infamous output power limit rule that went into effect in 1990.

This series of proposals, with a recurring anti-AM thread, started almost immediately after Johnston became head of the FCC division in charge of amateur radio rulemaking.  He held on to that position for something like 30 years before retiring, through several restructurings of the FCC in which the bureaux and divisions underwent name changes that would rival the name changes of local banks over past generation or so.  During the latter years of his tenure, the docket proposals slowed down somewhat and left AM and amateur radio in general in a relative state of peace, but not until Johnston finally succeeded in getting his long sought-after p.e.p. and consequent AM power reduction proposal passed.

And it is amazing that even today there are groups deeply rooted in the ARRL and other organizations that want to limit the bandwidth of AM and ESSB.  It is, and probably always will be, an ongoing struggle.

Very true.

The Electronic Comment Filing System provides immediate notice of proposals and allows an immediate public response. No more filtering by "representatives" with an agenda.

The volume can be huge, and the pro- and con- results can be deadly to those on the wrong side of the idea.

it should go back to the 1KW average DC input to the RF stage..

Or average rf power output.

Evidently, Canadians are smarter than United Statesians.  One of the arguments the FCC used in the docket proceeding was that it would have made the wording of the power limit rule too cumbersome, and would have unjustifiably cost them extra money to train their field inspectors, to mandate separate power standards for full  carrier and carrierless modes of emission.

The Canadians managed to do it without too much difficulty:

10.2 Amateur Radio Operator Certificate with Basic and Advanced Qualifications

The holder of an Amateur Radio Operator Certificate with Basic and Advanced Qualifications is limited to a maximum transmitting power of:

(a) where expressed as direct-current input power, 1,000 W to the anode or collector circuit of the transmitter stage that supplies radio frequency energy to the antenna; or (b) where expressed as radio frequency output power measured across an impedance-matched load,

(i) 2,250 W peak envelope power for transmitters that produce any type of single sideband emission, or

(ii) 750 W carrier power for transmitters that produce any other type of emission.

Don,

Can you help me understand the Canadian rule.  Is part a) effectively 1000 W carrier input?  Is that the limit applies to AMers in Canada?

For K6JEK...

Simple answer is yes, VE Amateurs are allowed 1 KW input power to the stage
connected to the antenna!  That is for any mode (AM, RTTY, CW, etc...) other
than SSB

1 KW DC input to the plate of a class C final at 75% efficiency equals 750
watts output from the stage.   

As for the average output power measurement  across an  impedance-matched load,
you use an RF Amp meter connected with 50 ohm coax to a 50 ohm dummy load.  Do the
math; simple Ohms Law...  Yeah, I know, RF is high frequency AC but you still get a close
measurement using the DC formula knowing the current and resistance (impedance)...

I am glad that this has re-surfaced. I was surprised that Glenn was involved as much as he was. But seemed to go in the ways that he has taken in past adventures.

My question is about the FCC spec for 375 watts of carrier modulated 100%. Is this the A.M. spec for 100% negative? Which is the technical limitation of any A.M. transmitter.
What happens to the P.E.P. rating when we are capable of 130% positive??

Fred

Contrary to popular misconception, there is absolutely no mention of 375 watts anywhere in Part 97.  That is totally 100% urban legend, along with the 6 kHz AM bandwidth limitation that so many hammy hambones insist resides somewhere in the FCC rules.

I would wager that fewer than 50% of to-day's hams could even explain what p.e.p. is, beyond "what the meter kicks up to when I talk".

As Don says, 375 watts is an urban legend. 97.313 says: (b) No station may transmit with a transmitter power exceeding 1.5 kW PEP. How you comply with that is up to you. You can run more power and not modulate 100%, and still meet the 1500 watt PEP rule.

Thanks Pete,
You have shed a completely different light on this. Now I understand the "myth" part.

Fred

How about running 1500watts carrier, and using "Downward" modulation?

1500W Pep output there too...

Might raise a few eyebrows!

Don't know what it would be like on the reciever end though.

How about running 1500watts carrier, and using "Downward" modulation?
...
Don't know what it would be like on the reciever end though.

It would sound alright.  There would be a huge ol' honkin' carrier, and no background noise. 

There would be no distractions from the received audio.

All of this has been hashed out before.

Don doesn't like to toot his own horn, but he was involved with a couple of other hams on this matter.  Check out:
http://www.qsl.net/wa5bxo/asyam/aam3.html

--
73 = Best Regard"S"
Geoff/W5OMR (/5 Baja Spring, TX)

Well, read that article, I guess I was thinking more of Reverse Carrier control than downward modulation.

Now that makes sense, but I would change (i) to read, "3kW."

I also like the 1.5kW carrier with downward modulation.

And yes, we are indebted to you guys for keeping AM a viable part of AR.  :)

Maybe we could petition the FCC to adopt the Canadian regs?

Phil - AC0OB

Would sound about as crappy as the mis-adjusted riceboxes you frequently hear attempting to run AM when the voice peaks activate the ALC and cause the carrier to drop in strength at every syllable.  A piss-poor way to promote AM at best, it would likely generate negative interest in the mode.

On many of the current Icoms, 756 PRO Series, 7600, 7700, 7800, and several others it doesn't sound that bad, and in many cases, it's not even noticeable. The audio can be further improved by connecting directly to the modulator (wider response) through the Accessory jack in the rear of the units. If you use audio equalizers, compressors, etc. connecting here, bypasses a lot of the front-end audio tailoring.

Yes ,
I certainly remember when Docket 20777 was being unrolled. I was at a ham radio event.Perhaps an ARRL convention. Johnston W3BE was there talking up the new proposed rule change. Kevin WB4AIO stood up and challenged Johnny Johnston . The future of AM was hanging in the balance . I was afraid of the future. BUT it turned out good with all of the support for the preservation of AM
> Let me make one thing perfectly clear in regard to AM power. A 375 watt carrier AM signal @100% peak modulation is actually 187.5 watts PEP double sideband. It is well known that when viewing a full carrier double sideband emission on a spectrum analyzer ,the peak levels of the sidebands are -6 db from the carrier value at 100% modulation. THERFORE your alleged full legal limit rig like a BC610 or Junkston 500 is only equal to a barefoot ricebox  when it comes to receiving  your signal on a single sideband receiver. When it comes to cutting through the garbage one MUST run enough power to equal the playing field. 1500 watts PEP double sideband is perfectly legal. In order to add enough carrier for proper demodulation at the receiving location assuming 100% modulation peaks we need 3000 watts of carrier !!. It realy wants to make me puke when someone claims they are running full legal power by stating they are running 375 watts carrier. Yes there is a 4:1 PEP to carrier ratio for 100% positive peak modulation  with AM emission. This is due to the peak voltage and phase relationships of the sidebands and the carrier. The reality is AM is a combination of the audio frequencies and the carrier frequencies. We all know that a 500 watt DC inpoot PA stage requires 250 watts of audio to reach 100% modulation. That 250 watts of power is your actual talk power. With conventional plate modulation with a typical PA efficiency of about 75% .The 250 watts of audio power  you think you are delivering to the antenna is reduced to that the efficiency of the class C stage leaving you with 187.5 watts or so. Let us think of building a modulator that makes 1500 watts of power. Use that power to modulate an appropriate PA stage. In my case the plans are on the books for another 4-1000 transmitter with 6Kv plate voltage at full strap.
The reason why we have power limits in the first place is to limit interference potential as well as possible RF safety reasons. A carrier from an AM signal does not cause interference unless it is in your bandpass. A carrier has NO occupied bandwidth. Therefore has NO interference potential.It is the sidebands that cause interference .
 The one FeeCCee rule that seems to be overlooked by many people is to run the minimum amount of power for the desired level of communications.  Basicly a good signal to noise ratio based on good engineering standards. I find that in many cases the usual 100-150 watt power class suffices in many cases . Sometimes the so called legal limit in many cases works well. There are time when well over a kilowatt is needed to communicate under stress and durress times.
In closing it is safe to assume if you have a transmitter such as a Junskton kilowatt or some 1Kw broadcast transmitter ,running such a transmitter is STILL below 1500 watts PEP double sideband energy and therfore perfectly legal.
Tim WA1HnyLR

This....This Statement Made by Tim....shud be Framed and made available at the forefront of this Forum For all New ones to Read and for some of us oldsters for a refresher...I like it when Tim speaks......Keep the World Straight Tim Well Done OM....

73
Jack.
KA3ZLR.

Guys,

You can’t just selectively ignore some frequency components of a transmitted signal at the transmitter!  You can do this at the receiver of course if you wish.  With an AM transmission, the carrier is there and if the carrier out is 375 watts, the PEP signal is at least this amount.   With modulation, on AM, the total power rises above this.  No amateur math tricks will get you past professional engineers at the FCC.   The PEP rule is total power independent of bandwidth, not sideband energy only, for all modes.

The output rule is based for interference purposes, it isn’t that “they” don’t want to keep you from communicating afar. (There is no limit on ERP!) If “they” did, you wouldn’t have the Amateur License privilege.   On the low bands, the bandwidth is relatively low and regardless of the mode, any mode, the signal is allowed to dwell at 1500 Watts maximum.  Even with voice AM we are talking about dwelling at 1500 Watts for a few milliseconds.  Appliances that are sensitive to r.f. will see this.  There is no trick or averaging here; the appliance’s electronics have wide bandwidth.

Obviously it is difficult for many to grasp the properties of time-varying transmitted modulated r.f. signals, but let’s not be silly about AM and PEP theory.

TOM

Maybe Tim's definition of AM PEP would serve us better, the FCC doesn't agree with this definition.    The total of the carrier and the peak power of both sidebands is what the FCC defines it as.

The definition is Mother Nature's definition not the FCC's.  This is called Physics.

For once the FCC agrees with Mother nature and physics, unlike things such as BPL propagation or the range of DTV transmissions.

so what do you guys do when you have a 1KW carrier AM BC rig and need to carve the power down a bit? Reduce operating volts? Reduce drive?

YOU KEY UP THE CARRIER FULL BLAST AND SPEAK SOFTLY!

But that whole idea is based on the long-debunked premise that the amplitude of a modulated carrier is actually varying up and down in step with the audio.  The ARRL handbook and slopbucket promoters of every ilk have long pounded into our heads that this is a false premise, a theory that was dismissed in the 1920's.  The carrier is steady, unvarying, and any additional power resulting from the modulation is contained in sidebands, independent of the carrier.  This is clearly displayed on the scope of a spectrum analyser.


It is the average, or mean power that determines the loudness and thus the interference-producing potential of a signal, not the amplitude of occasional voice peaks.  If you work a transmitter into a light bulb dummy load, it is the average power that determines the brilliance of the bulb, not the instantaneous peak power.  That same average power that lights up the bulb determines how loud a signal is at the receiving end and how much interference it causes.  With voice modulation the maximum p.e.p. occurs only infrequently and even then dwells only for a few milliseconds at most. Thus, it contributes little, if any at all, to the interference generated by the signal.

The only useful purpose of p.e.p. is for determining the maximum undistorted output capability of an amplifier.  When the amplifier reaches saturation point, whether it be 100% duty cycle or only for a nanosecond, it has run out of headroom, and there can be no further increase in output power.  If you try to exceed the headroom limit of the amplifier, distortion and thus spurious products outside the normal bandwidth of the signal will result.  The concept of p.e.p. was created to define the saturation point, or headroom limit, of an analogue system.  It has nothing to do with the effective quantity of power.  The concept caught on in amateur radio circles in the 1950's because it allowed the manufacturers to inflate the power ratings of their factory-built slopbucket leen-yars when they ran their ads. 

Actually, the 2:1 ratio of peak-to-average power (remember the "2 kw" slopbucket leen-yars?) was based on two-tone test modulation.  With the human voice, it is more like 8-10:1.  An undistorted slopbucket signal running 1500 watts pep will typically run 150-200 watts average output power.  The way the slopbucketeers who actually bother to observe the 1500 watt limit jack up their output power, is by driving the leen-yar well past its headroom capability and into saturation with resultant splatter (as evidenced any time you tune across the phone bands), or else by using heavy "speech processing" that may contain the bandwidth, but result in a nasty, irritating, distorted signal that is painful to listen to.  So the pep power limit penalised SSB stations running clean undistorted signals as much as it (allegedly) did for AM.

And, regarding those "wide bandwidth' appliances, they are not supposed to receive radio signals, period, at any power level.  If they do, it is due to some kind of malfunction of the appliance itself, not the fault of the radio signal.  There is no justification in reducing the power of a licensed radio service because of the shortcomings built into devices that were never intended to be radio receivers in the first place.  Look at the  label on any Part 15 device: "(1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation."


I would venture to say that fewer than 50% of to-day's licensed hams could even explain what pep is, beyond "what the meter kicks up to when I talk".  Try putting enough selectivity in front of your pep meter to allow it to discriminate between the sidebands and the steady, unvarying carrier, and as you tune across the passband of the signal you will get exactly the same readings as displayed on the spectrum analyser as it reads the actual power output from the transmitter. 

If you are running 1000 watts of steady carrier output, and modulate that carrier with 500 watts of (instantaneous peak) sideband power to achieve 100% modulation, where does all that total power, in excess of 1500 watts, come from? 

It is pure fiction, "phantom" power that shows up only because of limitations inherent to the measuring instrument.

For those who are interested, here is a thread from 4 ½ years ago in which Don is on the same soapbox:

http://amfone.net/Amforum/index.php?topic=3615.0

Don, I wonder if you ever did contact Johnny Johnston as I recommended then or are you going to continue to complain about him behind his back how he screwed us over until you are gone?  I’m not a Johnny Johnston fan, nor do I know him, but I do find it hard to believe that he was able to act autonomously in the FCC.

You never mention that the 1500 Watt PEP rule affected all of ham radio and that CW gained, SSB gained a hair, and the VHF and microwave people gained a great deal of output power in the 1500 Watt PEP output rule change.

There is no limit on Effective Radiated Power (yet).

I said “You can’t just selectively ignore some frequency components of a transmitted signal at the transmitter!  You can do this at the receiver of course if you wish.  With an AM transmission, the carrier is there and if the carrier out is 375 watts, the PEP signal is at least this amount.   With modulation, on AM, the total power rises above this.  No amateur math tricks will get you past professional engineers at the FCC.   The PEP rule is total power independent of bandwidth, not sideband energy only, for all modes.”  This is all true Don.

PEP is solely a voltage versus time measurement.  There is no distinction of the frequency sub-components.  The net voltage seen at the output of the rf transmitter is the sum of all of the rf and modulation functions together in one net time-varying voltage function.  (For every mode the PEP level, the average or mean power, the frequency components, the properties of the components are different   This is why they are classified as different modes!)
 
Quote from Don ”But that whole idea is based on the long-debunked premise that the amplitude of a modulated carrier is actually varying up and down in step with the audio.  The ARRL handbook and slopbucket promoters of every ilk have long pounded into our heads that this is a false premise, a theory that was dismissed in the 1920's.  The carrier is steady, unvarying, and any additional power resulting from the modulation is contained in sidebands, independent of the carrier.  This is clearly displayed on the scope of a spectrum analyser.”

??? Here you go off on an erroneous tangent as usual.  I never said anything about a varying carrier did I.

Don said “It is the average, or mean power that determines the loudness and thus the interference-producing potential of a signal, not the amplitude of occasional voice peaks.  If you work a transmitter into a light bulb dummy load, it is the average power that determines the brilliance of the bulb, not the instantaneous peak power.  That same average power that lights up the bulb determines how loud a signal is at the receiving end and how much interference it causes.  With voice modulation the maximum p.e.p. occurs only infrequently and even then dwells only for a few milliseconds at most. Thus, it contributes little, if any at all, to the interference generated by the signal.”

This is full of errors, I won’t even address them all.  Mean power transmitted has very little to do with loudness at the receiver.   Today the rest of us use good receivers with AGC and so the loudness is dependence on the modulation characteristics not the mean power received.  You keep bringing mean power into every argument of yours.  I assume that you feel that we can gain an edge in the old AM power argument by “using” mean power. 

In the old thread http://amfone.net/Amforum/index.php?topic=3615.0
I mentioned that the range of the mean power of the 1500 Watt PEP SSB signal is below or above the present AM legal limit signal, highly dependent on the speech processing of the SSB audio.  The AM signal, due to the high percentage of the carrier power, is pretty well boxed in on its mean power.

You keep saying that interference is based on mean power, but you never provide proof of this.  First of all, we must go back to the word interference.  I said that the FCC rules are based on limiting interference.  Interference is a broad term.  Interference can be to Amateur radio from other Amateurs, Amateur transmissions interfering with non-ham radio equipment, Amateur transmissions interfering with non-radio equipment and we know that non-radio appliances cause interference to Amateur radio reception.  But here we are referring to the power of r.f. transmitter output. 

One interference I have gotten from AM’ers is the sidebands of sibilant energy 16 kHz away from the carrier of a wide AM transmission.  This energy at 13 to 16 kHz away from the carrier is completely unnecessary and was about 10 dB below the carrier signal level when it occurred.  It definitely was quite an interference to reception by almost everyone on our net.  By mean power measurement, there would be little power there but the interference was quite significant, proving that this interference is not solely based on mean power but in this case is based on short-term energy only and its relative frequency placement.

Interference can be possibly due to mean power or can be due to the envelope voltage peak, not just restricted to the mean power of a transmission as Ed Hare ARRL RFI chief mentioned the thread 
http://amfone.net/Amforum/index.php?topic=3615.0 . 

Don you have never stated what time constant is to be used in your AM versus other modes mean power comparisons.  What is your time constant number? 5 milliseconds, 50 milliseconds, 500 milliseconds, 5 seconds, 50 seconds (to allow for the non-speaking periods to fudge the mean power number down further)?

The SSB signal is in the same boat as AM in regards to your view of disparity between the Peak Envelope Power and the mean power.  This is just basic physics of the signals and every mode has different PEP to mean power ratio.  I venture to say that virtually no one in Amateur radio has a true mean power meter.  No one in their right mind uses a spectrum analyzer to accurately measure actual transmitter power levels either.

Since the SSB signal has no carrier, the PEP to mean power level varies even more widely than it does for AM.  Why don’t we hear any bellyaching at all for the SSBers Don about output power?  Their maximum mean power level is typically the same as the legal limit AM signal.

Don, to settle this matter of the apparently unjustly underpowered AM power limit what would you do?  Would you have everyone get a “mean power” meter?  What is the mean power level number you would declare as the legal limit?   What is the time constant implemented in your measurement?  Is the 1500 W PEP SSB signal the reference level?  What would you declare as the mean power level of a 1500 W PEP SSB signal?  Then finally what would the carrier level of this new legal limit AM signal translate to?

Don, if you had the “power” to implement these FCC Amateur output power changes, would it stop your belly-aching?

Seriously Don, I want to see you post power number answers to all of the previous questions I just posed.

Not to speak for Don, but I think a valid point is made by the fact that there's confusion between the two of you that the old 1 KW measurement method was simple and easily understood whereas the PEP method isn't, particularly with AM.

The old way?  Plate (or collector, or drain) current * B+ <= 1000.  Easy to measure, easy to understand.  ANd lots of classic rigs were built with this standard in mind. 

Then suddenly there's a "benefit", foisted on us for a reason unknown, that's not widely understood and not measurable with existing metering in the rig.  Even now PEP wattmeters aren't universally used amongst the ham population.  And in the process, suddenly classic rigs became illegal and AMers were kinda shafted.    Or so it seems to me.

I discussed this and other issues, including Docket 20777 in person with him at several Dayton FCC forums and he never would give a straight answer, but always sidestepped the issue with irrelevant responses.  I also submitted numerous formal comments and reply comments to the FCC while this and other AM-related proceedings were pending, so I am sure he was well aware of my take on the issue.  Various others AM'ers reported approaching him at other FCC forums and at hamfests and received essentially the same brush-off.   Other than off-the-record comments I reported him making at hamfest forums at which I was in attendance, all allegations (limited to his official acts as head of the amateur radio rulemaking division of the FCC) that I ever made concerning Johnston, are for things on public record in official FCC documents.  I have a paper file several inches thick on the subject. Johnston is in his mid 80's now, long retired and no longer connected with the FCC.   What would be the point in trying to resurrect or continue this debate with him now?



How much did AM gain?



That interference was due to the spectrum distribution of the sideband energy in the signal, either due to the audio bandwidth of the signal modulating the carrier, or due to spurious distortion products from the transmitter.  If the carrier could have turned off without affecting the sideband spectrum (perhaps by turning off the DC plate voltage to a plate-modulated upside-down tube final), you would have noticed no difference whatever in the sibilant energy causing interference 13 to 16 kHz away from the carrier (or suppressed carrier) frequency.  Yet without the carrier, the p.e.p. would have been drastically reduced.


For AM and SSB power measurement using voice modulation, I would suggest a time constant identical to that of the standard VU meter (http://sound.westhost.com/project55.htm) used in audio work. A VU meter is designed to have a relatively slow response. It is driven from a full-wave averaging circuit defined to reach 99% full-scale deflection in 300ms and overshoot not less than 1% and not more than 1.5%. Since a VU meter is optimised for perceived loudness it is not a good indicator of peak performance.

. 
They didn't get a "power reduction" imposed on them that purported to reduce the historic power privilege they had enjoyed ever since the mode came into existence, or that may have rendered some of their equipment obsolete.  Besides, I wonder what percentage of the QRO SSB crowd, particularly contesters and DX'ers, bothers to strictly comply with the power limit, even if they had the means to accurately measure it.  As I said before, I would wager that fewer than 50% of the present-day amateur licensees with HF privileges could explain what p.e.p. is, beyond "that's what my meter kicks up to when I talk".


I would set the power limit back to what it was before, using average rf output, instead of DC input.  For AM, CW, FM and other full carrier modes, that would be 750 watts carrier power.  For SSB and other suppressed carrier modes, I would set it at 750 watts average (mean) power output, using a meter designed to reach 99% full-scale deflection in 300ms and overshoot not less than 1% and not more than 1.5%.

But now that modes like CW, FM and RTTY gained a 100% power increase with the p.e.p. BS, to avoid taking back privileges previously granted and to still maintain a level playing field, perhaps those figures should be doubled.

It didn't take rocket science for the Canadians to come up with an equitable output power limit:

The holder of an Amateur Radio Operator Certificate with Basic and Advanced Qualifications is limited to a maximum transmitting power of:

    * (a) where expressed as direct-current input power, 1,000 W to the anode or collector circuit of the transmitter stage that supplies radio frequency energy to the antenna; or
    * (b) where expressed as radio frequency output power measured across an impedance-matched load,
          o (i) 2,250 W peak envelope power for transmitters that produce any type of single sideband emission, or
          o (ii) 750 W carrier power for transmitters that produce any other type of emission.

Scroll down to paragraph 10: Restrictions on Capacity and Power Output (http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf01226.html#fre)

And after digesting all this once again, and knowing Don has experienced that I know of no dealings with the Crown and with his well produced signals I monitored many times...I Kinda Think The Fella Knows what he's doing...and I still support Timmys statement for Change...it should be drafted and sent in concert with Dons Writings to the Crown(FCC) and pushed for change....and soon.

73
Jack.

Don,

Thanks for your answers on Johnny,  I guess at this point we’ll never get the true inside story.

You have abandoned the mean power path apparently and now stand for “return to old rule” for the AM power level.  This would match the Canadian AM level.  The Canadian rule appears to have a 1.25 dB “grace” margin for AM PEP versus SSB PEP.  Applying this 1.25 dB or 1.3333 X margin to our 1500 W PEP rule would yield a 500 Watt carrier output level for us.

Again I consider this a silly argument (“another country does this”) and not based on any technical merit. But you are free to propose this to the FCC.  If they pass it, it would be a only a “nicety” on their part.  But this would be 500 W carrier out, not 750 W carrier out.  So you have 2 goal options here.

A few milliseconds is a long time in electronics, and I still believe that any professional engineer at the FCC is going to stick with 1500 W PEP output for all modes as an equitable rule.  Good luck OM.

Returning to the old rule, but expressing power levels in terms of rf output power instead of DC input to the final, essentially means defining output power in terms of mean power rather than peak power. 750 watts of mean power output without consideration of the p.e.p. would actually be a big increase for SSB over the present rule.  It would be a slight decrease for AM, since the hypothetical unmodulated carrier power would be 750 watts, so to be precise, the AM carrier power would have to be reduced slightly to keep the mean power of a modulated signal under 750 watts.  So maybe to better preserve the original AM power level, AM power should be defined in  terms of carrier output, just like AM broadcast stations.  Why hasn't the FCC redefined AM broadcast output power so that WLS, WSM, WOR and WBZ could say they are running 200 kilowatts instead of 50 kw?  It seems that the Canadians took a simple approach that works, without reducing anyone's privileges or unnecessarily complicating anything.  750 watts carrier output would essentially have left the old power limit intact.

Years before the 1983/1990 rulings, ever since Johnston had taken over the helm as chief of the division or bureau in charge of amateur radio rulemaking in the early 70's, proposals began rolling out of the FCC to use some form of p.e.p. as a power standard.  The first time, in the early 70's, as part of a "restructuring" docket, they proposed p.e.p. output. In that one, the proposed figure was 2000 watts, since that represented "approximately" the maximum allowable output power under then-existing rules, citing that as the maximum power attainable in the case of high level plate modulated AM running 1 kw DC input. Then, in another proposal a few years later, they switched to p.e.p. input as an "interim" standard to use until they could further study and address the power issue in a separate proceeding.


What is silly about it?  The Commission's stated objection to the AM community's comments and petitions was the purported difficulty they would have had in writing a short, simple rule that would cover all modes while maintaining existing power levels for everyone.  This was a recurring theme in numerous responses to petitions and comments.  If the FCC personnel were incapable of figuring out how to do it, but a neighbouring country managed to figure it out simply and eloquently, what is wrong with citing their success and borrowing from their ideas, particularly in light of the FCC's apparent admission that the learning curve was too steep for their personnel?  I'd say the Canadian rule has more technical merit than the U.S. one.



What professional engineer?  During the power limit proceeding, one of the arguments the FCC used against any form of special provision that would protect the pre-existing AM power level was that since users of AM were such a small minority in the amateur radio community, they couldn't justify the extra expense for training their field inspectors to measure AM to a different standard than SSB. A "professional engineer" would need no "special" training to figure out how to measure the carrier output of an amateur AM transmitter because these principles were well known dating back for decades before this power issue came up, and especially since FCC inspectors routinely verify AM power outputs up to 50 kw at standard broadcast stations.  What a bunch of bogus hogwash!

As far as accurately measuring mean, or average power output, check this:

Bird APM-16 (http://birdtechnologies.thomasnet.com/item/wattmeters-and-line-sections/portable-wattmeters/apm-16?&seo=110)

The engineer at the FCC who will have to evaluate your Petition and have a big influence on deciding whether to implement your NPRM (and its resulting costs) or not.  I did not intend for this guy to be the technician that you picture as going on field enforcement calls.

Tom said:
Tom, I fear that you view the world through rose colored glasses. I beleive that professional engineers no longer exist at the FeCeCe. I think the organization is inundated with lawyers and business types who attempt to sell frequency segments to the highest bidder and damn the amateur radio weenies!

FCC Office of Engineering and Technology
http://www.fcc.gov/oet/

Just get one of these and call it done.

Pete posted: http://www.fcc.gov/oet/

I do not know Mr.Knapp and never had any dealings with him. This is what I found on a quick Google search. Note: emphasis made by me.

Julius Knapp Named
Chief, FCC Office of Engineering and Technology


Last week Julius Knapp, a career FCC employee was named by the Commission as Chief of OET, succeeding Ed Thomas who left last year. Consistent with recent FCC practice, there was no public announcement and the OET website, as of this posting, shows the position as "vacant". My congratulations to Julie on this well deserved promotion that recognizes his long contribution to public service at FCC and excellence in engineering, technical policy, and management.

Julie served as the Chief of the FCC laboratory from 1992 to 1997 where he was responsible for the FCC’s equipment authorization program. He has held a variety of other positions during his thirty years with the FCC, including heading the Frequency Allocations Branch in the late 1980’s where he was responsible for FCC frequency allocation proceedings for the cellular service, private land mobile services, and mobile satellite services.

He is the winner of the 2001 Eugene C. Bowler Award, presented annually to an outstanding government employee. He has also been the recipient of both the FCC’s Gold and Silver Medals for his outstanding service and commitment to the Commission. Julie received a Bachelor's degree in electrical engineering from the City College of New York in 1974. He is also a member of the Institute of Electronics and Electrical Engineers, Inc. Electromagnetic Compatibility Society and is a Fellow of the Radio Club of America. (Source of background: Part-15.org)

Hi Mike,

I have perceived a lack of "professional" engineers in AMerica for many years now.  The lawyers at the FCC usually have an engineering degree as far as I know, like Knapp.

God forbid an agency of the federal goverment should try to promote commerce.

As far as I know, it's been years since any of the commissioners themselves have been anything but lawyers.

Most of the technical standards and rules that cover the various services are formulated in the bureau that governs that particular service.  On regulatory details and technical matters the five commissioners normally defer to the expertise of the bureau personnel (who usually are engineers), and rubber-stamp the decisions as presented.

If Petitions for Reconsideration are submitted by the public in opposition to a rulemaking decision, the same people who formulated the rule are the ones who act on the petition.  Very rarely do the FCC's career civil servants* rule against their own decisions. Bureau personnel get to be judge, jury and executioner in matters such as amateur radio rulemaking.  The full Commission rubber-stamps the bureau's decision, and if the matter is taken up in federal court, the judge can be expected to "defer to the expertise" of the FCC.  With few exceptions, the bureau chief and his assistants are free to act as petty dictators whenever there is public opposition to their decisions.

The Administrative Procedures Act requires the release of a rulemaking docket followed by a comment period, but the rulemakers are under no obligation to pay any attention to the comments received if they choose not to. Usually, the comments do have an impact; a good example is the rejection of the bandwidth proposal in Docket 20777.  But I recall that the comments the FCC received regarding the AM power issue, including those from ARRL, were overwhelmingly in opposition to reducing AM power, and a Commission employee reportedly remarked that the Private Radio Bureau people were "in shock" at the number of comments received on the subject, which outnumbered the comments they received pertaining to the hot-button amateur radio proposal before the Commission at the time, the No-Code Technician licence.

It is usually futile to attempt to seek relief through congressional representatives, since FCC decisions on issues involving amateur radio usually affect only an insignificant minority of the total population, and members of the Senate and House have bigger fish to fry, such as whatever war happens to be going on at the time, the economy, major social issues, the next election, etc.  About the only action they can be expected to take is to forward your letter to the Commission, which is forwarded on to the bureau in charge.  The bureau personnel formulate a response to the member of congress, who then forwards that response to the complaining constituent.  Again, it is the same people who originally formulated the rule who ultimately act on the complaint.

*This is how Johnston described himself while presiding over one of the FCC forums at the time when the power issue was pending.

fixed it for you.  ;D  You guys like to argue too much. ham radios supposed to b fun.  :P :D

It not arguing; it is called public education.  A lot of the guys on the air to-day think the power limit was always 1500w p.e.p., totally unaware that it ever was anything else.

Oceania is at war with Eurasia.  Oceania has always been at war with Eurasia.

Tim,

Unfortunately, the FeeCCee rules on power refer to the PEP supplied to the antenna feedline from your transmitter, and does not exclude the carrier. A rig such as the Johnson Kilowatt or an old 1KW AM broadcast transmitter will easily do 3KW of PEP output. The PEP output is the peak vector sum of the RF voltages coming out of the transmitter, carrier plus any sidebands. But, you know this all already.

Better to promote A3H with SSB AM for 375W in the one sideband (twice the talk power) and 1/2 the receiver bandwidth for a total of 6 dB over DSB AM.

yah I know. I'm glad Don's been carrying the heavy load on this for so long - without people like him we'd have nothing today. I've only been on AM since late 1984 which makes me a short timer at 25 years. I cant imagine waging war against the ignorance for as long as he has.

being a advocate for anything is very tiring at times.

and numbers are your enemy when the people you are trying to go your way see a larger number "for them" than "for us" regardless which side you're on.

i would throw a carrot in there for the slopbuckets - our objective should be to get the 1kw DC rule back for AM. But amer's dont constitute enough of a force by themselves. In politics you must engage the larger group in coalitions that may not care about your specific concerns to advocate for you, but if you make them part and parcel of your concerns by throwing them a bone, they will advocate for themselves on your behalf.

I would increase the SSB power limit to 2500 watts, make it plain that ssb will be measured by a PEP standard, and that the old 1 KW DC input standard saying nothing about pep at all;  would be restored for AM as a package proposal.  As long as you get what you desire, throwing them a bone so they will advocate for you as well as themselves is how you make such a change happen.

less technical, more political, guys. Not one in a hundred hams know or will ever understand (or care) why AM got a raw deal. But they do understand "yeah baby, more power is good!"

I totally disagree. If you are concerned about the PEP output that includes the carrier, it would be far better to reduce the carrier and run most of the power in both sidebands, than to transmit that bogus A3H crap which is nothing more than slopbucket with poor sideband suppression.  If you are going to do that, you might just as well run regular slopbucket and get it over with.

Much better to run 1500 watts double sideband, and transmit just enough pilot carrier to give a synchronous detector something to lock onto.  If you want to spend a tidy sum of money, the Sherwood SE-3 will demodulate DSB with the carrier reduced 15 dB or so, and it will sound identical to full carrier AM, complete with full fidelity and no selective fading.  You could  run the upside-down tube circuit and the listener at the receiver would not be able to tell the moment when you dropped the DC to the final from full carrier to -15 dB or so, except maybe by  looking at the S-meter.

For those who don't want to pay the price for an SE-3, there are several software defined synchronous detectors available, that reportedly cost only about $20 or so, if you don't mind having your receiver tethered to a computer.

But still, the FeeCee's definition of  p.e.p.,  §97.3(b)(6): The average power supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating  conditions.  How can you have "one RF cycle" of carrier, plus the rf cycles of USB and LSB all at the same time?  This implies the mistaken belief that existed early in the 20th century before the theory of sidebands had been fully explained, that the amplitude of the carrier wave varies up and down in step with the modulation envelope. To make it mean what the FeeCee apparently intended, it would have to read something like the peak vector sum of power supplied to the antenna feedline, including all carrier and sideband components, at the crest of the modulation envelope.

Looking at it from another perspective, why isn't W1AW in violation of the rule when they simulcast on several bands for their information bulletins? Strictly in terms of transmitting power, what's the difference between having a carrier, one each simultaneous USB and LSB that happen to be adjacent to each other in the same band with an unmodulated carrier in between, compared to having three each simultaneous LSB's on 1.8, 3.8 and 7.2 mHz, plus three each simultaneous USB's on 14.2, 21.4 and 28.8 mHz?  Or even simultaneous CQ's from the same station at a Field Day site? Wouldn't the vector sum of all those simultaneous transmissions add up to more than 1500 watts as indicated by a nearby non-selective field strength meter indicating the instantanous peak field strength?

But, alas, maybe someone would say that the unmodulated carrier in between USB and LSB is illegal, so let's call the AM signal an A3H signal with a SSB suppressed carrier signal adjacent to it.

It would be best to run single side band if one is concerned about talk power and PEP.

§97.3(b)(6): The average power supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating conditions. 

That can be captured on a scope. Whether it is composed of the carrier, either or both sidebands, or any combination thereof is mostly unimportant. It is only necessary to capture one RF cycle at the crest of the modulation envelope taken under normal operating conditions.

They do say average, not RMS. Thank goodness they don't ask enginers to measure the RMS power of that single cycle because any distortion would cause a conniption fit since there is a condition of modulation, that RF cycle is not a sine wave bit it is distorted by the audio wave, albeit only slightly.

for 50 ohms:
774.5V peak to peak
387.25V peak
273.8V RMS
5.476A RMS
1500W RMS

It seems to get worse, BTW if taken literally. or does it?
The average voltage of a sinusoidal waveform is equal to 0.637 times its peak value.
387.25V peak
246.7V Avg.
4.934A Avg.
1217 watts Avg.
(1217 * 1.233 = 1500, so if this were converted to RMS it would allow 1500 * 1.233 = 1848 watts RMS in that RF cycle at the crest of the modulation envelope)

However, note: The average voltage is normally determined from just one half-cycle of the waveform because the average value of a full cycle is zero. But the FCC requires it to be measured over the full cycle.

(source: http://www.free-ed.net/sweethaven/ModElec/acee/lessonMain.asp?iNum=0102 )

Therefore taking §97.3(b)(6) literally:

PEP power = "average power supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating conditions."

The average voltage supplied to the antenna transmission line by a transmitter during one (complete) RF cycle at the crest of the modulation envelope taken under normal operating conditions is always zero
-except for the small amount of distortion present in the wave (it is not a perfect sine due to the modulation and PA distortion as well as any E I phase issues due to reactance in the load).

Therefore the average current supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating conditions is always approx. zero.

Therefore the average power supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating conditions is always approx. zero.

Therefore

Any attempt to measure the average power by summing all the voltage and/or current points along the one RF cycle under normal operating  conditions results in a value very, very close to zero.

The following corrolary is that the emissions limited to 1500 watts of actual power are the distortion+noise products contained in the cycle of RF supplied to the antenna that are derived from an unsymmetrical distribution of voltage points between the positive and negative half-cycles of the one RF wave.

Assuming a perfect load and the transmitter's power as measured by the method of §97.3(b)(6) to be 40db down (minimum standard for good practice?) from the transmitter's RMS PEP level which is not regulated, the RMS PEP wattage present when 1500W average power was measured would be 18,480,000 watts.

So, any more problems to be solved tonight?

(I also believe this would stand up to the FCC as well as the fellow's claim that he does not have to pay income tax stands up to the IRS.)

There is no such thing as "RMS power".  The proper term is average power.

Average power = RMS voltage X RMS current.  It is not the same as average voltage X average current.

RMS voltage and current are defined as effective voltage and current, that is, the d.c. voltage across or current through a given resistance that would produce the same heating effect as the a.c. in question.

Mean power (of a radio transmitter) is defined (http://www.its.bldrdoc.gov/fs-1037/dir-022/_3253.htm) as: The average power supplied to the antenna transmission line by a transmitter during an interval of time sufficiently long compared with the lowest frequency encountered in the modulation taken under normal operating conditions. [NTIA] [RR] (188) Note: Normally, a time of 0.1 second, during which the mean power is greatest, will be selected.