The AM Forum

Sources have indicated to me that the FCC is floating a proposal for a "Super Class" Endorsement - phone only, for the HF bands. This special endorsement will permit varying levels of output power, up to 50kw for amateur radio operators - depending on the fee paid.

The aim is to generate more money to support the bureau's amateur section's operations.

The new "Super Class endorsement" will be open only to Extra Class licensees who have been licensed for 10 years or more. The amount of permitted power increase will be based on a yearly fee scale, tri-level. Level 1 is maximum 50kw, Level 2 is maximum 12kw and level 3 shall be maximum 5kw. The yearly fees are respectively: $10k, $6k, and $2500. Level 1 applicants will be required to post an additional $10k "performance bond", during the period that the power endorsement exists. Operation in the General portion of the band will be limited to 5kw for all Super Class ops.

All Super Class operators will be subject to an FCC field engineer inspection during the year, and all Level 1 ops will have an initial inspection plus a during the year inspection.

This is the upshot. I've probably gotten some things wrong, and missed a few details...

                        _-_-bear

I can't see the Feces ever going along with a 50 KW amateur limit....

50KW?

Is it April 1st yet?

Is that carrier power or P.E.P.?

The Tron was reportedly seen at First Skowhegan National Bank excitedly applying for a $10K loan. The plans for a new 50KW SBE rig were allegedly offered as collateral.


T

I guess I better upgrade the condutor size on the open wire line a bit ;)
Joe, W3GMS

I heard it was 100 kW and you could operate anywhere between 2 and 30 MHz. But it was the AM mode only.

How many 'pills' is 50kw?

That depends on your symptoms!

21E's and BC-5's are going to get really pricy....but I'm ready. ;)

Is it Bird pills now??


klc

You did miss the footnote¹, to wit:

¹Activities excluded from utilizing the "Super Class" endorsement include contesting and dog-Xray.

I wonder if this could have been subsidized by various local power companies?

sounds like internet lies to me...

50kw output would make for some interesting zorches on the air.

Could they really collect the power fee?  They can't even collect a $21,000 fine from a renegade operator.

Folks, just remember ya heard it here on "AM Fone" first!  ;D

For some odd reason (planning?) we have 480 3 phase here...

Lets set RF fire to some creosote bushes :o

73 DG

makes my 15,000 watts look like a drop in the bucket  ;D

...and I just bought a Globe King 500 and it's already obsolete.

 :P

It'll make a nice VFO/Driver!

Sheesh. Good news if true, but a bit spendy...

Dennis, Now I'm glad I let you talk me into those 3CX2500s.  ;D ;D ;D

There may be a few out there who could put an old buzzard 5 KW rig on the air but if we are talking iron, it gets really big and heavy. I think the only way to run a transmitter with 50 KW would be with poor DC filtering so we could watch our speakers get ripped out of the cabinets by the hum on selective fade ;D ;D ;D That would be best heard on 20 meters on 14.275.

4 KV scares me,that stuff would have to run on 6 KV or better.

Hmmm... OK so 50KW ....hmmm .... now how many FETS can I fit on this heatsink ... OK ... Ummm... ZORCH!!!!!


STEVE QIX !!!!!!!! HELP ME !!!!!!! WAAAAHHHHH!!!!!

50kw?  Could you imagine oh say, K1MAAAAAN  on a 50 KW station???  Dear Lord....

Other than bragging rights, what does the 50kw get you?  Stuck in an even smaller segment of the extra portion of the band, and limited even more as to who you were going to get into a QSO with.
Sounds like a target for wanna be broadcaster types.

It is April 1st somewhere..

1. a scheme in lieu of them finding and fining violators?  - there really are no violators to speak of..
2. a scheme like the BATF $200 tax for those wishing to own a machine gun? -they are also subject to inspection, mainly to be sure the weapon is where it is supposed to be.

If any of it is true, then imagine the hubub it will cause in the commenting. I can hear the screaming now.

FETS? if you must.. I think there are some 500-900W ones out there running at 50-100VDC, mainly designed for MRI and such. Hmm.. I work for a semiconductor company. samples.. Hmm.. Boss, I want to write this article for that trade rag. Can I order some samples to get the project started?

Finally, the KW level ought to be specified as 'carrier' for AM and FM and PEP for SSB.

My concern if you can call it that, is the cost and whether a 5KW signal will make much difference over 1500W. Is that really worth it? $2.5K per year is a lot of money and would require spousal approval for those lucky family types.. The price for a real improvement, such as 10KW, becomes outrageous, it would be a bit unfair to some people who are not wealthy. I hate to see supposedly 'hobby' things divided by money where licensing fees are the divisor. It's one thing to divide by "ability to procure equipment" and another to divide by "ability to pay fees". Still I would not oppose it.

For your consideration:

http://webpages.charter.net/k4hal/license.htm (http://webpages.charter.net/k4hal/license.htm)

From Jan 2006 as best I can tell.

Hope y'all had a great Thanksgiving.

ldb
K5WLF

Its like why pay a prostitute when so much is free?

You really expect the current QRO stations to cough up what amounts to a yearly fine. I can just hear JJ's response to that ::)

Aside from day to day operations I've always wondered about contests and how difficult it might be for a 1500W station to compete with a big operator who can't keep his hand off the handwheel so to speak. It would be uncomfortable to have that trophy on the mantle and know it was won dishonestly.

I'm all for power levels being adjusted so AM does not have such a disadvantage dB wise. I would not suggest taking power away from SSB operators. That would be unfair. Therefore it only makes sense for the rules to freely allow 1500W in each sideband when running a conventional AM setup and 1500W in the sideband of AM-compatible transmissions. The rule could read "1500W PEP in any sideband".

There's no way a super-power amateur radio station on a typical antenna less than 100' high is going to be in compliance with FCC and OSHA non-ionizing radiation exposure standards. Even the current 1,500 watts PEP is pushing the limit. 10 or 50 KW on VHF-UHF 2 meters-1215 MHz..Into a gain antenna? Forget it.

The tower climbers I hire now carry radiation meters and can wear RF-proof suits.

That would be nice for AM, but I doubt the feecee would go along with that kind of power for any mode.  1500 watts peak in each sideband would equate to 3 kw total peak power in the two sidebands, enough to 100% modulate a 6 kw carrier. Their primary  concern would be the extra work they would have to deal with involving RFI issues in residential areas, even though 99% of the complaints would be due to crappy consumer electronics junk, not poorly engineered transmitter installations. This, in addition to the alleged hazard of rf radiation exposure.

OTOH, the present-day power limit for AM, if one is willing to go along with the bogus "375 watt carrier" theory, would allow a measly 187.5 watts of total peak sideband power, or 93.75 watts PEP per sideband.

At 100% modulation with a pure sine wave tone, the total sideband power is exactly 50% of the carrier power.  With voice modulation, 100% modulation occurs only at the crest of voice peaks, so the real sideband power ofa full-carrier AM phone signal modulated to 100% can be validly expressed in terms of PEP.

That PEP= 4 X carrier power figure is "phantom" indication, based on a virtual reading that occurs when the sideband voltages and carrier voltage add up in a voltage-indicating instrument, such as an oscilloscope or a "wattmeter" that is really not a power-indicating instrument at all, but an rf voltmeter with the scale calibrated in watts.  Where do 1500 watts of actual power come from, when the total peak sideband power is only 187.5 watts, added to a steady 375 watts of carrier power?  

Speaking of the prevailing bio-hazard paranoia, in the case of non-ionising radiation, the safety concern is over the heating effect on bodily tissue. As in the case of the light bulb dummy load, the heating of living tissue in the vicinity of an rf radiator is an effect of average, not peak power.

I guess this means I have to down-size to apply for the 50kw license?  ;D
Crap...I guess I need a few more heat sinks

Doesn't the general public know that a well built AM signal is usually out of phase over 90% of the time with the harmful cellphone and the especially harmful SSB signals so as to reverse any damage caused by those malicious signals??  They should be educated so they will promote Amateur Radio operations in the AM mode and start to heal themselves! 

Scientific studies conducted recently also confirm that high level plate modulated AM radiation actually helps repair and reinforce the atmospheric ozone and related phenomenon and can be a great boon to reversing the Global Warming of our planet! 

I think the powers that be want to keep this information on the downlow because it's such an inexpensive solution that they will not be able profit on these disasters as planned.

In view of the discussion the rumor expressed in the original post seems less than probable.

It may have been discussed before, but would a reduced carrier relative to the sidebands help? On the GRC-106 military HF set, the carrier is about 50-60 watts, yet the set makes 400W PEP, cramming it all into the upper sideband. Everyone who has heard it says it sounds great. One person said it had a lot of 'swing' on their meter.

I heard you are required to be a 20 WPM real extra to get the QRO tag.

Why confine it to one sideband?  Use DSB reduced carrier, receiving with a synchronous detector.  SSB plus carrier sounds  like crap on an envelope detector no matter what kind of transmitter is used.

But SSB with pilot carrier is a good idea.  Nothing new, AT&T was using it for international telephone links in the 30s.  Running hi-fi SSB + pilot carrier, with a sych detector at the other end, can be made to sound just like AM. That's where the ESSB guys are missing the mark.

You're comparing average and peaks powers.

That makes the correct amount of sense to be used as a government regulation. Because so many people put a great deal of store in whether someone took the extra examination before or after the rules were changed, maybe the FCC should be petitioned to take away certain priveleges to those who can not pass a 20WPM Code test. It could read something like "only those who have passed a Morse Code examination may use Morse Code in the CW portions of the band".



I don't think I intended it to be confined to one sideband, I proposed 1500W in any sideband. The GRC-106 had only a USB filter, although I have the mod kit ($300 from a Japanese gentleman) to give it LSB as well. The question is where to drill the hole for the USB/LSB switch. ahem. That ought not be done on a pristine CARC finished set. But your point is well taken.

There is no reason except the need for a synchronous detector that DSB reduced carrier could not be run. Isn't that a similar effect of the ultra- and super- modulation schemes that have been used and discussed? The '106 intelligibility sounds great with the 50W carrier and the other 350W (however one wishes to slice the math) in the USB. It was designed for high voice intelligibility on USB and AM-compatible modes, and for RTTY using USB and for CW. A synchronous detector is not needed for reception of that radio set. I don't know if it would sound better or not, I don't have access to one.

So the well designed military rig that can be received on a normal AM RX runs about 12.5% carrier relative to PEP (50W/400W for the purpose of the question, disregarding whether the modulation is confined to one sideband or two).  Disregarding synchronous detectors, which many people do not have, - At what decreasing level relative to the 'book' 25%/100% carrier/PEP level does the advantage of reduced carrier DSB start to lose value due to receiver distortion and any other poblems?

For this high power endorsement the FCC is requiring 35 WPM. It shows greater technical skill and definitely fulfills the FCC's desire for the "Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art."

I understand they will waive the QRO fees if you design and homebrew (from scratch) your own QRO rig, thus demonstrating you are genuinely dedicated and truly out of your mind.  This requirement, of course, is contingent on the candidate first demonstrating his ability to copy one minute solid of standard 60 wpm RTTY.

T

When I'm listening off a basic diode output, both the R390A and the SP600 start sounding nasty when the station reduces carrier below 70 percent of book.  Turning on the BFO and getting a good zero can cover for some of the missing carrier level and improves the audio.

I'm not sure how they accomplish that.  Due to inherent laws of physics and the mechanics of modulation and demodulation, full carrier SSB is distortion free only at low percentages of modulation, something  like 20-30%.  As soon as the mod percentage exceeds that, the envelope pattern begins to show distortion as the envelope of the signal is no  longer shaped the same as the waveform of the audio that modulates it.  At 100% modulation with a steady tone, instead of the familiar sine-wave modulated envelope pattern, it resembles a two-tone pattern on a SSB  rig.  That's exactly what it is; the  carrier is one  tone, and the one sideband is the other.

I discovered that for myself back in the mid 70's.  I built up a SSB generator at 64 kc/s carrier frequency, using a mechanical filter removed from a 64-108 kc/s telephone multiplexer unit. I experimented with injecting carrier with the SSB signal and sure enough, beyond about 30% modulation, something appeared to be pulling at the envelope of the negative peaks, and at higher percentages it developed a sharp peak that eventually cut off  the carrier, instead of  the usual rounded shape.  This theory behind this phenomenon can be clearly demonstrated with rotating vector diagrams.

Another example of this same phenomenon is when one receives SSB using a receiver with BFO and diode detector, a common practice in the early days of amateur SSB before most ham receivers had a product detector.  You had to turn up the AF gain, often wide open, and run the rf gain as low as possible, in order to clarify the signal even after the frequency was properly tuned in.  With this configuration, the BFO substitutes for the missing AM carrier. With the rf gain set too high, the SSB signal modulates the output from the BFO at too high a percentage, and the signal sounds distorted.  By turning down the rf gain, you reduce the "percentage of modulation" of the steady carrier from the BFO, and the audio comes through with little or negligible distortion.  

One possible work-around, at least theoretically, is to use a square-law detector instead of a linear detector.  The square-law detector inherently distorts the signal in exactly opposite fashion to the inherent distortion of full carrier SSB. A diode detector is more or less a linear detector.  Early broadcast receivers used a triode tube as a grid-leak detector, mainly because this detector offered much-needed gain over a diode detector, and the designers didn't want to waste a triode tube by tying the plate to the grid to make it function as a diode.  The inherent audio distortion in those old sets is very obvious to to-day's ears, but it was tolerated back then because the public was not accustomed to anything better. At least in theory, full carrier SSB would have sounded  better than normal AM on those receivers.

An interesting experiment to try might be to de-tune one of those old receivers to cover 160, or feed it with a converter so that it covers a ham band, and have someone transmit SSB with carrier and listen to the result.

The only thing I can think of with those military sets is that they reduce the apparent distortion by using some kind of pre-distortion of the audio signal before it reaches the balanced modulator.

Regarding reduced carrier AM, I remember W3PHL's signal ran 600 watts DC input for the carrier and he modulated with several kilowatts of audio.  Lacking a synchronous detector, the only way to clearly receive his signal was to switch in a narrow filter and copy one of the sidebands as SSB.

I would say that the  carrier could be reduced to maybe half the normal power level before distortion would become objectionable, if an excessive amount of  compression is not used.  This would act somewhat  like a  cliper circuit; due to the inherent peak-to-average content of the typical human voice, much of the time the modulation would be less than 100%.  The "overmodulation" peaks would be highly distorted, but occur infrequently enough that the distortion would be tolerable.  Unlike SSB + carrier, DSB reduced carrier produces no inherent distortion until the modulation exceeds 100%, but beyond that, the distortion is worse than what results from overmodulation of a conventional AM transmitter.  That was the basis of Villard's 1948 QST article describing a high-level balanced modulator (the "upside-down tube" circuit), titled "Overmodulation Without Splatter".  The idea was, on a conventional diode detector, the increased distortion was a worthwhile trade-off against the splatter generated by occasional overmodulation at voice peaks. 

and to keep the riff raff out.

Those rigs will tune 2-30, so any ham band from 80-10 will do. Attached is the mike-to-antenna path through a set like that, 50W carrier and 400W peak. There is a lot of control, I guess it helps. If the antenna ever is done, I'll fire one up and you can maybe hear what it sounds like. It sounds sort of like talking loudly into a good quality old bell telephone no matter whether the operator is whispering or speaking loudly.

If you as above say half the normal, that is what this thing seems to be. with 50W carrier and 400 peak. But the RF out looks pretty good, better than a hammy ssb rig with the carrier turned up. I don't recall if the RF had the appearance you cite.

Wow, there is a lot of stuff in that schematic.  A theory-of-operation section would be more useful, but that is probably not included in a military operators manual.  Maybe in a depot maintenance manual. It was probably even classified Confidential at one time.

They must use some kind of processing to bring up the effective audio level yet keep it readable.

The one sideband + carrier would exacerbate the distortion vs percentage of modulation problem and thus carrier vs pep levels, beyond what would be expected with DSB reduced carrier, since SSB +carrier is not even capable of approaching 100% before distortion kicks in.

The broadcast industry once experimented with "compatible SSB".  It used a very complex system of pre-distortion to achieve broadcast quality results with an ordinary home receiver.  I think it was KDKA that transmitted it for a while. I didn't work out for some  reason, so they soon dropped it.

The partial manual I have (schermatic) is not marked such, but I have never seen the whole thing anywhere. It is supposedly >1000 pages and has all the theory in it. That radio set is long obsolete, a 1960 design. The most high tech thing it has is silicon transistors. Not a single IC. I can imagine how large it would be if each transistor and diode were replaced by a vacuum tube section. Maybe a 6FT rack or two.  Looking at the drawing, it has a lot of stuff, but the methods for audio leveling, peak RF control, and average RF control are not astonishing. The time constants are interesting.

Only of 50C5s are used.

I could just imagine operating 50 KW from my 75'x100' suburban lot.  Won't that be  the day. ::) ::) ::) ::)

Nah, just go mobile. caw mawn. (or mobeel I guess.)

http://video.google.com/videoplay?docid=1996452407910943036#

I already have a license like that at work.
750,000 watts. It's not as much fun as one might think.
When I stop transmitting nobody ever calls me on my tx freq.

Hello All!

     I can run ALL THE POWER I want on the CB band. No big deal!

Tnx,

Well, actually, you may not do that. If some think they can that is a different thing. Doing it is still a rather big violation...

Just to be upfront with everyone, my source on this was http:/www.WikiGridLeaks.com... a real story!!

 ::)


73's all!

                    _-_-WBear2GCR

Yeah, and I bet you get into a lot of TV sets in the tri-state area too.

It would be worth the effort to see a closeup video of your reaction - if you unkeyed that 750kw rig and heard a perfect recording of Irb coming back to you ....  :o :o :o ;D

K1JJ:

Heck, with that much strap Irb might answer him in real time!

hehhehheh...    Irb would start in right away about Dave running "obscene power".  Dave would axe if Irb was on narcotics. Irb would say, "that's quite a message" and compliment him on his Empire Buster.  Dave would cite him for treason.  And on and on the Irb-riffs would go... ;D

Not much of a story at a link I got to work but it sure has people looking at this thread ;D ;D ;D ;D


http://en.wikipedia.org/wiki/Grid_leak (http://en.wikipedia.org/wiki/Grid_leak)