QST AM Article and SSB Power

[W2XR]

"Clarke's Second Law: The only way of discovering the limits of the possible is by venturing a little past them into the impossible".

Additionally, one of the oldest sci-fi themes around is the civilization that never makes it off it's planet, just rots away, ossifies from it's own dumbing down and stagnant welfare states. 

Rick, it appears that this may well be coming to fruition at this point.

73,

Bruce

[N2DTS]

I think I could stuff a third 813 into the big rig.
2000 volts at 600 ma, about 900 watts carrier!
I think four would fit....

Brett

[k4kyv]

I have not read thru part 97 in years, but I think there is a paragraph that says an amateur operator shall only run enough power to obtain reliable communications with the party they are communicating with at the time. I think that in itself blows all other arguments out the window and is the key thing which gets overlooked time after time.

That has been in the rules from the very beginning of licensed amateur radio. It states that one must run the minimum power necessary to  carry on the desired communication. But what is the "desired communication"?  Does it imply a certain degree of signal quality and signal-to-noise ratio, or does it mean that both stations in a QSO are supposed to run right at the ragged edge of intelligibility?

Sky wave propagation is so fickle that about the only situation where that rule could be made to stick would be local cross-town communication via ground wave on MF or HF, or direct wave on VHF.

[N3DRB The Derb]

desired communication

for me that would be crushing any stupid HAWWWW HAWWWW HWAWWWWW bleating ignoramus billy bob slopbucket that dared to try to qwirm me like a bug with my steel jawed maul.

[k4kyv]

Here is the Bird meter the FCC used to check my power. It may have been an older model before the pep was added, but I don't remember. The only thing I remember is that he was only concerned about my max power out and wanted to see if I had any reflected power getting kicked back to cause my neighbors interference. That was it. No modulation tests or anything.

Doesn't say much for the expertise of that FCC inspector.  I suppose he would have also told you that reflected power would kick back into your transmitter and cause the finals to run hot.  

Reflected power wouldn't have anything to do with nearby interference. It just means you are running your transmission line as tuned feeders and not as a flat feedline. With coax this might result in excessive feedline losses, but the reflected power in itself would not contribute to local interference.

http://birdtechnologies.thomasnet.com/item/wattmeters-and-line-sections/categories-wattmeters-and-line-sections-wattmeters/4391a?&plpver=10&origin=compare&filter=0&CTypeID=2

Here is what they should have used: http://birdtechnologies.thomasnet.com/item/wattmeters-and-line-sections/portable-wattmeters/apm-16?&seo=110  The drawback is that they are not cheap, and are specified only down to 2 mHz.  I wonder if they would work satisfactorily on 1.8-2.0.

My new HB transmitter has the pi-network designed for 50 ohms. With the RF amp meter at the input side of the open wire line antenna coupler I just use 50 ohms to determine where the current reading should be. So with just over 3 amps into 50 ohms it yields about 500 watts of carrier output power. As long as you keep it below about 4 amps max there is nothing to worry about and you can run 100% modulation without any worries. The RF amp meter (thermocouple type) should only wiggle slightly when you modulate.

With 100% sine wave modulation, the thermocouple ammeter should kick up about 22.%.  With voice, the kick-up should be barely perceptible. The Bird 43 should not kick up at all, since it actually measures average rf voltage, with the scale simply calibrated in watts.  Average rf voltage should not change with modulation if there is no carrier shift. The APM-16 would kick up 50% with 100% sine wave modulation.

I wonder what that inspector would have done if you had been using a typical 1930's configuration consisting of a balanced antenna tuner, connected to the transmitter through clips directly to the tank coil, and feeding open wire tuned feeders with no 50Ω coax link anywhere in between.

[kb3ouk]

Well, i think that the pep rules dont really make any sense at all, because the way i read them , then 1000 watts of carrier is legal for am, then when you modulate the carrier you end up with 1500 watts of peak power in your sidebands. But the 4 times the carrier is equal to the pep of the am signal does not make any sense to me because i remember reading a book once that explained how am works and this was the example that was given:

An amplifier has an input of 1000 watts. The plate voltage is 2000 volts and the plate current is 500 ma. When modulated fully , the modulator causes the input voltage and current to double (4000 volts at 1 amp). So it is saying that the peak input on modulation peaks is 4000 watts. so if the amplifier has a 70% efficiency, the carrier output is 700 watts and the peak would be 2800 watts.

It explains that in order for the modulator to develope this amount of peak power across the load of the plate circuit, the output of the modulator needs to be equal to half of the plate input of the amplifier. So the modulator is giving 500 watts of power to a final with an input power of 1000 watts, meaning the total power being delivered to the final is 1500 watts. Now if the amplifier is operating at 70% efficiency, the carrier output is still 700 watts (it is the same amplifer in the example above), but this time it is saying that the peak power of the sidebands is 70% of 500, or 350 watts, which means that the peak power of the carrier and sidebands combined is only 1050 watts.

Now if this makes any sense is it easy to see why the pep rules make regulating the power of an am signal difficult?
Shelby

[W3SLK]

Any power level is legal........ as long as you don't get caught! 

[W3RSW]

Hey Mikey, I just watched VJB's and Bert's Timonium 2008 CD again and caught your mug. Just about as bad as mine.  

Insert Quote
Any power level is legal........ as long as you don't get caught!

"Caught"?  That implies guilt or intent.  Surely not us! (ahem.)

 If you don't drastically exceed ham norms of the present or even the past, it shouldn't take much of a lawyer to show a typical QRO AM operator is legal and trying 'very hard' to comply with the intent of the law, given the speciousness of the technical standards.  .

 After all if enforcement is sporadic and can be shown to be such neat stuff as arbitrary and capricious, and you appear to, or do know what your talking about then the proof is on them.
....or I should hope so in what may still be a country based on fair law.
Operators like Don would be a good candidate for inspection, heh, heh.  He'd talk rings around a typical tech.  (Don't meant to be too patronizing Don, but facts are facts. Your good!)

[k4kyv]

Any power level is legal........ as long as you don't get caught! 

So is any speed when you drive, as long as there is no cop in sight.

Tell me, what usually happens when you drive down the interstate and try to stay right at the posted speed limit?

Wonder how many of those who constantly piss 'n moan about "dem dar AM'ers runnin' illegal parr", conscientiously obey the posted speed limit 100% of the time when they drive.  Who is a greater detriment to the public interest, someone who speeds on the public highways, or some ham whose occasional voice peaks exceed the "legal limit"?

[W3RSW]

Yeah, and remember the 55 mph limit when virtually the whole country was a nation of outlaws? 

Well we still are; it's just that a 70mph limit is a bigger base, hence smaller ratio for the "5 to 10 over allowable." 

Most staties don't care if your over the limit somewhat unless it's the "end of the month" or you pass them.  They like to feel that they're special and king of the road.  The key is to treat them as such, but only formally when 'protocol' requires.

We've all been raised for endless generations to play the proper 'serf' on occasion. By now it's probably encoded in our genes. 

Sometime ago I had hunting camp buddies who were Pa. state troopers along with some game wardens.  Great stories. 

It's who ya knows....    always has been, always will.

[kb3ouk]

Yeah, around here it doesnt seem like the cops start to come out until the end of the month, then they are every where.

[Opcom]

I think more hams are going to run QRO, at least for phone.  They will be driven to it by the number of RFI spewing appliances out there raising the noise level and making reception of <= 100 w. rigs with average antennas impossible.  I don't know anything about these qrp weak sig. modes -- maybe they can get through somehow.  We pretty much can't control all the garbage unfiltered gadgets out there, a lot like me can't afford to move to the country, and separate rx antennas and noise canceling boxes only go so far.   The one thing we can do, is up our tx power and antennas.  The new S3 is now S9.

Unfortunately, 10 % av. power only serves to make SSB ops run out and buy these speech processors, the latest being sold by Ten Tec, who's ad claims "almost 6 dB" increase in power.  I'm sure 8 out of 10 buyers will be ops who run these things with all knobs fully clockwise and of course they don't use scopes and have average reading watt meters.  Just wait until a lot of them buy that Ameritron solid state 1.2 kw amp.  It's all a recipe for unintelligibility, fan and saliva sounds.   

Rob

We complain that many SSB users, the new hams, etc don't build. Be thankful for that when it comes to amplifiers. It would be interesting to see the amp makers build in some circuitry that shuts the amp down or throttles it back when distortion is detected. With processor controlled amps, the user would have a hard time geting around that "feature".

[Opcom]

Yeah, around here it doesnt seem like the cops start to come out until the end of the month, then they are every where.

or every 28 days.

[k4kyv]

Yeah, and remember the 55 mph limit when virtually the whole country was a nation of outlaws? 

Well we still are; it's just that a 70mph limit is a bigger base, hence smaller ratio for the "5 to 10 over allowable." 

You have to play sort of a guessing game.  If you follow the posted limit to the letter, people honk at you and try to run you off the road to get you out of their way.  You have to play a guessing game of how much over the limit to go to avoid both provoking road rage from other drivers and getting a ticket from the cops.

[W3SLK]

Rick said:

Well we still are; it's just that a 70mph limit is a bigger base, hence smaller ratio for the "5 to 10 over allowable." 

Except in VA where they clamp you to the letter.

Incidently Rick, that mug is getting pretty well worn, heh, heh. 

Don said:

Wonder how many of those who constantly piss 'n moan about "dem dar AM'ers runnin' illegal parr", conscientiously obey the posted speed limit 100% of the time when they drive.  Who is a greater detriment to the public interest, someone who speeds on the public highways, or some ham whose occasional voice peaks exceed the "legal limit"?

Don is correct. It is the same thing. I remember Rich Measures saying after building his 4CX10000 amp (or plywood box as he refered to it), "It isn't illegal to have a car that can do 200+ MPH."

[N3DRB The Derb]

most of these freakz are running a pair of russian GU 35's in their LINYARS at the same time talking smack about how wide amer's are.

[W3RSW]

..and that's a "fack" Derb, that's a fack.

"or every 28 days"
Good one Opcon....
Natural periods always take precedence.


..and I like the similarity to owning a Farrari.  Just because you have 500 hp, doesn't mean you drive everywhere at 200 mph.

But there is, perhaps, the excessive filament power required; "Friends of Coal, tm" being helped immensly.

Rick's Law # 62-56 A
Do not run filament power in excess of plate input power or your 1/Green. 

For the more scientific of you,
The crossover point of a Gentleman AM'ers station is when filament power equals Plate input power.
   On special occasions (HM rally, etc.) you may be permitted to equal average output power.

[W3SLK]

There was fellow that used to run a pair of 8877's being pushed with his FT-1000D on AM. He sounded real good and his amp was computer controlled and very nicely constructed. I used to have his URL but I don't know what happened to it. 

[W3RSW]

There you are.  8877's are very filament wattage friendly.  Indirectly heated oxide cathodes.  Too bad they're so expensive.  So the Filament 1/Green law is even harder to violate., urk.

..or do I have my recriprocals upside down? Help!

[kb3ouk]

I think i am right on this but indirectly heated cathodes do use less power than filament type cathodes, dont they?

[WQ9E]

I think i am right on this but indirectly heated cathodes do use less power than filament type cathodes, dont they?

Correct, but that warm-up wait time for the indirectly heated cathode to reach safe operating temperature can be excruciating at times! 

[kb3ouk]

Yeah thats why filament type cathodes are used a lot in  mobile gear because the filaments can be shut off when not transmitting and then come on instantly when it is time to transmit.

[KM1H]

The strangest thing is that the boomy ESSB guys seem to stand out the most and get picked out easily. Proabaly cuz they are the only ones with the bassy voice tones to hear and everyone else sounds like white noise when combined.

I thought ESSB required a compatible detector and software on RX to lock to the pilot?

There are plenty of fine sounding SSB signals, just find someone using a phasing system. These days Im pissed I sold off my CE 100V and 200V in the mid 80's for a pair of C Lines.

Yeah, and remember the 55 mph limit when virtually the whole country was a nation of outlaws?

And it fueled the explosive growth of CB

Correct, but that warm-up wait time for the indirectly heated cathode to reach safe operating temperature can be excruciating at times! 

Its 6 minutes on a YC-156 and 8 is better. But what a great linear tube. One of those would make me toss all the old iron and glass around here

Carl
KM1H

[K5UJ]

Last night I did something I have not done in a while, I tuned down to 3800 from the window  with the rx on LSB.  Every single SSB station I heard with no exception was way way over processed.  And there was a station about every 3 to 5 KHz.  And this was just ragchew operating, not cq contest or dx chasing.  Every last one sounded like they had run out and bought an RF speech processor and cranked it all the way up.  yeck.

[k4kyv]

Last night I did something I have not done in a while, I tuned down to 3800 from the window  with the rx on LSB.  Every single SSB station I heard with no exception was way way over processed.  And there was a station about every 3 to 5 KHz.  And this was just ragchew operating, not cq contest or dx chasing.  Every last one sounded like they had run out and bought an RF speech processor and cranked it all the way up.  yeck.

Those are the ones I feel in no way apologetic about calling "slopbuckets".