AM Transmitter Rally Final Proposal based on all input - PLEASE COMMENT!

[KF1Z]

On final comment, then I say no more about this, or any other topic.

I looked back through some old threads...
I found all the answers I need.


Still curious about the QRP  limit for the rally though.....
It was a real question, after all.

bye

[k4kyv]

Don,

I'm curious -  I assume you're using I squared R to figure power with the current meters and openwire line?  How do you come up with an accurate "R" to use for the calculation?

Or do you also measure voltage across the line with a floating scope probe and use E X I ?

Into calibrated dummy load, use Ohm's law: IČR.  With the open wire tuned feeders, adjust for maximum deflection while making sure the tubes stay safely within CCS ratings.

[Steve - WB3HUZ]

Five watts DC input to the final amplifier. There, it's settled.

On final comment, then I say no more about this, or any other topic.

I looked back through some old threads...
I found all the answers I need.


Still curious about the QRP  limit for the rally though.....
It was a real question, after all.

bye

[K5UJ]

Rob,

good sig last night into WV.

Don, rig is fixed. needed 3 mica caps changed and new finals.

Hey Derb, tnx but you worked the w. coast -- you da man!

[steve_qix]

Still curious about the QRP  limit for the rally though.....
It was a real question, after all.

Hmmmmmmmm..... QRP limit for the rally?  No limits here     CRANK UP THE WICK 

[WA1GFZ]

Flea market is the folowing weekend right?

[N3DRB The Derb]

Rob,

my station is still pretty JS IMO but it's a lot less JS than it was. Even with setbacks the long term trendline is on the upside for sure. Time for some good 180 proof white lightning homebrew transmitter making.  

working Cal on 75 AM is more exciting to me than working ZedL on 75 slopbucket which I did when I was toyin around with DX for a year in the mid 80's. more sense of accomplishment.

I wish ARRL would issue AM endorsements for WAS, WAC, etc.

[steve_qix]

Flea market is the folowing weekend right?

Right !

[Pete, WA2CWA]

I wish ARRL would issue AM endorsements for WAS, WAC, etc.

There is for WAS. See
http://www.arrl.org/awards/was/wasapp.pdf
This has been in existence for about the last 7 or 8 years.

[steve_qix]

Hey Brian (W5HRO) - that's a class E modulation graphic    Here's another one from the same group.  I didn't think that one was out there anymore.  Use it in good health 

[K5UJ]

Hey Brian (W5HRO) - that's a class E modulation graphic   

That modulation was so extreme that I first mistakenly thought it was slopbucket   and i thought "What's Brian doin'?" 

Derb, maybe with the new/old low band L tuna I'll have a shot at the clip lead award
No doubt working west coast on AM requires optimizing on several fronts, makes working DX with slopbucket seem like shooting fish in a barrel.


Rob

[K1JJ]

I'm curious - WITHOUT a reference picture of the unmodulated AM carrier, (or carrier lines drawn in) there is no way to know if that modulated waveform picture shows modulation of 100%, 200%. 300% or 400%, etc., positive peaks, correct?  Or is there a way by reverse detective work?

BTW, the pic above shows the classic "shark fins"  waveform we often talk about associated with a transmitter that will cleanly pass extreme lows effectively.   I find this polarity is only possible using a rig that will do this.

T

[Bill, KD0HG]

Tom, the unmodulated carrier is shown in both of Steve's pictures...It is 2 divisions 'tall'..

100% mod is 4 divisions tall, as it should be, or 2x voltage, 200% is 6 divisions, or 3x the carrier.

[N3DRB The Derb]

There is for WAS.

wow. who got enlightened I wonder? I'll have to go out for that. When the sunspots return it will be not that hard.

condx have to be about perfect for a "average 100 watt" am station to work coast to coast on 75. my report was a 3X5 and I gave him a 4X5 - no doubt having a antenna made for such things would help a lot.

[KF1Z]

Tom, the unmodulated carrier is shown in both of Steve's pictures...It is 2 divisions 'tall'..

100% mod is 4 divisions tall, as it should be, or 2x voltage, 200% is 6 divisions, or 3x the carrier.

I think it was more of a general question, relating more to W5HRO's avatar, than to Steve's pictures.

[K1JJ]

Tom, the unmodulated carrier is shown in both of Steve's pictures...It is 2 divisions 'tall'..

100% mod is 4 divisions tall, as it should be, or 2x voltage, 200% is 6 divisions, or 3x the carrier.

Yep, that's right, Bill.

But what I'm axing is if there was no "2 divisions tall" reference of an unmodulated carrier, are there clues in that 200% modulated waveform that it's more than 100% modulated?  IE, does the height of 200% modulation appear different than a 100% modulated waveform in shape, form, etc.   I always thought not, but wanted some other opinions.

I'm looking for someone to say, "No, you can't estimate  the % of modulation when using a negative peak limiter with over 100%  positive peaks without an unmodulated  reference carrier to look at. There are no telltale signs."  (Or are there?)

T

[Pete, WA2CWA]

There is for WAS.

wow. who got enlightened I wonder? I'll have to go out for that. When the sunspots return it will be not that hard.

condx have to be about perfect for a "average 100 watt" am station to work coast to coast on 75. my report was a 3X5 and I gave him a 4X5 - no doubt having a antenna made for such things would help a lot.

Back in the early days of the new 21st century (early months of 2003) , WA3VJB, K3MSB, and myself danced with several Directors and ARRL staff on this issue.

[N3DRB The Derb]

Thank you for your efforts.  Anything that de-marginalizes AM activity from the wider spectrum is a good thing. I'll start going out for the award soon as I get some new QSL cards made.

[Bill, KD0HG]

All I can say is an AM signal modulated 200% positive is going to sound awful on an envelope, or diode detector, but OK on a synchronous or product detector.

Once you go past 125% positive peaks, it looks great on a peak-reading wattmeter, but it ain't very good sounding AM. It's DSB with a bit of carrier.

Yeah, technology allows you to do 200% positive peaks, but you don't want to if the listeners are using traditional AM detectors.

We don't need to sound like SSB contesters, IMO.

FWIW, a few AM stations going to 200%-400% positive modulation is one reason why the FCC made the law 1.5KW PEP output, screwing all of us. Sorry, 10 KW PEP of DSB didn't cut it.

[WA1GFZ]

Bill,
You have been strapping the past few days.