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proper deadkey to swing ratio for AM operation ?????

B

BOOTY MONSTER

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theres been a few comments with differing opinions on this in a few threads so i thought id make a thread about it .
i try to deadkey about %25 of what im swinging myself .

what your opinion/how do you run your equipment ?
 

My 98VHP has a DK of 40 and swings to 225 with the power wide open.
I run the power at 9:00 o'clock which results in a DK of 10 and swings to about 125.

This setting along with my power mic seems to work best for 99% of my communication needs, get nothing but flowers on the radio from most people I talk too.

The radio is set up this way so that if I ever decide to throw a straight 6 LZ behind it it will perform perfectly in my opinion.
 
The answer depends on the waveform, distortion tolerance and measurement devices.
 
According to the rules that I have been taught, a 4 to 1 ratio is perfect, anything over that is just useless, and anything under is not fully modulated and leaving a lot on the table.

But what do I know?

PR
 
packrat said:
According to the rules that I have been taught, a 4 to 1 ratio is perfect, anything over that is just useless, and anything under is not fully modulated and leaving a lot on the table.

But what do I know?

PR
Click to expand...

4:1 is correct for sinusoidal modulation which happens in the lab. Real audio usually isn't a sinewave.

Another glaring error found in publications from an anti AM group in Newington.
 
Generally, what I do is see what the finals of the (illegal) linear power amplifier are, take about 20% of that off the top and adjust the AM carrier power such that at 100% modulation, I'm reading about 4 times what original unmodulated carrier power is.

Example:

Typical two pill MRF-455 box. Each final rated for ~60 watts = 120 watts max. I'll call that 100.

So I adjust the input via the radio's adjustable power so dead key read "post linear" is 25 watts. Mode = AM.

I then put the watt-o-meter in peak reading mode, key up and say audiooooooo in the mic. If the needle "swings" to right about 100 watts, I'm sounding good.

There you go.

Your mileage may vary.
 
'For many types of voices, the approximate ratio of PEP to average power
during a modulation peak in a single-sideband phone signal is 2.5 to 1.
In a single-sideband phone signal, the speech characteristics determine the
PEP-to-average power ratio'-a DIRECT QUOTE from an element 4 study guide.

http://w5yd.org.msstate.edu/new_site/files/Element4_Study_Guide.pdf

AND it is on the element 4 EXTRA CLASS TEST as '2.5 to 1', so it MUST be correct.....even if the question is ambiguously answered.
 
im just a chicken bander . whats a phone signal and how is it related to CB am and ssb use ?
 
In a perfect world I would say 1/4 of max as stated above BUT I liked modulation in excess. Swing is where it's at. We used to have people in my area that had the "big balls" theory going on. They thought that if you had a 2K linear and you dead keyed 1500 and swung to 2K that was awesome... I proved them wrong in my mobile... I walked all over them with 630 watts... I dead keyed about 18 watts and swung to 630(ish) and I was crystal clear, not over modulated, not tinny or basey, PERFECT... But it's all in your setup. I wasn't running junk, I was running my super galaxy with everything possible done to it and a TNT 400 with upgraded pills which allowed me to get the 630 between the drive of the radio and the 4 pills in the linear...

Everyone has their own way of doing things and some work and some don't...

As for your telephone question, it works the same as AM (Amplitude modulation) does. Back around 1870 they figured a form of AM transmission over a copper wire called undulatory currents. And that's when your telephone/telegraphs became popular.
 

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