Carrier or modulation

[dave457]

Saw this over at amfone...
Interesting subject

"So imagine this:

a transmitter capable of say, 600w carrier, but only enough modulator to hit 60-70% modulation

vs.

a transmitter capable of say, 250w carrier, but able to be modulated to 100+%



Which one wins during today's band conditions? if you could have only one of the two, which would you choose, and why?"

 

[Mustang 131]

Carrier every time.

 

[2NC995]

Yup. The big carrier, IME.

 

[Captain Kilowatt]

I saw that as well and immediately thought about the big international shortwave broadcasters. They used a massive carrier of several hundred thousand watts with modulation in the order of 80-90%. They have to combat all kinds of fading and interference and do that with a massive carrier. 80-90% modulation is more than adequate to get the information across.

 

[Shadetree Mechanic]

I have heard that the carrier is what gets you there. On ssb, compression in the audio stage is used to keep the average power up. So the signal doesn't go to zero between words. I think.

 

[AudioShockwav]

The carrier has to get you there.

73
Jeff

 

[kopcicle]

a transmitter capable of say, 600w carrier, but only enough modulator to hit 60-70% modulation

1440 to 1680 watts

a transmitter capable of say, 250w carrier, but able to be modulated to 100+%

1000 watts

1000 watts=60 dbm
1440 watts=61.58 dbm
1680 watts=62.25 dbm

So the difference isn't as much as you would think , but ...
Voice is approximately a 1:4 ratio.
It's the moments in between words where the carrier wins.

250 watts=53.97 dbm , 600 watts=57.78 dbm. That's a difference your ear can detect.

In practice it's a no brainer . Carrier wins .

It's just numbers and as always YMMV, Seek a second opinion, wash rinse repeat, the surgeon general warns that radio frequency energy may be hazardous to the health of rats in California, and never take the word of a politician in an election year.

 

[543_Dallas]

Just run as much as you need for desired communication and call it legal limit.

 

[AudioShockwav]

A lesson learned long ago.
Swing looks awesome on a signal meter, but when the guy gets to far out to stay in your RX the voice peaks don't get it done.
73
Jeff

 

[543_Dallas]

Those guys talking at a power mic at arms length are shooting themselves in the foot too. All that background noise kills them when you are at a distance and the signal is weak.