You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
The Feb 2025 Radioddity Giveaway Results are In! Click Here to see who won!

Reply to thread

Message

A lot of people think AM broadcast transmitters are class C but that is because all they hear is "class C plate modulated" and the rest either falls on deaf ears or shoots right over their head. The typical device that most CBers call a "modulator" is no in any way shape or form a modulator in the true meaning of it.They are simply a class C amplifier meant to have a really low dead key and a high "swing". A real modulator consists of simply a big audio power amplifier. The high level audio is fed through a special transformer called a ........wait for it ............modulation transformer. The audio is then fed to the plates of the class C carrier amplifier wich causes the amplitude of that carrier to change between zero and four times the unmodulated level. This is what happens in plate modulation in it's most basic terms. A typical 1000 watt AM transmitter needs about 750 watts of audio to modulate it 100%. CB type "modulators" use no audio and thus are not really modulators.

<blockquote data-quote="Captain Kilowatt" data-source="post: 404997" data-attributes="member: 39"><p>A lot of people think AM broadcast transmitters are class C but that is because all they hear is &quot;class C plate modulated&quot; and the rest either falls on deaf ears or shoots right over their head. The typical device that most CBers call a &quot;modulator&quot; is no in any way shape or form a modulator in the true meaning of it.They are simply a class C amplifier meant to have a really low dead key and a high &quot;swing&quot;. A real modulator consists of simply a big audio power amplifier. The high level audio is fed through a special transformer called a ........wait for it ............modulation transformer. The audio is then fed to the plates of the class C carrier amplifier wich causes the amplitude of that carrier to change between zero and four times the unmodulated level. This is what happens in plate modulation in it&#039;s most basic terms. A typical 1000 watt AM transmitter needs about 750 watts of audio to modulate it 100%. CB type &quot;modulators&quot; use no audio and thus are not really modulators.</p></blockquote><p></p>

[QUOTE="Captain Kilowatt, post: 404997, member: 39"] A lot of people think AM broadcast transmitters are class C but that is because all they hear is "class C plate modulated" and the rest either falls on deaf ears or shoots right over their head. The typical device that most CBers call a "modulator" is no in any way shape or form a modulator in the true meaning of it.They are simply a class C amplifier meant to have a really low dead key and a high "swing". A real modulator consists of simply a big audio power amplifier. The high level audio is fed through a special transformer called a ........wait for it ............modulation transformer. The audio is then fed to the plates of the class C carrier amplifier wich causes the amplitude of that carrier to change between zero and four times the unmodulated level. This is what happens in plate modulation in it's most basic terms. A typical 1000 watt AM transmitter needs about 750 watts of audio to modulate it 100%. CB type "modulators" use no audio and thus are not really modulators. [/QUOTE]

Top Bottom