[Milsurplus] TCS-12 was main Buff commo system???

[mstangelo at comcast.net]

It's been interesting following the discussion about the introduction of SSB.

That got me thinking. For voice (or music ) modulation and demodulation, AM modulation, was first used because it was the transmitter and receiver circuits
were easy to construct.

SSB was used by ATT for transatlantic voice communications in the 1920's and came into commonplace usage in the 1950's.  It is now the most effective analog
mode for medium to long range utility communications.

FM was patented by Armstrong in the early 1930's and is now used for short range utility communications and high fidelity broadcasting.

Let's disregard digital modes for the moment. Since SSB is optimum for long range
communications and FM for short range is there any reason for AM modulation today? I hope this isn't too far off-topic.

73,

Mike N2MS


-------------- Original message -------------- 

> At 08:15 AM 3/14/05, Grif wrote: 
> 
> >I wasn't aware that the FCC had any jurisdiction over what the military or 
> >the government did with their frequencies. Perhaps the military just chose 
> >to also stop using AM? 
> 
> You are correct. FCC has no jurisdiction. Each service has their own 
> "Frequency management office" under DOD. DOD established their own rules 
> about bandwidth and that was what ended AM. Typically their biggest 
> bandwidth allocation is 2.5 kHz, the minimum for SSB. 
> 
> Perry w8au 
> 
> 
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