[AMRadio] AM Broadcast Quality


W. Harris nbcblue at hotmail.com
Tue Dec 17 14:09:31 EST 2013







The specs on my Ranger audio chain and other Johnson transmitters is flat response from 250-3000 cycles. For the Collins 32V-3 it is 200-3000 cycles, which is all very adaquite  for good AM good voice  communications. I get very good audio reports on the Ranger. Any more response just ads to the bandwidth. For AM broadcast stations, 40-7,500 cycles is typical. We are not broadcast stations.

97.307 Emission standards
(a) No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice.

10 or 20 kHz bandwidth is not necessary for good AM communications on the ham bands. We are communicating, not broadcasting. 

Bill - K5MIL
 

> Message: 2
> Date: Tue, 17 Dec 2013 05:16:20 -0600
> From: Rob Atkinson <ranchorobbo at gmail.com>
> To: "W. Harris" <nbcblue at hotmail.com>
> Cc: "amradio at mailman.qth.net" <amradio at mailman.qth.net>
> Subject: Re: [AMRadio] AM Broadcast Quality
> Message-ID:
> 	<CALWD7Z5ODW0AFUed0fheyKQ0-6+TbWmMYqz5N+AmoqZJYzrT+Q at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Let's rewind this whole thing had have a rational discussion with some
> meaningful technical content instead of all this subjective stuff
> about "broadcast quality" whatever that means.
> 
> Bill, since you started it, why don't you start over again and begin
> with a statement about what you think, i.e. your technical definition
> of broadcast quality (in other words, audio frequency response by
> frequency and no. of dB down from the peak level) and what you think
> it should be, again giving us some numbers.  Maybe you think ham AM
> audio should be 20 dB down at 100 cyles, nothing lower, with a gradual
> rise of 15 dB to 3 kc and a gradual attenuation to nothing above 4.5
> kc.  That's an example.  You may have a different technical
> specification, but such a description would actually give us something
> to discuss in a rational way.
> 
> The other vague and subjective statement is the "communicate using no
> more bandwidth than necessary" thing.   Why don't you tell us what
> that means to you in specific terms once again?  Otherwise such a
> comment is needlessly provocative and contentious.
> 
> 73
> 
> Rob
> K5UJ



 		 	   		  


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