Amps
[Top] [All Lists]

Re: [Amps] Maximum RF output in practical application: 4-250A

To: "'Joe Isabella'" <n3ji@yahoo.com>, <amps@contesting.com>
Subject: Re: [Amps] Maximum RF output in practical application: 4-250A
From: "Joe Subich, W4TV" <w4tv@subich.com>
Date: Mon, 3 Jul 2006 12:23:33 -0400
List-post: <mailto:amps@contesting.com>
N3JI writes: 

> Really Joe??  So how many rigs do you have with an "ISB" button?  
> None of mine do.  It does however have an AM button, as well as 
> 4k+ (at -6dB) of SSB right out of the box.  

Modern radios will only do 4K+ of SSB if you bypass the if filter 
which is generally 2.7 to 3.0 KHz wide at the - 6dB point or use 
outboard equalization techniques to "make up" for the losses on 
both filter skirts.  Both techniques are bad engineering practice 
and can result in additional distortion and/or interference to 
adjacent users. 

> The justification for BW greater than 3k is exactly the reason 
> you stated -- this is Amateur Radio, and we should be free to 
> experiment as such.  

Nonsense ... that argument would have amateur radio returning to 
unfiltered and unshaped spark signals.  The rules already call for 
using no more bandwidth that necessary ... for voice circuits that 
bandwidth is "toll grade" audio.  

> That said, mis-tuned amps, slamming ALCs, etc. (in other words, a 
> lot of contesters & DX'ers) should be admonished for their operating 
> behavior, as well as anyone else that thinks "all knobs & meters 
> to the right" is the way to operate.  

I'm not defending the "all knobs to the right" crowd.  Their behavior 
is also wrong. 

> In other words, "Good audio is an Amateur Radio Tradition, not a 
> Crime" (borrowed tag line from another Amateur).

There is nothing wrong with good (clean) audio.  However, those 
who bypass or replace 2.7 KHz filters with 4 to 6 KHz filters or 
preemphasize audio into the microphone input of a rig in order to 
generate SSB signals from 4 to 6 KHz wide or 10 KHZ+ wide AM 
signals are "passing gas" in church. 

73, 

   ... Joe, W4TV 
 

_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>