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Re: [Amps] 300Hz sidebands

To: amps@contesting.com
Subject: Re: [Amps] 300Hz sidebands
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 26 May 2021 02:15:22 -0700
List-post: <mailto:amps@contesting.com>
On 5/26/2021 1:31 AM, Conrad PA5Y wrote:
As Bob AH7I pointed out at 1KW out the sidebands are 10mW, so I will continue 
to use the amp

Conrad,

As an engineer, I LOVE your proper sense of perspective. Here in the former colonies, I often see splatter 0n 40M, most of it produced by Yeasu rigs, that extends 2-3 kHz on both sides of the intentional bandwidth, and only 20 dB down. That's 10W from a 1kW transmitter, and the signal is 3 times wider than a clean SSB signal.

Any ham who transmits SSB with one of these atrocities is violating the FCC regs on bandwidth that specify (and I'm paraphrasing here) that occupied bandwidth shall be no greater than that required for the means of transmission. In other words, if you're splatting wider than an un-distorted SSB signal, you are in violation.

For years, I've had the P3 spectrum display with SVGA option hooked up to my Elecraft K3, and I occasionally watch roundtable SSB QSOs. Typically one or two stations will be textbook clean, while others will have that splatter than I've described. And it's not subtle -- the difference jumps out at you. Obviously the same problems can be caused by poor or poorly operated power amps, but IMO, they're getting blamed for a lot of problems caused by these lousy rigs!

73, Jim K9YC


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