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Re: [Amps] Slow start-up of Amps on CW

To: amps@contesting.com
Subject: Re: [Amps] Slow start-up of Amps on CW
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Tue, 12 Mar 2024 12:30:34 -0700
List-post: <mailto:amps@contesting.com>
On 3/12/2024 12:07 PM, Steve Harrison wrote:
I would definitely consider FT-991As,

Yaesu radios have long had problems with bandwidth on both CW and SSB, producing clicks and splatter that are much wider than rigs from Kenwood, Elecraft, and Flex. See this link, which is my analysis of ARRL Labs data of popular rigs on CW. It was done with their blessing -- they sent me the electronic output of their measurements.

http://k9yc.com/TXNoise.pdf

In following years, I've traced SSB signals with wildly excessive splatter to Yaesu rigs. Splatter extends 2.5 kHz on both sides of the signal (that is, in the suppressed sideband, and on the other side of the active sideband) only 20 dB. W4TV traced the cause to the way Yaesu is doing signal processing in the transmit chain, and there are no user adjustments to fix it.

This can be heard any time with ragchewers in the SSB bands, and clearly seen on good spectrum and waterfall displays that can get narrow, like the Elecraft P3. Clean signals show up on the waterfall as vertical bars with bandwidth of 2.5-2.8 kHz; these dirty signals show horizontal shoots from both sides of the bar on voice peaks.

73, Jim K9YC

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