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Re: [RFI] Noisy transmitters...somewhat long...

To: rfi@contesting.com
Subject: Re: [RFI] Noisy transmitters...somewhat long...
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Tue, 23 Sep 2014 21:39:03 -0700
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On Tue,9/23/2014 8:10 PM, donovanf@starpower.net wrote:
The cleanest by far is the K3. The dirtiest by far is the FTdx5000.
The FTdx5000 is so dirty that its essential to install a bandpass
filter on the output of the transceiver, otherwise strong transmitted
noise is heard on many other bands. The bandpass filter completely
cleans up the problem.

Yes, BUT -- as my plots of ARRL data show, the FTDX5000 chews up 4-5 times more of the band on CW than does a K3, and bandpass filters won't help that, nor will they help phase noise on the same band (our CQP example, and Field Day). :) Another way of looking at it is that in terms of amplitude of the sideband trash, the FTDX5000 is more than four orders of magnitude worse than the K3. The surprise (to me) was the TS590S, a $1250 radio that was only one order of magnitude worse than the K3.

IMO, we all need to be leaning on the mfrs to clean up their act, just as Rob Sherwood did for the receivers. And we need to lean on ARRL to stop blessing every rig they test. IMO, the Yaesu and ICOM rigs shouldn't even be sold!

73, Jim K9YC
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