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Re: Topband: WATCH OUT !!Did you get a new cable modem from Comcast? Arr

To: topband@contesting.com
Subject: Re: Topband: WATCH OUT !!Did you get a new cable modem from Comcast? Arris Modem equal lots of QRM
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Thu, 23 Oct 2014 22:26:04 -0700
List-post: <topband@contesting.com">mailto:topband@contesting.com>
On 10/23/2014 3:33 PM, JC wrote:
So watch out  is you have Comcast cable modem, it is necessary to choke the
cable and the AC cord with FT240 # 31. With this fix ,the noise dropped from
s8 to s0 but still audible at Doug receiver.

By now this should be "Ham Radio 101" -- that is, assume that EVERYTHING with a digital clock, and EVERY switching power supply is a noise source, and be prepared to choke them using my RFI tutorial as a starting point. It's also a VERY good move to replace all switching power supplies with a linear supply, or even a linear supply float charging a battery. I'm doing exactly that with cable modem, WiFi Router, CATV box, Internet "radio," etc. In most cities, it's possible to find linear wall warts at second hand stores for a buck or less, and I also buy them at ham flea markets.

And all the gear in my shack (except for computers and power amp), run off my small solar system.

73, Jim K9YC
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