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Re: Topband: Desktop Power Supply Brand/Noise Question

To: topband@contesting.com
Subject: Re: Topband: Desktop Power Supply Brand/Noise Question
From: Gary K9GS <garyk9gs@wi.rr.com>
Reply-to: garyk9gs@wi.rr.com
Date: Sun, 21 Jul 2013 09:57:06 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Another couple of points.

About 10 years ago, at a local ham-fest, there was a guy selling brand new Lambda power supplies. They were adjustable from 10-15 V and he had models ranging from 20-50 amps. They were switching supplies.

I couldn't pass these up and bought 7 or 8 of them. They were a bit on the noisy side RF wise...nothing horrible but enough to be noticeable. I ended up wiring in some CorCom line filters that I had around the house and it completely removed the noise. I've used these supplies for years including being used on a number of different DX-peditions....they are light and fairly small. This fix worked just great.

The CorCom filters are frequently seen at ham-fests and surplus outlets although you can buy them new through component distributors like Digi-Key and Mouser. There are many models and they differ in mainly two categories. Voltage/Current capacities and the mechanical connections for bringing line voltage in and out. The most common have Fast-On type spade terminals or solder posts but I've seen many variations.



On 7/20/2013 4:11 PM, Gary K9GS wrote:
Hi Clay,

One thing you might want to check.

See if you can get inside the power supply...disconnect it first. Take a look on the PCB near the power connector. There may be a space on the PCB where you can install a power line filter....something like a CorCom or similar. Sometimes they leave them out on some models to save money.

If you Google CorCom you find info on the different models...just be sure to get the correct ratings. They also sell filters with built-in IEC connectors. An IEC connector is what the power cord plugs into. you may be able to get one that works.



On 7/20/2013 9:27 AM, Clay Melhorn wrote:
Hello to the group.I recently built an AMD quadcore machine I intend to eventually replace my trusty XP Pro machines. Foolishly got in a hurry to complete the build and purchased a PS from a local shop.It supplies the power required without issue, I have discovered why the price was so good.Jim Brown will love this one, virtually no RFC filtering, you get what you pay for and I know betterjust didn't realize the noise from 40m and down would be SO intense particularly on a Delta pennantthat points back toward the shack's general direction. The XP machines are very quiet.Live and learn. Question: Looking at another "good deal" how do the COOLER MASTER PS's rate for RFC filteringor are there others brand I should be looking at? http://www.newegg.com/Product/Product.aspx?Item=N82E16817171031&nm_mc=EMC-EXPRESS072013&cm_mmc=EMC-EXPRESS072013-_-EMC-072013-Index-_-PowerSupplies-_-17171031-L04B Will likely not waste time trying to make a Cadillac out of the Yugo I purchased.

Thankyou in advance,

Clay Melhorn N9IO Bonfield, ILWebmaster: KARS - Kankakee Area Radio Society - W9AZ http://www.w9az.com/

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73,

Gary K9GS

Greater Milwaukee DX Association: http://www.gmdxa.org
Society of Midwest Contesters: http://www.w9smc.com
CW Ops #1032   http://www.cwops.org

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