Topband: Desktop Power Supply Brand/Noise Question

[Gary K9GS]

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/
>>
>> _________________
>> Topband Reflector
>>
>

-- 


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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