[Elecraft] RFI on K3s

[Rick Robinson]

Dave, you have brought up something I have wondered about for some time. I
have had my kx3 for three plus years and have been on many lists and most
everyone wants a smps instead of a small 3 amp linear supply. Radio Shack
and many others made these supply's and they are plentiful at Hamfests for
10-20 USD. It seems like a lot of folks operate from home and want a smps .
Why, if the weight would not be a factor, do folks want to take a chance on
a potentially noisy ps ? I use a big linear supply which also feeds my
IC7200 but if the need arises I use a small linear supply. I do have a nice
switcher which I do not notice any noise but it is used a bench supply. It
is a Alinco something 330. Variable output and has noise shift. Anyway, I
don't want to hijack this thread, just wondering.

On Monday, June 20, 2016, Dave B via Elecraft <elecraft at mailman.qth.net>
wrote:

> Cant help thinking, that the charge to discharge "Efficiency" is probably
> no better than a good linear PSU, but you do I guess get the "Off grid"
> option for EMCOM work..
>
> There ARE (RF)quiet SMPS's out there, but not priced in a way that will
> suit the average Ham's budget.   You get what you pay for.  Oh, and they
> tend to be large too, due to the filtering.
>
> Quite honestly, for "Amateur" work, where the rig will usually spend most
> of it's life in RX, a linear PSU is just fine.   Plus, you can fix them
> when things fail.   Try that with a modern well suppresed QRO SMPS!..
>
> 73.
>
> Dave G0WBX.
>
>
> ~~~ Original message.
>
> From: Marc Veeneman<mveeneman at yahoo.com>
> To:pubx1 at af2z.net
> Cc:elecraft at mailman.qth.net
> Subject: Re: [Elecraft] RFI on K3s
> Message-ID:<768828B9-AF69-479E-8E38-2FBEEC234B0F at yahoo.com>
> Content-Type: text/plain;       charset=us-ascii
>
> My PowerWerx supply DOES generate those drifting noise spikes, ruining CW
> on 80 meters for me.  I have yet to find a 13.8 volt switching supply that
> can provide 25 quiet amps.  I've gone entirely to batteries rather than use
> quiet but inefficient linear supplies.
>
>  Now I only have SMPS noise when recharging the batteries.  So I leave
> that for non-hamming hours.  More testing is needed, but I did find one
> SMPS for LiFePO4 batteries that seemed RFI free.  It's an Optimate brand
> product but only produces 5 amps.
>
>
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-- 
Rick, W8ZT

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