[Elecraft] Walwart power?

[Jim W7RY]

Terry has the right idea!  A 3 terminal regulator PROPERLY buy-passed acts 
as a super filter. There is no need for any additional filtering. The output 
is extremely clean and regulated.

I would stay with a transformer type to cut down on the possibility of 
switching power supply noise.

I would also use a variable regulator and set it for the desired voltage 
i.e. 13.8 volts. A variable regulator uses just 2 resistors for setting the 
voltage. I would also use a little higher voltage wallwart so the regulation 
does not go away. When regulation goes away because of low input voltage, so 
does the filtering effect of the device.

73
Jim W7RY

----- Original Message ----- 
From: "John R. Lonigro" <johnlon at sbcglobal.net>
To: <Elecraft at mailman.qth.net>
Sent: Tuesday, December 23, 2008 5:13 PM
Subject: Re: [Elecraft] Walwart power?


> Hey, everyone:
> While using a wall-wart directly is probably not a good idea, you might 
> want to see what Terry  (WA0ITP) did to solve the problem.  Essentially, 
> he epoxied an LM7812 and heatsink to the back of a wall-wart, added a 
> couple of capacitors, and checked the output for any ripple.  Finding 
> none, he dubbed it the "Motel Power Supply" and is good to go for QRP 
> operation from a motel.  But you can go to his website (below) and read 
> for yourself.  He has quite a few good ideas on that website.
>
> http://www.wa0dx.org/wa0itp/mps.html
>
> Happy holidays to all!
>
> 73's, John AA0VE
> michael taylor wrote:
>> On Tue, Dec 23, 2008 at 5:43 PM, Burke Jones <tacgear at gmail.com> wrote:
>>
>>> Could I use a 12V 500ma to power my KX1 when at home?
>>>
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