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Walwart power?

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Burke Jones-2

Walwart power?

Could I use a 12V 500ma to power my KX1 when at home?

Burke Jones
N0HYD
Sent from my iPhone
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Dick Dievendorff

RE: Walwart power?

My guess is that the output of the average wall wart will have enough noise
and ripple to make it unsuitable for use with a radio.

Dick, K6KR

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Burke Jones
Sent: Tuesday, December 23, 2008 2:43 PM
To: [hidden email]
Subject: [Elecraft] Walwart power?

Could I use a 12V 500ma to power my KX1 when at home?

Burke Jones
N0HYD
Sent from my iPhone
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Don Wilhelm-4

Re: Walwart power?

In reply to this post by Burke Jones-2

Burke,

There are exceptions to everything, but in general, wall warts are not a
good power supply choice.
For most of the 12 volt wall warts, the no-load voltage soars to as much
as 17 volts and when loaded to full rated current, the voltage will sag
below 12 volts.

Now, if you can find one that is well regulated, it *might* be OK, but
it has been a long time since I have seen regulated wall warts advertised.

Most wall warts are designed to be used with equipment that contains an
internal regulator and filtering.

I would suggest looking for a 13.8 volt 3 (to 6) amp power supply.

73,
Don W3FPR

Burke Jones wrote:
> Could I use a 12V 500ma to power my KX1 when at home?
>
> Burke Jones
>
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Burke Jones-2

Re: Walwart power?

Thanks guys! You have confirmed my suspicions.....

Burke
Sent from my iPhone

On Dec 23, 2008, at 5:23 PM, Don Wilhelm <[hidden email]> wrote:

> Burke,
>
> There are exceptions to everything, but in general, wall warts are
> not a good power supply choice.
> For most of the 12 volt wall warts, the no-load voltage soars to as
> much as 17 volts and when loaded to full rated current, the voltage
> will sag below 12 volts.
>
> Now, if you can find one that is well regulated, it *might* be OK,
> but it has been a long time since I have seen regulated wall warts
> advertised.
>
> Most wall warts are designed to be used with equipment that contains
> an internal regulator and filtering.
>
> I would suggest looking for a 13.8 volt 3 (to 6) amp power supply.
>
> 73,
> Don W3FPR
>
> Burke Jones wrote:
>> Could I use a 12V 500ma to power my KX1 when at home?
>>
>> Burke Jones
>>

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michael taylor-3

Re: Walwart power?

In reply to this post by Burke Jones-2

On Tue, Dec 23, 2008 at 5:43 PM, Burke Jones <[hidden email]> wrote:
> Could I use a 12V 500ma to power my KX1 when at home?

The KX1 manual suggests it uses 300-700 mA on transmit, depending on
voltage. Assuming you don't need to rectify (or use a ultra-low
dropout voltage regulator) it should work but may limit your power
output to less than 3W max.

Some home / small office Ethernet hubs and switches use largish
wall-warts, I have a couple with 12Vdc, 1A wall-warts.

You may need to add a low-pass filter to filter any 60 Hz interference
and harmonics, such a passive 2nd or 3rd-order RC or LC low-pass
filter.

-Michael, VE3TIX
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N0tk

Re: Walwart power?

In reply to this post by Burke Jones-2

Burke

A better choice would be a power supply for a laptop computer. These are regulated units and will treat your KX1 more kindly than a wallwart. The wallwarts are generally unregulated so their voltage will be higher at light loads than what you see printed on their case.

Hope to work you Kx1 to KX1 sometime.

Dan N0TK

Highlands Ranch, CO

-----Original Message-----
From: Burke Jones <[hidden email]>
To: [hidden email] <[hidden email]>
Sent: Tue, 23 Dec 2008 3:43 pm
Subject: [Elecraft] Walwart power?

Could I use a 12V 500ma to power my KX1 when at home?

Burke Jones
N0HYD
Sent from my iPhone
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w1az@comcast.net

Re: Walwart power?

In reply to this post by Burke Jones-2

I have a Jameco ReliaPro plug in transformer. It looks pretty much the same
as the standard wall wart, but is actually a transformer instead of switching
based supply. There doesn't seem to be any noise and I think the regulation
is pretty good. The product number is 170245. It's rated at 12V/1000ma. I've
used it with both a KX1 and a K1.

Bernie
W1AZ

On Tuesday 23 December 2008, Burke Jones wrote:

> Could I use a 12V 500ma to power my KX1 when at home?
>
> Burke Jones
> N0HYD
> Sent from my iPhone
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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>
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Bob Nielsen-2

Re: Walwart power?

In reply to this post by Burke Jones-2

I use one of these with my K2 and it should work fine with a K1 or
KX1 as well:

http://www.mfjenterprises.com/Product.php?productid=MFJ-4103

Small, lightweight, quiet and works over a wide range of input voltages.

Bob N7XY
On Dec 23, 2008, at 2:43 PM, Burke Jones wrote:

> Could I use a 12V 500ma to power my KX1 when at home?
>
> Burke Jones
> N0HYD
> Sent from my iPhone
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
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John Lonigro

Re: Walwart power?

In reply to this post by michael taylor-3

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 <[hidden email]> wrote:
>
>> Could I use a 12V 500ma to power my KX1 when at home?
>>
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Jim W7RY

Re: Walwart power?

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" <[hidden email]>
To: <[hidden email]>
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 <[hidden email]> wrote:
>>
>>> Could I use a 12V 500ma to power my KX1 when at home?
>>>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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> Elecraft web page: http://www.elecraft.com
>

list1

RE: Walwart power?

I did this a few years ago. After mounting the parts for the regulator on
the outside of the walwart, I covered it with a large legos block from my
kids toy box. The kids never missed it.
Steve, W2MY

-----Original Message-----
On Behalf Of 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..............

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rkayakr

Re: Walwart power?

In reply to this post by Burke Jones-2

Burke

I often use a walwart when traveling with my KX-1. It has never harmed the KX-1, caused a black hole to open or caused other grave consequences such as bad tone reports. I generally use a 1 amp wart. The 6 watts you get from a 1/2 amp wart might be a bit skimpy on transmit.

Bob
Kd8CGH