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Successfully using a micro fan to keep K2 cool

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dw-4

Successfully using a micro fan to keep K2 cool

I happened to have one of these in my parts bins and it seems to work
just fine.
It sets on top of the unit in right-rear, on the heatsync.
I have it limited by a 47ohm resister soldered to the switched DC inside
the unit.
For standard qso usage, it keeps the heatsync just slightly warm to the
touch.
And its so tiny it has very little cosmetic effect on the unit.

I would suggest Elecraft manufacture this as an accessory, providing a
clamp assembly.

12VDC Micro Fan
Model: 273-240 | Catalog #: 273-240
1.6" square, .39" depth

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Ken Kopp-3

Re: Successfully using a micro fan to keep K2 cool

I've mounted several sizes of "muffin" fans to rubber
pipe caps. They're handy for cooling projects and
the rather soft rubber caps won't scratch finishes.

73! Ken Kopp - K0PP
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TR K2 #838

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by dw-4

How noisy is it ?

One idea I've had for a long time is to remove the elecraft fan on
the rear of K2 and find a hose of the proper diameter, somehow
mounting it in a semi-permanent fashon. at the other end of the
hose, a box with a big fan that can really blast some serious air
through the K2. Put the box on the floor or in the next room so you
don't have to hear it.

Any thoughts ?

TR, WB6TMY K2 S/N 838

At 09:24 AM 5/27/2009 -0700, you wrote:

>I happened to have one of these in my parts bins and it seems to work
>just fine.
>It sets on top of the unit in right-rear, on the heatsync.
>I have it limited by a 47ohm resister soldered to the switched DC inside
>the unit.
>For standard qso usage, it keeps the heatsync just slightly warm to the
>touch.
>And its so tiny it has very little cosmetic effect on the unit.
>
>I would suggest Elecraft manufacture this as an accessory, providing a
>clamp assembly.
>
>12VDC Micro Fan
>Model: 273-240 | Catalog #: 273-240
>1.6" square, .39" depth

Tel: . . . 707-832-4304

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AC7AC

Re: Successfully using a micro fan to keep K2 cool

CONTENTS DELETED

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dave.wilburn

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by TR K2 #838

With so many high volume low speed (and thus low noise) fans out
there, I would have a hard time justifying doing more than setting
one up on the heat sink on top (for 100w version). But operating
styles and locations vary, so YMMV.

73

Dave Wilburn
NM4M

W B Reese wrote:

> How noisy is it ?
>
> One idea I've had for a long time is to remove the elecraft fan on
> the rear of K2 and find a hose of the proper diameter, somehow
> mounting it in a semi-permanent fashon. at the other end of the
> hose, a box with a big fan that can really blast some serious air
> through the K2. Put the box on the floor or in the next room so you
> don't have to hear it.
>
> Any thoughts ?
>
> TR, WB6TMY K2 S/N 838
>
> At 09:24 AM 5/27/2009 -0700, you wrote:
>> I happened to have one of these in my parts bins and it seems to work
>> just fine.
>> It sets on top of the unit in right-rear, on the heatsync.
>> I have it limited by a 47ohm resister soldered to the switched DC inside
>> the unit.
>> For standard qso usage, it keeps the heatsync just slightly warm to the
>> touch.
>> And its so tiny it has very little cosmetic effect on the unit.
>>
>> I would suggest Elecraft manufacture this as an accessory, providing a
>> clamp assembly.
>>
>> 12VDC Micro Fan
>> Model: 273-240 | Catalog #: 273-240
>> 1.6" square, .39" depth
>
> Tel: . . . 707-832-4304
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>

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TR K2 #838

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by AC7AC

Well, I like mine cool. In my experience, cool equipment has fewer
breakdowns and lasts longer. Not only that, it has less drift.

There is a menu in K2 to calibrate the temperature probe that
controls the fan. I have mine set to a much higher temperature than
what it actually is. This makes the fan come on at a lower
temperature. I just put up with the noise.

My K2/100 drifts about 70 Hz from a cold turn on in the mornings to
"ambiant." If I begin rag chewing and really pound away it will
drift another 40 Hz. I live with this every day, and although it
gives me something to do while rag chewing, but I'd be happy to
improve the temperature stability further and reduce it a bit more.

So, Ron,

It got hot enough you couldn't put your hand on it... How far did it drift ?

TR, WB6TMT K2 S/N 838

At 10:24 AM 5/27/2009 -0700, you wrote:

>Good grief! How cool do you want to keep the K2?
>
>Several years ago I ran some tests for one of the engineers to check the
>K2's frequency stability vs. temperature. Several testers and I cycled the
>K2's internal temperature by hooking on a suitable dummy load and
>transmitting for extended periods so the 100 watt PA would cook the insides.
>(Some actually did the "brick on the key" routine from what I recall.)
>
>Mine was heated enough I couldn't keep my hand on the PA heat sink and the
>internal air temperature was well above 120F. That was done dozens of times
>with no deleterious effects on the K2 or the amp, then or since.
>
>I have used a 4" square muffin fan sitting in rubber feet on top of the K2
>running at a slow speed, not to keep it any cooler but to avoid the noisy
>little fan on the back from running.
>
>Ron AC7AC
>
>
>
>-----Original Message-----
>How noisy is it ?
>
>One idea I've had for a long time is to remove the elecraft fan on
>the rear of K2 and find a hose of the proper diameter, somehow
>mounting it in a semi-permanent fashon. at the other end of the
>hose, a box with a big fan that can really blast some serious air
>through the K2. Put the box on the floor or in the next room so you
>don't have to hear it.
>
>Any thoughts ?
>
>TR, WB6TMY K2 S/N 838
>
>
>______________________________________________________________
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>
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>
>
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>05/27/09 07:50:00

Phil Kane-2

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by AC7AC

On 5/27/2009 10:24 AM, Ron D'Eau Claire wrote:

> I have used a 4" square muffin fan sitting in rubber feet on top
> of the K2 running at a slow speed, not to keep it any cooler but
> to avoid the noisy little fan on the back from running.

How are you feeding power to the fan? I have one on top, but
it runs from a separate connection to the line that feeds the
K2, so it runs even when the front panel switch is turned
"off". I have to open the breaker that feeds the K2, the
KAT100, and the Rigrunner Plus as well as the fan to stop the
fan if I am not running the radio. I would really like to have
the fun turned on and off with the K2.

-- 73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

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AC7AC

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by TR K2 #838

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AC7AC

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by Phil Kane-2

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Don Ehrlich

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by TR K2 #838

This has been suggested many times by others.. now it is my turn to repeat
it I guess:

I mounted a 12 volt 4 inch muffin fan in a simple enclosure and placed it
on top of my K2 blowing downward. I put a suitable resistor in series with
the 12 volt supply so that the fan turned slowly and made no noise at all.
The muffin fan ran all of the time and the little microfan in the K2
(almost) never came on while running cw or ssb.

Don K7FJ

> How noisy is it ?

>
> One idea I've had for a long time is to remove the elecraft fan on
> the rear of K2 and find a hose of the proper diameter, somehow
> mounting it in a semi-permanent fashon. at the other end of the
> hose, a box with a big fan that can really blast some serious air
> through the K2. Put the box on the floor or in the next room so you
> don't have to hear it.
>
> Any thoughts ?
>

Don Wilhelm-4

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by Phil Kane-2

Phil,

Solder some wires to the terminals of D12 inside the K2 (the cathode is
positive 12 volts and turns off with the K2 switch). Make a small notch
in the rear panel above the coaxial power jack sufficiently large to run
the wires through would be my preferred routing for the wire, but make
your own choices on the routing..

73,
Don W3FPR

Phil Kane wrote:

> On 5/27/2009 10:24 AM, Ron D'Eau Claire wrote:
>
>
>> I have used a 4" square muffin fan sitting in rubber feet on top
>> of the K2 running at a slow speed, not to keep it any cooler but
>> to avoid the noisy little fan on the back from running.
>>
>
> How are you feeding power to the fan? I have one on top, but
> it runs from a separate connection to the line that feeds the
> K2, so it runs even when the front panel switch is turned
> "off". I have to open the breaker that feeds the K2, the
> KAT100, and the Rigrunner Plus as well as the fan to stop the
> fan if I am not running the radio. I would really like to have
> the fun turned on and off with the K2.
>
> -- 73 de K2ASP - Phil Kane
> Elecraft K2/100 s/n 5402
>
>

Greg - AB7R

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by dw-4

If someone is looking for something with a bracket, the fan option for the TT Orion
actually fits very nicely onto the K2/100 heatsink. I used it often especially
when running RTTY.

-------------------------
73,
Greg - AB7R
Whidbey Island WA
NA-065

On Wed May 27 13:05 , "Ron D"Eau Claire" sent:

>Mine is connected directly to the power supply too, Phil, but I switch off
>the supplies when I leave the shack, so it's off when the rigs are shut
>down.
>
>Ron AC7AC
>
>-----Original Message-----
>
>On 5/27/2009 10:24 AM, Ron D'Eau Claire wrote:
>
>> I have used a 4" square muffin fan sitting in rubber feet on top
>> of the K2 running at a slow speed, not to keep it any cooler but
>> to avoid the noisy little fan on the back from running.
>
> How are you feeding power to the fan? I have one on top, but
> it runs from a separate connection to the line that feeds the
> K2, so it runs even when the front panel switch is turned
> "off". I have to open the breaker that feeds the K2, the
> KAT100, and the Rigrunner Plus as well as the fan to stop the
> fan if I am not running the radio. I would really like to have
> the fun turned on and off with the K2.
>
>-- 73 de K2ASP - Phil Kane
> Elecraft K2/100 s/n 5402
>
>______________________________________________________________
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>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: [hidden email]','','','')">[hidden email]
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Don Wilhelm-4

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by Don Ehrlich

Don,

Not to argue with your success, it is generally more efficient to use
the fan to direct air AWAY from the surface to be cooled rather than
toward it. The heat of the fan energy is not added to the air that is
doing the cooling, but then those muffin fans do not add very much heat
energy, so it may be a moot point for the KPA100 heat sink.

73,
Don W3FPR

Don Ehrlich wrote:

> This has been suggested many times by others.. now it is my turn to repeat
> it I guess:
>
> I mounted a 12 volt 4 inch muffin fan in a simple enclosure and placed it
> on top of my K2 blowing downward. I put a suitable resistor in series with
> the 12 volt supply so that the fan turned slowly and made no noise at all.
> The muffin fan ran all of the time and the little microfan in the K2
> (almost) never came on while running cw or ssb.
>
> Don K7FJ
>
>

AC7AC

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by Don Ehrlich

CONTENTS DELETED

The author has deleted this message.

Phil-W6TQG

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by Phil Kane-2

I connect one side of the fan to power and the other to the PA Key Out
connector of my K2/100, so that the fan runs only while transmitting. Of
course the optimum method depends on the operator.

73 de Phil/W6TQG

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Phil Kane
> Sent: Wednesday, May 27, 2009 12:51 PM
> To: Ron D'Eau Claire
> Cc: [hidden email]
> Subject: Re: [Elecraft] Successfully using a micro fan to keep K2 cool
>
> On 5/27/2009 10:24 AM, Ron D'Eau Claire wrote:
>
> > I have used a 4" square muffin fan sitting in rubber feet on top
> > of the K2 running at a slow speed, not to keep it any cooler but
> > to avoid the noisy little fan on the back from running.
>
> How are you feeding power to the fan? I have one on top, but
> it runs from a separate connection to the line that feeds the
> K2, so it runs even when the front panel switch is turned
> "off". I have to open the breaker that feeds the K2, the
> KAT100, and the Rigrunner Plus as well as the fan to stop the
> fan if I am not running the radio. I would really like to have
> the fun turned on and off with the K2.
>
> -- 73 de K2ASP - Phil Kane
> Elecraft K2/100 s/n 5402
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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>

Phil-W6TQG

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by Phil Kane-2

If you want the external fan to run only while transmitting, connect one
side of the fan to power and the other to the PA Key Out connector of
the K2/100. Of course the optimum method depends on the operator.

73 de Phil/W6TQG

Bill Coleman-2

Re: Successfully using a micro fan to keep K2 cool

In reply to this post by AC7AC

On May 27, 2009, at 1:24 PM, Ron D'Eau Claire wrote:

> Good grief! How cool do you want to keep the K2?
>
> ...
>
> I have used a 4" square muffin fan sitting in rubber feet on top of
> the K2
> running at a slow speed, not to keep it any cooler but to avoid the
> noisy
> little fan on the back from running.

If you want to run RTTY or other high-duty cycle modes with more than
about 25 watts for any length of time, you need some supplemental
cooling for the K2. A muffin fan like you've described would be perfect.

I used a muffin fan much like yours for a while, and then I broke one
of the blades and had to replace it. The replacement is a 2 1/2"
muffin fan mounted the same way. I've been able to run 50 watts RTTY
through many contests with no ill effects.

Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Web: http://boringhamradiopart.blogspot.com
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

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