[TenTec] Noise from Fans

[Rick - DJ0IP / NJ0IP]

Jon,

That horizontal vs. vertical fins only applied to when the heat sink is
mounted on the back panel or sides of a box.  Doesn't apply when it is top
mounted (of course).

This was one of the complaints of the Ten-Tec transceivers.  They always had
horizontal fins on the back.  Probably better facilitated mounting the
transistors.  (I guess).

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)


-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of k6jek
Sent: Friday, March 07, 2014 12:42 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Noise from Fans

Nicely done.
 
Not on Ten-Tec but on other gear I've built temperature controllers. Most of
the time the fans run at a snail's pace and make essentially zero noise.
They only pick up the pace when they need to. Some ham offers a nice little
kit but I can't seem to find the contact information.

Incidentally, a friend who does thermal analysis as part of his engineering
practice pointed out that horizontal fins on heat sinks work poorly without
a fan. He threw out some numbers but I've forgotten them. I seem to recall
quite a difference between horizontal and vertical fins with the same
surface area. This was after I built a home brew AM transmitter with giant,
horizontally-finned heat sinks for the MOSFETs. I do remember him saying it
takes very little air from a fan to dramatically improve the situation. So
that's what added, just a little bit of moving air.

Jon

On Mar 6, 2014, at 3:02 PM, K8JHR wrote:

> Here is my solution - using very quiet computer fans.  See the link at the
bottom of the page:    "Cooling Fan Project"
> 
> http://k8jhr.com/project_links.html
> 
> I sometimes use a small resistor to slow them down, but they run on 12v
and usually spec out around 15-19 dB noise factor.
> 
> I just could not spend over $40 on the TT fan, when I could make one for
less than $10 - including buying a brand new fan.  Mine are CoolerMaster
fans that cost me $7 I think.
> 
> Maybe my plan will spur some other ideas.
> 
> ------------------------- K8JHR ---------------------
> 
> 
> On 3/6/2014 5:21 AM, Rick - DJ0IP / NJ0IP wrote:
> 
>> At the time, most small PC towers had small case fans that ran on 12v,
> 
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