[hpsdr] To Fan or Not to Fan

[John Ackermann N8UR]

Dave, note the newly updated errata sheet.  The 5V regulator is 
operating within spec, but as a linear regulator it's dumping a lot of 
heat moving 1.35 amps from 13.8 down to 5 volts.

My personal recommendation is to replace the 2.2 ohm 10 watt dropping 
resistor ahead of the regulator with either two 1.8 10 watt in series, 
or two 6.8 10 watt in parallel.  That doesn't reduce the total heat, but 
moves more of it into the resistors and out of the regulator.

John
----

g4fre at g4fre.com wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> running my lpu off 13.8v to power penny, ozy and mercury, after 4 hours 
> on receive i can burn my fingers on the lpu heatsink
> I have reverted to my  pico-psu 90 which hardly gets warm under such 
> conditions. I dont get noise issues, or none i can notice in my urban 
> environment
> Dave
> ww2r
> Tim O'Rourke writes:
>> ***** High Performance Software Defined Radio Discussion List *****
>> I am awaiting Pandora and wondering about fan requirements in general.
>> I have mine mounted in a mini-atx case with 5 watt pa and the 
>> temperature in the case does not seem to be an issue. That was the 
>> case until I installoed the LPU which disapates significant heat when 
>> left on for extended periods. Assuming that we will be using LPU for a 
>> while it seems like a fan for Pandora may be necessary even with out a 
>> high output PA.
> 
> 
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