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Measurements of Finals Temp changes with and without Fan shroud...

Mark Hatch
 

A couple weeks ago I released a fan shroud for the "tall" Sunil case. See https://www.thingiverse.com/thing:3790450

Since then, I was curious on its effectiveness vs just heat sinks or heat sinks and a fan.  So here are the results....

Test Setup:
- ubitx v4 with stock PA transistors and the new larger heat sinks being shipped with the case.
- Noctua 1800RPM 80mm 12V fan (Blowing in)
- Little Volt/Temp guage that I mounted on my front panel (unfortunately, I accidentally purchased the fahrenheit version...) Search for: " DROK Car Voltage Temperature Display" on amazon.
- Unfortunately I took the "shroud measurements" on a different day than "no shroud". So focus on temp gain from "ambient" as a comparison
- First set of tests were 5 minutes @ 40m into a dummy load
- Second set was FT8 CQ into a dummy load until the watchdog timer terminated transmissions.




The Results....

No Shroud .            Ambient                  After 5 Min Xmit             Temp Gain
Fan Off                   81F                          128F                               +47 
Fan On                   76F                           94F                                +18

WITH Shroud .        Ambient                  After 5 Min Xmit             Temp Gain
Fan Off                   83F                          128F                               +45
Fan On                   81F                           98F                                +17     

It looks like 5 minutes into a dummy load implies that a Fan is probably as good as a Fan and a Shroud. 

However, I went on to measure FT8 CQ (into Dummy, until watchdog kicked me out)

WITH Shroud .        Ambient                  After 5 Min Xmit             Temp Gain
Fan Off                   84F                          105F                               +21                      
Fan On                   82F                           88F                                +6   

Of course the missing measurement is the FT8 CQ with just a Fan. Thought of this test *after* I put everything back together. :-( .

Next time I tear things apart I will update with this missing result. Meanwhile, if anybody out there wants to run this test, I would sure be interested in the gain.

73
Mark
AJ6CU