Mark AJ6CU released a fan shroud for the “tall” Sunil case a short while back. See https://www.thingiverse.com/thing:3790450
He was curious to check out its effectiveness, against just using the supplied heat sinks or using the heat sinks with a fan. So here are the results….
- 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 gauge that was mounted on the front panel (measurements in Fahrenheit)
Search for: ” DROK Car Voltage Temperature Display” on amazon if you want one!
Unfortunately Mark took the “shroud measurements” on a different day than the”no shroud measurements”. So focus on the temperature gain over “ambient temperature, for a true comparison.
The first set of tests were for 5 minutes on 40m into a dummy load.
The second set was on FT8 CQ into a dummy load, until the FT8 watchdog timer terminated transmissions.
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
Operating for 5 minutes into a dummy load suggest that a fan is probably as good as a fan and a shroud.
On FT8 CQ (into Dummy load, until the watchdog kicked TX off):
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. Mark thought of this test *after* he had put everything back together. 🙁 .