[AMPS] Sucking instead of Blowing (was - This guy is gotta be kidding!)

[Ian White, G3SEK]

2 wrote:
>>Unfortunately that isn't at all relevant to forced-air cooling, where
>>the airflow is very turbulent and the flow pattern is quite different. 
>>
>€  fasten seatbelts
>
>>Air is blasted at the upstream side of the tube, cooling it well, but
>>the flow breaks away from the surface half-way around to form a
>>turbulent wake. 
>
>€  Not with the quiet, slow speed fan in a SB-220, Ian..
>
All practical cooling fans create turbulence. It's easy to check with a
streamer of smoke.

>>The downstream side is only cooled by eddies in the
>>wake, and there may even be negative pressure on the opposite side. 
>>
>>There is absolutely no doubt that cooling is less good on the downstream
>>side. 
>
>€  The  colour of the ink on the 3-500Z glass does not indicate this. 
>
Thank you - that's the information I was asking for. Can you confirm
that the ink is on the opposite side from the fan?

> >The only questions are: how much less good, and does it matter?
>>That's why I was looking for separate evidence whether the color of the
>>markings is dependent on the orientation of the tube.
>>
>€  Denial of reality - the greatest glitch in the human psyche. Alas. 

How very true for all of us. That's why I was asking for simple
information about what the reality IS, in the SB-220 and the L4-B.


73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.com/g3sek

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