CRT ss9900 cooler

Hello,

I just bought a new ss9900 v4 and i would like to install a fan on the heatsink to avoid heating problems.
But what is the right air flow direction?
Fan blow out heat from heatsink to ouside through the fan? or fan push in fresh air into the heatsink from outside?

Many thx for your help,

7351's

Fabrice

I would fit it blowing away from the radio so it pulls the air through the heatsink.
As the left one in the picture.
But that is just me lol.

Hi Fabrice,

The old fan question of suck or blow does the rounds every now and then. 


Unless you possess a degree in 'fluid dynamics' and some fairly complex computational modelling you'll never get a 'definitive' answer.

The heatsink for this radio is pretty well designed and so long as there is unrestricted air flow to allow normal convection to occur you shouldn't really need any sort of fan at all, but I know for some it's a popular 'modification' especially for 'tweaked' higher RF output.

I think for me personally I wouldn't want to put on small inefficient fans that can be rather noisy and especially if you run a power/desk microphone where those type of noises are easily picked up on your transmissions let alone impeding your own listening abilities. There'll be times when that 'back of the box' signal might be missed and the droning of fans might get to you after a while if running a long DX session.


That said, totally up to you though and if the radio is installed in an enclosed 'go-box' or some such you may have to assist cooling in some way or another.

All the best,
Victor

Many thx Alan and Victor for your replies.
I have tested my ss9900 this afternoon during 3h and I did not noticed any overheat so I do not plan to add fan for the moment but if I try it later I will share the result.
For my first test of this TX I made 2 QSO with Brazil so I would say it looks fine 

73 51

Fabrice

That's great news Fabrice and very well done with the contacts to Brazil!

Always, always, the fan should suck the hot air away from the heatsink. Always. 

73, Tom.

https://noctua.at/en/should-the-fan-be-mounted-sucking-away-from-the-heat-sink-or-blowing-onto-the-heat-sink

MadDogMcQ wrote:

Always, always, the fan should suck the hot air away from the heatsink. Always. 

73, Tom.

I would personally go with the fan drawing in cool air onto the HS, it's the way heat sinks and radiators are mostly used in PC's.

Got 4 hf radios in front of me and all 4 fans blow out away from the radio.
I know a pc fan blows through the heatsink but that normally has a case fan the other side blowing out and maybe one on the front blowing in it's all about air flow with a computer.

For what's it worth, here is my 2 pence (now 4 pence with inflation).

I have the Anytone AT-6666 badge version of this radio which is housed in a box.

To help keep the radio cool (because I like my loooong overs) I have an old computer fan blowing air over the heatsink.

This does keep the heatsink and radio case cooler.

So, blowing air over the radio works for me

Ray

To save the hassle it’s going back to basics,keep the rig on low power 4w and attach a 100w burner to top of case and save the rig.

Just an idea

73’s

Naeem