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Heatsinking the BS170s in the U2?

Keith Maton
 

I've got four BS170s fitted to my U2 kit and will be getting it boxed up in the next few days.

Is there enough physical space there to fit four of these clip on heatsinks?


73 Keith, G6NHU
Andy Cutland
 

I would say no. What I have done in the past where space is tight is cut long strips of sticky copper foil the same width as the body of the fet. Seems to work ok

73's
De Andy
GJ7RWT


From: Keith Maton
To: "QRPLabs@..."
Sent: Wednesday, May 29, 2013 5:34 PM
Subject: [QRPLabs] Heatsinking the BS170s in the U2?

?
I've got four BS170s fitted to my U2 kit and will be getting it boxed up in the next few days.

Is there enough physical space there to fit four of these clip on heatsinks?


73 Keith, G6NHU
"andyfoad@..."
 

1)You would probably be able to get away with not heatsinking it.
Mine is running 9v with 100% duty cycle. Runs hot but no harm so far.

or

2)If you have left a reasonable lead length on the BS170's then
you can use these style heatsinks and just give the BS170's a little
twist and bend over to fit the alternative heatsinks in the link below.

They don't take so much space.



Link sends you to RS.

Hope this helps.

73 de Andy G0FTD
"Philip"
 

Keith

Break a 20mm fuse and clean the glass and gunk out of the metal end caps
These end caps are a perfect snug fit on the BS170 body.

Before pushing on, solder a bit of brass or copper to the end caps
to make some mass to sink the heat.
You can see mine in this picture (a curly piece of copper soldered to a cap)



Works a treat (break the fuse in a bag to save your eyes)

Philip G4JVF

--- In QRPLabs@..., Keith Maton <nentecular@...> wrote:

I've got four BS170s fitted to my U2 kit and will be getting it boxed up in the next few days.

Is there enough physical space there to fit four of these clip on heatsinks?



73 Keith, G6NHU

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