Gary wrote:
Pete KE9OA wrote:
Oh, that's ok Gary. I hope you find the one you are looking for. Most of
that stuff from Surplus Sales of Nebraska came from the Inventory Disposal
sale from Rockwell-Collins, which means that it is of good quality.

Pete

"Gary" wrote in message
. ..
Pete KE9OA wrote:
start he

http://www.mouser.com/Search/Refine....N=1323038&No=0

if you know the parameters of the heat sink in question, a search
through these pages on the Mouser website should give you what you need.
there are several pages to go through, so you do have your work cut out
for you!

Pete

"Gary" wrote in message
...
I'm finding that if you're looking for any heatsink that there are
zillions of places to pick one up and that if you are looking for
a particular sink that it is a futile task. With a little help
from my friends, I'm putting together the mosfet amp in the 2006
handbook and I've pretty much secured everything on the parts list save
the heatsink. It is the same unit that was used on the original FARA
amp as well. Anyone have this beast in the junk bin or know of a
purveyor who might?? I've scoured the web and no joy so far. The sink
is an AAVID part (#244609B02). Thanks in advance all.

Gary
ka9rao

Thanks for the advice. Mouser very nearly had a replacement. The unit
has horizontal fins instead of vertical and as my application is
convection-only, this likely tips the balance on effectiveness (safety).
Did find another site and it looks like a good one. It's Nebraska Sales
and Surplus. I've purchased from them before and have no complaints.
Thanks again for the quick replies.

Gary


Thanks one and all for the suggestions. Started soldering this evening
so there's no turning back...

Gary

I've found several good heatsinks and power supplies at Goodwill. I
purchased an old stereo amp that had 6 100 watt channels. The last one
I bought cost less than $20. I am really surprised at the way people
cast things like this off. It is now the heart of my home
entertainment system.

Jimmie

On Tue, 22 Jul 2008 00:36:31 -0700, Gary wrote:

Pete KE9OA wrote:
Oh, that's ok Gary. I hope you find the one you are looking for. Most of
that stuff from Surplus Sales of Nebraska came from the Inventory Disposal
sale from Rockwell-Collins, which means that it is of good quality.

Pete

"Gary" wrote in message
. ..
Pete KE9OA wrote:
start he

http://www.mouser.com/Search/Refine....N=1323038&No=0

if you know the parameters of the heat sink in question, a search
through these pages on the Mouser website should give you what you need.
there are several pages to go through, so you do have your work cut out
for you!

Pete

"Gary" wrote in message
...
I'm finding that if you're looking for any heatsink that there are
zillions of places to pick one up and that if you are looking for
a particular sink that it is a futile task. With a little help
from my friends, I'm putting together the mosfet amp in the 2006
handbook and I've pretty much secured everything on the parts list save
the heatsink. It is the same unit that was used on the original FARA
amp as well. Anyone have this beast in the junk bin or know of a
purveyor who might?? I've scoured the web and no joy so far. The sink
is an AAVID part (#244609B02). Thanks in advance all.

Gary
ka9rao

Thanks for the advice. Mouser very nearly had a replacement. The unit
has horizontal fins instead of vertical and as my application is
convection-only, this likely tips the balance on effectiveness (safety).
Did find another site and it looks like a good one. It's Nebraska Sales
and Surplus. I've purchased from them before and have no complaints.
Thanks again for the quick replies.

Gary


Thanks one and all for the suggestions. Started soldering this evening
so there's no turning back...

Gary

OK, I found a copy of the article that you're building. If it's the same
article that's in the 2007 handbook (titled "A Broadband HF Amplifier Using
Low-cost MOSFETs" bu WA2EBY), then maybe I can help with the heatsink.
I found a photo in the article that shows pretty clearly the heatsink as mounted
on the rear of the chassis. I'm guessing at the dimensions of the rear panel of
the chassis. The box is given as 3.5x6x8, but it's hard to conclude whether the
rear panel is 3.5x6 or 3.5x8.
I assumed the rear panel to be 3.5x8, did a bit of extrapolation and estimated
the size of the heatsink to be approximately 5.5" wide, 2.75" tall, 1.25" fin
height.
Newark shows a heatsink meeting those measurements (approximately) at
http://www.newark.com/54M0782/fans-h...ik-sk-85-75-sa,
and appears to be in stock. The given measurements for that heatsink are 160mm
wide, 75mm tall and 40mm fin height, with a thermal resistance of 1.2 degC/watt.
No clear area in the middle, so you'll likely have to drill & tap the base to
mount the transistors.

The heatsink itself is reasonable enough, but the caveat is that it's stocked in
the UK and drop shipped from there, with a $20 handling fee.

I stopped searching when I found that heatsink, so you might do a more thorough
search using those approximate measurements and find something suitable, and
less expensive.

Cheers!!!
==============

Dave M

Never take a laxative and a sleeping pill at the same time!!

Gary wrote:


I'm finding that if you're looking for any heatsink that there are
zillions of places to pick one up and that if you are looking for
a particular sink that it is a futile task. With a little help
from my friends, I'm putting together the mosfet amp in the 2006
handbook and I've pretty much secured everything on the parts list save
the heatsink. It is the same unit that was used on the original FARA
amp as well. Anyone have this beast in the junk bin or know of a
purveyor who might?? I've scoured the web and no joy so far. The sink
is an AAVID part (#244609B02). Thanks in advance all.

Gary
ka9rao

Aavid makes so many heat sinks that you almost have to buy custom to get
what you need.

Usually your best bet with heatsinks for a one-off is to find one that
meets your needs and use it, even if it's not identically the same thing
as the plans.

If you can find one with specifications get one that matches the thermal
conductivity to the air as what you have; if you can't get one with
specifications look for about the same or greater total surface area and
fin spacing.

The handbook used to have directions on bending heatsinks from sheet --
you basically make a bunch of nested 'U's with heat sink compound
between. I don't know how well that works, or if they still do it. I
suspect that for natural convection you'll be fine with that.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Gary wrote:


I'm finding that if you're looking for any heatsink that there are
zillions of places to pick one up and that if you are looking for
a particular sink that it is a futile task. With a little help
from my friends, I'm putting together the mosfet amp in the 2006
handbook and I've pretty much secured everything on the parts list save
the heatsink. It is the same unit that was used on the original FARA
amp as well. Anyone have this beast in the junk bin or know of a
purveyor who might?? I've scoured the web and no joy so far. The sink
is an AAVID part (#244609B02). Thanks in advance all.

Gary
ka9rao

Don't worry about finding the exact, go the next bigger heatsink! You
will not be sorry you did.

While you are at it, consider mounting a muffin fan on the sink to push
air though the ribs (if the plans don't already call for one.) Again,
you won't be sorry you did!

I have not seen the plans you are speaking of, but I am taking it for
granted it is a leen-e-air.

Regards,
JS

"Gary" wrote in message
...


I'm finding that if you're looking for any heatsink that there are
zillions of places to pick one up and that if you are looking for
a particular sink that it is a futile task. With a little help
from my friends, I'm putting together the mosfet amp in the 2006 handbook
and I've pretty much secured everything on the parts list save the
heatsink. It is the same unit that was used on the original FARA amp as
well. Anyone have this beast in the junk bin or know of a purveyor who
might?? I've scoured the web and no joy so far. The sink is an AAVID
part (#244609B02). Thanks in advance all.

Gary
ka9rao

Have you tried: