The posting to the list about not having an enclosure on a rig and what
can happen is the reason that I learned to make my own.? Too many projects
to buy enclosures that cost almost the price of the project in many cases.
So let me show you my latest enclosure for the 5W20A S/N 001 from
kitsandparts.com and the A added to the name is for Arnold because it
is a 1W on steroids.? :-)
The first photograph (...09.jpg) is the enclosure with one coat of Rustoleum primer
self etching from Home Depot paint department followed by one coat of color.
I was in a hurry to get the document done.? I have never seen self etching primer at
Wal*Mart and haven't looked at Ace.
Bottom is painted white with one coat of an old can of generic Wal*Mart.
Top is painted with one coat of Rustoleum Candy Apple Red (2X label
for primer plus paint).? Now this has got to be the closest to fire
engine red that I have found and this is my first use of it and it won't be my
last.? I love the bright color.? Hope the photo and your monitor does it
justice..
Second photo (...12.jpg) is the innards of the rig.? Couple of points.
Note the 'floor' mounting of the display.? I had some boards made up
at JLCPCB so that I could use the Keystone 621 right angle brackets from
Mouser for mounting and not have to put four holes in the front panel.
It is the QRPGuys circuit and parts.? My board layout as I set the kit
board aside for this project.
Also the 12mm x 20mm aluminum plates expoxied to the two PA transistors.
I found that a key down of 10 seconds without the heat sinks drove the
temperature to over 48 deg C (120 deg F for those that refuse otherwise).
With the heat sinks the temperature only went to 29 deg C.? Since I did
this transceiver with my parts and we hadn't come up with the kit heat
sinks, I tried the above in a pinch.?? If I can find the heat shrink
container, I'll try the kit setup and report in the document when I
release it.
The reason people use Al over Cu is that Al has twice the heat transfer
rate.
Third photo (...13.jpg) is the cover on.? I got the dimensions within
0.1mm for this case.? I need to work on the display nibbling, but will
3D print a border for it to hide the tool marks.
Yes, there are dust marks.? It was windy here at the time and I could
not get the parts from outside to the oven before some dust hit the
wet paint.? I may touch up later, but then it's going on the desk and
on the air.
Cost of enclosure was about $2 USD worth of Al.? The joy: priceless.
I try to keep unenclosed rigs away from the workbench when cutting is
in progress.
FYI
chuck, k7qo
