The heat shim

265 views
Skip to first unread message

Alex Varo

unread,
Feb 23, 2021, 10:20:00 PM2/23/21
to Hermes-Lite

Does anyone have better dimension instructions for the heat shim? I'm having a hard time understanding the one that has been posted on github.

Steve Haynal

unread,
Feb 24, 2021, 2:07:13 AM2/24/21
to Hermes-Lite
Hi,

Just to double check, have you found the jpeg diagram and .stl files here:

Also, the pictures of the heatshim here:

and in this list if you search, may help you make better sense of the drawings.

73,

Steve
kf7o

Alex Varo

unread,
Feb 24, 2021, 7:01:42 AM2/24/21
to Hermes-Lite
Yes, Steve I have seen the Jpeg. I don't understand the diagram on the right hand side, and where the hole should be drilled. Thats ok I've decided to not use the shim, no means of constructing it.

Thank
Alex
W6ACT

Gary Fiber

unread,
Feb 28, 2021, 12:52:57 AM2/28/21
to Hermes-Lite
Any feel for the correct angle and actual part size? FreeCad does not seem to allow finding out size measurements from the FCStd drawing. The current Hermes heat sinking is poor, I'd be afraid to try 5 watts output. The hand drawing gives some values, but not enough especially when FreeCad will support all dimensions needed. I own a Hermes-Lite 2.0 build 9.

Steve Haynal

unread,
Feb 28, 2021, 1:20:57 AM2/28/21
to Hermes-Lite
Hi Gfiber1952,

Didn't you receive a heatshim with your recent order of the HL2 from Makerfabs? You can get a feel for size and orientation from the wiki pictures:

And this post:

The github also includes .stl and .step files. There are free viewers for these. This is what is used for manufacturing. In fact, you can click on the .stl directly from github and it will display the 3D model.

The Hermes-Lite heat sinking is not poor. We've only had the heatshim addon for less than 6 months. Many, including myself, have operated the HL2 at 5W following the guidelines of sanding the slot, applying thermal paste, and using a nut and bolt for pressure for years. I've done several back to back 5W WSPR transmits as tests. The HL2 will disable TX if the temperature gets too hot, above 55C, so there is a little danger.

73,

Steve
kf7o
Reply all
Reply to author
Forward
0 new messages