• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Chinese MiniPA-100 Kits

Rick Miller

Member
Apr 1, 2015
27
40
23
53
IMG_0326.JPG
 

G4XRZ

New Member
Jan 31, 2022
6
3
3
65
Sorry for taking so long to respond. I had a hell of a time getting a good picture. I've attached a pdf file that I have marked up so you can see exactly where I cut.
Hello Rick. I really appreciate the info and images which make perfect sense and are totally clear. I do apologise for it taking up your time. These things always seem to take longer than we expect unfortunately. :(
Your help has been amazing. I very much look forward to building my units. I have ordered what appears to be a suitable heatsink from china - nicely oversized ! :)and also one locally to give me another option.

One last question if I may ?. Are you connecting the main PCB directly to the heatsink or are you using some form of insulation between the underside of the board and the heatsink ? (not the PA - the actual PCB) The reason I ask is that although the traces that are non GND are coating in some kind of white substance, I am not sure of the insulating properties of such. It does seem fairly resilient material but I would be interested to know your thoughts.


Thank you again. 73 DE G4XRZ - Joe
 
Last edited:

Rick Miller

Member
Apr 1, 2015
27
40
23
53
Hello Rick. I really appreciate the info and images which make perfect sense and are totally clear. I do apologise for it taking up your time. These things always seem to take longer than we expect unfortunately. :(
Your help has been amazing. I very much look forward to building my units. I have ordered what appears to be a suitable heatsink from china - nicely oversized ! :)and also one locally to give me another option.

One last question if I may ?. Are you connecting the main PCB directly to the heatsink or are you using some form of insulation between the underside of the board and the heatsink ? (not the PA - the actual PCB) The reason I ask is that although the traces that are non GND are coating in some kind of white substance, I am not sure of the insulating properties of such. It does seem fairly resilient material but I would be interested to know your thoughts.


Thank you again. 73 DE G4XRZ - Joe
The PCB should mount directly to the heatsink. The white masking on the bottom of the PCB should insulate just fine. I've heard others have tried to add a bit of insulating material only to discover oscillations. I suppose if you're worried about it you could use some nail polish to thicken up the masking, but I've not had any issues with this.
 

G4XRZ

New Member
Jan 31, 2022
6
3
3
65
Thanks Rick.
I may put a very piece of Kapton on the non GND tracks only. (the white coated parts). The Kapton is incredibly thin.
I can imagine people using small heatsinks having issues with thermal transfer from sink to PCB / components. The heatsinks they show in the images on ebay / ali etc are crazy small though. The ferrites can have quite varying properties with differing temperatures, The temperature variations from an adequate heatsink should definitely not cause an issue but some places are selling these units on a heatsink the size of the PCB ! - yikes !. That will certainly cause many issues only one of which is ferrite stability. :)
Many thanks again.
Joe.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Roadstar:
    good morning to all and Happy Thanksgiving to all:giggle:
  • dxBot:
    Greg T has left the room.
  • @ BJ radionut:
    solar storm report
  • @ k3zl:
    I am installing a G5RV and wanted to know if there is a way to enhance prior to installation.