ozQRP MST3 Construction And Operation Manual page 32

Step 10: Relay
The relay can only go in one way, so simply insert into the board and solder.
Step 11: Electrolytic capacitors
These are polarized and it is very important that they go in the correct way. Electrolytic
capacitors have a line down the side of the case indicating the negative lead and the positive
lead is the longer lead. The PCB component overlay has a '+' mark to indicate the hole for the
positive lead.
MST3 Construction and Operation Manual – Issue 1 Page 32