I recently found an error on my PCB used for the WSPR-TX-LP1 transmitter.
The error affects the unpopulated low pass filter.
What boards have the error?
This error can be found in Version 1 of the PCB with Revision number 5, 6 and 7. The version and revision can be found printed on the bottom side of the PCB. Se picture for an example of a revision 5 PCB.
Who will be affected of the error?
The error will effect you if you will be using the internal low pass filter with surface mount capacitors.
Who will not be affected?
· Users with a Mezzanine LP4 board will not be affected as the on board LP filter is not populated in this case.
· Also if you are using an external low pass filter you will not be affected.
· Finally, if you are using the internal low pass filter but are using through-hole mounted capacitors you will not be affected.
What exactly is the error?
The error is that the solder pads for the SMD capacitors named C1 to C4 are not connected. They should have a PCB trace to the round pad above/below them but does not.
See pictures.
Fixing the problem
To fix this problem, either bridge the gap with solder as seen on the right, or place a small wire between the SMD pad and the round pad as seen to the left.
This error will be fixed in future PCB revision starting with V1R8
73
//Harry