WSPR Without Tears
We'd suggest printing out the schematic and measuring and recording the voltages listed. Actually, it's
probably simpler to just measure the voltages (and write them down) on both sides of R5, both sides of
L1, and both sides of R2.
The higher voltage across R5 is the power supply rail. It should be between 4.5-5.0 volts. The voltages
on both sides of L1 should be about the same when not transmitting and one significantly lower than
the other when transmitting (LED on). The voltages on both sides of R2 should be about the same
whether transmitting or not. The voltages at R2 will vary depending on how pot R1 is set. The
important part is that they're above 0.0 volts and have pretty much the same voltage on either side of
R2.
If you find voltages that differ significantly from what's listed on the schematic, start by looking for bad
solder joints. If that fails, let us know because we're probably looking at a bad component, which we
will be happy to replace.
TAPR (c) 2018-2019 “WSPR Without Tears” 15 Of 20 Version 2.1
05/20/2019
