Square wave / harmonics

[inspector71]

Square wave / harmonics

[jnk0le]

You just need a simple low pass filter, to get rid of unwanted frequencies.

IMHO, currently PiFmRds works better, not RpiTx.

[ha7dcd]

Usually a simple low pass filter doesn't helps as the whole spectrum rich
in spuriouses when you take a look at closer look from spectrum analyzer.
You better build up your band pass filter for it and analyze before going
online.

You can find here more information about the 20m shield design:
https://www.tapr.org/pdf/DCC2015-QRPi-HA7DCD.pdf

On Sun, May 22, 2016 at 5:39 PM, jnk0le [email protected] wrote:

You just need a simple low pass filter to get rid of unwanted frequencies.

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#22 (comment)

[inspector71]

The task becomes too expensive if a filter is needed. I'm better off gutting the existing OEM unit and replacing it with a Pi plus a decent amplifier HAT. That way the money I'd waste on a filter gets spent on a useful HAT.

All the best.