11 Dec
2013
11 Dec
'13
8:20 p.m.
Subject:
Re: [44net] Raspberry Pi - FM transmitter
From:
David Ranch <amprgw(a)trinnet.net>
Date:
12/11/2013 04:49 AM
To:
AMPRNet working group <44net(a)hamradio.ucsd.edu>
Hello Tom,
One of my elmers tried setting something similar up for WSPR but even with adding the
various filters, the harmonics on the higher frequencies were very significant and went
well out of the HAM bands!
Well, the article says that the harmonics must be 43dB
down to meet FCC regulations, or maybe 40dB
when reading the complicated if-then-else-if sentences in those paragraphs (why not use a
table?).
That is quite harsh, for a 10mW transmitter. 1uW is not a lot of power. A homeplug
device probably transmits
a lot more than that.
Rob