Unwanted harmonics or just close

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MI3JXA
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Last seen: 10 months 1 week ago
Joined: 2014/12/25 - 17:34
Unwanted harmonics or just close

Hi,

I have had no joy getting decodes on my own wspr transmissions between my shed and my attic on my raspberry pi using some of the software
out there specifically for the pi. I am getting decodes when I use rpitx to transmit a wav file I created. The wav file is a recording of a wsjt-x transmit
with some ssb modulation applied using rpitx's scripts.

My pi is transmitting through an untuned 1/4 length 20m dipole in my attic through a low pass filter. My TS-820s in the shed is connected to a tuned 20m
long wire antenna. There's meters between the antennas. I'm getting unwanted harmonics on the kenwood around about 14.06/7/8MHz and a few
above the transmit frequency. I get two decodes from the kenwood which is passing audio to my computer. The first decode is on frequency, and second
either 10Hz or 100Hz up (from memory).

Are these harmonics normal as the radios are so close and am I right in calling them harmonics?

One last thought is that the converted wav file is modulated for ssb with a 2.5KHz low pass filter using the rpitx scripts. Have tried my best but haven't been
able to address the fact the ssb convert script is really designed for voice...just thought I would mention that.

Many thanks,

Chris
MI3JXA