<div dir="ltr"><div dir="ltr">Helmut, while tracing the DAC output in the two tone test it seems like it looses the packages at some point in the DSP chain and/or DSP doesn't work correctly. Noise floor jumps up and down sometimes in the baseband. That may be the cause why the IMD products are dancing there sometimes at the output of the Penelope.<br></div><div dir="ltr"><br></div><div dir="ltr">--<br><div dir="ltr"><div dir="ltr"><i><font color="#666666">73,</font></i><div><i><font color="#666666">Riho ES7AAZ</font></i></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Kontakt Riho B., ES7AAZ (<<a href="mailto:es7aaz@gmail.com">es7aaz@gmail.com</a>>) kirjutas kuupäeval K, 10. november 2021 kell 21:08:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">Helmut, it was a good idea to trace the DAC output. Thanks! I'm much clearer now. BTW, I'm using a Mercury for that which is actually a very good spectrum analyzer.<div><br></div><div>--<br><div dir="ltr"><div dir="ltr"><i><font color="#666666">73,</font></i><div><i><font color="#666666">Riho ES7AAZ</font></i></div></div></div></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Kontakt Riho B., ES7AAZ (<<a href="mailto:es7aaz@gmail.com" target="_blank">es7aaz@gmail.com</a>>) kirjutas kuupäeval K, 10. november 2021 kell 19:28:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Helmut, I don't have much lab instruments currently here. But I have a small 50Ω sma dummy load soldered to the piece of coax. If Penelope sees 50Ω dummy load the TX carrier signal looks damn clean. So, there is nothing wrong with Penelope here. If I connecting the Penelope to the PennyWhistle and sending singal out into the 20m delta loop and using small indoor antenna for RX the TX carrier looks terrible.</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Kontakt Riho B., ES7AAZ (<<a href="mailto:es7aaz@gmail.com" target="_blank">es7aaz@gmail.com</a>>) kirjutas kuupäeval K, 10. november 2021 kell 18:33:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">In Duplex there is only 15cm coax and opened T/R relay here So, no Mercury overdrive, more likely underload.</div><div dir="ltr"><br></div><div dir="ltr">--<br><div dir="ltr"><div dir="ltr"><i><font color="#666666">73,</font></i><div><i><font color="#666666">Riho ES7AAZ</font></i></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Kontakt Helmut Oeller (<<a href="mailto:dc6ny@gmx.de" target="_blank">dc6ny@gmx.de</a>>) kirjutas kuupäeval K, 10. november 2021 kell 18:2<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p>Not sure that you interpret TX display in Duplex mode correctly
!?</p>
<p>73, Helmut<br>
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<div>Am 10.11.2021 um 17:08 schrieb Riho B.,
ES7AAZ:<br>
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<div dir="ltr">Helmut, thanks for all tips and suggestions.
Sure, I will take a look into it what's going on here.
Fortunately I have a Pinocchio as well for measurements and
troubleshooting. Yes, the PowerSDR shows the signal how it's
going out from DSP. In Duplex mode it shows how the signal
going out from the radio.
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<div><i><font color="#666666">Riho ES7AAZ</font></i></div>
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<div dir="ltr" class="gmail_attr">Kontakt Helmut Oeller (<<a href="mailto:dc6ny@gmx.de" target="_blank">dc6ny@gmx.de</a>>)
kirjutas kuupäeval K, 10. november 2021 kell 17:07:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Riho, don't give up!
Penelope and Pennylane were (are) fine boards.<br>
Search for the reason. Check as already suggested signal
quality at the<br>
input of amp U6 (OPA2674), check 12V supply voltage for
ripple etc. and<br>
output match (T2). When I recall correctly PowerSDR shows
the base-band<br>
signal in TX mode and not the real output signal. Hence I
would<br>
recommend to use an external analyzer to evaluate the RF
signal.<br>
<br>
73, DC6NY<br>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><i><font color="#666666">73,</font></i><div><i><font color="#666666">Riho ES7AAZ</font></i><div><div><i><a href="https://www.qrz.com/db/ES7AAZ" target="_blank"><font size="1">www.qrz.com/ES7AAZ</font></a></i></div></div></div></div></div></div>