05-01-2019, 02:43 PM
Given my partial 'fail' trying to get some absolute results for OZ2M - and my Spectrum Analyser being in a non-functioning state (must get back to that one day), I contemplated using my SDR dongle to get further details as to the levels of spurious signals being generated by my Pi-WSPR project. My dongle is one of the 820T series which means that it really doesn't go below 30MHz. It's ok for checking the 6M output signal but not for 10, 14, 18 and 21 MHz.
I built up an up-converter yesterday to use in front of the SDR and was able to do screen grabs from SDR# to help confirm the in-band signal levels. The HF ones look pretty good and are limited by the noise floor observed. I haven't yet optimised the up-converter's LO level and that might improve the noise floor but, anyway,....
The SDR image grabs are at the bottom of the web page SDR Up-Converter Project (at http://www.vk4adc.com/web/general-projec...er-project ) because there are too many, and are too big in total, to add directly to this post. Open each image in a new tab or Save-image-as to see them in better detail.
If nothing else, they help confirm the tabulated values provided in an earlier post.
I built up an up-converter yesterday to use in front of the SDR and was able to do screen grabs from SDR# to help confirm the in-band signal levels. The HF ones look pretty good and are limited by the noise floor observed. I haven't yet optimised the up-converter's LO level and that might improve the noise floor but, anyway,....
The SDR image grabs are at the bottom of the web page SDR Up-Converter Project (at http://www.vk4adc.com/web/general-projec...er-project ) because there are too many, and are too big in total, to add directly to this post. Open each image in a new tab or Save-image-as to see them in better detail.
If nothing else, they help confirm the tabulated values provided in an earlier post.
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.