{"id":3882,"date":"2021-06-03T19:56:56","date_gmt":"2021-06-03T23:56:56","guid":{"rendered":"https:\/\/jeremyclark.ca\/wp\/?p=3882"},"modified":"2026-01-04T11:55:07","modified_gmt":"2026-01-04T16:55:07","slug":"hf-receiver-testing-zero-if-direct-conversion_b","status":"publish","type":"post","link":"https:\/\/jeremyclark.ca\/wp\/telecom\/hf-receiver-testing-zero-if-direct-conversion_b\/","title":{"rendered":"HF Receiver Testing – Zero IF Direct Conversion_b"},"content":{"rendered":"\n

Introduction<\/h2>\n\n\n\n

In the previous post (Ref.1)<\/a> I examined the signal flow through the RPiZonia Zero IF Direct Conversion Receiver by examining the Block & Level testing diagram. Figure 1 shows the schematic diagram. Figure 2 shows the Block & Level testing diagram. <\/p>\n\n\n

\n
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Fig.1 RPiZonia DIP Receiver Schematic Layout<\/figcaption><\/figure>\n<\/div>\n\n\n

<\/p>\n\n\n

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Fig.2 RPiZonia Block & Level Q Channel DIP<\/figcaption><\/figure>\n<\/div>\n\n\n

Reception SW Station 11.930MHz<\/h2>\n\n\n\n

In order to receive a shortwave station on 11.930MHz, the Si514 mixer is set at 10KHz below this frequency to 11.92MHz. To do this a Python program to write the Si514 is loaded into the Raspberry Pi Thony Python IDE as shown in Figure.3. The frequency is loaded into the variable FON. <\/p>\n\n\n\n

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Fig.3 Python Program si514_prog_write_34.py<\/figcaption><\/figure>\n\n\n\n

The baseband output of the RPiZ LPF is fed into a simple USB sound card that plugs into the RPi3. In order to decode the baseband, I use the amateur radio program Quisk (Ref.2<\/a>). I downloaded Quisk 4.1.15 from the RPi repository. I noticed that the default audio setting for Quisk was sound card hw:0. Adjusting the Quisk config settings over VNC viewer took time, so I used the procedure of Bastien Bourdon (Ref.3<\/a>) to adjust the boot order of sound cards, so that the USB sound card is hw:0 if it is present. Otherwise the boot order remains the same. This involves using terminal to edit several config files, which was very well explained. Figure 4 shows the received baseband, with the SW station located in the middle at 10KHz. It is decoded using the Quisk AM selection. Figure 5 shows a check on the Si514 signal of 11.92MHz. <\/p>\n\n\n\n

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Fig.4 Quisk Baseband Showing Rx Signal at 10KHz<\/figcaption><\/figure>\n\n\n\n
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Fig.5 Si514 Unbalanced Pickup on Mixer Pin2<\/figcaption><\/figure>\n\n\n
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\"\"<\/a>
HF Amateur Radio Blog Topics<\/figcaption><\/figure>\n<\/div>\n\n\n

Please send your comments, questions and suggestions to:
contact:<\/a><\/p>\n\n\n\n

\"YouTube<\/a>
YouTube Channel<\/figcaption><\/figure>\n\n\n\n

References<\/h2>\n\n\n\n

#1. – “HF Receiver Testing \u2013 Zero IF Direct Conversion_a”,
https:\/\/jeremyclark.ca\/wp\/telecom\/hf-receiver-testing-zero-if-direct-conversion<\/a>\/

#2. – “Quisk SDR Software”
http:\/\/james.ahlstrom.name\/
<\/a>
#3. – “Quickly setup a USB sound card on a Raspberry Pi 3”,
https:\/\/bastienbourdon.com\/2016\/raspberrypi-usb-sound\/<\/a>

#4 – “RPiZonia HF Zero IF Direct Conversion Receiver”
https:\/\/www.clarktelecommunications.com\/design.htm<\/a>
<\/a>
#5. – “HF Telecommunications Learn by Simulation”,
https:\/\/www.clarktelecommunications.com\/simulation.htm<\/a>
<\/p>\n","protected":false},"excerpt":{"rendered":"

Introduction In the previous post (Ref.1) I examined the signal flow through the RPiZonia Zero IF Direct Conversion Receiver by examining the Block & Level testing diagram. Figure 1 shows the schematic diagram. Figure 2 shows the Block & Level testing diagram. Reception SW Station 11.930MHz In order to receive a shortwave station on 11.930MHz,… Continue reading HF Receiver Testing – Zero IF Direct Conversion_b<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":3884,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,4],"tags":[],"class_list":["post-3882","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-elec","category-telecom","entry"],"_links":{"self":[{"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/posts\/3882","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/comments?post=3882"}],"version-history":[{"count":13,"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/posts\/3882\/revisions"}],"predecessor-version":[{"id":12775,"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/posts\/3882\/revisions\/12775"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/media\/3884"}],"wp:attachment":[{"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/media?parent=3882"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/categories?post=3882"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jeremyclark.ca\/wp\/wp-json\/wp\/v2\/tags?post=3882"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}