{"id":3842,"date":"2019-07-15T23:05:00","date_gmt":"2019-07-15T13:05:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2019\/07\/15\/the-fish-soup-10-homebrew-qrp-cw-transceiver\/"},"modified":"2025-07-21T16:10:39","modified_gmt":"2025-07-21T06:10:39","slug":"the-fish-soup-10-homebrew-qrp-cw-transceiver","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2019\/07\/15\/the-fish-soup-10-homebrew-qrp-cw-transceiver\/","title":{"rendered":"The “Fish Soup 10” Homebrew QRP CW Transceiver"},"content":{"rendered":"
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The box with the two grey knobs on the left is the Herring Aid 5, the receiver that took me 38 years to complete. The box on the right is a VFO I originally built for my first BITX40Module — it started out around 4 Mhz but I pulled turns off the coil until it was in the 40M CW band. The Altoids in near center has the buffers — a 40673 MOSFET and a 2n3904 BJT. The box in the back holds the Tuna Tin 2. There the oscillator has been reconfigured as an amp. A relay switches the output from the buffers between the receiver and the transmitter. That big switch in the center switches the antenna and the 12 V for T\/R. The circular black thing is piezo buzzer used for CW sidetone — I have it glued to the board upside down to keep the volume down. <\/b><\/div>\n

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The whole thing is mounted on a kitchen cutting board. A breadboard! <\/b><\/div>\n

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The most difficult part of all this was getting the needed 800 Hz drop in TX freq on transmit. You need to do this with a rig like this or else you won’t be in the other fellow’s passband. I did a lot of cut and try — in the end I put a 5 pf cap across the coupling cap from VFO to buffer. This 5 pf cap switches in on transmit via a small relay. It works. I just spoke to N8AFT out in Columbus, Ohio and I was in his passband. <\/b><\/div>\n

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So five transistors in the receiver, two in the transmitter and three in the VFO\/Buffer. So it is the Fish Soup 10. <\/b><\/div>\n

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It puts out about half a watt. On CW. I am feeling virtuous and vaguely superior. I’ve made several more contacts. It all works very well and is a lot of fun. <\/b><\/div>\n

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The box with the two grey knobs on the left is the Herring Aid 5, the receiver that took me 38 years to complete. The box on the right is a VFO I originally built for my first BITX40Module — it started out around 4 Mhz but I pulled turns off the coil until it … Continue reading “The “Fish Soup 10” Homebrew QRP CW Transceiver”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":3843,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[116,167,85,87,168],"tags":[],"class_list":["post-3842","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cw","category-herring-aid-5","category-minimalist-radio","category-qrp","category-tuna-tin-2"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/comments?post=3842"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3842\/revisions"}],"predecessor-version":[{"id":3845,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/3842\/revisions\/3845"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media\/3843"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=3842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=3842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=3842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}