{"id":9778,"date":"2017-04-23T20:15:00","date_gmt":"2017-04-23T10:15:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2017\/04\/23\/difx-my-new-ne602-rig-is-on-the-air\/"},"modified":"2025-07-22T03:16:13","modified_gmt":"2025-07-21T17:16:13","slug":"difx-my-new-ne602-rig-is-on-the-air","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2017\/04\/23\/difx-my-new-ne602-rig-is-on-the-air\/","title":{"rendered":"DiFX! My New NE602 Rig is On the Air"},"content":{"rendered":"
<\/a><\/div>\n

Pete would call this a DiFX: a transceiver that is Different from a BITX. This started with my effort to get an Si5351 working with a little 1 inch square OLED screen. Tom Hall AK2B helped me with the software (thanks Tom). Once I got that done, I figured I could build a simple receiver with a homebrew 11 MHz crystal filter, two NE602 chips, and an LM386 AF amplifier. That was working great, then Pete told me to turn it into a transceiver. I used some of Pete’s boards (thanks Pete). <\/b>

<\/b> The Epiphyte transceivers also use two NE602’s, but they ingeniously switch the BFO and VFO between the two chips. I didn’t switch the oscillators — instead I switched the inputs and outputs of the two chips using two DPDT relays (thanks Jim). A third DPDT relay switches the antenna between T and R, and turns on and off the PA stage and the AF amplifier. <\/b>

<\/b> This is a DIFX, but there is some BITX circuitry in there. The power amplifier stages are right out of the BITX Module, as is the AF amplifier (thank again Farhan). <\/b>

<\/b> The only real problem I ran into had to do with the very low power out of the NE602 VFO mixer on transmit and the impedance matching between the NE602 and the PA chain. I had to increase the gain on the first RF amp (pre-driver) using ideas from Steve Weber’s 40 meter SSB CW QST contest rig (thanks Steve). I experimented with various connections between the NE602 and the BP filter. Finally I got it going. <\/b>

<\/b> The heat sink on this one is different too: it is just the chassis. The IRF 510 is bolted (insulated) to the aluminum box. <\/b>

<\/b> I fired it up this afternoon and in spite of horrible conditions on 40, quickly had a nice rag chew with KJ4ZMV in Indiana. I haven’t even built a mic amp yet! I am running the D-104 right into the NE602 balance modulator. There are no signs of unwanted modulation or spurs. <\/b>

<\/b> FB! TRGHS! VIVE LA DIFFERENCE! <\/b><\/p>\n

<\/a><\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Pete would call this a DiFX: a transceiver that is Different from a BITX. This started with my effort to get an Si5351 working with a little 1 inch square OLED screen. Tom Hall AK2B helped me with the software (thanks Tom). Once I got that done, I figured I could build a simple receiver … Continue reading “DiFX! My New NE602 Rig is On the Air”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":9779,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[42,65,408,66,41,211,23],"tags":[],"class_list":["post-9778","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-40-meters","category-bitx40module","category-difx","category-farhan","category-juliano-pete","category-ne602","category-ssb"],"_links":{"self":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/9778","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=9778"}],"version-history":[{"count":1,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/9778\/revisions"}],"predecessor-version":[{"id":9781,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/posts\/9778\/revisions\/9781"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media\/9779"}],"wp:attachment":[{"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/media?parent=9778"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/categories?post=9778"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.homebrewradio.us\/blog\/wp-json\/wp\/v2\/tags?post=9778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}