{"id":1406,"date":"2012-10-17T21:36:55","date_gmt":"2012-10-18T05:36:55","guid":{"rendered":"https:\/\/k7nvh.com\/wordpress\/?p=233"},"modified":"2022-04-05T22:23:44","modified_gmt":"2022-04-06T05:23:44","slug":"iris-transmitter-part-2","status":"publish","type":"post","link":"https:\/\/digitalnigel.com\/wordpress\/?p=1406","title":{"rendered":"Iris Transmitter Part 2"},"content":{"rendered":"

So, for a bit of an update on my transmitter project. I’ve made a few minor wire fixes to the board. Mostly just adjusting what outputs on the ATmega are connected to what.<\/p>\n

Most of the work involved has been software. I’ve got a ham friend working with the same PLL chip, and I’ve used his code as an excellent reference on interfacing with the PLL.<\/p>\n

I’ve also got an existing APRS implementation, however it was blocking code, so I’ve been spending a lot of time rewriting my APRS implementation to be interrupt driven. Hopefully I’ll end up with a lot cleaner APRS generation.<\/p>\n

I’ve also redone the filters. The original filters I had designed had been, to put it lightly, awful. They were mostly an RF absorber. After replacing the filters with something reasonable, I’m measuring about a 1\/4W CW output. Maybe just a little higher.<\/p>\n

The processor is an ATmega328P, which talks to a ADF7012 PLL synthesizer to generate the 144.39MHz signal. The signal is modulated by means of a VCXO acting as the reference for the PLL. Total output power was brought up by means of an RF FET amplifier stage, to a level of approximately 250-300mW. The board required a power supply of a regulated 5V input, and included a linear regulator onboard to supply 3.3V to the ADF7012.<\/p>\n

Overall, so far I’m impressed with the results. Hopefully soon i’ll have APRS working totally, and I can start transmitting. Who knows, maybe I’ll show up on the map in your neighborhood.<\/p>\n

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So, for a bit of an update on my transmitter project. I’ve made a few minor wire fixes to the board. Mostly just adjusting what outputs on the ATmega are connected to what. Most of the work involved has been … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13,10],"tags":[],"class_list":["post-1406","post","type-post","status-publish","format-standard","hentry","category-electronics","category-ham-radio"],"_links":{"self":[{"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1406","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1406"}],"version-history":[{"count":1,"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1406\/revisions"}],"predecessor-version":[{"id":3227,"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1406\/revisions\/3227"}],"wp:attachment":[{"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1406"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1406"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/digitalnigel.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1406"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}