{"id":6003,"date":"2012-12-31T13:07:17","date_gmt":"2012-12-31T17:07:17","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=6003"},"modified":"2023-04-08T20:24:02","modified_gmt":"2023-04-09T00:24:02","slug":"the-continental-d323c-medium-wave-transmitter","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2012\/12\/the-continental-d323c-medium-wave-transmitter\/","title":{"rendered":"The Continental D323C medium wave transmitter"},"content":{"rendered":"\n

I found a 1981 Continental Electronics equipment catalog at an old transmitter site. These finds are great if one is interested in history and looking at the way things used to be done.  This particular transmitter is a 2,000 KW (2,000,000 watt) medium wave unit:<\/p>\n\n\n\n

\"Continental<\/a>
Continental Electronics D323C, Circa 1981<\/figcaption><\/figure>\n\n\n\n

I believe most units like this were destined for use by government broadcasters in either the middle east or Western Europe.\u00a0 I know there were several 1,000 KW medium wave stations in West Germany at one time. \u00a0 The Continental transmitter is basically two 1,000 KW units (323C) combined. \u00a0They used a modified version of Doherty modulation, that is called “Screen and Impedance,” which accurately describes how it works.\u00a0 More information from the Continental Catalog can be found here: Continental D323C.\u00a0 The tubes (or valves depending on where you are located) used in the D323C were 4CW25000A tetrodes as modulators and IPA the final was a pair of X2159, which is an impressive tube.<\/p>\n\n\n\n

\"EIMAC<\/a>
EIMAC X-2159 water-cooled power tetrode<\/figcaption><\/figure>\n\n\n\n

The tube sat anode up.\u00a0 The filament, grid, and screen connections are underneath.\u00a0 Cooling water was pumped through the two connections on the top at about 130 gallons per minute depending on the plate dissipation.\u00a0 With a 30\u00b0 C rise, that equals about 96,000 BTU per minute.\u00a0 The D323C had a dissipation of 400,000 watts for the carrier tube and 240,000 watts for the peak tube (640 KW total) under 100% modulation.\u00a0 That equals about 2 million BTU per hour.\u00a0 Notice the lifting hook, this tube weight in at 175 pounds.\u00a0 Tube date sheet here<\/a>.<\/p>\n\n\n\n

Continental no longer makes medium wave transmitters, their closest high powered broadcast product now is the 418\/419 and 420 HF (shortwave) transmitters.\u00a0 The 420D does a wimpy 500 KW using a solid-state modulator section.<\/p>\n\n\n\n

I remember in the early 1990’s when I was at the Harris plant in Quincy, they were working on a 1,000 KW solid state DX series AM transmitter for Saudi Arabia.  It had to be liquid cooled, which added another layer of complexity to an already complex system.<\/p>\n\n\n\n

I don’t know if there is much call for 2 MW medium wave transmitters anymore as there are more efficient ways to reach remote populations and I can’t even imagine what the electric bill would be like.<\/p>\n","protected":false},"excerpt":{"rendered":"

I found a 1981 Continental Electronics equipment catalog at an old transmitter site. These finds are great if one is interested in history and looking at the way things used to be done.  This particular transmitter is a 2,000 KW (2,000,000 watt) medium wave unit: I believe most units like this were destined for use … Continue reading The Continental D323C medium wave transmitter<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35],"tags":[32],"class_list":["post-6003","post","type-post","status-publish","format-standard","hentry","category-history","tag-am-transmitters"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/6003","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/comments?post=6003"}],"version-history":[{"count":9,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/6003\/revisions"}],"predecessor-version":[{"id":11471,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/6003\/revisions\/11471"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=6003"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=6003"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=6003"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}