Collins 30K Series Transmitter Data Site

The purpose of this site is to act as central resource, or clearinghouse, for information, schematics, images, and tech tips on the Collins 30K series of transmitters. Many have been very generous over the last year, sharing tech information, scans of Collins docs, and service information with me, and this is my effort to give back to the 30K community. Thanks to John Dilk K2TQN efforts, the story of my 30K-1 station appeared in John’s “Vintage Radio” column in QST during late 2007. Since that time, I’ve been sent numerous images, photos, and stories from other hams about the 30K series. You can view the complete story at

W1UJR StationOne of the greatest challenges I faced with the restoration of my 30K-1, and now with the 30K-4, is the lack of information. I felt collecting all this information which has been graciously shared with me, would be helpful to other 30K owners, and hams. Unfortunately much information have been lost over the preceding 60 years since the first 30K rolled off the line at Collins Radio. This site is an effort to capture, and share, what remains.

Let me begin with a few words about the 30K series. I have been a Collins fan since I was first licensed in the 1990s, but really fell in love with the 30K when I viewed one at the home of a fellow ham who owned the commercial version of the 30K-1, known as a 30K-5. Very similar in design, the 30K-4 and 5 are commercial models offering two discreet tank circuits for rapid frequency changes but lack the band switching arrangement of the 30K-1.

The 30K series was designed by Collins engineer Warren Bruene in 1945 and was first offered for sale the following year. It was, in some way, a “Hail Mary Pass” for Collins as the war contacts were drying up, and yet amateur radio operation was still banned during wartime. Collins forecast a pent up demand from the return of GIs from the war, and with the elimination of the wartime ban on amateur operation, hoped the 30K would fill the gap. Sales were somewhat limited as the 1946 cost of the 30K-1 transmitter and 310A exciter was $1450, the equivalent to approximately $15,000 in today’s dollars. According to Jay Miller’s, KK5IM, excellent publication, “The Pocket Guide to Collins Amateur Radio Equipment 1946-1980”, less than 100 of the 30K-1 are known to have been built, and few survive today, making the 30K-1 series a rare bird indeed. Less accurate records exist on the commercial variants, suffice to say they are not at all common.

Visually, the 30K transmitter series are most impressive to behold, housed in a cabinet 5 ½ feet tall, finished in black wrinkle paint, and weighing over 350lbs, this is a big transmitter! The design of the unit is pure art deco; vertical and horizontal chrome accent strips, a large window for viewing the 4-125 final tube, and a most impressive meter panel at the top of the cabinet, also housed behind glass. Looking every inch a serious transmitter, the 30K is of robust construction along the lines of commercial broadcast gear. Emission modes are CW and Fone (AM), with the plate input power given as 500 watts on CW, and 375 watts on AM. The 30K-1 offered coverage from 80 to 10 meters using two plug-in output coils. With a tube compliment of 11 tubes in the transmitter, and 10 tubes in the 310A exciter, the 30K station as much a delight to operate, as it is to look at.

In closing, my thanks to those who have taken the time to send in photos, scans, stories, or to share their experiences over the years, please feel free to contact me or forward information which you feel may be of value or interest to other 30K owners.

73 Bruce W1UJR