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DL3AO Germany flag Germany

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:My hometown is Esslingen am Neckar, situated in Southern Germany. The city was founded in the 9th century.

View to the older part of Esslingen. The church as you see it today was finished in the year 1310. The vineyard in the foreground produces an excellent red wine! (My QTH is beyond the hills)


After the end of World War Two I had the fortune to grow up in the "American Occupation Zone" of Germany. An Officer of the US Army, James F. Hall, operated the Amateur Radio Station D4AQV not far away from the house where I lived with my parents. His Amplitude Modulation with 500 Watts from a BC610 transmitter caused strong BCI in a wide neighbourhood. I listened to him in my medium wave detector. Although I only could hear his part, I was fascinated by the communications he made . He opened to me the world of Amateur Radio with far reaching consequences for my further life.

I got my call DL3AO in March 1949 when I was 15 years old. War surplus equipment was cheap and easy to obtain in those years.

My stations in the years 1949 and 1950:


My first stations in the years 1949 and 1950 used the US aircraft receivers BC454 and BC455 (Also called Command Sets). Transmitting was done with a two tube ECO-PA TX, using the tubes EF50 and LS50, Output was about 40 W. Modulation was "Screen-Grid".


Station between about 1952 and 1956:

The proven Command Twins (left) were still used for receiving, but now with the addition of a crystal controlled converter for 21 MHz and a BC453 (with an IF of 85 KHz) as a "Q5-er". The BC457 transmitter (right) was modified to a simple VFO driving the frequency doublers and an amplifier (right in the rack) with two tubes RL12P35 in the final. Output 100 W, "Taylor"-modulation (a modified screen grid modulation).

One transmitter I built around 1956:



This is a typical homemade construction of those years (partly made on mother's kitchen table!). ECO-FD-FD-BU-PA, Bands from 80m to 10 m.

Modulation (AM) was produced by the method of "Clamp Tube". The cheap 807's in the final were later replaced by the newly developed RCA 6146's. (Dial calibration and labelling of the TX still waits to be finished!). Propagation was excellent in those years and a lot of DX was worked with this transmitter.


SSB- Station from around 1958 to 1961:


Around 1958, SSB came more and more into general use. Like many other amateurs did, I grinded FT243 Quartz Crystals for obtaining the necessary (4-pole) SSB Quartz Filter. Left the receiver (behind the front panel is still the old RX configuration with the Comman Sets and converters)), right the SSB transmitter for 14 MHz. . The unit in the upper right corner was a GG amplifier using a 4-125A tube.


Time went by and, after graduating in Physics at the University of Stuttgart with a PH D, my homebuilt equipment could be complimented with commercial equipment:

Station in 1962 and in some following years:

Left: Transceiver KW2000 from KW Electronics in England. Right: Homebuilt GG amplifier with two 811A's.


Station around 1980:

Left a Collins 51J3 with a Hammerlund HC10 IF-Follower. Right a Collins KWS1 transmitter

Station after around 1990:

Transceiver is a Kenwood TS850. To the left a homebuilt linear amplifier with a T510-1 tube in the final. Beneath the table the HV Power Supply. The old Collins station is used when the nostalgia gets too strong....(Picture made in 2002).


Biography (non spectacular!): Married with Inge for 42 years (2009). Two children Dorothee and Peter, four grandchildren. Retired Professor in Geophysics from the University of Stuttgart. Research area: Earthquake Seismology and Physical Volcanology.



Inge and Rolf, in 2006



144224 Last modified: 2011-10-07 06:19:01, 6539 bytes

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