Biography

Hi, nice to see you on this page!

As far as I can remember, I have always been enthusiastic about radio. Born in Hamburg at the end of 1948, as a schoolboy aged fourteen, I became a member of the German DARC. In 1966 I got my license with the callsign DK1IS at the age of seventeen. From the beginning, I was QRV mostly in CW on the HF bands with the usual periods of reduced activity due to study, job, and family. I´m married and we have two grown sons. Since 1981 we have been living in Amberg, an Eastern Bavaria town about 60 km east of Nuremberg. After 17 years of working in the electrical industry, I changed to the new Amberg University of Applied Sciences in 1998 as a Professor of Electrical Engineering. Since 1999 I have been the dean of our faculty and since 2011 I´ve been a pensioner.

In 1999 DK1IS was the first LF station in Eastern Bavaria on 135.7 - 137.8 kHz. 24 countries worked on LF up to now: DL, F, G, GI, GM, HA, HB9, I, LX, OE, OH, OK, OM, ON, PA, S5, SM, SP, SV, RA6, UW8, YU, Z3, 9A3 (mostly in DFCW).
Since June 2013 DK1IS has also been QRV on the 472 kHz MF band. 20 countries worked on MF up to now: DL, EI, F, G, GM, HA, HB9, I, LA, OH, OK, OM, ON, OZ, PA, S5, SM, SP, YO, 9H1 (real CW only). For more information about this MF band see http://www.472khz.org/ (sorry, the site is currently out of service).
From 2018 to 2022 DK1IS was also QRV on VLF 8.27 kHz - a new and challenging mission! Tests with plain carriers have been recorded in DL, G, I, and SP.

Rig here:

HF: Kenwood TS-950SD, controlled by external GPS standard; Kenwood TS-50S (powered by solar cells plus accu). Since January 2022 additionally, there has been a Yaesu FT-818 ND QRP transceiver - it´s a lot of fun with this tiny item ranging between 1.8 MHz and 440 MHz!

LF, MF: Receiver RX1001, Exciter EX1001, both from Hagenuk, optionally controlled by external rubidium frequency standard from Rohde & Schwarz. Exciter running at 13.6 MHz respectively 4.73 MHz followed by a frequency divider for 1-Hz-steps on LF and 10-Hz-steps on MF. Homemade tube PA 2 x 4 x PL519 push-pull class B, broadband transformer coupled, max. 800 W RF on LF and MF, plate efficiency 73% at 600 V DC. QRV in CW, QRSS, DFCW. Alternative exciter (most commonly used now): Frequency synthesizer MG 100 M from Schomandl, 0.1-Hz-steps for CW and DFCW up to 100 MHz, optionally controlled by external rubidium frequency standard too.

VLF (2018 - 2022): Reception via remote RX site at our club station DL0AO, data transfer via www. Exciter for plain carriers: synthesizer MG 100 M from Schomandl, controlled by external rubidium frequency standard, running at 82.7 MHz and divided by 10,000 for 10-uHz-steps on VLF. Audio PA 2 x 300 W, only one channel used. At https://vlf.u01.de/ a summary of the current VLF grabber displays from the RX site at DL0AO can be seen (please note: the transmissions from ZEVS and the Alpha-stations are occasionally stalled).

Additionally, access via www to a remote RX site with Perseus SDRs and a lot of different antennas at our club station DL0AO too (about 6 km away in a forest) - especially from LF to 10,1 MHz due to continually increasing local noise level. Since June 2016 there has been one more remote-controlled Perseus SDR RX site in my garage, about 100 m away from my home and fed by a solar system, with no utility mains. 3-axis remote-controlled active RX antenna HD 2 from Dieckmann & Klapper, a former German marine antenna supplier. Noise level up to 30 dB lower than at home. Data transfer via a private 5-GHz-Ethernet-link. A kind of audio diversity by fast manual changing between the available receivers and their antennas often improves signal readability during tough conditions.

Main antenna: Marconi-T, 13 m high, 33 m top load with 4 wires, 3 m wide for VLF, LF, MF, and HF (on HF you rather may call it inverted ground plane), C = 660 pF, R = 30 Ohms, measured at 136 kHz respectively 12 Ohms at 473 kHz and 160 Ohms at 8.27 kHz. Autotransformer 50-30-12 Ohms for LF and MF. HF spare antenna with different radiation pattern and less efficiency: Vertical helix 8 m. Antennas remote selected and fed from the shack via 3 vacuum relais and 2 lines of RG 213, 25 m each. Additional active rod HE-011 from Rohde & Schwarz for the reception.

Couplers:

HF: Harris RF-615B in the arbor ("tuning house").

MF/LF: remote controlled (by barbecue grill motor) Hagenuk-MF-variometer tuner 120 - 550 uH in the arbor plus additional homemade honeycomb loading coil for LF, L = 1.75 mH, Q = 540 with forced radial air cooling for long key down periods. Antenna current 5 A, antenna voltage 8.9 kV RMS measured at 136 kHz, 750 W.

VLF (2018 - 2022): first matching transformer 8 to 50 Ohms in the shack, a second one 50 to 300 ... 450 Ohms at the arbor. Loading coil with 60 ferrite inductors 10 mH / 600 mA RMS in 4 ring-shaped layers, variation range by tappings and variable mutual coupling 10 ... 700 mH. Additional homemade variometer 7 ... 14 mH for fine-tuning. Antenna voltage 18 kV RMS at 8.27 kHz and 600 mA antenna current. Systems bandwidth without re-tuning: 180 Hz at -3dB.

Ground: 3 bare copper wires 6 m, buried 20 cm below the lawn with ground rods 1 m at each end + 2 ground rods 3 m + mains ground + water pipe system + all metal structures at the terrace side of the house.

Vy 73 es hpe to cuagn on the air!

Tom, DK1IS

For pictures of my LF/MF station see http://www.qrz.com/db/dk1is