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| Here is my E52b collection. This is a very interesting radio. This is advanced mechanical technology. I work as a broadcast equipment designer, and I have learned much by study E52b to get ideas in my products. |
1 ... E52b-1,
Shack Original paint. |
2 ... E52b-5,
Serial nr. 1466, from Trondheim, Black frequency
microfilm.  This receiver is 100% OK and trimmed. Original paint. Variable BFO reinstalled. |
3 ... E52b-1,
Serial nr. 1273, from Trondheim,  Variable BFO removed. |
4 ... E52b-1,
Serial nr. 2242, from LA8AK This receiver is 100% OK and trimmed. Variable BFO removed. |
5 ... E52b-1,
Serial nr. 734, Black frequency microfilm.  This receiver is 100% OK and trimmed. New paint, late war production without variable BFO |
6 ... E52b-7,
Restaurert Variable BFO reinstalled. |
| Köln E52bb is the best
short-wave receiver produced under WW2. The performance can be compared with the R390. R390 is a famous US receiver from the 50’s, 60's and 70's. E52 is a super heterodyne receiver with an IF frequency on 1 MHz. The MF filter is extremely good with a variable bandwidth from 200 Hz to 10 KHz and with a flat pass band. Mirror frequency is < 1: 50000. |
LA8AK's drawing
| This is a block diagram over
Köln. The HF amplifier have 5-gang tuned circuits. The oscillator capacitor tuning capacitor is synchronised with the HF amplifier capacitors in a 6-gang capacitor. This heavy filtering gives a very good rejection of unwanted signals. Both mirror frequency and large signals on frequencies near the operating frequency. The MF section is very advanced. It has 6 tuned circuits before the first amplifier. Then the signal pas a XTAL filter, amplifier and a second XTAL filter. The pass band of the XTAL filter can be selected from 200 Hz to 10 kHz with the pass band regulator. |
E52b-1
Specifications for the E52 'Köln'
| Frequency ranges Modes Power requirement Dimensions Weight Sensitivity Image rejection IF rejection IF frequency BFO Bandwidth Frequency stability |
1480-3020kHz 2980-6040kHz 5975-10050kHz 9950-17700kHz 17600-25200kHz A1, A2, A3 110-230VAC 50-60Hz, or 12VDC 245mm x 446mm x 350mm 40,8kg AM (wide) 3,5µV CW (wide) 1µV CW (narrow) 0,3µV Better than 94dB @20MHz Better than 100dB 1000 kHz XTAL - 1000,9kHz or 995 kHz - 1005 kHz continuously variable between 200 HZ - 10 kHz better than 30 x 10 E-6 °C |
E52b-1
Film, Demo of E52b
