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View Full Version : morphy richards digital radio & Elta GlobeStar 3569 in the tandem


Bernd
02-07-2007, 22:14
Hi all,

morphy richards Digitally radio (MR) has, as everybody knows, weaknesses in the medium wave receipt and the West German Radio DRM transmitter WDR-Langenberg on 1,593 kHz with only 10 kW of power is in Bonn hardly to pick up. The world receiver Elta GLOBESTAR 3569, also known as Roadstar TRA-2350P or originally redsun RP2000/RP2100 has an IF exit of 455 kHz. There came the idea to connect both radios with a suitable converter in the tandem. For the application comes a modified DRM KIT with the IC NE612 which Burkhard Kainka has developed in collaboration with the German radio amateur magazine Funkamateur and also has described on his internet page:
http://www.b-kainka.de/drm.htm
The crystal was changed to a 6 MHz type and the input filter by a 4.7 K potentiometer. The output of the converter is connected to a self made aerial socket to the MR. The MR is tuned to 5,545kHz, i.e. on the difference of 6,000 kHz and 455 kHz . Now in this combination the receipt of the WDR-Langenberg with an external aerial is free of disturbance and without dropout for hours. Likewise RTL on 1,440 kHz from Luxembourg, BBC on 1,296 kHz from England and especially strongly Vatican Radio on 1,611 kHz are receiveable without problems.
This connection offers the advantages of both receivers, without usually necessary PC for the DRM decoding. Beside the considerably lower power consumption, it avoids disturbances which appear usually especially in the medium-wave band by the radiated frequencies of the PC. The synchronisation is also quicker in the MR than, e.g., with the DREAM software. Other quartz crystal frequency are possible if you are adapting the DRM-Kit accordingly. However, the opposed frequency must always lie below the frequency of the oscillator, so that the frequency layout of the DRM signal is preserved. The aerial socket of the MR is a self made internal coaxial connection to the stick aerial and it is blocked by a VHF coil, so that the DAB receipt still remains possible. However, it is also possible without intervention in the receiver if you are connecting the signal directly to the stick aerial and uses the mass connection of the Line Out socket. It is to be noted that the front end receiver owns an external aerial connection also for the medium-wave band, however, the built-in ferrite rod is not switchable. The external aerial input is a connection to a coil around the ferrite rod. Therefore, disturbances can still occur.

Bernd