The Elektronika 26-01 is a rare Soviet portable radio with a clock, produced in small batches starting from 1984. Estimates suggest that no more than 10,000 units were manufactured. The device features a frequency synthesizer, allowing users to store 7 AM and 7 FM stations in memory, though it lacks a manual tuning knob, relying instead on push-button frequency control.
The radio's clock module is powered by a separate 1.5V battery and includes an alarm function that triggers the radio. Internally, the device uses a dense layout with two printed circuit boards and utilizes the A1508XL1 chip as the primary controller for the PLL and memory functions. The receiver also incorporates the A283D chip, which is equivalent to the K174XA10 or TDA1083.
The author investigated modifying the receiver to support the modern FM band (87.5–108 MHz) and add frequency display functionality. Research into the K1508XL series chips revealed a synchronous serial data bus, which allows for external control of the PLL dividers. Technical documentation for these chips was sourced from a 1995 reference book by Novachenko, Telets, and Krasnodubets.
The original receiver is designed for the Soviet FM band (65.8–73.5 MHz), which is currently largely inactive. The author considered several modification paths, including replacing the internal electronics with a modern SI4732-based system or bypassing the original synthesizer. Ultimately, the author chose to utilize the existing serial bus to manipulate the frequency settings via external control.
