Beauty Little Shortwave King ( 小短波王 ) BB9701

This Beauty FM/AM/SW pocket receiver model BB9701 is a Chinese custom design inspired by the Tecsun R9701, like several others did, such as the Kchibo KK-9701, Kchibo KK-9803, Kipo KB408AC, and ECB 9701.

The "Little Shortwave King (小 短波 王)" inscription on the front of the case was originally attributed to the Tecsun R-9701 world pocket radio which was a more complex design with double conversion and crystal-based local oscillator on the SW bands. However, on this "Beauty" custom design single conversion is used, despite sharing a similar single-chip with a transistor front-end concept.

Main specifications

• Frequency coverage
  • AM: 530 - 1600 kHz
  • FM: 88 - 108 MHz
  • SW: 6.94 - 22.20 MHz on 7 bands (49, 41, 31, 25, 21, 19, 16 m)
• Tuning indicator
• Band select indicator
• 3.5mm Mono earphone socket
• DC IN 3V socket
• Volume with Power Off/On knob
• Lock switch (band selection buttons are disabled when in Lock position)

Some technical details

This custom model is built around the Samsung S1A0426C02-S0 28-pin SMD One-Chip-Radio, similar to CXA1691, CD1691CB, or KA22426D (Samsung also made the S1A0426C02-A0 30-pin SDIP). Two IFT transformers (IFT1, IFT2) and two ceramic filters (CF1, CF2) handle the AM and FM IF signals.

A RF Front-End based on a single S9018 silicon transistor (Q1) in common-emitter setup is used to amplify the AM and FM signals. The output FM signal is passed through a BPF (L1, C3)  to the Samsung radio chip. The output AM signal is tuned using a combination of the ferrite antenna and a set of ceramic capacitors (no dedicated SW tuning coils in this design), and the Samsung chip local oscillator uses a set of four coils (Osc1, Osc2, Osc3, Osc4) shared between the eight AM bands.

The band select circuit is based on a flip-flop designed around two S9014 transistors (Q2, Q3).

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