BCL Radio

--- 2024-07-30 ---

In this radio circuit, there have been numerous changes. It has now settled as version 6.0 
This version has not actually been created yet. I am planning to order it soon and confirm the operation of version 6.0

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SANYO's LA1600 AM radio IC is a single-chip solution for AM tuning, with few external components required and the ability to receive shortwave signals. Its main specifications include an operating voltage range of 1.8V to 6V, a recommended voltage of 3V, and a 9-pin SIP package. In this article, we will explore how to create a radio that can receive shortwave broadcasts using this IC.

Typically, a "polyvaricon" capacitor is used in the local oscillator section of the circuit. However, using this component can lead to capacitance errors due to wiring capacitance and other factors, potentially leading to instability. Instead, we will use a "varicap diode" to achieve variable frequency, allowing station selection to be done using a volume control and providing more flexibility in the design of the radio case. We recommend centering the receiver around the 9MHz BCL band for best results.

We recommend the FCZ coil. If it is not available, a compatible coil can be made using a toroidal core. We recommend the Toshiba 1SV101 varicap diode.

To check the receiving frequency with a frequency counter, use the OSC terminal connected to pin 3 of the LA1600.

For reception on the 31m band (9MHz band), the following frequency relationship applies: 9.4MHz to 10.0MHz.

The specifications of the radio are as follows:

• Reception method: Single superheterodyne
• Reception frequency range: 31m-BAND (approximately 9.4MHz to 10MHz)
• Modulation: AM and SSB/CW (SSB/CW can be received by adding a 455KHz oscillator circuit)
• Low frequency amplifier: Connect an 8 ohm speaker to the speaker terminal
• Power supply: 9V or 12V
• IFT (intermediate frequency transformer) used for 455KHz: Labeled "black".
• Antenna: Wire approximately 5 meters long
• The main tuning dial : rough tuning.
• The sub tuning dial : fine tuning.