VHF/UHF receiver with TV tuner
Last updated: December 31, 2008
Under construction
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Under Construction
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| Prototype |
Final |
A VHF/UHF receiver based on a TV-tuner and a IF strip from an old VCR.
The TV tuner is a Samsung TCMK0601PD08A, the IF strip is based on a
Micronas MSP3417D-B2.
Building such a receiver depends on the content of your junkbox
and the possibility to find the needed datasheets.
Tuner
The TCMK0601PD08A contains 3 chips:
- TA1243: a RF modulator for VCRs. This chip is not used in the receiver,
but can be used as a signal generator during experiments.
- CXA3235: an all band tuner IC with on-chip PLL.
- LA7567: a VIF/SIF signal processing IC
Datasheets for all chips can be found on datasheet archives on the Internet.
Although the LA7567 contains a LF section, the needed components are missing
in the tuner. To get audio an IF strip was needed.
When used for TV signals, the LA7567 generates a 38.9 MHz local oscillator
signal from the IF signal with a builtin pll. For non-TV signals the
LO signal is generated with a Xtal oscillator:
38.9 MHz oscillator |
LA7567 VCO |
After the SAW filter a signal of approx. 5 mVtt remains. When injected in the
LA7567, pin 11 or pin 12, this is enough to set the LA7567 oscillator
to 38.9 Mhz. The resistors around the G1960M are based on values found
in a TV schematic. They are probably far from optimal, but it worked,
and no optimization of any kind has been done.
Sound IF strip
The SIF strip is build from an MSP3417D-B2 and a few surrounding components.
The Internet datasheet archives don't seem to have a datasheet for the MSP3417D,
but the MSP3410D.pdf and MSP34x7G.pdf datasheets contain enough information
to get the chip working.
I2C interface
The radio is controlled by a
I2C to USB converter
Radio
A GUI to drive the radio.
The program is written in Python using the wxPython graphical library.
Code can be found in the archive
Bandscope
The MSP3410 contains a peak detector (Quasi Peak Detector, QPD) that can be
used as a level detector when the MSP3410 is set to AM mode.
A scan from 50 MHz to 850 Mhz using a small dipole as an antenna.
The FM broadcast band is clearly visible.
A scan from 50 MHz to 850 Mhz of the cable (CAI) signal.
The Python code can be found in the archive
Downloads
Archive containing the Xcircuit files (encapsulated postscript) and the Python and C software.
