Measuring, control devices, instruments and RF spectrum analyzers
Oct 4, 2009 Homemade
Homebrew measuring, control devices, instruments and RF spectrum analyzers by radio amateurs.
Keywords: homebrew, homemade, amateur radio, ham radio, control, device, RF, spectrum analyzer.
Measuring and control devices
RF Signal Generator
This signal generator is intended for realignment of radio receivers. The unit is cheap and fairly basic, but perfectly adequate for its intended purpose. However, the output is not a pure sine wave, so the unit may not be suited for more exacting electronic development work.
TR1 is a high gain FET (Field Effect Transistor) and is configured as a Colpitts style oscillator. The oscillation frequency is set by the variable capacitor (C1+C2) and the five pairs of switched inductors. There is significant overlap between the ranges, due to the limited range of readily available inductors. However even by using specially would inductors, four frequency bands would have been needed to cover the range.
A 50 MHz microwattmeter with the AD606
A design for a simple microwattmeter. Input range -75 dBm to + 5 dBm. Frequency range 2 to 50 MHz. Level resolution is 0.1 dBm, frequency resolution is 10 kHz. Log-output about 0.5 – 3.5 Volt. Output for external counter. The meter uses a AD606 as log-converter, a MAX186 as ADC, a PIC16C84 as controller and a HD44780 type LCD. The PIC measures frequency and level of the input signal and calculates level in dBm using frequency-dependant factors.
Homebrew spectrum analyzer by n9zia
Here is a homebrew spectrum analyzer you can build using an old VCR tuner module. Frequency coverage will be from around 80 MHz to 920 MHz and varies slightly with tuner manufacturer. It will also require an old oscilloscope that is capable of X/Y mode with DC input and a receiver which can tune around 47 MHz AM and can also be modified to tap its AM detector.
It’s even possible to downconvert a 2.4 GHz signal down to VHF frequencies using a slightly modified MMDS downconvter. This will allow you to view 2.4 GHz signals with this analyzer.
GBPPR 0 – 1000 MHz Spectrum Analyzer
An experimental spectrum analyzer based around the work done by W7ZOI & K7TAU. Mostly based on junk box or easy to find, low cost components – hence the sloppy design. This is currently an in progress project. It will probably never be finalized and always updated.
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Tags: Ham radio
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