Radio & Electronics
Duplexer Measurements
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- Category: UHF Repeater
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Measuring things is fun! This article is about the components of the UHF repeater that was recently donated to the Wilson County Amateur Radio Club.
First, let's take a look at the duplexer. It is currently tuned for a receive frequency of 466.800 MHz and a transmit frequency of 461.800 MHz. If you're familiar with duplexer theory, feel free to move on to the measurements. Meanwhile, I'll offer a quick explanation:
Preamp Measurements
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- Category: UHF Repeater
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Measuring things is fun, but measuring MORE things is a lot of fun! This article is about the electrical characterization of the receive preamplifier that is part of the UHF repeater recently donated to the Wilson County Amateur Radio Club.
The preamp compensates for the unavoidable losses in the duplex filter and enables the receiver to hear better.
This unit was manufactured by Lunar Industries of San Diego, CA. I can't find any technical data on it, but that's unimportant for now. Let's put it on the test bench and find out what we have.
Common Emitter Amplifier
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- Category: Lab Frequency Standard
- Hits: 1901
This circuit will buffer the OCXO's output and feed it through a power divider so it can go both to the final output distribution board and the phase-locked loop controls. It's a low noise circuit that will compensate for power divider losses and isolate the oscillator from downstream noise.
I'm experimenting with circuits designed by KO4BB and adapting them to my needs.
Subcategories
Lab Frequency Standard 1
This started as a quest to build an atomic frequency standard based on a rubidium oscillator. After realizing that I could get much better short-term stability and long-term accuracy by building around an ovenized crystal oscillator that's disciplined to a GPS time reference, the project was retargeted.