RAN Technology

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Products and ideas to generate the frequencies we need
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How good can a crummy receiver be?

Hundreds of different simple SDR receivers have been designed around Dan Tayloe's Quadrature Sampling Detector or QSD.    Mine add nothing to the state of the art, and in fact subtract things, as I like minimalist solutions and the QSD is right in that sweet spot.   Following the evolution of Tayloe's design I delete the resistors in series with the sample lines for in...  READ MORE
ranickels
02/07/2024
Crystal Replacement
Replacing failed crystals

For decades, quartz crystals were used everywhere a stable frequency source was needed, even in some applications that depended on overtone (harmonic) behavior into the VHF range.    These crystals were less stable and more dependent on circuit parameters that fundamental types and thus more problematic.    Such was the case with the 94 MHz crystal in the 2 meter converte...  READ MORE
ranickels
11/23/2023
Crystal Replacement
"Crystal Plugs"

Crystal sockets were popular for pluging in . .. crystals, of all things!   But they were also used for other purposes, such as the antenna relay connection on some EF Johnson transmitters.    If you want to connect a VFO to a transmitter with just a crystal socket, for example, you're going to have to either carve up an old FT-243 type crystal or if you want to outbo...  READ MORE
ranickels
09/01/2020
Crystal Replacement
Spectral Purity using Epson Programmable Oscillators

  In the 5 or so years I've been using the Epson oscillators I've looked at the spectral output many times.    Without a doubt the harmonic output from the Epson oscillator is high as would be expected  from a square wave device.   The question to me has always been "does it matter"? PLL controlled digital oscillators have long been ...  READ MORE
ranickels
03/12/2019
Crystal Replacement
Four Channel Oscillator board

Epson programmable oscillators are a good substitute for quartz crystals in many applications, but they're a bit different to use.    First, they are active devices that require DC power, typically 5 volts at 45mA.    Second, like all ICs they are easily damaged by static and voltages that exceed the design limits.   Finally they are in DIP packates that are...  READ MORE
ranickels
12/08/2018
Crystal Replacement
Programmable Oscillators - the modern day "rock"

With the demise of  International Crystal in 2018, hams and experimenters lost the last US-based source of affordable one-off custom crystals.   (And the definition of "affordable" ended up over $30 each).     Sure there are some offshore sources but the reality is, manufacturing one crystal to a specific frequency is not simple or inexpensive, and all crys...  READ MORE
ranickels
12/06/2018
Crystal Replacement
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