The same protocol was used for my CR-1 DXing as well. I also used a 100 microamp meter in series with the headphones to make peaking these circuits accurately. Using the tone, the antenna tuning as well as the detector circuit can be optimized for maximum signal. I also used an RF signal generator that let me temporarily put a weak tone-modulated carrier on the frequency of a station that I was trying to hear. This included the use if a separate ‘spotter’ radio to first find signals that might possibly be strong enough to be heard on the crystal detector. Back then, I quickly adopted the standard protocols to help hear DX. My previous experience with crystal radio DX is well-documented on my website here. It is a difficult location for crystal radio DXing as separating weak DX signals from the blowtorches can be challenging. All of these signals are wide and strong, being well-over S9. My listening location, on the eastern shoreline of Mayne Island, puts me directly across several miles of saltwater from sixteen exceptionally loud 'blowtorch' signals whose antennas are located near the water on the other side of Georgia Strait.
just how good could an unmodified CR-1’s simple double-tuned design really be? I was about to find out. Crystal radio design is always a trade-off between these two critical characteristics.Īlthough I had heard good things about the CR-1, I must admit that I was somewhat skeptical. Reducing the load on the tank circuit improves selectivity but diminishes sensitivity. The detector diode, a 50’s-era 1N34, is tapped down on the tank for headphone impedance-matching and to reduce circuit loading. and are somewhat pricey!Īs can be seen in the schematic diagram above, the CR-1 is a simple double-tuned crystal receiver, utilizing a series-tuned tank circuit for antenna-tuning, coupled into the detector tank circuit. I am most appreciative of this kind gesture from a fellow radio amateur, knowing that these things are not too easy to find. He was happy to pass it on knowing that it was going to a good home.
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