Last week I reviewed a pack of six amateur band crystals available on eBay. The beauty of them is they are on popular digital frequencies. More precisely 7 and 14 MHz WSPR, FT8 and JS8 frequencies.
While you could get an SI5351 for less for more frequencies, there's a certain elegance about crystal control when it comes to simplicity and low current consumption. Eg a simple direct conversion receiver needs just three transistors and draws just a few milliamps. More in the video below.
Link to buy the crystals is here: https://www.ebay.com/itm/FT8-JS8-WSPR-Crystals-40m-20m-6-pack-/153793406116
Later I tried 14 MHz FT8 reception. Here's the results I got.
Then I took the receiver out portable, mainly receiving FT8 signals. But this time I had put in a rotary switch to select between 7 MHz WSPR, 7 MHz FT8, 7 MHz JS8 and 14 MHz FT8.
PS: Want to read about antennas? Consider this selection of antenna books. They are affiliate links meaning that I receive a small commission (at no extra cost to you) if you decide to purchase.
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