![]() ![]() If the selectivity is low, you would hear other neighboring stations at the same time. This increase in selectivity enables the circuit to tune into the station you want. The greater the Q, the more selective the circuit becomes. The ratio of this dynamic impedance to any loss resistance present is called Q. If they are in parallel (as in our circuit), the combined impedance is very high, and if they are in series, resonance also occurs but the combined impedance is very low. When the reactance (AC resistance) of capacitor C2 is the same as the reactance of the coil L1, resonance occurs at the frequency f=1/2π√(LC).įor example, with L1 equal to 300 uH and C2 equal to 100 pF:į = 1/2π√((0.0003 H)*(0.000000000001 F)) = 919kHz. What’s truly amazing here is that this circuit will work without any batteries and provide hours of AM listening fun. Use magnet wire to wind the coil if possible.įor this radio work well, you will need a good earth connection and at least 20m of wire as high as possible outdoors as an antenna. The tap is at about 5 to 10 turns to be coupled to the antenna. L1 is a coil wound on a ferrite rod with about 50 to 60 turns. The LS is a high-impedance piezoelectric headphone like the vintage 2000Ω “crystal earpiece”.Ĭapacitor C2 is a variable capacitor of about 300pF to 500pF. But any diode will work, only with less volume. The diode is ideally a germanium diode, like the OA81, as it has a lower forward volt drop. Building this is an excellent start in understanding how AM radios work: Shown below is a simple (and magical if you have ever built one) crystal radio circuit. AM is also used on all aircraft radios from 108 to 136MHz. This means that the transmitter radio (or carrier) signal is modulated with the music or speech content in a manner that the amplitude of the carrier is varied in relation to the incoming speech or music. Radio stations in the medium wave and short wave bands transmit their signals using Amplitude Modulation (AM). AM receivers are also simple and easy to build. ![]() But they are still popular as they have more channel space than FM stations and offer longer range coverage, especially at night via the ionosphere. Medium wave and short wave were the main broadcast radio bands until the advent of FM. On the other hand, short wave extends beyond that and up to about 30MHz. Here are some others that didn’t make it after their 15 minutes of fame.Medium wave is a band of radio frequencies extending from 530kHz to 1700kHz. When we know more, we’ll tell you more but for now, The Hideaway is the first of the Boise area Bar Rescue establishments to close.īut they’re not the first Idaho restaurant that was on TV to close. ![]() Public records still list “Fulbright Investments LLC” as the owner. They didn’t make any mention of who bought it or what it would become. “ Thanks to all our wonderful customers over the years the Hideaway has been sold our last day is July 30th so come by and say goodbye it’s been 11 great years but it’s time to hang up our hat and move on to retirement” Months went by, but now the bar has announced that they have officially been sold. We noticed the bar, which was listed for $2,725,000, had a pending offer right after the episode aired. The show didn’t tell you that she’s also a two-time cancer survivor, so this is a good thing all around. During the show, she revealed that she was about to have a surgery that would take her away from the business for two months. It would also give his girlfriend, who helped manage the bar, a chance to focus on her health. What the show didn’t show you is that the owner had been trying to sell the bar so that he could retire and enjoy more travel time. ![]()
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