Always Use an Isolation Transformer! Always Use an Isolation Transformer! Always Use an Isolation Transformer! PASSWORD FOR FREE EBOOK IS - allamericanfiveradio
Obviously the circuit won't oscillate with only one end of the crystal connected, but what happens if you replace the 68 pF capacitor with a short to ground?
Nice. Now use a 1000:8 ohm audio transformer for modulation and you'll get a nice AM Transmitter! Cool! Also, you could use fixed inductor in place of wound one and yet it'll do fine. Cool
Is there a video somewhere that explains how that circuit uses the crystal to oscillate? I understand the concept of the crystal, but I've never understood the feedback path that led to it oscillating.
The Crystal produces the signal. The transistor amplifies this signal. Crystal Oscillators for the Beginner ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xezzwJAZEQY.html
@@AllAmericanFiveRadio All the components are obvious in isolation, I've understood them for 40+ years. It's how they are working together that is a mystery. The crystal is resonating at a particular frequency if it's fed an appropriate signal. The signal seems to be coming from the emitter of the transister through those two 170pF caps. There is also the 68pF cap and the 10mH inductor playing some role. Are there any of these parts we could remove and still have it work? (Ie, muntzing it).
Do you have any particular radio in mind? Thank you! I have another video you may like. Superheterodyne AA5 from End to End ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-glakoNN4lwA.html
I always wondered how to make the square wave out of one of these a sinewave. Think I would up using an adjustable coil from a 60's-70's solid state radio to do the same.
A ( good ? ) use for Medium Wavebands ( ? ) ... now that the ( BIG boys ) have almost fully shut down their transmitters due to their HUGE power needs ( welcome back to young boy's communication in the 1960's ) ... DAVE™🛑
Nice little circuit Rick. I've built similar ones using the commonly available 1Mhz crystal oscillator 4 pin cans before, but I like your design much better. :)
Honestly! I always like this, I am a licensed amateur but started as an FM Pirate here in the Netherlands. ( I was 13 years old then, now 63 ) and to my great regret for others I still like to build transmitters myself also on bands where this is not allowed, here in the Netherlands we still have Pirates on WFM around 85MHZ but also on SW around 6.3MHz in AM modes and on MW around 1.6MHz in AM if you want to listen along you can do so on the SDR Twente ( Google ) Healthy and Friendly Greetings from Rotterdam, Rob
It is not 10 microhenry but 10 MILLI Henry. To get an idea: you can see it in the picture on 2.29 in the video. It is the one with the yellow core. When you want to make it in the same way as Richard did, also use/find such a yellow core ferrite (round) because its inductance, in this case, is related to the ferromagnetic properties of that core. Yellow stands for a certain type of ferrite material, with certain properties. It is a choke coil. When you want to make it on a cylindrical ferrite rod of 1 cm diameter, length 5 cm, you can do that experimentally. Start with 200 windings. When that does not work, make more windings on the coil. Till it works OK.
RFC coils are not critical and 10mH is just a nice round value here. Two or three dozen turns around a small ferrite toroid will do, as you can see just above the crystal in the video at 2:48. But you can buy these for cheap.
My first plain was to put the antenna on the coil closest to the tap. The RF was at the other end of the coil, so I moved the antenna to the other end of the coil. So I do not think you need the tap. Thanks for your comment.
you know? i always had a doubt about this subject.... the answer was pretty obvious, but i never got it until i saw it on your video, thanks friend =) Suscribed =)
I still do not udnerstand how this is driven. I was advised to try push/pull to make a beeper louder, but I am running with two AA batteries. If I were to split them like here to have +1.5V and -1.5V insted of doing 3V to 0V with a single mosfet, is there really any benefit?
Thanks for your comment. 3 volts is usually not enough voltage for a MOSFET. Here are a few videos that may help. Keep asking your questions! Simple MOSFET Experiment ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-otoeiVGu9uw.html MOSFET Biasing Experiment ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-nA9BBv4tPc8.html MOSFET Experiment ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-j47Yk7bJbxw.html
Can you do a video explaining the range switch schematics? It’s always been a source of confusion for me and I can never understand the path from probes to meter movement. I love your videos and the way you explain everything and highlight the paths in this video. Please keep them coming so the older analog stuff doesn’t get forgotten.
Oh that would be great it’s the multiple layer or wafers with front and back. Like 1F. 1B. 2F. 2b…..obviously you get it. When the range switch is turned 1 detent do the pointers on every level move that 1 detent too? How does the reverse polarity switch fit in to the path from jack to wafer levels to meter movement. My head may explode lol. The 260 in your video would be a perfect candidate. Thank you for even considering it.
@@robbo6460 Witch 260 do have 2, 5, 6, or 7? Yes all the wafer switches move together on each selection. The -DC +DC is there so you do not need to swap leads if the voltage changes polarity.
