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  1. Y

    Pie Network , Transmitter Tuning and Loading Questions

    Yes, mmfd or pfd. Schematic was wrong too,lol. That would be a lot of plates!
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    Pie Network , Transmitter Tuning and Loading Questions

    Yes, be advised my junk box. (boxes) are 50 years old. I have lots of tubes and transformers. I have almost everything one could need except, (LOL) , those few critical components that, (today) are extremely expensive! My military experience was with the R-390...
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    transformers back to back - why won't work?

    Possibly the transformers in the video are of the "impedance protected" design such as wall-warts. Either by design or poor construction the windings will heat up and increase in resistance, limiting the current, as the load increases. With limited current the output...
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    Pie Network , Transmitter Tuning and Loading Questions

    Thank you, hevans (hop), for your kindwords and true Elmer spirit. I agree with you 100%! From the Amateur's Code (as found in the front pages of the ARRLHandbook): #4 The Amatuer is friendly....Slow and patient sending , when requested, friendly advice and counsel to the begginer, kindly...
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    Pie Network , Transmitter Tuning and Loading Questions

    I was planning on building a circuit using a 6T9 tube ( AF4KBA Directory- Home brew from 1969 -1992 ARRL Handbook). I was going to start with 40 meter operation. The circuit shows the loading capacitor to be 1000ufd. I was hoping to get by with 365mfd. I was hoping there...
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    Pie Network , Transmitter Tuning and Loading Questions

    I understand the need for impedance matching.I read the ARRL text but still ask the same questions. I think I understandbut I'd just like confirmation. As I stated I plan to build a transmitter and use a 50 Ohm dummy load,so do I stil lneed the C2 capacitor and if I do what value...
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    Pie Network , Transmitter Tuning and Loading Questions

    Pie Network Transmitter Tuning and Loading questions: From reading texts I am aware that a pie network is needed to match the load (antenna) to the source (tube circuit). I also am aware when C2 is unmeshed( minimum capacitance) , it’s reactance is highest and maximum current from the tank...
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    Crytal Oscillator

    Thank you all for your input. I looked at a lot of oscillator circuits to build, this one appeared simple Wouldn't I know I would pick an odd circuit to experiment with. but It has served my purpose: to learn. The fact the authors of this circuit said they got 1 Vrms...
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    How to test CCFL ?

    A CCFL (Cold cathode Fluorescent Lamp) is just like any other tube fluorescent lamp. It's a tube with a small amount of mercury, Current limited High voltage AC is applied to ionize the mercury gas which when ionized produces UV light. The UV light causes the coating...
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    Crytal Oscillator

    I have another question: I've seen digital circuits using IC's to generate a square wave output. For testing activity purposes I quess it doesn't matter if the output is square or sine wave. I'm thinking you probably want a clean sine wave if building a...
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    Crytal Oscillator

    I agree with you, it is a voltage divider. The circuit is from "wiringelectronicscircuits.com". They state you can get 1 volt RMS out of it into a 50 ohm load. Maybe the 2nd stage (emitter follower is capable of that , but the first stage isn't producing enough...
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    Crytal Oscillator

    I believe Q2 is just an emitter follower stage and doesn't seem to have much effect on Q1 oscillating. Higher frequencies and the crystal itself, seem to have a great effect. A 10 Mhz computer crystal yields about 500 mV. Regardless I can't seem to get more than a...
  13. Y

    Crytal Oscillator

    The R8 potentiometer is closer to 300 Ohms in the actual circuit I built, maybe this is too much load, but It should still oscillate.
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    Crytal Oscillator

    I built this circuit, but can't seem to get much output. I feed the output into my 20 MHz scope with a X1 Probe. Crystal Controlled Oscillator Circuit This general purpose signal source serves very well in signal-tracing applications. The output level is variable to more than 1...
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    Crytal Oscillator

    Thank you Dave, now it is clear. I believe I will leave out the switch and detector, or maybe separate the detector and oscillator out put with two separate BNC connectors with a removable jumper. (then I will have two separate devices in the same box. Next step...
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    Crytal Oscillator

    I have several crystals (HCU style) ranging from 500KHZ to 10 MHZ and I would to experiment by building an oscillator project to test them. I found a simple transistor colpitts circuit that is followed by a didode (1N34) detector and transistor amplifier connected to a dc...
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    Primer on Transformers needed

    Ok, from your comments I understand: An air gap is needed to prevent saturation, but too much air gap will reduce inductance and efficiency. Laminatitions are needed to prevent eddy currents. High permability core is required to lower reluctance (increase efficancy...
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    Primer on Transformers needed

    First, thanks for responding. Yes, I have some theory (insigts) as to how they work but, I was hoping for some practical explanations. Most transformers shown on a schematic use the same symbols but obviously there's a lot of differences. I seen others posting questrions...
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    Primer on Transformers needed

    I am curious about the differences in transformer and choke design. I note core material, air gap size, laminations vs. Toroid are major differences. I just would like to understand in laymen’s terms how these things affect operation. Microwave high voltage transformers are of unique design...
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    Lorain Power Equipment....battery charger schematic needed

    I have acquired a H100F25, 100A 24V charger. The unit works, but I'd like to get a schematic as it has several circuit boards and if it ever fails I'd like to be able to repair. This unit is 45 years old and Lorain has changed hands many times. Hopefully some one is...
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