Crystal set

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Re: Crystal set

Post by Admin on Mon Nov 19, 2018 8:47 pm

Hello David,

I still have that project in Spain, and it is still working perfectly :-)

If you need any more pictures, for example, the underside showing the wires to the tubes then let me know.

If you want TX crystals for the 8m (3.5MHz) band then https://www.circuitspecialists.com/c7.html is a source for the 3.57954 MHz crystals as used for the American NTSC colour television system. 3.580 MHz is now widely recognised as a spot frequency for CW QRP because of the availability of these crystals.


The UK PAL TV system uses 4.43361MHz.These crystals cannot be used. They are outside of the 80m band.


You can usually put a coil (about 20 turns) in series with the crystal, then a 10-100pf variable capacitor across the crystal/coil and you can tune the crystal many kHz up and down to get a variable-crystal oscillator.


Very best regards and good luck with the project - Harry - SM0VPO

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Re: Crystal set

Post by dare4444 on Thu Nov 15, 2018 8:21 pm

Perfect! Post pics when you finish making the transmitter.

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thanks

Post by david99 on Thu Nov 15, 2018 4:03 pm

Thank you Smile on pictures the first steps
https://servimg.com/view/19997757/1

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Re: Crystal set

Post by dare4444 on Thu Nov 15, 2018 11:55 am

Hi David, it is a CW transmitter and operates from 80 meter amateur radio band to 15 meter. The crystal frequency has to be within this range, i.e, 3.5MHz to 21MHz.

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Crystal set

Post by david99 on Thu Nov 15, 2018 9:06 am

Hello 

My special works the Edison sytle old power electronics.



Im find the circuit schematic ,and I like build :

213.114.131.21/tx/2tubetx.htm

The tube circuit for me stranger Sad

My questons :

what value crystal set is needed for circuit ?

(for - to hz)

Thanks your answers

David

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Re: Crystal set

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