Electronics > RF, Microwave, Ham Radio

Fly swatter ham radio transmitter

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joeqsmith:
Shown with new tuning cap.  Running 5kV to the primary will cause it to breakdown but it easily handles 2kV.

joeqsmith:
Taken from the above article:

--- Quote ---The beauty of this program is the way that it stores the information for each Morse code character.  It uses the  first 5 bits of an 8 bit binary number (made up of 1’s and 0’s) to store the dot / dash information for each character and the last 3 bits to store how many dots and dashes there are.  For example the letter “L” is “._..” .  0100 would represent dot/dash/dot/dot with zero (0) for a dot and one (1) for a dash.  Since the Morse code representation of the letter is four characters long the end of its binary representation would be 100 which is binary for four.  Finally, put it together: “0100” + an extra filler zero + “100” gives us 0100 0 100 (01000100) in binary which is 68 in decimal.  The letter “R” would be 01000011, or 67 in decimal.  The easiest way to decode 010000011 is to take the last three digits, “011” which equals three, and use that number as the number of characters to take from the “front” of the number.  That gives us “010” as the code which is dot / dash / dot.
--- End quote ---

I think the basic idea is fine but punctuation characters are 6 places.   Looking at the last three bits,  I am thinking anything over five, is a six place character.  110 would be 6 places with the 6th (LSB) set low (dot).  111 would be 6 places with the 6th place set high (dash).  For example a '.' which is dot,dash,dot,dash,dot,dash  would be represented with 01010111.    A '?' would be 00110110.

joeqsmith:
I was thinking about adding a small amount of C in parallel with the spark gap.  Idea being I could apply more energy to the gap itself than what is available in the tank.  In turn it would further ionize the gas and reduce the impedance of the gap.   Of course, you would take longer for the current to fall off enough to clear the gap.  Not a good idea for a transmitter....

Article discussing several of Tesla's patents.
https://waveguide.blog/tag/spark-gaps/

joeqsmith:
Assembled and running with flyswatter.

joeqsmith:
Article on early detectors.  I've never heard of most of these.