Evergreen Exciter for the Special Night | RF Circuits

Wednesday, December 21, 2011

Evergreen Exciter for the Special Night

Magic Eye Transmitter
Several days ago I listened to the completely empty ten meters band. There was a lot of noises, quiet CB chewing and nothing else.
Suddenly I heard a slow, quiet, but very clear telegraph code, resembling W1AW QST. I have not heard the beginning, but wrote all heard:



..Santa placed tubes on the sockets and lit it.
The soft red glow from its ones tiny heaters brightened the room.
"The glow of the valves represents how man can show his thanks for the gift of God's Son that Christmas Eve long ago.
Teach the novices to let their lamps shine before men that all may see it and glorify God.
This is what is symbolized when the red lights shine on the twilight around the world
like hundreds of bright, shining candles, each of them representing one of God's beloved radio amateurs
whose signals are sounding for all to hear."


"Yes, red glowing" said Santa, "is the first color of Christmas." He pointed to the Rudolph, Red-Nosed Reindeer.
"But the second color is green" Santa reached into his bag and pulled out Magic Eye tube and set it into the socket.
"Teach novices about Magic Eye. Green is the second color of Christmas.
The stately evergreen with its unchanging color represents the hope of eternal lif.....


At this point I lost to hear mysterious broadcast, only a few dits and dashes appeared in the noise, someone laughed quietly and that's all.
But I realized that I have to add something green to my radio. I went to my attic and found a Magic Eye tube in my junk box.



MAGIC EYE TRANSMITTER HOWTO
It is easy to install 6E5 on the place of oscillator tube because socket's pinout of this amazing valve is nearly the same to pinout of common 6J5 and 6C5 triodes.
So, you can replace these tubes with The Magic Eye without any soldering. But if you want to see The Legendary Green Glowing, you have to apply some voltage to the Pin #6 (fluorescent screen).
It will not affect the excitation or amplification, this electrode do not cross the main electronic stream in the tube, so it is unecessary to use a regulated voltage in this circuit.
Let me demonstrate:



Magic Eye MOPA XMTR Schematic

As you can see this is my last year's SKN MOPA transmitter with some minor changes.

  1. 6C5 replaced with 6E5

  2. 6P3 (6L6) replaced with 6P7S (6BG6)

  3. adjusting capacitor C9 in exciter added

  4. amplifier's screen voltage powered by +400V through R7

  5. Magic Eye fluorescent screen is powered from the same source

  6. choke L4 in the amplifier's grid circuit (in place of 33k resistor)


I got more power, better tone, and, finally, The Magic Green Glow. Santa was right.

Merry Christmas!



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