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Author Topic: Link Coupling Grounding  (Read 1612 times)
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W9ZSL
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« on: April 14, 2019, 02:46:18 PM »

I'm a bit confused. I built the simple 2-tube transmitter in the '49 West Coast Handbook. It works great but now that I plan on using it as an exciter, I want to make sure I have the output wired correctly. It's the super-simple version for 160 / 80 / 40 meters. I wound an 80 meter output coil and it has a 4-pin plug. See diagram. There are 35 turns of #22 magnet wire on top going to pins 1 & 2 with 7 turns link to pins 3 & 4. Right now I have the socket wired with pins 2 and 4 grounded. Pin 3 goes to the center connector of the SO-239 for a coax connection. I read where links are concerned, the ground should actually be at the "neutral" or "cold" end of the RF upper coil. I've noted this is the case when it comes to grid links. The grounded side of the link is immediately below the upper coil with the end being fed from the exciter. Should I change my terminal arrangements and ground pin 3 of the socket and hook the antenna to pin 4?


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WA1HZK
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« Reply #1 on: April 14, 2019, 06:24:52 PM »

Usually 4 goes to 2 and the output link is wrapped around the cold (Ground) end of the coil. Then 3 is the lo Z output.
A balanced output would have 3 and 4 going to the load.
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W9ZSL
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« Reply #2 on: April 15, 2019, 08:14:35 PM »

Pins 4 and 2 are grounded. The difference is I wound the link below the L/C combo. The pix with the schematic show the coil wound that way. The link is not wound OVER the cold end, but under it. Pin 3 will go to the amp. Should work fine but I wanted to make sure. If I wind one for 40, I'll wind OVER the cold end.
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