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Author Topic: Tetrode Linear  (Read 25147 times)
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W2PFY
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« Reply #25 on: December 20, 2010, 08:18:40 PM »
How does one measure the grid current in one of them thar types with the grid mounted right to DC ground?

I think I seen a circuit where the negative part of the power supply was above ground for that purpose but I'm not sure how to do it.

 The grid in the YC-156 is only rated at 25 watts and from what I have been reading lately, that is one of the better tuning indicators.

 I have experience with tuning tetrodes and watching the grid I believe for the lowest current at resonance. I ask because I have a YC-179 I want to play with.

Any thought on this please?
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K1JJ
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"Let's go kayaking, Tommy!" - Yaz
« Reply #26 on: December 20, 2010, 08:24:11 PM »
Quote from: W2VW on December 20, 2010, 07:57:36 PM
Here's a pic of YC-156 guts. The grid flange is the plated ring in the bottom of the rightmost picture. The grid is the screen looking structure in the center picture.
It's pretty obvious that the grid dissipation cannot be doubled by cooling the grid flange.

http://www.wv7u.com/yc156amp/pictures/tube.jpg


It's almost scary that God could have created such a beautiful tube...sigh.
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
W2VW
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« Reply #27 on: December 20, 2010, 08:30:17 PM »
Float the B-, tied to the cathode return though a meter multiplier in parallel with a pair of back to back diodes for protection.

The Orr book has several examples.

Quote from: W2PFY on December 20, 2010, 08:18:40 PM
How does one measure the grid current in one of them thar types with the grid mounted right to DC ground?

I think I seen a circuit where the negative part of the power supply was above ground for that purpose but I'm not sure how to do it.

 The grid in the YC-156 is only rated at 25 watts and from what I have been reading lately, that is one of the better tuning indicators.

 I have experience with tuning tetrodes and watching the grid I believe for the lowest current at resonance. I ask because I have a YC-179 I want to play with.

Any thought on this please?
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W2PFY
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« Reply #28 on: December 21, 2010, 11:49:46 PM »
And yet another use for a YC-156. Note, the operator is more than arms length away!

http://www.youtube.com/watch?v=jnAeSy4679k
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K1JJ
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"Let's go kayaking, Tommy!" - Yaz
« Reply #29 on: December 22, 2010, 12:18:55 AM »
http://www.youtube.com/watch?v=90gL4FJs5b4&feature=related


Check out what the Wizard is up to.....

Actually looks like a decent job.

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
W2PFY
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« Reply #30 on: December 22, 2010, 12:36:04 AM »
And here is Tom Vu pi++ed because that guy has a bigger amp than him Angry Angry Angry


http://www.youtube.com/watch?v=7yPmugUXhTY&feature=related
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W2VW
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« Reply #31 on: December 22, 2010, 09:08:59 AM »
Quote from: W2PFY on December 22, 2010, 12:36:04 AM
And here is Tom Vu pi++ed because that guy has a bigger amp than him Angry Angry Angry


http://www.youtube.com/watch?v=7yPmugUXhTY&feature=related

It's not the size of the amp but what you do with it. It still helps to have a big amp though.
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WA1GFZ
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« Reply #32 on: December 22, 2010, 10:04:56 AM »
http://www.youtube.com/watch?v=iDn39wCYj3Y&feature=related
Tom Vu 2011


Any idiot can build a chicken band amp with a tiny tank coil and plenty of room in the box.
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K1JJ
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"Let's go kayaking, Tommy!" - Yaz
« Reply #33 on: December 22, 2010, 10:24:34 AM »
Quote from: W2PFY on December 22, 2010, 12:36:04 AM
And here is Tom Vu pi++ed because that guy has a bigger amp than him Angry Angry Angry
http://www.youtube.com/watch?v=7yPmugUXhTY&feature=related


Wow - The Reaper must be watching that guy closely for the next heart attack. Can you imagine waking up in a Japanese concentration camp and he's the channelmaster?   Shocked

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
WA1GFZ
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« Reply #34 on: December 22, 2010, 10:37:08 AM »
Ah an day off watching Chicken Band cash heat movies. Talk about making transistors beg for mercey. Background conversations interesting. Not the top of the food chain. Time to get off my butt and back to the big rig.
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