Author Topic: Dynode  (Read 7602 times)

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Re: Dynode
« Reply #16 on: December 20, 2017, 03:13:27 am »
I was recently given an old Dynatron oscillator box which uses Farnsworth's 1012 A vacuum tube.  This is a hv pentode having three grids, two of which are coated for secondary electron emission.  So this dynode operates in the negative resistance region.  The tube is spected to operate at up to 330 Mega Hertz, but the circuit in mine outputs 28 MHz.

This unit was a donation, so I'll pass it on by posting some pictures of what's inside.

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Re: Dynode
« Reply #17 on: December 24, 2017, 02:38:33 am »
thatd be nice....I have a box of tubes id like to understand how to use them as well :)

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Re: Dynode
« Reply #18 on: December 25, 2017, 08:19:59 am »
thatd be nice....I have a box of tubes id like to understand how to use them as well :)

Vacuum tubes are versatile.  Some of them have applications which can't be filled with solid state - for instance, the Farnsworth like 1Q3, the "split the positive" 6146A, and now this six and a half inch top hat 1012.  I've been working on getting some pictures uploaded.  A couple of hours today got a few images sized and formatted, but nothing hosted yet.  Tomorrow I'll be busy talking to the Sheriff about the latest prowler incident (about an hour ago), but I'll see if I can find some time to post something.  Finding information about the Dynatron was difficult and time consuming, and that search will have to be repeated for me to post those links which couldn't be saved at the time.  And it's fire wood season, which limits my time for productivity.

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Re: Dynode
« Reply #19 on: December 28, 2017, 00:40:47 am »
Here's some pictures.  I'll post some discussion when I have some battery time on my computer.

(https://s20.postimg.org/we6jq7s0d/Side.jpg)

(https://s20.postimg.org/pc8m3r8wd/Top.jpg)


(https://s20.postimg.org/f2674j665/Tube.jpg)


(https://s20.postimg.org/54v6bi159/Grids.jpg)


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Re: Dynode
« Reply #20 on: December 30, 2017, 02:30:39 am »
There's a lot of stuff to look at inside this cabinet.  A label on the red tube which contains the tuning crystal says that all of the caps are .02 mfd, and are rated for 10 kV.  So the transformer must put out around 5 kV.  It's comparable to a large MOT, so it's at least a kW.  The meter on the front goes to 1,000, but the maximum fuse size is 6 A, so the unit's power output must be between five hundred and seven hundred W, rf.  And it's pretty tricky how the angle of the internal coil in the center tapped tuning inductor varies the inductance of that coil's lower half.  The rotatable coil capacitively couples a third coil around the very bottom of the coil form into the circuit.

The vacuum tube itself deserves its own post.

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Re: Dynode
« Reply #21 on: December 31, 2017, 03:22:33 am »
Thats extremely interesting !!! The tubes I have came from an oscilloscope ....nothing like the unit you have there.I hope you find it useful !!!

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Re: Dynode
« Reply #22 on: January 14, 2018, 10:31:42 am »
theres an OZ dvd documentary , putuparri and the rain makers . theres actual footage of these aborigines finding the tiniest puddle of water in the desert then time goes by ...dance etc and eventually theres enough water to wash an elephant in , they dont , but its a decent size swimming pool and no camera magic is involved . they are in the desert and theres no other water source .


http://putuparriandtherainmakers.com/

we are only on tank water . it hadnt rained since sept or so . there was a storm a week ago , best thing ever !! 

being in desert maybe you could have recycled water in way of glass house and plants evaporate the water . plants want light , CO2 and water and give off H2O and Ox . in the nature shows they have demo of a plastic bag over a tree and at the end of the day theres a collection of water . sounds involved but if it were me Id think on that one . even some kind of under ground set up . solar distillery or something . theres solar composting toilets at the local park about 2km from here , they dont stink either 

as a bench mark we pretty much do everything wrong so anything better than , is a step in the right direction

pretty sure I seen a documentary of an Indian teacher going around schools trying to get kids back into trad food , corn etc and he had glass houses , might have been NM
« Last Edit: February 12, 2021, 13:34:59 pm by electrotek »

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Re: Dynode
« Reply #23 on: January 15, 2018, 22:58:15 pm »
The Aborigines are recognized as a distinct species, so it must be in the genus.  The native genus controlling the planet.  Out here, the mountain thunders all around, up and down overhead.
« Last Edit: February 12, 2021, 13:36:45 pm by electrotek »