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MarkS
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Joined: Sat Jun 30, 2007 4:07 am
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Back to Future!..erm forums

Post by MarkS »

Hi Fusor.net Forums It's been awhile since I've last lurked here and let alone posted here. FWIW I've been out in the world growing up since I started and stopped my fusor project 4 years ago. I had to leave my project behind and move into the dorms and now that I'm out in my own apartment and I've finally gotten most of the fusor's parts back together I'd like to get back into things. Right now the "fusor" is just a spherical chamber with most of the ports blanked off, a TC gauge and controller from a very generous Mr. Richard Hull himself, a view port, electrical feed, a dinky 500V @ 10mA bench supply, and welch 1402. The throttle valve, diffusion pump, and a chunk of vacuum hardware seems to be MIA. The big 19" supply pictured is a -30kV @ 10mA supply but it needs to have some cords manufactured from RF coax cable (theres a great DIY guide around here somewhere). The pictured set up was just a 5 minute deal and I have no intentions to be running any kind of operation supported by cutting boards and wood scraps (speaking of, can anyone point me to some tips on building a suitable bench/cabinet/cart for my fusor?). The conditions during the meager demo run were 40-50 microns with 500V potential on a copper wire grid with only the roughing pump churning away.

Anyways its great to be back on the forums and I'll be lurking around. I'm hoping to be getting neuts before the summer is out.
Cheers from Norfolk, VA.
Mark Siegel
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John Futter
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Re: Back to Future!..erm forums

Post by John Futter »

Mark
welcome back
The Glassman leads are easy to make.
You need a PL259 plug preferably with the teflon insulation.
You pull the centre pin out of the plug (leaving the insulator in place)and drill the insulator out to fit the inner insulator diameter of RG8 / RG213 coax.
The distance the inner of the coax protrudes into the supply needs to be measured then 0.25" added to this as the inner contact is spring loaded (this distance will be 8" or more).
The coax inner also needs to have a small brass washer soldered to it (same outer diameter of the insulator) with a dome of solder to make contact with the inner spring contact. The rest of the PL259 assembly is as if it where the proper connector with regards to terminating the braid. Plenty of HAM sites describe this assembly).

DO NOT make the lead longer than you need as it is also a capacitor (between inner conductor and outer earthed braid) that adds charge storage @ 30pf per foot
MarkS
Posts: 249
Joined: Sat Jun 30, 2007 4:07 am
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Re: Back to Future!..erm forums

Post by MarkS »

Hi John thanks for the reply! What you've described is exactly, almost word for action, what I did last time. I followed Wilfried Heil's guide (posted here: download_thread.php?site=fusor&bn=fusor ... 1190343950) and got away with using a foam core cable in the winter while it wasn't humid. And you're absolutely right about adding the extra quarter inch to the chunk of cable between the connected on the case of the supply, and the actual contact inside. FWIW I remember that chunk being exactly 8" the last time I measured.

On an unrelated note, is there anyone in my area, or relatively close by who is also working on a fusor/posting on this site? I believe Richard Hull is the closest, but after that I think it's Frank Sanns in PA.
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