On Sunday 12 July 2015 05:37:07 Erik Christiansen wrote: > On 12.07.15 04:09, Gene Heskett wrote: > > Thats what I get for living as long I guess. We broadcast engineers > > that actually understand, and can fix this stuff are a dieing breed, > > at least locally. All the people I had working for me in 1984 and > > whose hands I could guide to do this when I came to WV and WDTV-tv, > > have since passed, and only one of them was older than I. So I'm the > > official 'it' now. The station owner is fully aware of that, and > > pays accordingly. > > > > Those 'tank coils' are made out of pure unobtainium in 2015. So I > > have to see if Tarnex & 0000 steel wool will clean it up enough to > > replate it later today. Not one of my fav activities as I may have > > to take the coil out of its holders just to gain access inside it > > with my fingers. Thats not too hard, but putting it back together is > > a PITA since each turn has its own slot in the 4 micarta bars that > > hold it at the proper spacing between the turns. I'd probably need > > to post a pix before the description would make sense. > > Rather you than me, playing with that stuff, Gene. Back in '72, I > hob-nobbed with the guys in the radio amateur club at uni - staying at > arm's length from the Tx power stages, and their lethal power > supplies. After that, I went the digital path, where everything's > either 5v-ish or ground. > > But your picture of that tank coil comes across as a coil of fat wire > or thin pipe with the notched insulating posts 90° apart around the > circumference, holding the spacing to keep the inductance constant.
Close. it is 1/16" thick, 5/16" wide bus bar that has been curved into about a 6" diameter coil, spaced at about 1/8". The moving contact is a pair of phospher-bronze disks, plated of course, and stamped so that they do a good job of gripping the 1/16" edge. They are mounted to a sleeve that rolls on a 9" long 5/16" brass rod, which in turn is mounted to a pair of arms about 2.5" long, pinned to the 3/8 rod at both ends with an angular offset such that the disks actually track the slight angle of the bus bar as it winds around. The disks are big enough to get a grip on most of the 5/15" width of the bar. I believe, but no brand name is visible, that they were originally made for the industry by either Drake or Johnson, last made probably in the '70's. In any event, Gates Radio would have removed any makers labels so they they would be the only approved spares supply. Someone I think still makes monster sized versions, intended for use in the antenna tuners in the doghouse at the base of the tower. There are something like it in the base housing at the tower site Steve put up 4 years ago with the initial 25kw build, but the hill slipped and took the tower down. In the meantime, some of the land he had access easement rights across to get to the new site was sold, and the new owners have locked him out of access to work on it, going so far as to erect an empty building to block the only access road. Its in rough country and is about 3 miles of sphincter tightening 4wd road to get there in good weather. I've had my 99 GMC up there 3 or 4 times. > Take two posts out, and it might make a fine toast rack? With skin > effect, I can see that a bit of silver plating would do more good than > goanna oil on a bad back. > > It must be heart-warming to have the old skills still in demand. It is, yes. But what happens to these people when I fall over? They are then at the mercy of whoever they can round up, at probably north of a thousand a day & found starting at the instant the key goes in the switch. I heard $1250 not too long back. There are lots of little mom & pop am broadcasters that don't have that sort of money in the bank, and many, faced with that, will simply go "dark". Even the parts suppliers are now rounding up, or having made to specs, the various power transformers used in this stuff. And charging us $750 for a 5 lb transformer I know Peter Dahl would have made for $200 a decade back. But the iron is much better, so they are now smaller & lighter, and run cooler by quite a bit (20C?) compared to the 60 yo OEM iron available then. Grain oriented silicon steel was a huge thing when it became available circa the '60's. But Peter has retired, and the shop has been sold & moved to Hammond, with the custom shop pretty well closed down now. > The telecommunications department at NEC, where I spent the last 12 > working years closed some time ago, and the entire telecommunications > division at Siemens, where I spent 18 years, seems to have been sold > off and closed locally. So much for the digital stuff. (The two > substantial redundancy packages were very heart-warming, though.) Good, as it allowed you to get started on a working shop it sounds like. Me, I am a hobbiest, doing much of this for the enjoyment of being able to point at the innards in a BP rifle breech and say I made it, and its now 10x as accurate as it was when I bought it 15 years ago. Or a piece of furniture that I carved the parts for on that toy mill. My youngest son who was just here, took a look at that blanket chest and pronounced it wood porn. ;-) But he is driving a Cooper S, which doesn't have enough room left when two people and a suitcase behind the seat, for a spare pack of gum. Its a hot rod though, and can show most Merican iron the short way home by running off and hiding from it. > And getting old still beats the alternative. My younger brother has > just come off a great-new-hope chemotherapy program a few days ago, > 'cos it isn't doing any good. Surgery, radiotherapy, and a prior > chemotherapy program are all done and dusted. Good thing he's packed > in more adventures and scrapes than most, for what that's worth. If he has what it takes left, he should write a book. I should too for that matter, I have quite a list of BTDT's myself. But my excuse is I'm too busy to write a book. :) It sounds like his time is now limited though, and thats a saddening thought for all 3 of us. My condolences. > Erik Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Don't Limit Your Business. Reach for the Cloud. GigeNET's Cloud Solutions provide you with the tools and support that you need to offload your IT needs and focus on growing your business. Configured For All Businesses. Start Your Cloud Today. https://www.gigenetcloud.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
