Sorry, my license doesn't have those numbers and letters in it- I always stayed in commercial broadcast- never could figure out those dots and dashes!
Radio station (and probably TV) transmitters had to have a "positive" discharge system for the power supply. Usually this was some sort of mechanical method that when you opened the door of the xmtr cabinet, a copper bar would drop down on the terminals of the power supply capacitor. (They also usually had a proper shorting stick built-in!) In normal operation, you shut down the xmtr and the bleeder resistor would discharge the power supply. But when you were lucky enough to have a Federal Communications Commission inspector visit, one thing they always wanted to do was check the safety features of the xmtr. That meant simply opening the cabinet while the rig was on the air. It usually made a nice big spark, and with the first-generation computer controlled rigs, it often scrambled the brain of the computer. Been there, done that, got the t-shirt.
I got out of broadcast shortly after I installed a 5KW AM transmitter that advertised that it couldn't be taken off the air because of an antenna fault- it would pulse it's full power until the fault had been cleared away. It didn't take long to realize that the fault could be me accidentally getting against the antenna, and clearing it meant being fried.
Cameras are so much safer! Ken Hart kwhart1@xxxxxxxxxxxxFirst Class (now General Class) Radiotelephone Operator with Ship Radar endorsement.
----- Original Message ----- From: "Grif" <kgriffit@xxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx> Sent: Tuesday, March 01, 2011 7:12 PM Subject: [pure-silver] Re: old Norman P400D battery pack
N7IVS here,,, real radios glow in the dark, and hollowstate rules ;-)I've blown the end off several screwdrivers over the years. Seems I just can't learn to build a proper shorting stick with resistor. At least I've learned to close my eyes. I've got a pole pig waiting for the RoundTuit to go with a bunch of 4cx250's and all the other stuff. I've got access to a couple of xxx1000 triodes, but because of my age, I think the "proper" looking final is a pair of 813's even if they don't allow the roof of the shop to glow at night.So many hobbies, so little time. All this electroylitic talk is just going to get in the way of the Linholf and my father in laws graphlex 22 tlr, but then it's almost fishing season, and I really really want to spend some time on my buddies sailboat this year. Decisions decisions.At 03:23 PM 3/1/2011, you wrote:Capacitors are nothing to fool around with. Some years ago I was building a power supply for a ham linear amplifier. I bought an oil filled 4 mf cap at a hamfest and was working on it. About 6 or so hours after the supply had been off I accidentally dropped a screwdriver and it shorted the cap. The noise it made was deafening. The screwdriver jumped about 6 feet. 3 kV across 4 mf is enough to kill.Bert ex-KA4BBS =============================================================================================================To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.=============================================================================================================To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.----- No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1204 / Virus Database: 1435/3475 - Release Date: 03/01/11
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