charlie@oakhill.UUCP (Charlie Thompson) (09/23/89)
My microwave seems to be slow a cooking stuff. I checked the AC current with a clamp-on ammeter and it was 12 AMPS. Sounds like its drawing lotsa current but not nuking very fast. Two questions arise: 1) Where can I get a new HV diode (cheap). 2) How can you check microwave output vs. current drawn? Thanks in advance. Charlie Thompson WB4HVD
ISW@cup.portal.com (Isaac S Wingfield) (09/25/89)
Charlie Thompson writes: >My microwave seems to be slow a cooking stuff. I checked the >AC current with a clamp-on ammeter and it was 12 AMPS. Sounds >like its drawing lotsa current but not nuking very fast. Two questions >arise: > >1) Where can I get a new HV diode (cheap). > >2) How can you check microwave output vs. current drawn? > >Charlie Thompson >WB4HVD A while back, I worked for a small division of Litton Industries, and at the annual inter-division "technology transfer" seminars, I met the chief engineer of Litton's microwave oven division. In the course of casual discussions, I found out that a good way to determine the "microwave wattage" is to use simple calorimetry; put a measured amount of water at a known temperature in the oven, and run it a measured time to produce a *small* increase in temperature. The rest is left as an exercise for the curious... He also said that they never used one of those expensive "leakage meters"; they just bent the leads of a NE-2 out like a dipole and went around the seal with it. No light, no leakage. No responsibility if these things don't work, though. Isaac isw@cup.portal.com
jim@foobar.hf.intel.com (Jim Garver) (09/26/89)
In article <2410@radio.oakhill.UUCP> charlie@oakhill.UUCP (Charlie Thompson) writes: >My microwave seems to be slow a cooking stuff. > >2) How can you check microwave output vs. current drawn? My Magic Chef service manual specifies a procedure to do this. A measured amount of water is nuked for a specific period. The change in temperature (delta t) is then plugged into a formula resulting in calories of energy which you can convert to watts. Consult an applied physics book or I can look it up for you. Better yet, convert that thing to a high power FM 2.5 Ghz transmitter and nuke the neighborhood! Plans are available in a recent issue of 73 magazine. The same author originally presented the project in RF Design magazine where he won 3rd place in the design contest (shoulda been first). With plenty of MDS pirate receivers/antennas around you can probably gain an audience. Are there any MDS broadcasters left? They shut off the one in this area. It was a good signal source for microwave receiver projects. -- _\ _\ Jim Garver __|__<tektronix!psueea | uunet!littlei>!foobar!jim \ \ WA7LDV & N3170N _____( )_____ jim@foobar<.hf.intel.com|.uucp> Development Tools Operation, Intel Corp. Hillsboro, Oregon 503-696-2094
jst@cca.ucsf.edu (Joe Stong) (09/26/89)
In article <346@foobar.hf.intel.com> jim@foobar.UUCP (Jim Garver) writes: >Better yet, convert that thing to a high power FM 2.5 Ghz transmitter and >nuke the neighborhood! I hope there was an intended smiley here. Eeeeeek! Someone doing this would give local neighbors cancer and cataracts!
kencr@haddock.ima.isc.com (Kenny Crudup) (09/26/89)
>In article <346@foobar.hf.intel.com> jim@foobar.UUCP (Jim Garver) writes: >>Better yet, convert that thing to a high power FM 2.5 Ghz transmitter and >>nuke the neighborhood! In article <2427@ucsfcca.ucsf.edu> jst@cca.ucsf.edu.UUCP (Joe Stong) says: >I hope there was an intended smiley here. Eeeeeek! >Someone doing this would give local neighbors cancer and cataracts! And cooties, too! We all know there is no reason to be emitting high- power EM radiation in the air....they just said so on the radio station I'm listening to in the office.... -- Kenneth R. Crudup, Contractor, Interactive Systems Co.(386/ix), Cambridge MA Don't worry- I haven't lost my mind....its backed up on tape *somewhere*.... Phone (617) 661 7474 x238 {encore, harvard, spdcc, think}!ima!haddock!kencr kencr@ima.ima.isc.com
rma@mhgki.ATT.COM (atkins, robert m) (09/27/89)
In article <2427@ucsfcca.ucsf.edu>, jst@cca.ucsf.edu (Joe Stong) writes: > In article <346@foobar.hf.intel.com> jim@foobar.UUCP (Jim Garver) writes: > > >Better yet, convert that thing to a high power FM 2.5 Ghz transmitter and > >nuke the neighborhood! > > I hope there was an intended smiley here. Eeeeeek! > > Someone doing this would give local neighbors cancer and cataracts! Anyone comtemplating converting a microwave oven into a high power transmitter should have more worries about his own health than his neighbors. In the far field (say 100ft) of a 10 degreee beamwidth antenna (several foot dish) running 500W of rf power the field strength would be less than 0.5mW/sq.cm. This is (I believe) within recommended exposure limits and would pose no health threats (though I wouldn't want to spend 24hrs a day, 365 days a year in such an environment). More of a problem would be stray rf in the shack. If anyone is contemplating this conversion (and yes, it can be done) they had better know what they are doing and have some kind of rf field strength monitor around. There is no doubt that exposure to high levels of microwave energy can cause cataracts. The evidence for inducing cancers is somewhat less certain, but its not something I would want to completely ignore. Be Careful. Microwaves are quite friendly if you know how to treat them right, but they can bite if you don't. Bob Atkins KA1GT
storkus@arrakis.nevada.edu (Mike Storke) (09/27/89)
Ken Crudup says "...there's no reason to send ep up into the air..." (I'm sorry, my quoting powers are not yet fully developed - but I'm working on it!! It is definately to that effect :-) ) WRONG! A good use for a microwave with high power (provided you can either turn it on and off fast enough or modulate it) would be EME (why do you think radar operates on UHF and higher frequencies?). 73's all! - Mike, N7MSD *************************************************************************** Mike Storke, N7MSD * The opinions, ideas, etc. expressed here are mine, Box 462 * mine alone, and bear no resemblence to the 4750 Gym Road * University of Nevada System's or anyone else's for
storkus@arrakis.nevada.edu (Mike Storke) (09/27/89)
Sorry about the screwed - up signature, send all replies to: storkus@arrakis.nevada.edu. I'll fix it (promise :-) Mike *************************************************************************** Mike Storke, N7MSD * The opinions, ideas, etc. expressed here are mine, Box 462 * mine alone, and bear no resemblence to the 4750 Gym Road * University of Nevada System's or anyone else's for