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137
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eHam Forums / HomeBrew / RE: How to test a toroid?
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on: January 10, 2012, 12:57:37 PM
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I use an old Heathkit grid dip meter and a 1% capacitor that I've soldered alligator clips to. I simply find a dip, then use the formula ((2piF)^2)/C=L to find inductance. Be aware, though, that stray capacitance in your circuit will probably be different than from this simple set-up. The calculators at kitsandparts and at formulas at amidoncorp work great. Another online calculator is the one at http://www.dl5swb.de/html/mini_ring_core_calculator.htm. You can have a little control over final inductance by pinching or spreading out the turns. Once you've got them where you want, hold them in place with Q-Dope (dissolved polystyrene), beeswax, fingernail polish or hot glue. GL
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138
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eHam Forums / Elmers / RE: question about headset's
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on: January 10, 2012, 12:38:16 PM
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Ive got a pair of military DCs; wore them forever way back when. But they're heavy--probably due to the noise suppression material in them--and after a few hours they feel like I'm wearing a vise clamped over my ears. A hint for those who do use them; a wrist-size sweatband around each ear cup will keep the sweat at bay on hot days/hot contests.
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140
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eHam Forums / Elmers / RE: CQ CQ QRM, what is that?
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on: January 04, 2012, 05:58:38 PM
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Move the plasma, or turn it off. Generally, some plasma TVs and monitors cause a lot of QRM. That's why many hams get rid of theirs and opt for LED screens instead. GL
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142
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eHam Forums / Misc / RE: QSL Cards
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on: January 02, 2012, 06:12:28 PM
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Try a local print shop. They often have supplies of card stock, and can cut it to whatever reasonable size and color you want.
I, too, make my QSL cards. I like "full bleed," which is color all the way to the edge of the card, so I have to use the three cards to one sheet, like you do. If your cards have a border, and your printer can handle the smaller sizes of card stock, then you've got it made. GL
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143
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eHam Forums / Misc / RE: Workbench stools
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on: January 01, 2012, 09:44:35 AM
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The wife found a swivel stool, with back, armrests, and foot ring, on Amazon, and she loves it. She had our kitchen counter top made 36" tall, and this seat is adjustable so that the armrests can just slip underneath the counter top. The five-wheel base works well on our tile floor, and on carpet, and she's yet to complain about it.
Unfortunately, it's a no-name brand made in Taiwan, and its limit is 250#, but it is a really nice stool.
When searching, use the term "lab stool" or "architect's stool," and you should find it. Again, the wife loves it.
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144
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eHam Forums / Misc / RE: Does anyone know what a "lid" is?
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on: December 30, 2011, 08:37:14 AM
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"Lid" is CW slang for "poor operator'" or "beginner;" generally someone who thinks they "know it all," but, in fact, know little; or those who practice poor operating procedures.
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145
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eHam Forums / Misc / RE: An Amateur Operator Reference Library - what's in your bookcase?
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on: December 30, 2011, 07:27:12 AM
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In addition to Handbooks and Antenna Books from ARRL, I have most Antenna Compendiums, Kraus' Antennas, Orr's Handbook, Henney's Radio Engineering Handbook, Maxwell's original Reflections, handbooks by Therman and Lenk, Elements of Radio, several on electromagnetic fields, including Maxwell's, RSGB's HF Antennas for All Locations and HF Antenna Collection, W1FB's QRP Notebook, Antenna Book, Solid State Basics and Solid State Design, Hayward's Experimental Methods of RF Design, Harden's Databook for Homebrewers and QRPers, GQRP's Low Power Scrapbook, Circuit Handbook and Antenna Handbook, Low Band DXing, ITT's Reference Data for Radio Engineers and several others like it, lots of TAB books, and back issues of Sprat, QRP Quarterly and QRPp, and I also keep The American Heritage Dictionary close at hand (but anyone can tell you I don't use it much).
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146
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eHam Forums / Misc / RE: Do Ham's READ?
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on: December 29, 2011, 09:17:23 AM
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Do ham's (sic) know how to use apostrophes? A newspaper editor once said that apostrophes were like power tools; if you don't know how to use them, it's best to leave them alone. How ture.
But you're right; Google can answer almost any question anyone might have. If not, there's the local library...and eHam, too!
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147
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eHam Forums / Elmers / RE: Spelling, Punctuation, Etc.
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on: December 29, 2011, 08:38:43 AM
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I've got to think that some of the posters are not hams yet; they're just asking basic quest6ions that all hams already know the answers to. At least I hope that assumption is valid--it's sometimes hard to tell.
Then, again, some of us are old and decrepit, or we're just not keeping up with the state-of-the-art. I've found that as we age two things happen; one is that we tend to forget things...but I don't remember what the other is.... Sri.
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148
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eHam Forums / Elmers / RE: dipole vs tribander
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on: December 28, 2011, 09:56:10 AM
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There is such a thing as a triband (three band) dipole...but I suppose you really mean a 3-el triband yagi vs an inverted V, right?
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149
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eHam Forums / Elmers / RE: Educational Electricity / Electronics Kits (eg, n-in-one project kits)
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on: December 27, 2011, 07:09:59 PM
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Ramseykits.com has a set they call "The Learning Center," with four of the types of kits you are looking for. PL130A is a 130-in-one lab kit for US$39.95, PL200 is a 200-in-one lab for $84.95, PL300 is a 300-in-one lab for $109.95, and PL500 is a 500-in-one lab for $249.95. This lab includes a 152-page basic course manual, a 78 page advanced course manual, and a 140 page programming course manual. Ramseykits claims this kit covers everything from the basics to digital programming, and might be useful for elementary grades through high school. You might want to add an electronics design program, perhaps something like Spice, to your curricula. I've seen several computer programs that teach basic electricity and others that explain RF fairly well. You shouldn't have any trouble searching the web for something useful. Ramseykits also has two soldering labs: SP1A for through-hole components and SM200K for surface-mount soldering. I also believe I saw some n-in-one kits at our Radio Shack just before Christmas. www.radioshack.com GL
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150
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eHam Forums / Elmers / RE: Using a VFO rig - how to zero-beat stations and request 'follow me'
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on: December 25, 2011, 05:04:38 AM
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Simon, as pointed out, drifting VFOs are nothing new. However, you shouldn't expect other ops to correct for your problem--that's just not very good operating practice, nor respectful of operators who have invested in good equipment so they wouldn't have to deal with fine tuning on each comeback. You may want to experiment some with the VFOs components to try to minimize drift; you may look into "huff and puff" stabilization circuits, for example, or experiment with swapping out some of the VFO caps with caps having different temperature characteristics until you tackle the drifting problem. If your rig doesn't consume too much power, you might consider leaving it on all the time, and orienting it so that heat from the finals doesn't find its way into the VFO. GL
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