- Blank RF Probe tips - 9 Updates
- Using magnets with tiny SMD devices - any electronic concerns? - 2 Updates
| Michael Black <et472@ncf.ca>: Mar 28 07:55PM -0400 |
| analogdial <analogdial@mail.com>: Mar 29 12:54AM Michael Black wrote: > But it's no longer so easy to find tube sockets and shields. It looked > like a good idea back then. Lots on ebay. Brand new from China, if that's not a problem for you. I don't quite understand Chinese manufacturing priorities. You can find new compactron and 10 pin decal sockets, too. |
| Michael Black <et472@ncf.ca>: Mar 28 11:19PM -0400 |
| oldschool@tubes.com: Mar 29 04:36AM -0500 On Tue, 28 Mar 2017 04:15:37 -0700 (PDT), "pfjw@aol.com" <pfjw@aol.com> wrote: >XAM equipment of that vintage often (very nearly always) used germanium transistors - so be very careful of the part numbers. >Peter Wieck >Melrose Park, PA Thats good to know. Thanks! I was just reading recently that the earlier transistors were made with germanium, but it is rare and thus costly so they changed to silicone. |
| MJC <gravity@mjcoon.plus.com>: Mar 29 10:57AM +0100 In article <46vmdcdgb2qu79l64s5cf9uobdrdbuj34g@4ax.com>, oldschool@tubes.com says... > I was just reading recently that the earlier transistors were made with > germanium, but it is rare and thus costly so they changed to silicone. Definitely silicon, not silicone. In chemistry, one letter makes a big difference! Mike. |
| oldschool@tubes.com: Mar 29 05:03AM -0500 >brass sheet, and one could make end caps with those. >For things that don't need shielding, old markers to work. > Michael One of the kits linked in this thread, uses cpvc plumbing pipe, but they cover it with adhesive copper foil. Thats a good idea. They have some special caps on the ends, but I dont see why the pvc caps made for that pipe would not work. Glue on the front one, leave the read one loose. or put a little tape on it. Copper plumbing pipe would make a good shell too, and the rear cap could be a copper pipe cap with a rubber grommet drilled in (for the wire), but I have not figured out what to use on the front that is non-conductive, and still strong enough for the probe tip. I was looking at some of the old Eico probes. I used to have some of them (I wish I would have kept that stuff). There were 5 of them, all color coded. Yellow was direct, blue was RF, Green was demodulator, red was low capacity, and there was one more but I have not found pictures of that one, or what it did. Anyhow, I have a direct one, just coax with a regular probe on the center lead and an aligator clip on the shield. But I want to make a RF probe. I dont really see a need for a demodulator, or low capacity, but I may in the future, now that I picked up a scope. |
| Foxs Mercantile <jdangus@att.net>: Mar 29 10:04AM -0500 > It's the truth, and I have a thing called "Freedom of speech"! Funny how the "freedom of speech" usually only applies to the person claiming it. I have a similar freedom, calling out people for being ignorant assholes when they wish to publicly display it. On truth and democracy: There is a cult of ignorance in the United States, and there always has been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge." ISAAC ASIMOV, "A Cult of Ignorance", Newsweek, Jan. 21, 1980 -- Jeff-1.0 wa6fwi http://www.foxsmercantile.com --- This email has been checked for viruses by AVG. http://www.avg.com |
| "pfjw@aol.com" <pfjw@aol.com>: Mar 29 09:23AM -0700 RANT WARNING! On Wednesday, March 29, 2017 at 11:04:22 AM UTC-4, Foxs Mercantile wrote: > cultural life, nurtured by the false notion that democracy > means that "my ignorance is just as good as your knowledge." > ISAAC ASIMOV, "A Cult of Ignorance", Newsweek, Jan. 21, 1980 As we are quoting fairly a learned writer, and one who also wrote a great deal of science fiction, here is an equally appropriate quote from another learned writer, who also wrote science fiction: "You are not entitled to your opinion. You are entitled to your informed opinion. Nobody is entitled to be ignorant." Harlan Ellison https://en.wikipedia.org/wiki/Democracy_Index Democracy arises only from exceeding wealth readily shared at every level of society. And even a brief look at other so-called democracies in this world, starting with India, and that obvious reality becomes clear. The United States is 21 (of 76) on a world scale, between Japan and Italy - both very recent converts to the title of 'democracy' on a world scale. A pretty sad condition for a so-called Beacon. And to the extent that we fail to protect our least able citizens and residents, that is the extent to which we fail as a democracy. To the extent that we fail to educate our young to live, play, work and grow on the *WORLD STAGE* is the extent to which we fail as a nation to grow and participate in that world stage. We cannot go it alone - hell, we do not even make one single simple LDC screen in this country. We are a net-importer of agricultural goods (due, in large part, to the consumption of illicit pharmaceuticals), we cannot meet any of our most basic requirements from steel to energy to minerals to necessary pharmaceuticals to much of anything else solely from domestic sources - NOR CAN THE REST OF THE WORLD FOR THEMSELVES, EITHER. So, we are necessary participants whether we recognize it or not. Best to learn about all this and understand it, rather than be caught blindsided by it, perhaps? We need to be smarter, harder working, faster, better educated, more thoughtful, less ignorant, cleaner and brighter than the rest of the world at every level of our society or we *will* fail. We need to make use of our incredible wealth, and not concentrate it into the hands of a very, very few - or we will lose all of it. We, the United States, are 5% of the world's population. Yet we consume just about 25% of the world's total resources. Ignorance will not protect that primacy. Nor will denying the consequences and necessities of that primacy. For us to live as we live, individuals in China, North Korea, Bangladesh, India, Pakistan, Congo, Sudan, Yemen, Somalia, Haiti et.al. *MUST* live as they do. Stop whining about what you don't begin to understand, stop living by received wisdom, and start to understand reality. As we are quoting, here is another one: "But you were always a good man of business, Jacob,' faltered Scrooge, who now began to apply this to himself. Business!' cried the Ghost, wringing its hands again. "Mankind was my business; charity, mercy, forbearance, and benevolence, were, all, my business. The deals of my trade were but a drop of water in the comprehensive ocean of my business!" Charles Dickens America is no greater than the least of us. Peter Wieck Melrose Park, PA |
| Jeff Liebermann <jeffl@cruzio.com>: Mar 29 09:33AM -0700 On Wed, 29 Mar 2017 10:04:02 -0500, Foxs Mercantile <jdangus@att.net> wrote: >> It's the truth, and I have a thing called "Freedom of speech"! >Funny how the "freedom of speech" usually only applies to the >person claiming it. He who yells the biggest, loudest, and longest, wins. These days, freedom of speech mostly means WikiLeaks and commercial advertising. >I have a similar freedom, calling out people for being ignorant >assholes when they wish to publicly display it. Let he who knows all cast the first complaint. >cultural life, nurtured by the false notion that democracy >means that "my ignorance is just as good as your knowledge." >ISAAC ASIMOV, "A Cult of Ignorance", Newsweek, Jan. 21, 1980 Yep. Just ask any voter for the names of their recently elected officials. Most can name the president, and that's all. At best, they remember the names, but not their associated office. In a way, that's probably a good thing because if the GUM (great unwashed masses) knew what was happening in government, we would have continuous rioting and revolution. Political ignorance might be a good thing. Ignorance is worse in technical fields, and we're all to blame. As technical areas such as computahs and electronics grow, the number of buzzwords, acronyms, trade names, and calculations necessary to be considered knowledgeable also grows. Jump into this maze of technobabble, after an extended absence, and even the most intelligent person will appear to be quite ignorant. I've had that experience dealing with radiation, modern medicine, and cycling. I'm currently providing a splendid example by making a fool of myself in another newsgroup demonstrating my ignorance of lighting and optics. It's all part of my "Learn by Destroying" paradigm, which in this case, involves destroying my reputation. I'll survive. Would you call me an ignorant asshole for failing to instantly assimilate the accumulated wisdom of some 500 years of optics? Part of the problem is that Mr Oldschool is not responding to suggestions and answers to his questions. He usually drifts off on another topic, as if all the effort people have put into answering his questions was of no importance. Failure to appreciate is a capital crime, and I certainly feel unappreciated as all my comments have not even been acknowledged. So, I'll offer one last suggestion before I give up. The "classic RF probe" is a marginal and crude device that was long ago replaced by far better amplified probes. The "classic RF probe" quits at about 100MHz, has a rather lumpy frequency response, and will load down high impedance circuits. If you have volts of signal to work with in a tube device, it will work as expected. If you're working on a modern low voltage device, you'll have problems. What's better is a FET input RF probe, something like these, which can be built: <http://cjh.polyplex.org/electronics/RFCascodeProbe/> <http://www.instructables.com/id/DIY-1GHz-Active-Probe-for-Under-20/?ALLSTEPS> If you must use tubes, I could probably design a cascode Nuvistor RF probe for the occasion. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| bitrex <bitrex@de.lete.earthlink.net>: Mar 28 02:46PM -0400 > I have been through many scanners all over the US, and the world. No issues, ever. Traveling with everything from high end cameras to sensitive medical equipment. > Peter Wieck > Melrose Park, PA The one you have to worry about is the one in the post office. I've had packages containing prototypes likely seized before. Because they looked scary. Customer gets sent an empty box, "your package was damaged in shipping", deny everything. |
| "pfjw@aol.com" <pfjw@aol.com>: Mar 28 01:49PM -0700 OK - a few things. a) Airport and shipping security are facts of life whether one is from the back of beyond or downtown NYC. Every manufacturer on the planet understands this. b) Older devices would simply be immune to stray fields of the sorts found in airports, flying above 5,000 feet (cosmic rays), walking down the street (how many cell/bluetooth devices/routers/GPS devices and more do you think you are passing in, around and through on a moment-to-moment basis? Newer devices would be designed to be immune. After all, we are not discussing EMPs, just stray fields. c) Magnetic fields propagate by the inverse-square. Twice the distance = the √ of the first distance. And so forth. d) As previously noted, the magnetic field is bridged, and alternating. e) As previously noted, the field is released when the part is placed - so there is no, repeat, no induced field beyond the shield (part) itself. And as all sorts of these devices are already deployed all over the planet in many configurations without apparent untoward effects as of yet, I suggest that the need for paranoia is minimal. https://www.youtube.com/watch?v=gp5JCrSXkJY Peter Wieck Melrose Park, PA |
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