Path: ...!news-out.netnews.com|netnews.com!postmaster.netnews.com!weretis.net!feeder6.news.weretis.net!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!feeder.usenetexpress.com!tr1.iad1.usenetexpress.com!69.80.99.22.MISMATCH!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Tue, 02 Apr 2024 15:09:33 +0000 From: John Larkin Newsgroups: sci.electronics.design,sci.electronics.repair Subject: Re: Favourite Test Equipment Date: Tue, 02 Apr 2024 08:07:56 -0700 Organization: Highland Tech Reply-To: xx@yy.com Message-ID: References: <9k7j0jlnbhs8qfg5m17pium0835meean83@4ax.com> <1hol0j97e09qaijhuh3745rqheoj2gqjtf@4ax.com> X-Newsreader: Forte Agent 3.1/32.783 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Lines: 158 X-Trace: sv3-PfAgnRrIohSK+3xfzkQqctEihPGosdZfbNLdWDbE5kfcGRaOj34E9geQSQyySE56WyWEG5/jByNtj7S!Y6D/IwjB9RXuQdvCOEhKKvDYCZ+gqmV3oB4agWfLBPwi5dUccCbFy2wg1TBztI5OMPadXplu2eIZ!+h601w== X-Complaints-To: www.supernews.com/docs/abuse.html X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Bytes: 8710 On Tue, 2 Apr 2024 09:56:33 -0000 (UTC), Phil Hobbs wrote: >john larkin wrote: >> On Mon, 01 Apr 2024 17:37:49 +0100, Cursitor Doom >> wrote: >> >>> On Mon, 01 Apr 2024 09:15:42 -0700, John Larkin >>> wrote: >>> >>>> On Mon, 1 Apr 2024 12:09:00 -0000 (UTC), piglet >>>> wrote: >>>> >>>>> Jan Panteltje wrote: >>>>>> On a sunny day (Sun, 31 Mar 2024 18:41:18 +0100) it happened Cursitor Doom >>>>>> wrote in <9k7j0jlnbhs8qfg5m17pium0835meean83@4ax.com>: >>>>>> >>>>>>> Hi all, >>>>>>> >>>>>>> I'm starting to get a bit fed up with having my test equipment blow up >>>>>>> just when it's needed. This is the drawback with vintage gear; if it's >>>>>>> not used frequently then it can go *bang* the next time you switch it >>>>>>> on. It makes for good practice in repairing stuff, but wastes a lot of >>>>>>> time which could be better spent doing other things. >>>>>>> I think it's time I modernised my test gear. I was just wondering if >>>>>>> anyone has any recommendations they can share. Is there a particular >>>>>>> piece of test equipment you couldn't live without? Something you're >>>>>>> particularly impressed with? I'd be interested to know so I can >>>>>>> perhaps acquire said item and thereby reduce the number of explosions >>>>>>> I experience. >>>>>>> >>>>>>> Thanks, >>>>>>> >>>>>>> CD. >>>>>> >>>>>> My 10 MHz Trio dual trace analog scope is from 1979 or there about, I >>>>>> blew up a channal once myself in the first week >>>>>> when I accidently touched a booster diode in a TV I was repairing with >>>>>> it, fixed it locating the problem with the other channel. >>>>>> Later I cracked the graticule when a soldering station fell on it from >>>>>> the table (scope stands on the ground) >>>>>> Made a new graticule. >>>>>> So, and still working perfectly, OK for all things I build with micros. >>>>>> For RF to about 1.6 GHz I use RTL_SDR USB sticks and the spectrum analyzer I wrote. >>>>>> and for AC DC measurements I have some made in China digital meters and an analog one. >>>>>> also a Voltcraft clamp-on meter for current when you do not - or cannot >>>>>> interrupt things with the meter impedance. >>>>>> Also have a Voltcraft soldering station. >>>>>> Blew up one of my digital meters a while back (volts on the resistance >>>>>> scale) but fixed it again (replaced resistor). >>>>>> Many other test equipment I designed and build, like amplifiers LF and >>>>>> RF, SWR meter, radiation meters, gamma spectrometer, >>>>>> GHz stuff for satelite, transmitters low and very high power, what not, >>>>>> a frequency converter to use the RTL-SDR sticks and so the spectrum >>>>>> analyzer on higher and lower frequencies. >>>>>> Have a SARK100 SWR analyzer too. >>>>>> Things last forever here... >>>>>> Scope used on a regular basis.. >>>>>> RTL-SDR stick 24/7. >>>>>> Digital meters used every day. >>>>>> Use my self designed lab power supply every day.. >>>>>> What more do you need? >>>>>> Learn to use the stuff, understand what's important, and that is it >>>>>> When I started in electronics as a kid I did not even _have_ a meter, >>>>>> still stuff worked. >>>>>> Build my own scope at some point back then when I somehow got the parts >>>>>> Not much pocket mony as a kid. >>>>>> UNDERSTAND your systems, what electrons do. >>>>>> Showing of with boat anchors may impress people, especially the clueless... >>>>>> But it does not help you one bit. >>>>>> Anything with an accuracy better than 1 percent in most cases is just >>>>>> like apes screaming load trying to impress other apes. >>>>>> >>>>>> >>>>>> >>>>> >>>>> Many wise words there. >>>>> >>>>> Boat anchors can still be great as they require you to understand better >>>>> what is being measured and don?t hide things away with abstraction and >>>>> unhelpful software. >>>> >>>> A color digital scope is fabulous. It can measure volts and time and >>>> frequency, save and analyze waveforms, display pre-trigger, and you >>>> can lift one with one hand. And the traces are in color! >>> >>> I know they have their advantages, but they can also tell lies by >>> showing glitches in waveforms that are internally generated by the >>> scope rather than the DUT. >> >> I've never seen that. Aliasing is obvious. >> > >Some instruments do kick crap out of their inputs. I have an otherwise very >nice Krohn-Hite tunable filter box that is hard to use because of its >terrible kickout. > >Scopes generally don’t do that, because there are vertical amps and >attenuators in the way. > >However, you do need to understand a little bit about how sampling works. >For instance, say you’re looking at a noisy signal. You want to see some >more detail, so you start cranking the horizontal scale knob to the right. >Everything looks fine until you get past the maximum sampling rate. > >The scale keeps getting finer, but the display breaks up completely, >turning into a lot of nearly vertical lines. Of course that’s because it’s >gone from real-time to equivalent-time sampling, but it’s puzzling the >first time you see it. (To the analog-only folks: ET is useful, but >requires careful attention to triggering and averaging. ) > >In general, 1980-2005ish vintage boat anchors really rock, but you have to >get the best. Just yesterday I bought a Tek TDS 684C—1 GHz BW, 4 GS/s >simultaneously on all four channels, with fabulous knob response. It was >$300, about 1.5 cents on the dollar versus new. You've seen my SDxx sampling head collection. Must have been worth $250K new, twice that adjusted for inflation. > >When I was at IBM, bought one brand new in the late 90s (probably $20k) and >used it for nearly everything. > >> >>> For such occasions, it can be very useful >>> to keep an old analogue scope. I've got 13 of 'em! >> >> I have several oldn Taks on carts, as antiques, but I never expect to >> power them up again. >> >> We do have a bunch of 11801 samplers that still work. They are all >> solid-state except for the raster-scan CRT. >> >> >I’m a big fan of those too, and use them often. I have a very nearly >complete collection of sampling and O/E heads, too—just missing the SD-32 >50 GHz sampler. Some day my 11802 will die. I'll mourn it. > >Right now I’m working on a lab amplifier, based on three paralleled >SAV-331+ pHEMTs. Characterizing its noise performance is turning out to be >a bit of a puzzle, despite a pile of top-of-the-line boat anchors, but I’ll >keep that for its own thread. The old HP analog noise figure meters got way sub 1 dB, with some sort of lock-in technique. I remember some germanium jfets that got below 1 dB at low MHz (for a Raydist navigation receiver, pre-GPS) and was astounded. Come to think of it, I slightly helped get GPS started. That's another story.