Dan's Data letters #122
Publication date: 17 August 2004.Last modified 03-Dec-2011.
The FBI may be after him, too
Sorry to be a nuisance with something that most people probably have no problems with... but how do you reply to a newsgroup thread? Each time I try I just end up with this error message:
"Outlook Express could not post your message. Subject [whatever], Account: '202.108.36.140', Server: '202.108.36.140', Protocol: NNTP, Server Response: '440 Posting not allowed', Port: 119, Secure(SSL): No, Server Error: 440, Error Number: 0x800CCCA9"
Mal
Answer:
That error happens when a news server sees an incoming connection from an IP address from which it's been configured
to reject posts - generally because that IP address belongs to a
newsgroup spammer.
202.108.36.140 is the IP address of news.cn99.com. Cn99.com is a Chinese ISP with some vague spam connections (hardly any Chinese ISPs don't have spam issues...), and news.cn99.com's address is listed on a few block lists, most notably Spam Prevention Early Warning System (SPEWS).
SPEWS is well known for being one of the most, if not the most, "Ready, FIRE!, Aim..." of the popular block lists, and has made many enemies over the years (just do a Google search for "spews" and see what you get in the very first page of results...). But you're probably at this point wondering not why cn99.com's on block lists, but why the news server for your Australian ISP (which is what I presume you're accessing newsgroups through) thinks you, a customer of that ISP, are cn99.com's news server.
I'm guessing that it's because you're on dial-up (are you?), and are separated from the public Internet by a proxy box at your ISP (as is common for dial-up customers), and have been given an IP address for the connection between you and that proxy box that by coincidence matches that server out there on the Net. If the news server doesn't know the difference between 202.108.36.140 incoming from the Net and 202.108.36.140 outgoing from a customer (which the Internet at large won't be able to see, and which you shouldn't actually have been given, I think), and if it's configured to use the SPEWS list to block spammers, this problem could arise.
Hot running
If you turn on an electric motor and then forcibly stop it from turning, does it continue to use power?
Of course, the motor won't be doing any work, but will it be converting electricity into heat, or doing nothing at all?
Chuck
Answer:
Yes, it'll be using power, and getting warm.
Brushed motors will, in this situation, behave pretty much like a dead short, and develop a whole lot of torque; this is why brush-motor-powered R/C cars are most likely to eat a gearbox or blow a speed controller if their wheels are jammed and you punch the throttle. Brushless motors will, generally, handle a stall condition better; computer fans are a good example. When stalled, they draw more current than when running, but not a huge amount more, and they can stay stalled all day without burning up. What they're meant to be cooling may burn up, but the fan motor won't.
Easier than head-shrinking
You mentioned that your Sennheiser HD 590s aren't too clampy on your head, and I'm wondering if you know a good way to loosen the new style of Sennheisers further, without cracking out the Zippo. I have HD 497s, and I guess I have a big head, because after a couple of hours my ears feel like I've just finished a game of rugby. Do you have any non-warranty-voiding methods of loosening the fit, or should I just get my ears pinned?
Dave
Answer:
A naked flame would, I think, be inadvisable, but you probably
could soften the headband a bit with a hair dryer, with no risk of melting anything.
I spoke the above to Dave from the comfortable position of someone who's never tried it - but he gave it a go, and it worked perfectly!
Well, except for the fact that he decided to take the hair dryer to where the headphones were, which was at his office, which apparently generated a funny look or two.
Silence quest
I am looking for a PC which will generate as little noise as possible while still offering decent performance. I am using a 1.8Ghz P4 at the moment, but in conjunction with a very noisy PSU supplied with my case. The Zen looks promising, but I don't want to stick a 3GHz P4 in it if it will bring the noise level near your average PC. I am also looking at Antec's Sonata case, but I'm still not sure about that either. Is it possible to run a 3Ghz P4 and keep it reasonably cool at around 30dB?
If money wasn't a limiting factor I would get a Zalman.
Peter
Answer:
The little Zen can handle pretty hot processors, but its thermally controlled fan will make it, as you say, at least
as loud as a regular beige-box PC with a single PSU exhaust fan if it has to run at full power.
If you don't need a tiny case, then building your computer with a conventional motherboard in a low-noise case like a Sonata might work well for you. There's a good selection of low noise coolers for Athlons and P4s these days (the Spire CopperStream II, for instance). Super-quiet PSUs are also commonly available, but never provide a great deal of air flow; you need other exhaust and preferably also intake fans in addition to them.
To really silence a PC you'll need to add an acoustic-foam-lined "periscope" to the exhausts; that's where a lot of the noise gets out. Similarly, you can add automotive panel damping material to the case sides (cheap damping foam isn't likely to work very well). But if you build the abovementioned Sonata system, there's a good chance you won't mind the noise it makes without such modifications.
Sprechen sie vinyl?
I have recently been reading about phono preamps to hook up my turntable to a simple "line in" on my "no phono input" stereo, and to copy the music to digital format on my computer. Is it feasible to homebrew such a preamp ala the Chu Moy headphone amp, with additional RIAA-type filtering? What specifications are important in such a device?
Sean
Answer:
You could build a phono preamp (ideally from a kit from an electronics store), but you can also buy them really cheaply,
which is what I'd do.
Here's an example store, about which I know pretty much zero but which looks OK.
The reason these things can be so cheap is that their component count is pretty low. All they are is an amp and a simple filter network. And they don't need spectacular audio specs, because records don't have spectacular specs in the first place - for instance, there's no point taking the roughly 60dB signal-to-noise ratio of even a very good LP and amplifying it through a 90dB SNR device. 75dB gives tons of headroom, and costs less.
Phono preamps also need no gain control, and many of the cheap ones run from a plugpack, too, which is a good thing because it moves the hum-generating transformer far away from the very-low-voltage signal path.
Wanted: Non-crap camera
I am after a digital camera, possibly with a camcorder function, and my husband insisted I email you first. After the argument on how does a perfect stranger know what kind of functions we need, he just blatantly said he is not buying anything unless you are consulted.
I hope you are good at this or he gets NONE all next week.
It needs to have in built re-charge capabilities or after market recharge battery pack, as I am using this camera to sell all my husband's Transformers on eBay (hehehe) and will need to take a hell of a lot of photos without it going dead and needing to buy more batteries. This is a current frustration. We need a basic camera but not the bottom of the line. We don't want to spend too much, but we need a decent unit.
Can you help us?
Cathy
Answer:
Many digital cameras can run from an AC adapter, but they often don't come with it. Many cameras these days also have
very good battery life; if the battery doesn't die before you're ready to take an hour off from photographing anyway,
it's no big deal.
If you just get a camera that runs from cheap non-proprietary batteries, though, you can easily have one set of batteries charging while you shoot with another and you'll be fine. While proprietary batteries are more popular than they used to be, it's still not hard to find cameras that run from AAs. If a camera has a cheap proprietary battery, of course, then that's also fine.
Pretty much any current consumer digicam will take OK pictures of moderately small things like Transformers, but if you want to take lots and lots of pictures pretty quickly, and have them all look good and consistent, and be able to fill the frame with a coin-sized area of the subject to show detail, then you'll need a small amount of extra gear and a camera with good close-up capabilities.
The extra gear is no big deal. One basic tripod (any dirt-cheap entry-level Velbon piece of crud'll do) and one hot light, to bounce off a piece of white cardboard rigged above the shooting area (or a low white ceiling). A 500-watt halogen flood light from the hardware store will be more than adequate for the lighting. It'll also keep the room nice and warm.
The reason for this extra stuff is partly to give every picture the same lighting (and allow you to just take one Transformer off the table and pop another one in, spend two seconds reframing and shoot again), and partly to avoid the nasty flat atomic-bomb-flash look you'll get if you just use the camera's built-in flash. Diffuse reflected light from above makes all kinds of pictures look much better, and digital camera white balance can correct for the yellow-ness of the light from a cheap halogen flood. (Back in the film days, you would have needed to mess around with film type and/or filters for the light or the lens, to avoid these pictures all having a funny colour cast. Software white-balance is a lifesaver here.)
You'll need a backdrop too, but a white sheet from the linen cupboard, or a suitably large sheet of white paper (for small subjects, A3-size paper is often adequate), will do.
(I ramble on at great length about how to take pictures of small-ish objects in my photo tutorial.)
There are quite a few cameras that'll fit the bill here, but if you narrow it down a bit more (only cheap-ish cameras, only cameras that use cheap CompactFlash cards for storage) the field thins out a bit.
Consider a Canon PowerShot A75 (review one, review two). Under $AU400 from a cheap place like Dirt Cheap Cameras here in Australia. The basic A75 package doesn't include rechargeable batteries or a charger, so expect to pay, oh, another $AU70 for eight AAs and a good charger. Lots of people on eBay sell OK NiMH AAs and fast chargers for them.
The tripod and the floodlight shouldn't cost more than another $AU50 between them; again, eBay's a good place to find cheap (and nasty, but good enough) tripods. Your local hardware or discount store should have a floodlight for you.
Note that the A75 only comes with a 32Mb CompactFlash card, which you could squeak by with for studio purposes, but you're likely to want something bigger. If you pay more than $AU50 including postage for a 128Mb CompactFlash card (eBay again!), you've been swindled.
The Nikon Coolpix 4300 might suit you, too (review one, review two). It's maybe $AU450 from cheap Aussie dealers, and it uses a proprietary battery that's only meant to be good for an hour and a half of use, but you can get a spare battery on (wait for it...) eBay for $AU30 (including delivery), so that's no big deal. These current small Nikons are very small, without being so minuscule that adults can hardly use them; they're great everyday large-pocket cameras, and like all Coolpix-es they have excellent close-up capabilities. The 4300 only comes with a miserable 16Mb memory card, though, so you will need a bigger one.
I hope this answer passes muster. Good luck, Mr Gorsky.
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