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Posts posted by EnigmaOne

  1. Somebody e-mail EDM Design to see if that transmitter kit is made in Africa or California. Who, me? I don't need one, I still have the FM transmitter I made more than 40 years ago with germanium transistors! ;D

    Lucky guy...my germainum plant died a few years back. Can't do nuttin' with it.

    I tried uploading the zip archive (only 2MB) but the board is fussin' at me about it. Anyway, if'n you want the article in its entirety (downloads and all), let me know.

  2. Hi Guys,
    I found what I think is the "South African" stereo FM transmitter kit on Google. Their description and spec's of this product is detailed (many pages) and good. I'm curious that I can't find their address anywhere on their website, but they mention shipping by US-postal service. Their website ends with ".ZA" which is the country of Zambia, isn't it? http://home.global.co.za/~edm1/

    Zaire is sticking in my mind as the country for the tld "ZA" but I certainly could be wrong on that count.

    Anyway...The order processing is routed through edmdesign.com, so you can:

    [email protected][example.user]# whois edmdesign.com
    Whois Server Version 1.3
       Domain Name: EDMDESIGN.COM
       Registrar: DOMAINDISCOVER
       Whois Server: whois.domaindiscover.com
       Referral URL: http://www.domaindiscover.com
       Name Server: NS1.DOMAINDISCOVER.COM
       Name Server: NS2.DOMAINDISCOVER.COM
       Status: ACTIVE
       Updated Date: 02-sep-2004
       Creation Date: 02-sep-2004
       Expiration Date: 02-sep-2005
    >>> Last update of whois database: Tue, 1 Feb 2005 07:49:08 EST <<<
    The Registry database contains ONLY .COM, .NET, .EDU domains and
       27834 Canyon Hills Way
       Murrieta, CA 92563
       Domain Name: EDMDESIGN.COM
       Administrative Contact, Technical Contact, Zone Contact:
          27834 Canyon Hills Way
          Murrieta, CA 92563
          http://www.emailaddressprotection.com [email]
       Domain created on 01-Sep-2004
       Domain expires on 01-Sep-2006
       Last updated on 01-Sep-2004
       Domain servers in listed order:

    and that should give you the contact information you crave.

  3. Glad whatever I was able to contribute was of some assistance to you. :)

    Now, as I'm looking at your photos, I'm just letting my mind coast along a bit as to what kind of overall plan you want to craft on this.

    If it was something that belonged to me, I would definitely put a ball-glide on each side of that panel, to reduce your lifting load, and to stabilize the side-to-side position of the panel as it travels.
    I'd add a clevis bracket on the top center of that sliding panel (behind the brass lift hardware) and mount your linear actuator in the center of that stationary vertical surface below the TV screen. Some sort of mechanical linkage (which I haven't puit too much thought into) which would allow for a panic situation disconnect from the top linear actuator clevis would be a feature to include out of prudence.

    I'm thinking that you should be able to spring mount the "south end" clevis attachment point so that it's fixed, in the "side-to-side" and "front-to-back" directions (x-axis and z-axis); but free, within limits, to move in the vertical direction (y-axis). If the travel of the panel is blocked by an obstacle (child, cat, somebody's tush) the spring will be vertically compressed, but won't compress under normal lifting condtitions. That vertical displacement can be used to operate a safety switch that will reverse the motor direction to lower the panel if something is in the way.

    Alternatively, one could monitor the motor current and, if it exceeds a certain level, the same safety protocol would be implemented.

    Things like this are more involved to describe that they are to "just do it." Sorry you don't live on the Left Coast, or I'd send you a guy I know, who could do what I'm thinking about in a few hours time.

    Don't get offended, but my mind distills volumes of verbage like this to a couple of iconic phrases, at the oddest times. In scanning through this thread one last time, I had to supress a giggle when I saw:

    "Desperate Housewife"
    provide some pictures.
    This, on the heels of having just cleaned out my nephew's Internet cache, and ridding it of spyware--again.

    ::: slapping-self and getting more coffee :::

  4. Last time I upped my inventory of solid state lamps, I bought from BlackFeather Electronics. Cost was good, and they generously adjusted their pricing in accordance with the quantities ordered. All-in-all, they were very good and fast on the turn-around.

    They've since moved their brick-n-mortar and I haven't had a chance to do any ordering from them in the interim. They may be worth a look on your part.

    A guy here was arrested for temporarily blinding airline pilots with a laser pointer.
    Was he like the one in New York, who was supposedly painting the eyes of a commercial jet pilot (flying at something like 5000 feet or more at 2 or 3 hundred miles per hour) with a handheld green laser pointer?
  5. I see what you mean. That thing needs the slot routed-out a bit larger, and the sliding panel should be mounted on good quality ball glides.
    Your carpenter should be able to understand that much about the situation.

    With 15mm/s thrust rate, be aware that the time to open up the panel will be on the order of 41 seconds. Not bad, but don't be in a hurry. I see that they say that they'll be introducing some higher speed models early this year. At 20lbs of force, it might be worth it to see what they offer the public on that count.

    Definitely install ball glides on both sides of the sliding panel (possibly 'L' bracketing the panel to ball glides mounted on the rear sides of that slot, though hidden would be much better), and it really depends on where you have to stuff the motor/gearbox. Possibly right behind the panel and attach the clevis at an appropriate point in the center of the panels width.

  6. Like Ldanielrosa says, you're probably looking for a "jack-of-all-trades" type of person; and getting a look at the situation certainly would go a long way towards getting a solution in the shortest possible time.

    Electronics is the easy part. Custom carpentry is really where I get into trouble.

    Looking at the link you provided, I'm reminded that we'd need to know the distance that the frame slides (up, down, over, whatever) and a look at the kind of space available to mount the mechanism. (Most of this kind of thing is usually done when the cabinetry is being constructed.)

    Given that information, it looks as though structural CAD files are available from the supplier that would be of use to you.

  7. There are several ready-made sub-assemblies that can be made to work in your situation...

    Linear actuators can be made to do the lifting for you:

    ...and there a wide range of consumer-oriented remote control modules that can be used to control the linear actuator.

    It's best if you have (possibly a more innovative and tech-savvy) carpenter come over and look over the information and your situation to give you a cost estimate on the additions to your existing entertainment center.

    It really shouldn't be that difficult to do.

  8. If you are searching for Service documentation for what would be considered to be a low, medium, high or production volume office/repro-center photocopier; you will have to get that kind of information directly from the manufacturer/distributor or field service firm. If you can.

    Be forewarned:
    Manuals are not inexpensive, are generally considered to be proprietary (or trade secret) information, and are (in most cases) clearly identified as such. All of the 'big players' in that I'm aware of firms will refuse to sell a manual--even at several tens of times their actual cost--lest they lose their service franchise.

  9. Have you 'scope'd the secondary of a power transformer that has a rectifier bridge, big filter cap and a fairly heavy load? The peaks of the sine-wave are flat-topped when the rectifier conducts.

    As a matter of fact, I recall seeing something like that, although I can't recall if I was looking at the voltage across the secondary, or the current through it. I'd imagine that it could have been the former at some point, because the occasion I'm remembering was when I was comparing the overshoot of standard rectifiers with that of hot carrier rectifiers (FRRs).
  10. You could run 2 - 6 Volt batteries in series, and tap the batteries to provide 6VDC for the glow plugs.
    If the proper connections are present on the glow plugs (two connection terminals on the glow plug itself, instead of an internally grounded terminal and a single external terminal), then run two in series. I'd imagine that you don't have an odd number of cylinders on that thing.

    Are you sure that tractor started out with a 12 Volt system? Most I've seen (of course it's been decades) were 6 volt system machines.

  11. Salesmen! ::) They rarely know anything about the things they sell.

    The first salesman was a simple waste of human flesh.

    The second salesman was talking (politely phrased) out of his posterior.
    It's more likely that the shop you went to has only one BNC connector style in the proper impedence. Most pedestrian 75-ohm cable is in the aluminum-shielded variety, for which the crimp-style connector will be needed because I still don't know of a realistic procedure for soldering aluminum shields to anything.

    75-ohm cable can be had in copper braid shielding styles, but it's not as common, and the center conductor is usually stranded. It is for this style of cable that the solderable connectors are intended.

    If the cable you have is the run-of-the-mill aluminum shield type, then you're stuck using the crimp-installed BNCs.

    Please suggest to both salesmen who gave you "advice" that, they would be better-off considering a career in used car sales. At least the customers expect to be lied to, in that type of setting.

    Yeah....it may be best to let it go for right now. ;)

  12. For DC through audio circuits, you can use hot-melt glue without problems.

    For RF circuits, or circuits that use switched-DC that approximates RF frequency rates, use GE Silicone Sealer.

    The reason being that hot-melt glue, while possessing excellent insulating properties at low frequencies, is not certified for use at radio frequencies.
    Some brands of silicone sealer will actually appear as a dead short at frequencies approaching those of the 11 meter band. This is why I specify 'GE brand' silicone Sealer. It has been shown to possess superior dielectric qualities at the switching frequencies involved with 10-100 Mb/s network connections.

  13. Among notable others, my Boylestad & Nashelsky text is missing at the moment (my son claims innocence), so I'm left with Malvino's "Devices" text--and the like--from which the 3 graphics were scanned.

    Thus far, all other references that I have at my disposal concur with Malvino; either verbatim, or with a 'C =' or 'Iripple =' formula that derives directly to the one presented. I will dredge-up the B & N text--simply because I like that one better anyway--and compare. I doubt that it will, according to my recollection, differ substantively.

    A high-current transformer usually has a pretty good voltage regulation because it has a very low resistance. Therefore it would produce a fairly low ripple voltage.

    Until you draw current close to the design spec of the transformer; which increases the percentage ripple output--the value for 'C' remaining constant.

    Personally speaking, I prefer transformers to putt-along at about 50% of their manufactured output current rating. It's all part of the balancing-act of staying within your (hopefully) generous engineering overheads.

    For a single-phase power supply, the equation errs on the side that most engineers would prefer to err on: Providing a flatter output waveform across the designed range of load currents. One would then simply pay attention to the surge current for high values of C, adding a regulator, some shorting protection and a set of output caps.
    I can live with the fact that attempting to refine a more exact solution--in the face of typical tolerances for e-caps--amounts to an exercise in false economy and wasted time.

    I still want to get my hands on who took my textbook(s).
  14. ...and, if it's good enough for AOpen, who am I to disagree??? ;)

    "Today AOpen shows us something that, while it could be considered revolutionary, may also be very "old school" to many of our readers out there. AOpen is putting vacuum tubes back onto the desktop platform.

    The pictures below are of the AOpen AX4B-533Tube. It's an i845E based board that supports both 400MHz and 533MHz bus Pentium 4 CPUs with DDR RAM up to PC2100 spec. The ICH4 hub is used with the i45E at this time which brings native USB 2.0 support to the board. While this board hosts a myriad of overclocker features, what's really the attention getter is the audio system on-board.

    One of the greatest gripes about onboard sound today in the mainboard market is the quality of the sound. While there have been solid advancements and onboard sound has certainly grown leaps and bounds in the last year, AOpen wanted to come in and do it like no other company has.

    While no full specs were yet available to us, AOpen has taken a lead from the high-end audio component producers and used a vacuum tube system on their mainboard which they say produces overall sound quality that cannot be duplicated on silicon.

    The first picture shows the overall board layout. The sound components are clearly visible at the lower edge of the board. You might also notice only three PCI slots. AOpen has also included an onboard NIC on this board. Considering that, and the fact that anyone purchasing this board is very likely to use the onboard sound, AOpen sees three PCI slots as being plenty.

    Close ups of the tube and other components show off that this isn't just for decoration. The header that you see in the second picture above is not a power header, but rather the plug that handles the audio out jacks.

    You old guys will remember that vacuum tubes need some high-end power as well. And just who-the-heck is he calling old? AOpen has fitted the board with components spec'ed at twice the 200 volt power requirement by the tube system in order to produce a solid and stable platform. Seems to be no skimping here.

    The last picture shows the AX4B-533Tube running an audio system in the AOpen booth, and from what we heard, their tube board seems to be just what the audiophile may be looking for. Another interesting software feature that will be shipped with the board is CD Player software. While this does not seem to be anything new, AOpen's solution can run the CD player without booting into a Windows OS. The CD Player loads immediately after the BIOS."


    Credited to: HardOCP.com, Monday, June 3, 2002

  15. I think that in the dessert the dry sand or dry earth for that matter will not be much of a shield. As I said a BIG coil should work and the more current the power line carries the more power is induced in the BIG coil! ;D

    In thinking back on this some more (yeah, more than 30 years now), and checking my recollections against those of a couple of other guys who were in the same class with me (my phone bill is going to be high this month); we've been able to piece-together a bit more of a picture of what was said:

    The trenching was shallow, because pieces of wood (Maybe it was diagonally staked in place?) were used to hold the cable down to be covered-up. (I totally forgot about that part.)

    Power lines that run through that general region now, are on the order of several mega-volt transmission lines, and carry current well in excess of 1000 Amps. I have to think that they certainly weren't light-duty, low-current lines back in the purported era of the story, as told to us. In view of this, I'd wager that the shielding effects of dry ground would only be evident at something below a meter.

    The teacher held up his thumb as a size indicator of the cable supposedly used. The significance of this hit me only last night...he had to be talking about something like MMC250 or MMC500 cable, for which I2R-losses wouldn't be a huge factor. (The copper, alone, would be worth some serious money today!)

    This guy's property was--evidently--measured in terms of miles, making one helluva secondary winding. One guy remembered a diagram on the blackboard, about this story, that showed a single-direction dimension line in units of "miles" but can't remember how many. (I'd be impressed if he could.)

    One guy thinks that the coupled power was DC-stored, and the other guy remembers that the power was used directly. I remember some statement about there being an issue with the voltage induced in the coil.


    ...I still don't know what to think about it; although I still believe it to be theoretically possible, if not somewhat improbable.

    I guess I should start writing some letters to the companies that may have been involved in something like this, if it ever happened.
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