vampires and power usage

England has loads of slang that the USA doesn't use. Most of which we've never heard. Ask about this on alt.english.usage and the English posters there can give you lots of stuff.

I think you are in the position I'm in in our respective countries, knowing few or no people who recent slang. Old slang doesn't capture our attention because we know what it means.

Ethernet required a direct connection to the conductor of the cable, if I remember correctly. The receiver side was high impedance, so it didn't present a significant load to the signal, and the vampire tap was designed to create only a small hole through the shield and inner dielectric so it wouldn't produce much of an impedance bump. Plus the cable was marked with rings to indicate where you could put a tap without having multiple taps end up a multiple of a wavelength apart.

When transmitting, an Ethernet transceiver acted as a current source, putting a fair bit of current into the 25 ohm load (50 ohm cable heading off in each of 2 directions). If two transceivers decided to transmit at the same time, the high DC level on the cable was used to detect a collision.

Original Ethernet used a baseband signal, and on a moderate-sized network every station listened to every other one directly. There's no "head end" to echo upstream signals back downstream again. There's no notion of "upstream" and "downstream".

Dave

Here, they were called "Stinger taps" and I had an unused tap block and stinger, along with the strand clamp and drop hook in my toolbox, until at least 2001. It might still be around, but I haven't used that toolbox in so many years that i don't remember. I brought it home the day i was laid off, then I was declared disabled, and unable to work, so it has been under one of my benches here at home, ever since.

Actually, there are two types of coaxial networking that used 75 ohm cable. The simple, small network like Dave describes below witch were non directional, and one that is usually part of a community loop where pairs of one forward channel, and one return channel are used for data, with a heterodyne signal processor at the headend to upconvert the return channel to a forward channel witch is built with back matched taps.

This system predates the current cable modems, but used standard, off the shelf CATV components to build a private WAN along with the RF modems. Some were mixed systems, of RF fed to clusters of the simpler coaxial networking. The first system like that I heard about was the Ohio State University campus in the '70s or early '80s. Their private CATV system connected all the buildings, then tied the existing, smaller networks together. I met two of their IT people at a hamfest, and they were bragging about their design, till I told them about the systems I maintained for the US army, years earlier. There was no return channel equipment on the market, so we had a pair of 12 channel 'Vicoa' (Later called Coral) systems set up as forward and return to carry the weather data from an airfield to the main base where it added to the other nine forward channels that fed the classrooms and airfield ready rooms.

We also built the first emergency alert system into a CATV system that took control of the civilian CATV service to the barracks and on base housing. A custom made coaxial relay was added to the existing system to seize control of the private system. The ETV studio was 12 channel, like the civilian system. A toggle switch (with a hinged cover and a lead seal) would feed the same audio and video to all 12 modulators, and switch the remote relay so an alert could be spread, no matter what channel a TV was on. After we proved the concept, it quickly spread to other bases, and new builds of civilian systems. The last system I maintained was a 36 channel RCA headend, in the early '80s. It had the optional IF loop through and auxiliary IF input for the alert system. The Audio and video was fed through a separate modulator with a IF output amp, instead of a channel module. I rewired the rack by strapping the loss of signal output to the relay control, and connected diodes to isolate each channel from the emergency control system. I also looped the emergency video through the local access control room so I could flip one switch and feed the same signal to all

The loss of signal mod caused a message to appear a half second after the carrier dropped out from a TV station, or satellite feed. That let the tech on night shift check the alignment of the converters after stations signed off, at night.

(Snipped because I found it less-relevant-than-I-expected to the subject line)

I was expecting to see stuff about power consumption by "wall warts".

Those have been called "vampires" by being 2-pronged/"fanged" constant consumers of small amounts of electrical energy that can become somewhat significant in terms of electrical energy consumption if one has several being powered 24/7, though this is well behind a refrigerator and behind most climte control and lighting electricity demand.

I do believe that there should be some "energy efficiency" requirements of those. I find many "switchmode" cell phone chargers to do well in that area, as I estimate from their heat output when loaded (mostly somewhat less than that of wallwarts" with iron core physical transformers) and when unloaded or largely-unloaded (they become outright cool to the touch when being connected to a cellphone that has detected that its battery got fully charged).

I also see many "wallwarts" with more-traditional iron core transformers easily consuming a watt or two less apiece if they get made with heavier gauge wire, more turns of wire per unit area of wound-around-core-cross-section, and/or thinner core material laminations preferably of some decent material - preferably "29M6" or only one or two minor steps cheaper than that. Maybe requiring next larger size (usually step up in most-traditional inch measurements for an "E-I" transformer core has longest dimension upped 5/16 inch, another upped 1/4 inch and the third upped 1/8 inch, and there are often some options to more mildly increase only the "stack thickness" of a laminated core by 1/8 inch that will even alone fairly often do well).

- Don Klipstein ( snipped-for-privacy@misty.com)

That may explain why they haven't become known as 'vampires' in the UK. Everything which plugs into a wall socket has to have THREE pins. The live and neutral receptacles have safety shutters, which are moved aside as the ground pin (which is somewhat longer) enters. Even in the UK, no self-respecting vampire would use three teeth. Ian.

Then tell me why you didn't reply in a more appropriate part of the thread? I was answering some questions from another poster.

That was where the thread started when I first saw it. Either my news server went screwy for a while or I failed to notice the thread before.

I now see that there were earlier articles having to do with power supplies that are constantly plugged in.

- Don Klipstein ( snipped-for-privacy@misty.com)

Part of the thread is in alt.home.repair AND sci.electonicts.repair.

Another part is only in ahr.

I think I brought in ser, and the answers about wall warts are in the other part of the thread.

You read ser iirc. So it's not that your server is screwy or that you failed to notice.

There is almost always a third possibility, even though often people (I'm not referring to you) don't want to believe it (Either it's amnesty or it's deportation)

OH, I should have read this sentence first. OOPs. To find the posts in ahr, you should come with the subject name and the date, because there is so much traffic on Ahr that it will be hard to find otehrwise. Or use groups.google and the exact subject name.

I was reading ahr. I could have glanced too quickly through a range of subject lines towards the end of the alphabet. I scan through subject lines more carefully in the range starting with "C", "F" and "L" since I pay more attention to lighting and fluorescent lamps than to most other stuff that comes up in ahr.

- Don Klipstein ( snipped-for-privacy@misty.com)