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12:35 AM
@Kortuk Huh?
 
jpc
12:48 AM
@Kortuk The intended usage is to generate 60Hz so even the 100th harmonic is just 6kHz. Maybe the LC will work after all.
 
@JamesDyson I saw your picture of the yagi-uda array. That is what it was called when we worked with it in my antenna theory class.
@jpc I think it would work. 99% sure. I would like to see how well it works with the LC.
@jpc, I wanted to note most class D amps operate at well above 100kHz so the switching loss should be negligible for what you are looking at.
 
jpc
@Kortuk I promise to try it but I am not sure if it will happen tomorrow. :)
 
@jpc, I would love waveforms and such
 
@Kortuk Ok .... Do you know any good sized brackets for this?
 
@jpc I look forward to it. I hope it is as sexy as promised.
@JamesDyson Nope, I have only taken a class, never used anything past patch and monopole antennas.
@JamesDyson I can ask someone whom might, I will let you know.
 
12:55 AM
@Kortuk Thank you very much :)
 
jpc
@Kortuk Btw. maybe this is not used much because most inverters use a simple ternary output (+220,-220 and 0) with 0 used near the zero crossings and still get a decent "sine-wave" after some filtering. Maybe motor control would be less forgiving and require a more sophisticated approach?
 
@JamesDyson Don't go getting your hopes up!
@jpc Motor control, serious motor control, just needs a very high power signal, but you are leaving my expertise.
 
jpc
@Kortuk Nevermind. :) I will just try to check if this works at all. :)
 
@jpc I asked a question on the same subject a while back... you might be interested in the replies.
4
Q: 3-phase Motor Speed Controller

BG100Background If you look at my profile description, you'll see that I'm involved in building and wiring up Carnival floats that are powered by an 800KVA, 415v, 3 phase Generator. Electrically, they generally have about 10 or 15 motors, thousands of light bulbs and a 20KW sound system. Problem 3-...

 
@Kortuk Hahahahahah I have my full trust in you :D
 
1:03 AM
haha
 
Made A room for that disccusion (If get any news)
 
That explains that.
We can flag you in here.
The entire history is kept.
I can go look up conversations I had when the room opened.
 
jpc
@BG100 Have you gave it a try?
@BG100 I don't really need a motor controller or any other kind of high powered inverter right now. I am just curious if "magic sinewaves" work in practice. :)
 
@JamesDyson, I am not sure you noticed, you can add any room to favorites and then hit rejoin favorites from there on out and it logs into all of your rooms.
 
@jpc No, not yet. I might some time, but some of the answers I was given made me think twice about playing with stuff like this :)
When it comes to motor control, I don't think a perfect sinewave is needed.
 
1:14 AM
Yeah, where else would the motor music come from.
 
@Kortuk Haha... yeah
well for what I needed it for it wouldn't need to be perfect
 
@Kellenjb microwaves101.com/encyclopedia/circulators.cfm handles the sending and receiving on one antenna.
 
jpc
@BG100 I once made a simple dimmer with MOSFETs and a HV driver chip. I worked well with the light bulb but failed quite spectacularly with a small motor. The inductance kickback during the (really short) dead time killed half of the elements on the board, including a through hole ceramic cap which got nicely split in half with its contents sprayed all over the place.
Afterwards I found a nice patent in which they controlled the MOSFETs in 4 phases so that there was always a path for the current but I did not have a chance to try it out.
 
@Kortuk Interesting.
 
jpc
@Kortuk I believe that in most applications this is handled in a push-to-talk like fashion instead.
 
1:25 AM
@jpc Yeah, it seems to be a tricky thing to build. I wish it was easier because I could really do with a whole bunch of them!
 
@Kellenjb they save an antenna. If you terminate the from load and back you get an isolator on the fly
 
@kortuk you can do a single antenna with the "push to talk" method as well
 
@jpc Circulator? I am referring to something like radar.
@Kellenjb, not for CWFM radar
 
@Kortuk I know it can be done with the circulator, but the method but i am mentioned will work with a single antenna as well
 
most radar systems send and receive at the same time. Most RF systems like Wifi do also I believe.
@Kellenjb I would agree.
 
jpc
1:28 AM
@BG100 This was at 220V but I also did my share of welding using a 12V 400W transformer and a scope probe. And another one (yeah, you think I would learn) with a 13MHz power generator, a "this is certainly GND" attitude and another scope probe.
 
@Kellenjb Sortof.
@Kellenjb Not sure how you would do the switching.
 
jpc
@Kortuk Continous Wave, right. I was not aware of the application.
 
@kortuk I dont know how either, but i have now had 2 people who have dealt with radars from a military perspective say they have done the pulse method
 
@jpc, no worries, on a walkie talkie they can still use one to protect receive circuitry, but I think they normally turn it off.
@Kellenjb Interesting. Military may like that, they are going to the SARS now, which is awesome.
(synthetic aperture radar system)
Where they use DSP and a lot of datapoints to fake having a very very large dish.
 
@Kortuk btw, 802.11n was the first to do full duplex i believe
 
1:32 AM
@Kellenjb, interesting, I thought they were at it now, but was not sure when.
@reemrevnivek, allo, get any messages while you were gone?
 
Yeah, a few :)
Thanks all.
 
802.11n also "can" do multiple antennas with beam stearing
 
haha
 
jpc
@Kellenjb I was under an impression that early WiFi was half-duplex. But this means that old b/g amplifiers will not work with n, even at 2.4GHz.
 
@Kellenjb That was the entire point of 802.11n as far as I am concerned.
 
jpc
1:33 AM
@Kortuk @reemrevnivek LOL :)
 
@jpc That does not meant that, it just means that early hardware does not have the components to do full duplex, the amplifiers are not really a problem with that.
@Kellenjb If you cannot stear a beam you are not enough of a badass to get my 100 bucks.
 
@jpc all n gear will operate at half duplex when needed
 
jpc
@Kortuk I always thought that the amplifiers were half-duplex as well.
 
@Kellenjb I think he meant the other way, G operating at N. That is a given though.
@jpc you normally have LNA for receive and PA for output. The sharing of the line requires high quality circulator or such.
 
 
1:36 AM
when g tries to talk to n, n will just run as if it were g
 
@reemrevnivek Is that what you wanted?
 
@BG100 we only had 10 users per day
?
 
@Kellenjb Thats what the stack api stats showed...
before the site graduated
 
jpc
@Kortuk Thanks for the clarification.
@BG100 That is a little hard to believe.
 
o_O Wow. That's some traffic!
 
1:42 AM
@jpc Yeah... on average, around 10 new people joined per day
 
And at launch, several hundred people joined?
 
The graph is a rolling view of the number of people joining...
Basically, every 15 mins it grabs the current number of users on the site, and subtracts the number of users that were on the site exactly 24 hours ago, and plots that on a graph
so no... not several hundred
 
jpc
@BG100 oh, these are new people? :)
 
Yeah
 
@bg100 makes so much more sense now!
 
1:47 AM
If you average a period on the graph, that's the number of people who joined over that period.
haha... sorry, should have explained that better
The title should be "New users per day" really
Not sure why there was a sharp drop in the number of people joining about 3 hours ago
 
@BG100 are you sure thats not an artifact of the averaging?
 
@Kellenjb Maybe... I'm only averaging over the 15min sample interval... but I guess the API might be giving me an averaged figure
 
I ask that because it looks like the sharp drop follows the exact same rate as the sharp jump at release time
 
Yeah, you're probably right
I'm not sure what all these people are doing, because they're not asking questions...
 
jpc
@BG100 I believe this is called lurking. :)
 
1:54 AM
btw... my x axis is based on UK time... I'm guessing most of you are in the US.
 
jpc
@BG100 Given the current channel participation I doubt it. :)
 
lurking and voting...
 
jpc
@BG100 Maybe not, I think I miscounted Kortuk as a European. ;]
 
If you already have a stack exchange account its just so easy to add yourself to another site, so it doesnt surprise me too much
 
@Kellenjb Yeah, and I think the badges graph proves this...
Users over the last month...
 
2:02 AM
@jpc What mate?
@jpc I have a number of Dutch/british friends and work for a Belgian company.
 
jpc
@Kortuk Yeah, I have seen your employers page and must have (wrongly) coded that you are from Belgium.
 
:)
@Kortuk Any news?
 
@JamesDyson Sorry bud, you have got atleast a business day.
@jpc hahahaha
 
Hahahaha ok :)
 
@jpc Born in Paris, France, raised in Texas
 
jpc
2:16 AM
@Kortuk :)
 
anyone know how to add a resource and specify working times in microsoft project?
 
hmmm?
 
@Kellenjb Tools > Assign Resources
Then double click an empty resource slot
 
@BG100 i actually just figured it out. was struggling with the 2010 version :-)
 
ah... I only have 2007
I hate project with a passion
 
2:24 AM
Hhahahaha
 
2:38 AM
@BG100 yeah, me too. some how it just calculated that a task that is estimated to take 40 hours to complete will take less then a week at 10 hours a week
 
@Kellenjb, it takes a bit but I like the 2010 version.
 
2:56 AM
What device can measure the amount of water though a line? http://ur.ly/H58q #arduino
 
@jpc I had to put the France or people assume I mean Paris, Texas.
And I hate that.
 
There is a place called Paris in Texas?
 
3:14 AM
Yesa
Growing up in Texas people thought I was fibbing.
'bout being from France.
 
jpc
3:36 AM
Ok, I am going to sleep (it would be 4:35 AM if we used AM here but since we don't it is just 4:35). The USB CDC installation .inf just won't work tonight.
Good night/day. :)
 
3:57 AM
@jpc Night mate, it is 23:00 here, I was going to ask why you were up so late.
 
4:33 AM
@jpc think "Kevin Vermeer", backwards... typing then becomes natural ;)
 
 
1 hour later…
5:52 AM
What hardware or software solutions can be used to prevent of stack overflows? http://ur.ly/H5GC #hardware
 
6:21 AM
@tyblu No, not for everyone.
 
 
3 hours later…
8:53 AM
How many GPS channels make sense? http://ur.ly/H6dT #gps
 
9:37 AM
mornin'
 
@W5VO, Morning mate. I am having a hell of a time.
 
anything in particular?
 
Work issues.
 
 
2 hours later…
jpc
11:22 AM
@tyblu I guess I will stick to autocompletion.
 
11:54 AM
How to do circuit analysis using Matlab? http://ur.ly/H7DS #matlab
 
jpc
2
Q: Reducing the memory address bus by adding banks

200ok404notfoundIf you are trying to control memory from a CPU, then if you use two banks instead of one, you can remove the first address line. If you use four banks, then you can also remove the second as well. Why is this?

Maybe somebody has an idea how to reformat the question? Since "removing address lines" is IMHO more than vague.
 
 
1 hour later…
1:05 PM
@jpc - Sorry....I've thought about changing it before, but I decided it would be more confusing than just leaving it. The nice thing about having such a nickname is that it's available whatever I sign up for...
 
1:18 PM
 
jpc
2:14 PM
@reemrevnivek No, its not a problem anymore since @Kortuk told me about the autocompletion. :)
@tyblu lol
 
2:49 PM
Need help identifing the power rating for this resistor. http://ur.ly/H7Ww #power
 
3:29 PM
@tyblu - Glad I'm not the only one who noticed that our initials are now "ED"
 
 
2 hours later…
5:57 PM
Why is it so problematic to have close to zero standby power consumption? http://ur.ly/H7jf #powersupply
 
 
3 hours later…
8:34 PM
Sorry for some noise, have to figure something out:
[meta:test]
[metatag:test]
{tag:test}
[meta]
[tag-meta:test]
grr... Off to Meta.SO to read the FAQ...
Aha! [meta-tag:test] is the syntax.
 
8:49 PM
8/16 bit microprocessor for hobby project http://ur.ly/H8yu #memory
 
 
3 hours later…
11:38 PM
@jpc Your welcome!
@reemrevnivek I laughed a lot.
 
11:51 PM
Is it normal for LM317 to give a higher voltage without a load? http://ur.ly/Ha2I #voltageregulator
 
0
A: Are Wifi waves harmful?

KortukI will take a moment to expand a bit. Currently Henry has pointed out the only affect that non-ionizing radiation can have, heating. People commonly perceive this "heating" effect as a threat which will not amount to more then a hundredth of a degree at most, and it actually significantly less. ...

 

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