Electrical Engineering V3

[LoneWolf_Recon]

I think it would nice to add some study materials in the op, if you could Chryseus:

[URL="https://hamstudy.org/"]US/Canada Amateur Radio Licensing Quizzes/Flashcards/Studying[/URL]
[URL="http://rsgb.org/main/"]UK Amateur Radio Licensing & Information[/URL]

[Chryseus]

[QUOTE=LoneWolf_Recon;47233679]I think it would nice to add some study materials in the op, if you could Chryseus:

[URL="https://hamstudy.org/"]US/Canada Amateur Radio Licensing Quizzes/Flashcards/Studying[/URL]
[URL="http://rsgb.org/main/"]UK Amateur Radio Licensing & Information[/URL][/QUOTE]

Added.
I'm a bit sad there are no nearby clubs where I live, I looked at the foundation exam example and it was piss easy, got most of them right without reading anything :v:

[Zero-Point]

Got the power supply for my CNC machine in the other day. I was hoping to get an American brand by selecting "North America Only" on eBay's listings, but I guess I should've known better.
I mean sure it outputs 36 volts like it's supposed to, but until my motors/controller come in I can't tell how well it'll hold up under load. What's worrisome though is that with no load, it actually takes well over 3 seconds before the output voltage starts to drop. Oh and the fan rattles, even at low speeds. :v:

Oh and the stickers have Chingrish on them. Everyone loves Chingrish.

[pentium]

My first QFP reflow! :dance:

[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8351.jpg[/img]
[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8354.jpg[/img]

[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8349.jpg[/img]
Fuck. :suicide:

[Fourier]

[QUOTE=pentium;47234334]My first QFP reflow! :dance:

[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8351.jpg[/img]
[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8354.jpg[/img]

[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8349.jpg[/img]
Fuck. :suicide:[/QUOTE]

Why aren't ICs so intelligent that if something goes wrong they rewire themselves inside

[woidoi]

[QUOTE=Fourier;47235809]Why aren't ICs so intelligent that if something goes wrong they rewire themselves inside[/QUOTE]

wouldn't that be considered AI?

[Aloveoftheworld]

Hey thanks for this thread i'll have to get into this, i am already into ham radio but want to learn more and make my own stuff and understand it, will be checking out some books at the libarry.

Heres a pic of my radio atm.
I also have a cb radio but no antenna for it, will post a photo later, i do havea feed line that only has one end already with a connector on it? can i turn that into one?

[IMG]http://i.imgur.com/szwLtham.jpg[/IMG]

RTLSDR :
[IMG]http://i.imgur.com/nR66JEph.jpg[/IMG]
COULD USE SOME PHOTOS ON HOW EXACTLY TO MAKE AN ANTENNA / CONNECTION IT TO MY RTLSDR, any help highly welcomed.

[Fourier]

[QUOTE=scratch (nl);47236063]wouldn't that be considered AI?[/QUOTE]

Of course.

[Chryseus]

[QUOTE=Aloveoftheworld;47236189]
RTLSDR :
[IMG]http://i.imgur.com/nR66JEph.jpg[/IMG]
COULD USE SOME PHOTOS ON HOW EXACTLY TO MAKE AN ANTENNA / CONNECTION IT TO MY RTLSDR, any help highly welcomed.[/QUOTE]

It depends on what exact model you have, basically you need a connector to connect to the SDR and some 50 ohm coaxial cable (I.E RG58), you can hard wire the antenna or use a suitable female-male connector, BNC is the most popular type of connector for RF, if you do a lot above 1GHz SMA is usually a better choice.
If you don't know what connector your SDR uses post a picture of it.

[pentium]

Okay, so it appears my reflow worked, it's something else on the card that is still fucked.

[Cakebatyr]

[QUOTE=Aloveoftheworld;47236189]Hey thanks for this thread i'll have to get into this, i am already into ham radio but want to learn more and make my own stuff and understand it, will be checking out some books at the libarry.

Heres a pic of my radio atm.
I also have a cb radio but no antenna for it, will post a photo later, i do havea feed line that only has one end already with a connector on it? can i turn that into one?

[IMG]http://i.imgur.com/szwLtham.jpg[/IMG]

RTLSDR :
[IMG]http://i.imgur.com/nR66JEph.jpg[/IMG]
COULD USE SOME PHOTOS ON HOW EXACTLY TO MAKE AN ANTENNA / CONNECTION IT TO MY RTLSDR, any help highly welcomed.[/QUOTE]

The RTLSDR uses a MCX type coaxial port, you can cheaply get [url=http://m.ebay.ca/itm/331274064758?nav=SEARCH]MCX-male->BNC-female[/URL] adapters on eBay or digikey (kinda not really).

I'd also suggest buying a [URL=http://m.ebay.ca/itm/161113252073?nav=SEARCH]bunch of BNC panel mounts[/URL] these are the things you construct your antenna around. Cables wise I'd suggest something from [URL=http://www.monoprice.com/mobile/Product/Details/6923?mainCategoryId=102&categoryId=10221&subCategoryId=1022101&cpnCd=]monoprice[/url].

In general you want to keep the length of cable as short as possible, the shorter the cable the less energy will be lost before it gets to the receiver.

Now for antennas: the most basic you can get is a [URL=http://www.antenna-theory.com/antennas/halfwave.php]half wave dipole[/URL]. This can be constructed simply by buying some speaker wire, measuring a quarter wavelength (speech of light / ____MHz / 4) cutting it, soldering the two wires to the panel mount and pealing the two sides apart.

[LoneWolf_Recon]

[QUOTE=Aloveoftheworld;47236189]

[...]

RTLSDR :
[IMG]http://i.imgur.com/nR66JEph.jpg[/IMG]
COULD USE SOME PHOTOS ON HOW EXACTLY TO MAKE AN ANTENNA / CONNECTION IT TO MY RTLSDR, any help highly welcomed.[/QUOTE]

Assuming you have the RTL-SDR/NooElectric SDRs, they use MCX connectors which I'd highly recommend getting an adapters over to SMA or BNC depending upon what frequencies you'd like to investigate. The Terratec and white 'rounded' SDRs should use a SO-259/PL-259 connector which is much easier to interface and find locally.

There's a handful of tutorials out there for making discone antennas (which are leagues better than the whip antenna that's shipped with the dongle), such as [URL="http://www.reddit.com/r/RTLSDR/comments/1derg4/so_i_made_a_discone_out_of_coat_hangers/"]this[/URL], [URL="http://helix.air.net.au/index.php/d-i-y-discone-for-rtlsdr/"]that[/URL] and [URL="http://www.instructables.com/id/Discone/?ALLSTEPS"]these[/URL] tutorials.

Course there are already some [URL="http://www.benelec.com.au/pdf/02674%20Data%20Sheet.pdf"]manufactured discones[/URL] that you can buy.

Here's a pretty informative [URL="https://www.youtube.com/watch?v=9q2TYdo9cWY"]video[/URL] on the various connectors for SDR.

[QUOTE=pentium;47236949]Okay, so it appears my reflow worked, it's something else on the card that is still fucked.[/QUOTE]

You're running that monitor on its MDA/Composite port right? I assume in just text only mode. What's the problem with it, it looks like the screens just saturated color wise making me think that the resistor ladder (I'm guessing that's on the output stage to the monitor) may be screwed?

Also, all the searches I'm finding for that card have their jumpers [URL="http://old.vgamuseum.info/images/palcal/ati/18700ver2b.jpg"]shorted[/URL].

[editline]1st March 2015[/editline]

Ninja'd

[Cakebatyr]

For books I'd suggest the [URL=http://www.amazon.com/ARRL-Handbook-Radio-Communictions-Communications/dp/1625950195]ARRL Handbook[/URL], do be aware the information doesn't dramatically change one year to the next so feel free to get a slightly older edition. And the [URL=http://www.amazon.ca/Practical-Antenna-Handbook-Joseph-Carr/dp/0071639586]Practical Antenna Handbook[/URL] its a very easy read and is all about RF radiation propagation and antenna theory.

[Chryseus]

[t]http://i.imgur.com/wdZehkq.jpg[/t]
Almost done sorting out my Pye 75A tube radio.

[b]Edit[/b]
P75A I mean.

[DrLuke]

Mhh, I love HAM!

I've got to finish my APRS beacon.

[Gulen]

Thought you guys would enjoy this:

[video=youtube;bbLshnfu0wY]http://www.youtube.com/watch?v=bbLshnfu0wY[/video]

[TCWilliamson]

[QUOTE=Gulen;47237929]Thought you guys would enjoy this:

[video=youtube;bbLshnfu0wY]http://www.youtube.com/watch?v=bbLshnfu0wY[/video][/QUOTE]

Aah, good old tesla coils... I really need to get around to building mine.

Check out this one, the world's largest:

[media]http://www.youtube.com/watch?v=SqF3Wp2D_OM[/media]

[Quarternions]

Quick question, I had some spare parts lying around :

A 6VA Transformer and some high amperage diodes. So I whipped something up real quick :

[img_thumb]http://i.imgur.com/xjwbwvx.jpg[/img_thumb]

So I rigged the top 0 115 0 115 in series since we are using 230v here. Same goes for the bottom it outputs 12v each so rigging them in series makes that 24v right ?

I then made full wave rectifier. This is where I am a bit stuck (and yes I know I need to learn more about electronics before dicking arround with AC, and I am reading a lot).

Questions :

How does 6VA work, does it mean 12 volts = 0.5w and 24v = 0.25w.
I need a smoothing capacitor to smooth out the waves but I have no idea what value.

I read some info on this website : [URL]http://www.radio-electronics.com/info/circuits/diode-rectifier/rectifier-filtering-smoothing-capacitor-circuits.php[/URL] but have no idea what rLoad means.
I know this is really basic but I have this stuff lying around and I just want to finish this.

[pentium]

Remember kids: When burning 8k images to 16K chips some devices do not like the unused space at the end of the memory map. When possible you can double your data to fill the entire chip using:

K:\> copy /B ati.img+ati.img new_ati.img

[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8367.jpg[/img]

[Fourier]

[QUOTE=pentium;47238308]Remember kids: When burning 8k images to 16K chips some devices do not like the unused space at the end of the memory map. When possible you can double your data to fill the entire chip using:

K:\> copy /B ati.img+ati.img new_ati.img

[img]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8367.jpg[/img][/QUOTE]

What the heck, good that you figured it out

[Chryseus]

[QUOTE=quincy18;47238271]Quick question, I had some spare parts lying around :

A 6VA Transformer and some high amperage diodes. So I whipped something up real quick :

[img_thumb]http://i.imgur.com/xjwbwvx.jpg[/img_thumb]

So I rigged the top 0 115 0 115 in series since we are using 230v here. Same goes for the bottom it outputs 12v each so rigging them in series makes that 24v right ?

I then made full wave rectifier. This is where I am a bit stuck (and yes I know I need to learn more about electronics before dicking arround with AC, and I am reading a lot).

Questions :

How does 6VA work, does it mean 12 volts = 0.5w and 24v = 0.25w.
I need a smoothing capacitor to smooth out the waves but I have no idea what value.

I read some info on this website : [URL]http://www.radio-electronics.com/info/circuits/diode-rectifier/rectifier-filtering-smoothing-capacitor-circuits.php[/URL] but have no idea what rLoad means.
I know this is really basic but I have this stuff lying around and I just want to finish this.[/QUOTE]

Yes it will be 24V AC out, if you use a bridge rectifier and filter it with a cap your peak DC voltage will be around 24V * sqrt(2) = ~34V.

6VA is the same as saying 6W max.
At 6V this is 1A.
At 12V this becomes 0.5A max.
At 24V 0.25A max.
Do the math and you see they are all 6W.

As for what value cap you should use a general rule is 10,000uF per amp, depending on how much noise you can tolerate anywhere up of 1,000uF per amp is usually perfectly fine, in your case I'd use 470uF 50V.
You pretty much need to double this for half-wave rectifiers or full wave center tapped rectifiers (2 diodes).

Rload simply means the load you connect it to, represented as a resistor.

[Quarternions]

Ahh oke, but 10.000uF per amp doesn't that mean that I should be using 2500uf. Also I have some 470uf (and some other higher value caps) lying arround but they are only rated for 25 volts.

So if I hook up my the bottom 12 volts in parallel it should give me around 16v. I then smooth the waves with the cap and use a spare lm338t for some nice regulated power supply (until 6 watts).

[Cakebatyr]

Doh! Just placed a digikey order, but forgot one component.

[Zero-Point]

Already up to $880.60 on this CNC project, and I haven't even bought the metal or plasma cutter yet. :suicide:

[LoneWolf_Recon]

[QUOTE=Zero-Point;47240404]Already up to $880.60 on this CNC project, and I haven't even bought the metal or plasma cutter yet. :suicide:[/QUOTE]

How thick were you planning to cut? Also, pics?

[Zero-Point]

[QUOTE=LoneWolf_Recon;47240413]How thick were you planning to cut? Also, pics?[/QUOTE]

No pics because I don't really have any hardware to show just yet. All that's come in so far are the bearings (v-groove and regular), power supply (which as stated previously may or may not hold up because China), interface break-out board (the year 2015 and they still use LPT ports, lol), and energy/cable chain (spent WAY too damn much on this thing, should've definitely done more research into it before buying this shit, $200 for 16 ft!). Still waiting on the motors/controllers, lead-screw for Z-axis, #25 chain/sprockets, an LVDS adapter for that old laptop monitor (gonna use it as the screen for the control PC, which was given to me by my brother and his wife because they thought it was broken, boots just fine and has plenty of grunt, but oh lawd is it filthy), and of course I still have to buy the metal (which is proving difficult, because the shop's hours are the same as my work hours and winter has been surprisingly busy for HVAC contractors this year) and the plasma cutter (found a Hypertherm Powermax 45 factory refurb'd for a decent price, and it has the added benefit of having the interface controls built-in, and it's easy to jury-rig it to use the hand-torch without voiding the warranty. They'd like you to use a machine torch-head for CNC of course, but that's another $600+ that I'd rather not spend).
As for how thick, as stated before it's a surprise birthday present for my mom so she can make sheet metal art with it, maybe make a little money on the side with it, so nominally I'd say she shouldn't need to cut anything ticker than 1/8-1/4", but the ability to cut thicker may prove useful, so the PMX45 is better in that regard than the PMX30 I was initially looking at.

[pentium]

[quote](the year 2015 and they still use LPT ports, lol)[/quote]

Consumers may no longer use serial and parallel but industry has no reason to abandon it. It's not like it's obsolete or anything. You can still buy lab equipment that supports GPIB.

[nikomo]

Literally anything you can get your hands on, is obsolote by definition, pentium.

[Zero-Point]

[QUOTE=pentium;47240973]Consumers may no longer use serial and parallel but industry has no reason to abandon it. It's not like it's obsolete or anything. You can still buy lab equipment that supports GPIB.[/QUOTE]

Yeah, but the price of these and their target demographic is for DIY-ers on a budget. There ARE USB CNC breakout-boards out there, but they want $120+ for those (haven't seen one from China yet, at least the ones I HAVE seen look incredibly cheap).
I'm just kinda lucky I have two old systems with LPT ports on their boards, that makes it convenient.

[Chryseus]

[QUOTE=quincy18;47239117]Ahh oke, but 10.000uF per amp doesn't that mean that I should be using 2500uf. Also I have some 470uf (and some other higher value caps) lying arround but they are only rated for 25 volts.

So if I hook up my the bottom 12 volts in parallel it should give me around 16v. I then smooth the waves with the cap and use a spare lm338t for some nice regulated power supply (until 6 watts).[/QUOTE]

It depends on what you're powering, a low noise amplifier or audio you will want somewhere between 4,700 to 10,000uF per amp, for most general purpose applications 1,000uF per amp is just fine.

The LM338T can only go to within 2V of the input voltage, so your output range will be 1.2V to 14V, the power dissipation of the regulator is (Vin - Vout) / Iout