Wikipedia:Reference desk/Archives/Computing/2010 February 27

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

February 27

Freeware app like Camfrog?

Is there a freeware app available that has features similar to Camfrog? I'm in China, my brother is in one state in the US, and the rest of my family another. I'd like to be able to participate in and/or host video conferencing with more than 2 accounts. Camfrog allows X accounts to all video conference together, but at the hefty fee of $45.95 per account and $200 for a server license. 207.7.138.117 (talk) 04:06, 27 February 2010 (UTC)

ekiga --194.197.235.240 (talk) 19:44, 27 February 2010 (UTC)

VirtualBox RDP

I am using VirtualBox for virtualization. The host OS is Windows 7 (Ultimate, 64-bit) and the guest OS is Windows Server 2008. I am trying to enable RDP connections through to the guest VM. At the moment I only have one physical system to test this on, but ultimately I will need to do enable this for external IPs. Within VirtualBox, I have enabled the Remote Display server. I have changed the port to 3390 since the default 3389 is already being used by Win7; authentication method is null to keep things simple for now. The VM network adapter is NAT. From within the guest OS, I can confirm that a class A IP is being created. (According to the VirtualBox documentation, ping does not work over NAT, so I am unable to ping the system.) The setup seems fine, but I am unable to determine the IP to connect to in RDP. Documentation indicates that this should be the host IP (not guest IP), suffixed with the defined port (:3390). I am able to successfully connect with the loopback 127.0.0.2:3390. However, as my goal is to enable external connections, this will not suffice. I checked ipconfig /all and tried all IPs given there, but none of them seem to work. Also, when I check online sites for my IP, it is yet different than what is given in ipconfig (given in signature); this also does not work. I have been looking at this for several hours but am stumped; any ideas for resolution? 124.214.131.55 (talk) 09:33, 27 February 2010 (UTC)

Nevermind. After much frustration, I ended up just installing it on another partition and was able to use RDP without any problems. I'll figure out the problem another time. 124.214.131.55 (talk) 12:49, 28 February 2010 (UTC)

I highly recommend placing any questions about VB on a VB forum. I've done much better asking on ubuntuforums, though I have ubuntu host. Magog the Ogre (talk) 03:12, 1 March 2010 (UTC)

PrtSc (Print Screen)

Hi

If I have multiple windows on my screen, how do I print the one on the forefront only?

Thanks, NirocFX

41.193.16.234 (talk) 12:17, 27 February 2010 (UTC)

Try Ctrl Alt & PrtSc at the same time. --220.101.28.25 (talk) 12:25, 27 February 2010 (UTC)

That is incorrect. You press Alt+PrtScr. --Andreas Rejbrand (talk) 13:21, 27 February 2010 (UTC)

Aargh. How did I make that mistake! Corrected!. Here's the text of the relevant Windows help section in XP
"To copy the window or screen contents

• To make a copy of the active window, press ALT+PRINT SCREEN.
• To copy the entire screen as it appears on your monitor, press PRINT SCREEN."

Note that all the "forefront" screen has to be visible (not off the edge of the monitor), any part not visible won't be copied--220.101.28.25 (talk) 14:13, 27 February 2010 (UTC)

The Print screen article discusses this, and covers environments other than Windows. -- Finlay McWalter • Talk 14:41, 27 February 2010 (UTC)

Thanks Guys

I'll remember that next time.

Thanks, NirocFX

41.193.16.234 (talk) 09:06, 28 February 2010 (UTC)

Shortwave 6

I was just mucking around with my grandad's Roberts R 9967, when I flipped into SW6, or Shortwave 6. This particular shortwave makes a noise like a robot or computer from Lost in Space...beeps and boops and bops. Does anyone know why it is making this noise, it's really fascinating! The noise comes when I get near electrical equipment or ferrous metals. Please answer back!--Editor510 ^{drop us a line, mate} 14:11, 27 February 2010 (UTC)

The noise comes also after 15.70 MHz. Hope that also helps.--Editor510 ^{drop us a line, mate} 14:54, 27 February 2010 (UTC)

Shortwave is fully of communications channels - often digital - it's almost certainly one of these.

I would guess that the signal is being picked up by big metal objects, and the object acting a sort of passive boosting transmittor (like an earphone Ear trumpet except electrical).

I don't really know what you are listening to but the shortwave article mentions a time signal at 15,000kHz (that's 15MHz) (in the USA) and probably within the accuracy of your old radio. - that's the sort of time signal used to control radio controlled watches/clocks etc.

Or it might be something else completely.87.102.67.84 (talk) 17:06, 27 February 2010 (UTC)

See Time signal and the related articles WWVH , WWV , CHU (radio station) etc - see if the descriptions of the signals match what you're hearing. (like electronic birdsong ?)

87.102.67.84 (talk) 17:09, 27 February 2010 (UTC)

You can take a quick look at Utility station and High frequency too. Graeme Bartlett (talk) 06:31, 2 March 2010 (UTC)

PC to Home stereo

I am having a sound issue when I connect my PC to my home stereo amplifier. I get an annoying hum. I have tried different cables, different inputs on the amp, even a new sound card for my PC. I did some research about ohms matching transformers but, am not sure what to get or if that is even the answer. This problem does not exist on anything else I send PC audio to.[self amplified speakers, TV monitor, even my DeWalt work radio]What could solve this problem? Please help, I have been struggling with this for more than a year.74.47.146.203 (talk) 22:27, 27 February 2010 (UTC)

Most soundcards have several sound outputs, including the normal stereo speaker output, the headphone output, and sometimes a surround-output (the rear channels). Make sure you're in the speaker port (which is usually coloured green) and not the headphone one. Also make sure the PC's sound output level is set at or near maximum (both the OS's general volume control, and that of the specific application you're using) and have the amplifier's own volume setting very low. Make sure you're not plugging the cable from the PC into the "phono" inputs on your amplifier (sounds like you've done that). Make sure the cable between the two isn't running near an obvious source of interference (cordless phone base-station, wireless router, microwave oven). -- Finlay McWalter • Talk 22:34, 27 February 2010 (UTC)

Sorry, when I say "sounds like you've done that" above, I really mean "sound like you've already tried and rejected that possibility" -- Finlay McWalter • Talk 22:52, 27 February 2010 (UTC)

If you have the two plugged into different power outlets, you may have a ground loop. -- kainaw™ 22:49, 27 February 2010 (UTC)

(edit conflict - long answer, may not add much) It's also possible that you are getting a hum loop (I think the article Ground loop (electricity) may be covering the same thing), also induction from a 50/60Hz source on the loop of wire that goes from PC mains plug <> PC <> Audio out <> Audio In <> Amp <> Amp mains plug can cause hum (like an aerial).

The second can usually be fairly well elimanated by moving wires - as described above - make sure no audio wire goes near mains cable or transformer (better cables can sometimes help - ie coaxial or twisted pair, avoid cables with bare metal end plugs ie the chrome plated type)

A matching transformer might should be a solution - though it will also act as a low pass filter - removing low frequencys - so not a very good solution for audio. Other solutions include using a digital connection, or better still an optical digital connection (toslink) - I realise your amp might not have these as an option. If you get a matching transformer (aka audio isolation transformer) - get the cheapest - the devices are flawed at low frequency - it's not work spending a lot - for what you get.87.102.67.84 (talk) 23:59, 27 February 2010 (UTC)

Question: are either or both of the devices earthed (ie 3 pin connector) ? Sometimes a fix is to connect an extra earth between the two devices (this isn't an option if one of the devices is unearthed) If both devices are earthed - a fix can sometimes be to remove an earth connection - you may see this suggested on the internet - it isn't a safe thing to do..

Another Question - can you test the amp to see if it works ok with other things - a CD player or whatever - it's possible that the amp is gone bad? Also check the amp connections - eg plug - if possible rewire it just to make sure that you have a good electrical connection.87.102.67.84 (talk) 23:04, 27 February 2010 (UTC)

Also the amp - is it very old or obscure - if so can you say what make, or better - the input impedance on the inputs? (This is unlikely to be the problem unless the amp is over 50years old)87.102.67.84 (talk) 23:09, 27 February 2010 (UTC)

The best set of advice I found was here http://www.audioholics.com/tweaks/connecting-your-system/ground-loops-eliminating-system-hum-and-buzz (unfortunately it may have a dodgy flash animation that is blocked. otherwise the advice is good - but US centric)87.102.67.84 (talk) 23:59, 27 February 2010 (UTC)