1457:"Feedback"

This forum is for the individual discussion thread that goes with each new comic.

Moderators: Moderators General, Prelates, Magistrates

User avatar
keithl
Posts: 638
Joined: Mon Aug 01, 2011 3:46 pm UTC

1457:"Feedback"

Postby keithl » Mon Dec 08, 2014 7:04 am UTC

Image

title text: A new study finds that if you give rats a cell phone and a lever they can push to improve the signal, the rats will chew on the cell phone until it breaks and your research supervisors will start to ask some questions about your grant money.

Looking at this XKCD at a B&B in Berkeley using wireless. Riots a few blocks away - reception varies with news helicopter position.

User avatar
Eternal Density
Posts: 5547
Joined: Thu Oct 02, 2008 12:37 am UTC
Contact:

Re: 1457:"Feedback"

Postby Eternal Density » Mon Dec 08, 2014 7:49 am UTC

Forget wireless, I'm having enough problems getting good reception over wired broadband! Signal to noise ratio keeps dropping and disconnecting everything a few times a day :(

But there are a few spots in my house where I can get a mobile phone signal. Sometimes. So yeah on the rare occasions I try I end up standing on my bed or in the bath.
Play the game of Time! castle.chirpingmustard.com Hotdog Vending Supplier But what is this?
In the Marvel vs. DC film-making war, we're all winners.

User avatar
azule
Saved
Posts: 2132
Joined: Mon Jul 26, 2010 9:45 pm UTC
Location: The land of the Golden Puppies and Rainbows

Re: 1457:"Feedback"

Postby azule » Mon Dec 08, 2014 8:00 am UTC

You place it, however it needs to be orientated, in the window. After that, no touchie! Tethering is now your best friend.
Image

If you read this sig, post about one arbitrary thing you did today.

I celebrate up to six arbitrary things before breakfast.
Time does drag on and on and contain spoilers. Be aware of memes.

TheEngineer
Posts: 44
Joined: Wed Nov 24, 2010 2:40 pm UTC

Re: 1457:"Feedback"

Postby TheEngineer » Mon Dec 08, 2014 8:30 am UTC

RIM suggest that holding an apple works best with their products.

User avatar
da Doctah
Posts: 904
Joined: Fri Feb 03, 2012 6:27 am UTC

Re: 1457:"Feedback"

Postby da Doctah » Mon Dec 08, 2014 9:24 am UTC

I think the more important question is: why aren't you standing on a chair holding a pineapple?

User avatar
Neil_Boekend
Posts: 3220
Joined: Fri Mar 01, 2013 6:35 am UTC
Location: Yes.

Re: 1457:"Feedback"

Postby Neil_Boekend » Mon Dec 08, 2014 10:08 am UTC

I was a minute ago, but I chose a folding chair. Reception was great though.
Mikeski wrote:A "What If" update is never late. Nor is it early. It is posted precisely when it should be.

patzer's signature wrote:
flicky1991 wrote:I'm being quoted too much!

he/him/his

rmsgrey
Posts: 3430
Joined: Wed Nov 16, 2011 6:35 pm UTC

Re: 1457:"Feedback"

Postby rmsgrey » Mon Dec 08, 2014 1:02 pm UTC

Back in the day, we used to do similar things with TV antennae.

User avatar
orthogon
Posts: 2960
Joined: Thu May 17, 2012 7:52 am UTC
Location: The Airy 1830 ellipsoid

Re: 1457:"Feedback"

Postby orthogon » Mon Dec 08, 2014 1:55 pm UTC

rmsgrey wrote:Back in the day, we used to do similar things with TV antennae.

(Ahem) Terrestrial TV is still a thing!
xtifr wrote:... and orthogon merely sounds undecided.

rmsgrey
Posts: 3430
Joined: Wed Nov 16, 2011 6:35 pm UTC

Re: 1457:"Feedback"

Postby rmsgrey » Mon Dec 08, 2014 2:20 pm UTC

orthogon wrote:
rmsgrey wrote:Back in the day, we used to do similar things with TV antennae.

(Ahem) Terrestrial TV is still a thing!


Yeah, but since the digital switchover, there's no "barely watchable" - it's either full quality or garbage, with no feedback on improved signal...

User avatar
Neil_Boekend
Posts: 3220
Joined: Fri Mar 01, 2013 6:35 am UTC
Location: Yes.

Re: 1457:"Feedback"

Postby Neil_Boekend » Mon Dec 08, 2014 2:30 pm UTC

rmsgrey wrote:
orthogon wrote:
rmsgrey wrote:Back in the day, we used to do similar things with TV antennae.

(Ahem) Terrestrial TV is still a thing!


Yeah, but since the digital switchover, there's no "barely watchable" - it's either full quality or garbage, with no feedback on improved signal...

Dunno about DVB-T, but most DVB-S recievers can get simple signal and quality indicators on screen. Those can be used to direct the dish, assuming a near infinite amount of patience (there is usually a few seconds delay in this signal. That means that the feedback loop is severely damaged)
Mikeski wrote:A "What If" update is never late. Nor is it early. It is posted precisely when it should be.

patzer's signature wrote:
flicky1991 wrote:I'm being quoted too much!

he/him/his

User avatar
suso
Posts: 195
Joined: Wed Jan 17, 2007 6:23 pm UTC
Location: Sky Grund
Contact:

Re: 1457:"Feedback"

Postby suso » Mon Dec 08, 2014 4:23 pm UTC

I was wondering if this was some reference to Hak5's wifi pineapple:

http://hakshop.myshopify.com/products/w ... t=81044992
Imagine theres no signatures....

User avatar
Flumble
Yes Man
Posts: 2051
Joined: Sun Aug 05, 2012 9:35 pm UTC

Re: 1457:"Feedback"

Postby Flumble » Mon Dec 08, 2014 10:29 pm UTC

suso wrote:I was wondering if this was some reference to Hak5's wifi pineapple:

http://hakshop.myshopify.com/products/w ... t=81044992

Oh wow, I didn't know there were pentesting routers on the market. Maybe I should buy one someday. Wifi access in trains* is unreliable at best, so maybe that should help.

*don't judge us Dutch! :o

User avatar
azule
Saved
Posts: 2132
Joined: Mon Jul 26, 2010 9:45 pm UTC
Location: The land of the Golden Puppies and Rainbows

Re: 1457:"Feedback"

Postby azule » Mon Dec 08, 2014 10:40 pm UTC

Any reason some think this is about Wi-Fi? It is clearly about cell phone signals.
Image

If you read this sig, post about one arbitrary thing you did today.

I celebrate up to six arbitrary things before breakfast.
Time does drag on and on and contain spoilers. Be aware of memes.

steaxauce
Posts: 6
Joined: Fri Aug 15, 2008 1:54 am UTC

Re: 1457:"Feedback"

Postby steaxauce » Tue Dec 09, 2014 3:07 am UTC

I think this is a good analogy for the stock market. It's basically what most traders do for a living.

Farabor
Posts: 152
Joined: Wed Apr 06, 2011 9:46 am UTC

Re: 1457:"Feedback"

Postby Farabor » Tue Dec 09, 2014 4:27 am UTC

azule wrote:You place it, however it needs to be orientated, in the window. After that, no touchie! Tethering is now your best friend.


You're assuming the router is orientable......

(Okay, I've been doing too much topology lately. Anyone want the first homotophy group of a sphere adjoined to a circle by a single point?)

User avatar
Neil_Boekend
Posts: 3220
Joined: Fri Mar 01, 2013 6:35 am UTC
Location: Yes.

Re: 1457:"Feedback"

Postby Neil_Boekend » Tue Dec 09, 2014 7:03 am UTC

azule wrote:Any reason some think this is about Wi-Fi? It is clearly about cell phone signals.

Wifi and cell signals encounter the same kind of problems.
Mikeski wrote:A "What If" update is never late. Nor is it early. It is posted precisely when it should be.

patzer's signature wrote:
flicky1991 wrote:I'm being quoted too much!

he/him/his

Kit.
Posts: 1079
Joined: Thu Jun 16, 2011 5:14 pm UTC

Re: 1457:"Feedback"

Postby Kit. » Tue Dec 09, 2014 11:51 am UTC

Neil_Boekend wrote:
rmsgrey wrote:Yeah, but since the digital switchover, there's no "barely watchable" - it's either full quality or garbage, with no feedback on improved signal...

Dunno about DVB-T, but most DVB-S recievers can get simple signal and quality indicators on screen. Those can be used to direct the dish, assuming a near infinite amount of patience (there is usually a few seconds delay in this signal. That means that the feedback loop is severely damaged)

Any digital RF receiver can do it. Not every one shows it to the user, though.

The signal quality information that is (or can be) available:
1. The signal level (say, in dBmV).
2. The signal/noise ratio. Every digital sample is a discrete dot in a signal phase space. Noise makes real samples to form (probabilistic) clouds around that ideal dots. The distance between the closest dots divided by the "typical" cloud size gives the SNR. It will require some time to calculate the cloud size statistics.
3. The rates of recoverable and non-recoverable digital errors. Digital RF signal is protected by error-correcting codes, so a receiver can assemble their statistic as well. Also, some time is required to gather the statistics.

Mental Mouse
Posts: 64
Joined: Tue Mar 18, 2008 1:31 pm UTC

Re: 1457:"Feedback"

Postby Mental Mouse » Tue Dec 09, 2014 12:09 pm UTC

This is a classic example of the dire effects of random reinforcement: In B.F. Skinner's classic experiments with operant conditioning, he noted that animals (in the classic experiment, pigeons), could also be "conditioned" by an arbitrarily presented stimulus. Rereading the article (it's been a while), I see that he actually used a regular clock, from which I infer that pigeons are pretty bad at recognizing short time intervals. But randomly timed reinforcement will do the same thing, the key point being that the reward is not actually dependent on the animal's behavior. Skinner himself drew the connection to superstition and "luck" rituals....

User avatar
Neil_Boekend
Posts: 3220
Joined: Fri Mar 01, 2013 6:35 am UTC
Location: Yes.

Re: 1457:"Feedback"

Postby Neil_Boekend » Tue Dec 09, 2014 1:00 pm UTC

Kit. wrote:
Neil_Boekend wrote:
rmsgrey wrote:Yeah, but since the digital switchover, there's no "barely watchable" - it's either full quality or garbage, with no feedback on improved signal...

Dunno about DVB-T, but most DVB-S recievers can get simple signal and quality indicators on screen. Those can be used to direct the dish, assuming a near infinite amount of patience (there is usually a few seconds delay in this signal. That means that the feedback loop is severely damaged)

Any digital RF receiver can do it. Not every one shows it to the user, though.

All DVB-S (digital satellite TV) recievers I have seen and worked with (quite a few. I used to do tech support in retail, so I handled probably 50 different models) did show that on screen. For aligning the dish it wasn't as useful as an E15 satbeeper but it was an incredible useful diagnostic tool.
Before your post I assumed that DVB-T (digital ground based) receivers had a similar feature.
Mikeski wrote:A "What If" update is never late. Nor is it early. It is posted precisely when it should be.

patzer's signature wrote:
flicky1991 wrote:I'm being quoted too much!

he/him/his

Kit.
Posts: 1079
Joined: Thu Jun 16, 2011 5:14 pm UTC

Re: 1457:"Feedback"

Postby Kit. » Tue Dec 09, 2014 1:58 pm UTC

Neil_Boekend wrote:
Kit. wrote:
Neil_Boekend wrote:
rmsgrey wrote:Yeah, but since the digital switchover, there's no "barely watchable" - it's either full quality or garbage, with no feedback on improved signal...

Dunno about DVB-T, but most DVB-S recievers can get simple signal and quality indicators on screen. Those can be used to direct the dish, assuming a near infinite amount of patience (there is usually a few seconds delay in this signal. That means that the feedback loop is severely damaged)

Any digital RF receiver can do it. Not every one shows it to the user, though.

All DVB-S (digital satellite TV) recievers I have seen and worked with (quite a few. I used to do tech support in retail, so I handled probably 50 different models) did show that on screen. For aligning the dish it wasn't as useful as an E15 satbeeper but it was an incredible useful diagnostic tool.
Before your post I assumed that DVB-T (digital ground based) receivers had a similar feature.

A typical DVB-T (or -T2) "receiver" is just a TV set that is designed to work with digital channels, as well as with analog ones. They may have service menus that allow qualified personnel to look at these data, but it's not how they are supposed to work for an end-user, who normally just puts an antenna cable into the TV set (and usually the antenna is already pre-installed and pre-oriented on the roof), then asks it to automatically scan for the list of the available channels. Then the digital channels are supposed to just work.

User avatar
slinches
Slinches get Stinches
Posts: 1009
Joined: Tue Mar 26, 2013 4:23 am UTC

Re: 1457:"Feedback"

Postby slinches » Tue Dec 09, 2014 8:00 pm UTC

Kit. wrote:Then the digital channels are supposed to just work.

Yes, this works great for everyone who is within a few miles of the towers, has unobstructed line of sight and no other interference sources. For the other 90% of people in the "coverage area" (that used to receive poor, but watchable, analog reception) it's a black box that doesn't work. Luckily, my TV does have an accessible signal level indicator.

It took a whole day of wandering around on my roof to find the best spot for the antenna, but now I get 4 of the 5 major local network broadcasts and several of the others (~35 total channels). Well worth the effort considering that I'm only paying about $10 per month in replacement pineapples instead of $80 on cable TV.

User avatar
azule
Saved
Posts: 2132
Joined: Mon Jul 26, 2010 9:45 pm UTC
Location: The land of the Golden Puppies and Rainbows

Re: 1457:"Feedback"

Postby azule » Tue Dec 09, 2014 8:50 pm UTC

I thought I saw one channel come in. I just have of those digital receivers (a paper sized rectangle). Are you talking about also using a giant on-roof antenna?
Image

If you read this sig, post about one arbitrary thing you did today.

I celebrate up to six arbitrary things before breakfast.
Time does drag on and on and contain spoilers. Be aware of memes.

User avatar
slinches
Slinches get Stinches
Posts: 1009
Joined: Tue Mar 26, 2013 4:23 am UTC

Re: 1457:"Feedback"

Postby slinches » Wed Dec 10, 2014 1:26 am UTC

Yes, an on-roof antenna, but not giant at about 3x4ft as mounted. By the way, for anyone in the US who is looking into OTA broadcasts, there are decent coverage maps at the FCC and tvfool.com which gives much more detailed technical info on the available channels.

sfnhltb
Posts: 5
Joined: Mon Jun 29, 2009 10:21 am UTC

Re: 1457:"Feedback"

Postby sfnhltb » Tue Jan 27, 2015 3:03 pm UTC

Mental Mouse wrote:This is a classic example of the dire effects of random reinforcement: In B.F. Skinner's classic experiments with operant conditioning, he noted that animals (in the classic experiment, pigeons), could also be "conditioned" by an arbitrarily presented stimulus. Rereading the article (it's been a while), I see that he actually used a regular clock, from which I infer that pigeons are pretty bad at recognizing short time intervals. But randomly timed reinforcement will do the same thing, the key point being that the reward is not actually dependent on the animal's behavior. Skinner himself drew the connection to superstition and "luck" rituals....


Derren Brown did a fun human version of the experiment a few years back as well. Can probably find it on youtube or whatever but the ones I found were locked in my region.


Return to “Individual XKCD Comic Threads”

Who is online

Users browsing this forum: No registered users and 50 guests