All posts tagged wifi


A view from kitchen to den to theater room

Foreground: a Tivoli Model One AM/FM table radio in our kitchen. Attached to its external input is the remote for the Roku 3 in the theater room (background).

Midground: our den TV playing the 007 movie “Never Say Never Again” (.mp4) on a 1st generation Roku box set on the Plex Channel, which is pulling the movie over wifi from a computer in our office.

Background: our theater room TV playing the same movie over Powerline from the same computer on a Roku 3 (3rd generation), which is transmitting the sound to its remote.

Not seen: In the bedroom, another Roku is playing the same movie from the same computer over wifi.

What you would hear in the kitchen is the radio playing the sound from the theater room. It feels a lot like being at the drive-in.

This particular setup has little practical value unless you really like to listen to movie sound in the kitchen (it’s not bad). But the Roku 3 can also play Pandora, TuneIn radio, or SomaFM radio, which is of value in the kitchen. Furthermore, you can pause either movie or radio from the remote attached to the radio.

In my previous post, I had railed against the Roku 3’s introduction of a new source of wifi interference (“Wi-Fi Direct”) on the same channel as our router, and even tried to put a tinfoil hat on it to block its radio emissions. I have since realized that Roku 3 isn’t significantly stepping on the toes of our wireless router, despite being on the same frequency.

X10 Video Sender

X10 Video Sender (analog)

I became sensitized to this potential issue when I previously discovered that our X10 video sender, broadcasting on the same 2.4 GHz band as 802.11b/g wifi, squashed any wifi signals unfortunate enough to be on or near the same frequency.

The Roku 3 is not obtrusive like the lead-footed X10 sender. There are people writing on the Roku Forum who say their wifi was squashed by the Roku 3 (bad previous software update relating to screencast?), but not me.

Reading taken near the other Roku in our den before tinfoil hat...

Wifi Analyzer “waves” depict channel spread and signal strength of nearby wifi routers.

My mistake was analog thinking in a digital setting. The X10 sender IS analog, and emits energy continuously on its frequency.

Despite the Wifi Analyzer’s graphic that visually lulls you into thinking analog carrier wave, the Roku’s built-in software access point (AP) is only periodically sending out small ID and keep-alive packets on the channel unless it is actively sending content. Even then, there are large, i.e., multi-microsecond gaps between most competing packets.

I have had an occasional issue with jerky playback of .mkv files ripped from DVDs by MakeMKV software. It happens when I use Plex Media Server to transcode them on the fly and send them over wifi to 1st generation Roku boxes. (Of course, by using 802.11g wifi, I am not even up to Plex’s minimum recommended configuration, so that may be a big factor.)

Anyway, I saw that issue recur, noted the high signal strength of the Roku’s AP, read about the problems others were experiencing, then freaked out and presumed Roku 3 was the culprit. It isn’t. As I just proved to myself, two simultaneous video streams (first of “Fawlty Towers” and “The Swimmer” in .mkv, then 007 in .mp4) over our wireless network behave the same way whether Roku 3 is plugged in and transmitting audio or not. (Audio has a much lower bandwidth than video.)

So now I am free to enjoy the Roku 3’s Wi-Fi Direct features.

Being able to plug into the remote (which cuts the sound in the theater room) lets you either listen to the sound privately on headphones, even outside your house, do as I did with the kitchen radio, or plug it into a boombox in the workout room.

You can use the Roku app on your smartphone to stream a slide show of your phone photos to the big screen. You can also use it to stream any sound files on your phone to the big sound system. You can even do both at the same time.

The Roku 3 I bought was refurbished and at a reduced price. I found that the sound was intermittent when I plugged headphones into the Roku remote. But I was able to fix that by spraying a shot of QD Electronic Cleaner (like WD-40 for radios and TVs) into the jack and onto the plug. Handy stuff to have around for scratchy volume controls and tuning knobs, too.

The tinfoil hat wasn’t as becoming as I thought, anyway.

I made a tinfoil hat for my Roku 3...

It’s very attractive, though.

I still haven’t gotten around to having our house wired for internet. But I wanted to see how much a wired Ethernet connection (vs. wifi) would improve the performance of a Roku box.

I found a refurbished Roku 3 on sale at Woot! and picked one up. This is the top of their line, but the reason I wanted it was for the wired Ethernet connection (and a 5x faster processor). I connected it to a Windows 7 computer by gigabit switch.

The Roku 3 also boasts a remote with headphone jack for private listening, and direct cast to TV from the Roku app on your smartphone. These features were the source of a ridiculous problem. Ridiculous, because it never should have gotten out of the lab this way.

Reading taken near the other Roku in our den before tinfoil hat...

Roku 3 interferes mightily on channel 11 before tinfoil hat…

I noticed on my Wifi Analyzer app that there was a new item on our current wifi channel 11: the Roku itself. It was broadcasting on our channel, jamming it, resulting in degraded wifi performance. (see the next post for a correction to this.)

No need for any transmission at all since my connection is wired (unless you want to use the direct cast feature or headphone attached to the remote). But it turned out that I couldn’t shut wifi off. In fact the only way to stop it was to unplug the Roku 3.

I did some Googling and found that others discovered this, too. The best and most current thread is this one from Roku Forums:

Yet another Wi-Fi Direct is jamming my home network thread 

No workaround has yet been found besides a “Faraday cage”. This consists of blocking the transmission with a metal screen. Aluminum foil was mentioned as working for one poster.

After tinfoil hat.

Roku 3 still interferes on channel 11 after tinfoil hat.

So I tried it. I covered up everything I could, leaving the wires sticking out the back and a little hole for the infrared port.

As you can see at left, the Roku’s own wifi was attenuated somewhat, but not enough to stop it from interfering. (The readings were taken beside an older Roku box in the den.)

I think I will go back to the Roku LT until Roku pushes out a software or firmware update to let you turn off wifi.

Roku probably should have used Bluetooth to implement these features. Or, considering how cluttered the 2.4GHz band is, they probably should have just left the features out, or made them work only on the 5 GHz band.

(By the way, the Roku 3 on wired Ethernet connection worked well. I was trying a semi-competitor to Plex, called Media Browser. MB was able to play a Windows TV (.wtv) recording smoothly, once the puny Celeron processor in my mom’s old Win 7 computer transcoded and buffered enough of the file for it to get started.)

Bulletin for all cranks: you are going to have to do better than a tinfoil hat if you want to keep the NSA from monitoring your mind.

(See the next post for a retraction of the comments about my degraded wifi performance. But I still wish there were a capability to turn off Roku 3’s wifi.)

2014-10-04 07.53.08

After the change. We are the blue curve.

Yesterday I looked at the Wifi Analyzer app on my smartphone at home, and found that there was a pileup on channel 1 in the crowded 2.4 GHz band. I had switched us to channel 1 a few years ago, because it was then uncluttered.

No longer.

One of our nextdoor neighbors was now on channel 1 with us. Maybe he got a new router. I’ll have to ask him next time I see him at the mailbox.

Another neighbor has the middle channel 6.

There are 13 wifi channels used on the 2.4 GHz band in the US. Channel 11 is the highest I could select on my old warhorse Linksys WRT54G router (802.11g protocol). That allows for signal spread up to channel 13 on the high side. Here are their frequencies:

1:     2.412 GHz
2:     2.417 GHz
3:     2.422 GHz
4:     2.427 GHz
5:     2.432 GHz
6:     2.437 GHz
7:     2.442 GHz
8:     2.447 GHz
9:     2.452 GHz
10:   2.457 GHz
11:   2.462 GHz
12:   2.467 GHz
13:   2.472 GHz

After I made the change, 2 out of 3 of our Roku boxes seemed to have trouble adapting to these new channel. I did a factory reset to get another one of them working. The other one didn’t like the channel even after a reset.

It occurred to me that our X10 video sender might be interfering. It also operates on the 2.4 GHz band, with 4 channel choices:

A: 2.411 GHz
B: 2.434 GHz
C: 2.453 GHz
D: 2.473 GHz

(Note that X10 channel A and Wifi channel 1 are almost the same, as are D and 13.)

I had set X10 on Channel D years before by trial and error. I hadn’t understood why D worked better at the time, but that frequency was as far away from the lower channels where our router was operating as it could get. It was jamming the high end of the band which we now occupied.

So I had to switch the X10 sender to a lower channel. Since our channel 6 neighbors’ router is physically much closer to the X10 sender, I elected to go with X10 channel A, to the possible detriment of our channel 1 neighbor.

The 2.4 GHz band is cluttered, Bluetooth, wireless phones use it, too. Microwave ovens really fritz it up.

A better solution than playing “2.4 keep away”  is to get a newer router that uses the 5 GHz band (802.11n or 802.11ac).These routers should improve the performance of Plex as well. Or get a video sender/receiver on the 5.8 GHz band.

The best solution for streaming home media is Ethernet wiring (which I plan to do), but phones and tablets still need wireless.

I may get a newer router operating in the higher band (which can I see from another app is entirely unoccupied in our immediate neighborhood), then switch the X10 sender to whatever frequency is least used by the neighbors. I will also have the sender on only when we are actually using it.

The third Roku (model LT) was able to establish a link to the router with the X10 sender off. (Later note: I now have a Roku 3 using Powerline in the theater room rather than wire for Ethernet.)

By the way, X10 manufactures both the video sender/receiver and home automation items, but the two product lines have no technical relationship to each other. The X10 automation control protocol is sent over house wiring, and its associated wireless protocol operates on 310 MHz, far away from wifi frequencies.