Monthly Archives: July 2015

Physical patching – down the wormhole with a borescope!

Summary: Virtualised environments don’t need physical patching. My home, sadly, does but a cheap USB borescope made the job simpler and quicker.

This week I’ve been busy setting up my home office ready for Monday when I start my new job. One of the most time consuming tasks has been running network cable (CAT6) for connectivity – my previous experience with PowerLine technology was somewhat mixed and I decided that hardwired was the way to go now that I’m working from home all day every day. Unfortunately the layout of my house meant a couple of long runs (one 70m, one only about 20m) through multiple walls and floors/ceilings. Some parts of the cable run were relatively easy but others involved going through areas where I had limited visibility and access (ie behind masonry walls and through floorspaces) and didn’t want to make a mess (ie cut access panels or chase cables into plaster).

electrician-rodsEnter the DBPOWER® USB HD Borescope (what is a borescope?) which I bought via Amazon for a mere £18. This nifty geek tool lets you put a camera inside small spaces and see the output on a computer screen in real time, and when combined with a set of electrician’s wiring rods (£8 from Amazon) it was great for threading cable. I still had to drill holes through both the floor and ceiling (about 16mm to allow the ethernet connector – I was being lazy and not crimping my own) but navigating around obstructions, finding the exit hole, and pushing the cable through would not have been possible without this kit.

It’s wasn’t all smooth sailing. The borescope’s magnified view makes it pretty difficult to recognise what you’re looking at – the built in lighting can help but the focus jumps around in dark areas making it challenging. The electrician’s rods are good for pushing in a straight line (and with some flex) but the borescope I bought didn’t have a gooseneck (some do, though costs generally go up) so directing the camera inside floorspaces was pretty difficult.

Still for a total cost of £25 I managed to run my cables and avoided more hours spent on DIY making good, plus it appealed to my geek tendencies. A good job well done!

Chromecast causing wifi interference – resolved

Summary: I’ve found Google’s Chromecast to be a great streaming device but in rare cases it can misbehave and cause wireless access issues.

I bought my first Chromecast the day they were released in the UK (March 18th 2014), totally by chance, and I’m a big fan. Once setup they’re simple enough to use that my 2yr old son can now use a tablet to power on our TV and watch a program of his choosing via BBC iPlayer or Plex without any help from me – and that’s something my in-laws can’t manage. I’m not sure it’s socially a good thing but at least the technology works!

Chromecast wifi analyzerHowever I have noted a few issues, notably with their use of wifi. When you first plug in the Chromecast it’s in ‘master’ mode which means it acts as an access point, thus allowing you to join its wireless network with a tablet and configure it (and also opening up at least one vulnerability). Once the initial setup is complete however it’s supposed to go into ‘managed’ mode which means it should stop being an access point and act only as a wireless client but mine was still intermittently acting as an AP and therefore causing interference, as seen by Wifi Analyser (highly recommended by the way). In my case (and for others too) I saw additional wifi signals, always on the same channel as my home wifi, and the signal strength was greater than my home wifi when I was near the Chromecast. The Chromecasts didn’t broadcast an SSID (it showed as ‘?’ in Wifi Analyser) with a MAC address starting in fa:86:ca, which belongs to Google (although none of the OUI lookup databases seemed to know it).

This useful article about how Chromecast uses the Wifi network, including packet captures, goes into some possible causes although it’s been 18 months since the Chromecast was released and firmware updates may have resolved some issues mentioned.

How do I fix it?

The fix, at least for me, was a factory reset of the Chromecast – hardly worth of a blogpost! However I’d ‘reset’ mine several times by simply going into the Chromecast utility on an iPad (or Android tablet) and after a reboot I’d go through the setup again (inputting wireless password, naming the device etc) and that DIDN’T fix the issue. A factory reset can be done by holding down the power button on the Chromecast for 25 seconds until the light on the device flashes or via the Chromecast app (detailed walkthrough here).

It’s also worth checking that it’s running the latest firmware (31432 as of May 22nd 2015, according to Wikipedia) – it should update automatically (and in fact you can’t stop it doing so which isn’t ideal) but sometimes a factory reset gives it the kick up the proverbial it needs to update. If you need help the official Google Chromecast forum is a good place to start as is the online troubleshooting wizard.