DAB: mijn eerste digitale radio

▼ Alles in het leven is tegenwoordig digitaal, maar de radio is eigenlijk niet veranderd sinds de invoering van FM in de jaren '50. Maar als we dit promotiefilmpje van een jaar geleden mogen geloven is de radio nu ook hard op weg om digitaal te worden! Dat wilde ik zelf wel eens horen, dus gister heb ik mijn eerste digitale radio gekocht.

Tegenwoordig luister ik eigenlijk zelden nog naar de daadwerkelijke radio. Wel luister ik veel naar fragmenten van NPO Radio 1, maar dat doe ik dan via de podcast feed, of, als ik te laat ben (de fragmenten zijn minder dan een dag beschikbaar via de feed), via de website. Plus naar de podcast van Met het Oog op Morgen. Op die manier kan ik luisteren waar en wanneer ik wil via 'm iPhone.

In het verleden luisterde ik ook wel via een radiowalkman, maar het probleem is dat in Den Haag de ontvangst van Radio 1 abominabel is: de zender IJsselstein/Lopik is ver weg en komt daarom zwak door (veel zwakker dan Radio 2 en 3FM vanaf dezelfde toren) en de steunzender in Den Haag is heel zwak en is dus niet echt een alternatief. Op de fiets raak ik dus steeds het signaal kwijt.

Met dit alles in het achterhoofd heb ik bij de winkel om de hoek een Sangean DPR-65 Basic aangeschaft. De DPR-65 ontvangt zowel FM als DAB+ (Digital Audio Broadcasting), maar geen AM/middengolf. FM werkt zoals te doen gebruikelijk, met een goede scanfunctie om snel zenders te vinden en vijf voorkeuzeknoppen om ze onder op te slaan. DAB initialiseert automatisch bij het voor het eerst aanzetten. De radio gaat dan op zoek naar zenders. Op dit moment zijn er twee DAB-zenders in de regio Den Haag: vanaf de communicatietoren zendt de publieke omroep uit, en vanaf een gebouw in Rijswijk de landelijke commerciëlen. Bij DAB zendt iedere zender een zogenaamde "multiplex" uit, die meerdere kanalen bevat. Hiermee kan ik momenteel de volgende kanalen ontvangen:

Naam	Multiplex
100% NL	DAB+
10 Gold	DAB+
3FM Alt	NPO
Arrow CR	DAB+
BNR	DAB+
Classic	DAB+
Efteling	DAB+
JUIZE!	DAB+
NPO 3FM	NPO
NPO FunX	NPO
NPO R1	NPO
NPO R1Ex	NPO
NPO R2	NPO
NPO R4	NPO
NPO R5	NPO
NPO R6	NPO
NPO Test	NPO
Qnonstop	DAB+
Q-music	DAB+
R Maria	DAB+
RADIO538	DAB+
Radio 10	DAB+
Sky Hits	DAB+
SkyRadio	DAB+
SLAM!FM	DAB+
Sublime	DAB+
SublYou	DAB+
Top 2000	NPO
Veronica	DAB+

Ofwel: de zenders worden in alfabetische volgorde weergegeven. Met de op/neer-toetsen kan je hier dan doorheen lopen en met "select" een nieuwe zender selecteren. Hiervan kan je er weer vijf onder de voorkeuzeknoppen zetten. Tussen kanalen binnen dezelfde multiplex overschakelen gaat vlot, maar van de ene multiplex naar de andere duurt wel een paar tellen. Het geluid is digitaal, en heeft dus geen ruis of andere bijgeluiden. Wel kan de ontvangst wegvallen, met name als je onder een viaduct doorgaat en dergelijke. Volgens mij is er flink nagedacht om de overgang niet al te abrupt te maken.

De geluidskwaliteit voor spraak is heel goed, voor muziek nogal variabel. In sommige gevallen klinkt het gewoon goed, hoewel iets minder helder dan dezelfde muziek met CD-kwaliteit. Maar soms klinkt de muziek als een MP3 uit de jaren '90.

De DPR-65 is een klein tafelmodel radio met sprietantenne, en dus niet ideaal voor gebruik op de fiets. Maar hij is klein genoeg om in m'n zak te steken. Als ik de antenne dan half uittrek is de ontvangst prima in de stad, veel beter dan Radio 1 op de FM. En het grote voordeel is dat je nooit hoeft na te denken over schakelen tussen de hoofdzender en een steunzender, want bij DAB zenden alle landelijke zenders op dezelfde frequentie uit, via een zogenaamd "single frequency network".

Naast de landelijke zenders wordt er nu ook gewerkt aan een vijftal regionale multiplexen waar de regionale publieke en commerciële omroepen gebruik van zullen maken. Deze regio's komen niet overeen met de (provinciale) dekkingsgebieden van de regionale omroepen, dus niet alleen zullen er meerdere regionale publieke omroepen per regiomultiplex uitzenden, ook zullen sommige regionale omroepen via meerdere regiomultiplexen te horen zijn. Bijvoorbeeld, ik was in de buurt van Maassluis, waar ik de multiplex zuidwest kon ontvangen, waarop ook Radio Rijnmond zit. Radio Rijnmond gaat ook via multiplex west uitzenden zodra die de lucht in gaat per 1 september. Maar op dit moment is bijvoorbeeld Radio West nog niet via DAB te ontvangen. Er zijn vooralsnog geen plannen om lokale zenders via DAB uit te gaan zenden.

Binnen is de ontvangst van de NPO-kanalen nog niet erg goed: aan de ene kant van het huis gaat het net, aan de andere kant absoluut niet. De commerciële omroepen komen wel sterk door. De NPO gaat echter in de loop van 2015 fase 3 van de DAB-uitrol uitvoeren, waarmee de ontvangst binnen een stuk beter moet worden. Om dit te bereiken komen er nog flink wat zenders bij, ook in kleinere plaatsen zoals Hoek van Holland en Oegstgeest. Ik hoop ook dat de zender in Den Haag een wat sterker signaal gaat uitzenden, want je zou toch denken dat je op maar een paar kilometer van de zender een goed signaal binnen zou moeten krijgen.

De DPR-65 werkt met twee AA-batterijen en kan daarnaast met een USB-kabel gevoed worden. Als je oplaadbare batterijen gebruikt kan de radio zelfs de batterijen opladen. Je hebt zo dus zowel het voordeel van USB-voeding als het gebruik van normale batterijen! Wel jammer dat-ie er nogal hard doorheen gaat. Met twee oplaadbare batterijen deed ik twee uur en tien minuten. Weliswaar zijn dit niet erg nieuwe batterijen met beperkte capaciteit, maar toch.

Conclusies

DAB is vooral erg handig: geen geknoei meer met frequenties, zoek gewoon je favoriete zender op in de lijst. Met name in de auto lijkt me dit erg handig, ik zou bij het kopen van een nieuwe auto of autoradio dan ook kijken of je zonder enorme kosten een model met DAB kan krijgen. Wandelend of met de fiets kan DAB ook voordelen hebben, en zo niet, dan kan je altijd terugschakelen op de FM. Maar ik zou wel kijken naar de batterijduur. Als je niet zo'n fanatieke radioluisteraar bent kan streamen via je smartphone een goed alternatief zijn, hoewel dit flink ten koste van de mobiele megabytes en je batterij kan gaan.

Voor thuis zou ik nog even de kat uit de boom kijken: de dekking binnenshuis is vaak nog slecht, en thuis kan je ook via de kabel of je TV-settopbox naar de radio luisteren, of via het internet.

Permalink - posted 2015-06-04

The hell that is Disk Utility

▼ A while back, I gave my sister a 1 TB 2.5" USB HDD for backing up her Mac using Time Machine. But somehow she couldn't perform backups anymore lately. The drive contained two volumes: a regular one and an encrypted one. The regular one wouldn't mount and Disk Utility wouldn't repair it.

No big deal, just wipe the drive and start from scratch, I thought—assuming it's not a hardware problem. That was easier said than done. I ended up spending half the day yesterday just trying to repartition that stupid USB drive.

At first, it seemed like this didn't work because I had Core Storage enabled on it for the encrypted partition. I managed to revert the CS partition back to a regular partition. But then repartitioning wouldn't work: I was unable to modify the first (broken, unencrypted) partition. Or make modifications to the second partition stick.

This isn't my first Disk Utility rodeo, so I booted into: the recovery partition, Snow Leopard and Leopard and tried the same thing using those versions of the Disk Utility. No joy.

I tried various ways to nuke the drive and its partitions using the command line diskutil and hdiutil commands. Which of course fail silently if you don't use them with sudo. And failed a bit less silently with sudo. The various utilities all failed at unmounting the existing partition(s).

The Finder, Disk Utility, diskutil, hdiutil, nothing would unmount the drive.

Did I mention I used the "force" flag? Didn't make one iota of difference.

I even made an fstab to keep the drive from automounting, but that didn't work.

All the while, every search for help only led me to forum posts where people kept telling the original poster that you can't unmount your boot drive.

So then I thought I'd try to have Linux wipe out the drive. But I couldn't let a VM connect to the drive because MacOS immediately took it after connecting the USB cable and then held on for dear life.

So maybe my Time Capsule wifi base station is a bit simpler in its disk handling, so I decided to hook up the drive to it and then have the TC initialize it. Good plan, except for the part where the Time Capsule wouldn't recognize its password with the drive connected.

This is where I gave up with the drive clicking away connected to the Time Capsule. The next morning, I disconnected the drive from the TC, hooked it up to my laptop, saw icons for both partitions, unmounted them and used Disk Utility to repartition as if yesterday's hair pulling session was all a bad dream.

I spent the rest of the day zeroing out the drive to make sure the hardware was ok, with no further problems.

Why does this stuff have to be so difficult?

Permalink - posted 2015-05-31

Review: the Braun Oral-B PRO 6000 electric toothbrush—with bluetooth!

▼ I'll spare you the details, but I recently needed to up my game in the toothbrushing department. I've been brushing my teeth with an entry-level Oral-B electric toothbrush for almost a decade, but I thought I could do better with a more advanced one that provides a warning when you brush too hard. (This can damage your gums.) Turns out there's now a model that has bluetooth. After all, everything is better with bluetooth:

However, at first I decided against getting the model with bluetooth, as it doesn't really add much functionality: the Oral-B app will show you a timer during brushing, and keep track of how often and how long you've brushed. That's basically it. And the app can also do this by listening for the sound of the toothbrush! Also, the models I had my eye on come with a little wireless display that provides the same feedback as the app (not the statistics, though). But I got a rebate that made the Oral-B PRO 6000 the same price as the Oral-B Triumph SmartGuide 5000, so why not get the 6000 with bluetooth?

The price I paid online before rebate was € 100 plus € 5 shipping. The 6000 comes in a big box that contains:

• The toothbrush
• An inductive charger
• A holder for four brush heads that attaches to the charger
• The SmartGuide wireless display (with batteries)
• Seven brush heads
• A travel case
• A DVD
• Documentation

Out of the box, the toothbrush' battery is empty. It takes about 24 hours to completely charge, but I was able to brush my teeth after about half an hour. I needed to set the clock on the SmartGuide, but there was no need to do anything to pair it. The seven brush heads are all different, I assume they're meant as a sampling of what's available. I'm using the "sensitive" one, which has softer hairs and is easier on the gums. I wish they'd put the name/type of the brush head on the packaging, though! The documentation for these on the various Oral-B websites and the paper manual is fairly incomplete, but the video on the DVD shows them all. I've also seen displays in stores that will help you buy the right ones. Note that the DVD is smaller than usual and thus won't fit in most computer DVD drives.

The travel case is at least twice as big as it needs to be. But I guess if I want to travel with my electric toothbrush, I'll have to use it or risk the toothbrush starting to brush the rest of my luggage when the on/off button gets pressed inadvertently. I usually just take a regular toothbrush when I travel, but it's hard to go back when you're used to electric brushing. It really gets your teeth much cleaner.

I'm not sure which model I used before (there's no model number on the device), but the old one didn't have any lights. So you never knew when you needed to charge it. The PRO 6000 is much better in this regard: it has three (blue) LEDs that indicate the battery charge, which cycle during charging. There's also another blue light that comes on to indicate bluetooth is active. When brushing, every 30 seconds, a green light will flash and the motor will pause for a moment to indicate that it's time to move on to another quadrant of your mouth. And finally, there's the light that made me get this new toothbrush: a red one that comes on when you press the toothbrush against your teeth too hard. At first I thought this didn't work, but it turns out the warning light only comes on when you press the brush really, really, really hard. Much harder than I ever would. So buying this new toothbrush for this feature was a waste of money.

So what about the bluetooth?

I'm glad you asked. Although in retrospect the instructions are clear, I had trouble following because I assumed I needed to pair my iPhone with the toothbrush using the bluetooth settings. But that's not how it works. You set up your toothbrush using the settings inside the Oral-B app. The bluetooth comes on when you lift the toothbrush off of the charger, or you can press the mode select button. (The toothbrush has a bunch of modes which I don't use.) There's a bunch of additional settings for the app and/or the toothbrush, but nothing particularly exciting.

If you want feedback during brushing, make sure the app is open and on the timer screen. Then, simply start brushing and you get a counter that counts to two minutes, switching to different quadrants every 30 seconds. Same as the SmartGuide, which comes on automatically when you start brushing. (When idle, it shows the time.) As such, live feedback on your phone during brushing is not particularly useful. Even the SmartGuide is only somewhat useful. (And remember, if you have a non-bluetooth toothbrush, you can still use the app by using the microphone to detect when you start and stop brushing.)

However, one thing that is nice about the app is that it keeps stats on how long and how often you brush. At first I thought this wasn't all that useful, as I always brush my teeth before bed. But I'm actually not that good with brushing during the day. Studies have shown that you should brush twice a day—there's no benefit to doing it more often. Having the app keep track of this for me to keep me honest could be helpful in the long run.

The toothbrush only talks to the phone when the app is open. But it will store up to 20 toothbrushing sessions, and sync those back to the app if the app is open on the timer screen when you start brushing. So you only have to open the app before you start brushing once a week and you'll have accurate stats. Apparently the toothbrush has a built-in clock, because it knows how many times I brushed on which day.

You can share an electric toothbrush with family members by giving everyone their own brush head, which let you attach a colored ring to keep them apart. The container that sits next to the charger holds four brush heads, and attaching/removing them is easy enough. However, the app can't tell the different users apart, so the stats won't be very meaningful when the toothbrush is shared.

The verdict

I like Oral-B electric toothbrushes. I've never used any other kind, so I can't compare. But the Oral-Bs are all good—I'm not going back to brushing manually any time soon. The PRO 6000 is better than the cheap ones, mostly because of the battery level LEDs. The hardware also looks a bit more solid. The other LEDs, the SmartGuide and the bluetooth are nice, too, but not a game changer. So save your money unless you really want those brushing statistics. Until the toothbrush becomes smarter and gains more sensors so it can tell you more about how well you brushed which teeth, I'm afraid bluetooth doesn't really make brushing your teeth all that much better.

Permalink - posted 2015-05-29

Bring on the 2.5, 5 and 25 Gbps Ethernet!

▼ I'm at the RIPE meeting in Amsterdam this week. Yesterday, one of the first presentations was one from Alcatel-Lucent's Greg Hankins: Evolution of Ethernet Speeds: What’s New and What’s Next (PDF, see here for a link to the video recording).

Apparently, we're going to get some new Ethernet speeds in the (relatively) near future, such as 2.5, 5 and 25 Gbps. I can't wait!

My first computer with Gigabit Ethernet was the PowerBook I bought in 2003. It's now more than a decade later and my current Apple laptop... doesn't have any Ethernet at all. But for 20 to 30 euros/dollars you can get a 10/100/1000 Mbps Ethernet adapter that connects to either a Thunderbolt or a USB3 port. That's exactly as fast as the Ethernet port on my old PowerBook, even though according to Geekbench 2, my late-2013 MacBook Pro is more than ten times faster than the 1.25 GHz PowerBook (32-bit scores are 7110 vs 658). The SSD in the MBP is also about ten times faster than the HDD in the PB at about 800 vs 80 MB/s. USB is 5 Gbps instead of 480 Mbps, Wi-Fi 1300 vs 54 Mbps. It's just the Ethernet that's been completely stagnant.

So why is that? We've had 10 Gigabit Ethernet since the early 2000s. But the problem with that is that originally, 10GE was designed to work over fiber, which can easily handle that bandwidth. It took a lot of work to make 10GE work over copper, and that never got cheap in the way that GE got cheap so we never got 10/100/1000/10000 Mbps Ethernet ports the same way we went from 10/100 to 10/100/1000 Mbps Ethernet ports on our laptops and desktops. Even the biggest and baddest Mac that you can buy today, the Mac Pro, only has two 10/100/1000 ports, and no extension slots for adding 10GE.

The problem with all of this is that Gigabit Ethernet tops out at about 119 MB/s. That's more than enough to saturate any internet connection that a mere mortal can afford, but it's not enough to keep up with our SSDs or even a RAID array when copying files locally, with SSDs that easily go over 500 MB/s these days. With 2.5 Gbps Ethernet we'd get a lot closer at about 300 MB/s, and 5 Gbps Ethernet would be even better at about 600 MB/s. With modern designs, I expect that 5 but certainly 2.5 Gbps over regular twisted pair cabling can be made sufficiently cheap that these speeds will be supported routinely, and USB3 can easily handle 2.5 Gbps and probably also 5 Gbps. 2.5 and 5 Gbps are also intended to run over existing cat 5e/cat 6 cabling over distances of 100 meters, the same as Gigabit Ethernet. Traditionally, higher speeds over copper require more advanced cabling and/or support shorter distances.

There will also be 25 Gbps Ethernet that will be a nice step up for big servers that now use 10 Gbps, and perhaps 50 Gbps in the future. See the presentation for what's new for 10 and 40 Gbps and even 400 Gbps.

Permalink - posted 2015-05-12