TV reception and black magic

Well, I spent some more time fiddling with the antennas. I've actually turned the VHF beam southeast to try and pick up KSBW and KCBA (Salinas) from Fremont Peak. Here's where things stand:

DTV stations that come in perfectly, with no issues: KPIX, KQED, KBCW, KICU, KCSM, KTEH, KKPX, KCNS, KSTS, KTSF, KGO, KMTP, KBWB, KFSF, KNTV

DTV stations that are marginal - most of the time they're fine, but sometimes they pixelate or drop out: KRON, KTVU, KDTV.

DTV stations that come in at least sometimes, but are not 100% coverage: KSBW, KCBA, KRCB.

DTV stations that don't come in at all, but I don't see why not: KTLN, KTNC.

If I go up to the roof and aim the UHF a little bit more northerly from where it is now, KRCB, KTLN and KTNC seems to come in a little better, but KTVU and KRON start getting more marginal. We're talking about maybe 5 degrees, with an antenna whose half power beam-width is more like 30 degrees.

The only thing I can think of is that perhaps the pre-amp is being overloaded and that it's pushing the weaker signals down a little. If that's the case, then the analog shutdown next February will help somewhat.

The shutdown will certainly help KSBW and KCBA, which currently suffer co-channel interference from KXTV-TV and KOVR-TV. We also will likely be able to pick up KAXT-LD. At the moment, KAXT-LD is co-channel with KTNC-TV. One worry is that KRCB-DT is going to be co-channel with KMUV-LP, but fortunately it will be in the opposite direction, so the antenna's front-to-back ratio should bury it. The bad part about that is that we will have no chance at all of picking up the other UHF channels from Fremont Peak: KQET and KSMS. But KQET is redundant if you can receive KQED and KTEH already (KQET-1 is the same as KQED-1, KQET-2 is the same as KTEH-1 and KQET-3 is V-Me, which is on KTEH-5), and KSMS is a Univision affiliate like KDTV.

Statistical stupidity

ABC News recently had a video on My Yahoo that had the "worst" foods purported to be good for you (alas, I don't have a deep link to the video). First on the list of diet soda. The silly woman said that those who drink diet soda are heavier than those who don't, so you shouldn't drink diet soda.

Uh, newsflash: You've got the cause and the effect backwards there. People who are heavy drink diet soda because they know they're heavy. The ones who aren't heavy drink whatever the hell they want because whatever they're doing is working for them (or at least isn't a problem).

It's like saying bariatric surgery causes obesity because only obese people have it done.

Solving the CableCard / OpenCable conundrum

One issue I've always had with satellite TV is that before recently, every tuner has required so-called "home run" wiring. That is, a coax run all the way from the receiver to either the dish or a multiplexer, with no splitters in-between. The reason for this is that there needs to be a communication path from the tuner back to the dish (or multiplexer) so that it can select which set of transponders it wants to tune at that moment. If you've got a couple of dual-tuner DVRs, that's quite a lot of coax. The latest little innovation from DirecTV is the SWM-8, which neatly solves this problem. It allows you to connect up to 8 tuners using as many splitters as you need (with the caveat that you need to have at least one branch of the splitters pass DC power from an indoor mounted power supply module). The way it works is very similar to SDV cable TV systems. There are 9 channels set aside - 8 of them provide one tuner's worth of signal down from the dish, and one is a shared upstream request channel from the tuners back to the SWM. Each tuner requests a channel to be allocated to it from the SWM at startup, and as the channels are changed, it requests a different satellite transponder be sent down its allocated SWM channel.

With this system, the satellite system itself can become arbitrarily complex, but the complexity can be hidden behind the SWM. Already the SWM can handle a single 5 LNB Ka/Ku dish plus two auxiliary dishes (one for international programming and one for carrying local channels for some markets).

As I've previously noted, this system is somewhat similar to SDV systems for cable - the only difference being that SDV channels are shared by all subscribers, not allocated solely to a single downstream tuner.

Verizon's FIOS offering already includes a box that transitions from fiber to coax for the household. In principle, that box could also provide addressable decryption so that the house simply sees all of the subscribed channels as clear QAM - no need for CableCard at all.

This same idea could apply in the world of cable TV as well. Each household would have an addressable box that would perform pre-tuning and decryption for a set of tuners within. There would be a spec for the channelization and for the upstream communication protocol. The channel data would be clear QAM. The same box could also have an Ethernet jack and provide IP service as well, for subscribers to cable-delivered Internet. Since the box obscures the cable infrastructure, it offers greater flexibility to the cable company in laying out their networks.

Final TV setup

I've finally decided on how our TVs are going to be set up from now on. I thought I'd share how I did it.

In our house, we've got 4 TV receiver type devices. Two of them have DirecTV HR21 DVRs, one is a TV in the guest bedroom with an ATSC tuner, one is an HD HomeRun ATSC decoder on the network for the computers.

We actually have 8 RG6 cable runs in our house, which is a lot given its small size. To the extent possible, it would be nice to give all of these cable runs the same signal, so if we decide to move a receiver around it won't be a problem. It also turns out that splitting the signal that much causes problems for some of the channels. Plus, we only have two cable runs to the living room, which causes a problem for the HR21 (ordinarily) because it has 2 tuners plus the AM21 ATSC tuner (which would require a third cable run for its antenna feed).

Fortunately, all of this can be worked out.

We start at the TV antenna. There are actually going to be two of them - one is a ChannelMaster 4228 UHF antenna. This will capture most of the DTV signals. However, we are going to have a couple of VHF-hi channels post 2/09 - KGO and KNTV. For those, I have an AntennaCraft Y5-7-13 VHF-hi antenna. Both of those feed into a ChannelMaster 7777 mast-mounted amp. The 7777 can take a separate VHF and UHF input and amplify and combine them into one feed into the house. The amplifier is necessary because of all of the losses caused by all of the splitters used to feed all of the drops.

We also have DirecTV. The fix for the living room running out of cables is an SWM-8. The SWM-8 allows a single feed to be split with conventional splitters and drive up to 8 DirecTV tuners. Not only that, but the SWM also has an input to diplex in the terrestrial antenna feed too! The downside of that is that we need to power the pre-amp. So we need to inject power into the antenna line, but after the SWM, which is awkward. Fortunately, there is an RG6 run from the distribution point out back into the garage, where the pre-amp's power supply can live. The only thing left is to figure out how to inject that power into the line after the SWM.

Well, it turns out that you can use an ordinary satellite diplexer to do just that! Just connect the VHF/UHF line to the OTA-in port on the SWM with a short length of RG-6, connect the satellite port to the line coming from the power supply in the garage, and connect the combined port to the lead going to the CM7777. The satellite leg of the diplexer has a DC power-pass on it, and the VHF/UHF side has a DC block. A regular power injector would probably do this job with slightly less loss (since the diplexer has a needless low-pass filter on the VHF/UHF port), but it was handy and worked.

The SWM also has its own power injector. If you use a splitter on the SWM1 port, it needs to have a power-pass port, and that port must be connected to the port in the house to which the SWM's power supply is connected. In our case, however, I just connected one line from the bedroom directly to the SWM-1 port. Inboard of the SWM power supply, I am using a diplexer to break out the VHF/UHF and satellite signals for that receiver.

The SWM-2 port has a 1-4 splitter feeding two lines to the living room and one line each to the guest bedroom and the port for the HDHomeRun (which is actually in the dining room). If we want to upgrade the guest bedroom from standard TV to DirecTV, we simply need to diplex that port.

The only downside to this setup is that we now are only able to use SWM compatible receivers. Turns out that isn't likely to be a problem going forward, since we already have the two HR21s we're probably going to have for the foreseeable future, and if we wanted to add a receiver later, we would probably only be able to get compatible ones new.

More on the DirecTV HR21

So we've had a few days now with the HR21, and I have to say, it's nice. As I said in my last post, I don't particularly miss the TiVo menu system. The HR21 shows a picture-in-picture view of the current program while you're in the menus or in the guide, unlike the TiVos. I also hooked our receivers to the network, which enabled home media viewing and DirecTV on demand. It took a day or two for the on demand feature to work, but now that it does, it's quite compelling. I've already downloaded an episode of Californication that Scarlet had missed from last season (of course, you can't get shows on-demand for channels to which you do not subscribe). They also have some extra channels that have concerts, Olympic stuff, and even an Adult Swim VOD channel.

Among the new niceties with the HR21 is that PPV events now are not charged until you actually watch them. It is free to record a PPV event - or even download one with on-demand. You only get charged when you start watching it. The downside is that, like iTunes rentals, you have a 24 hour window in which to finish watching.

The AM21 seems to work pretty well. The only quirk is that although we've selected "channels I receive" as the default guide, the over-the-satellite local channels still show up, even though we don't actually get them. This means that when you're picking a show to record, you have to make sure to pick the one that is over-the-air. Fortunately, they're easy to spot - they have a sub-channel number (like 9-1 instead of just 9).

The HR21s have an eSATA port on the back, which allows you to replace the internal hard drive without any tools. I don't know if we'll take advantage of this or not. Unfortunately, it doesn't cascade the two drives, so when you plug in an external drive, you lose access to the recordings on the internal drive. But adding a 1TB drive (and they're not that expensive anymore) would triple the capacity. Time will tell if that is necessary or not.

Wiring the system up with the SWM module was just as easy as wiring up any older multi-switch. I decided to keep the terrestrial wiring separate, but the SWM-8 does have a terrestrial input so that you can diplex everything together. DirecTV apparently has a new LNB in the works that integrates an SWM-8. That will make DirecTV much more like cable TV than it is now - just one wire leaving the dish that can be split with ordinary splitters as many ways as desired (feeding up to 8 tuners). But with the SWM-8, you can achieve the same thing right now if you want (though the SWM modules are not cheap, unfortunately).

There's only one feature missing from our setup that I'd like to see added - the ability for two DVRs in the same household to share content over the network. Right now, I have to set up a series link (aka season pass) for The Soup on both DVRs to be able to watch it in either room. If DirecTV would allow sharing content over the network - even if they don't allow downloading directly to a PC - that would be just about perfect in my book.

DirecTV - good product, incompetent service

So we finally decided to move with the cheese. Every DVR we've ever owned has been a TiVo, and the last few have been so-called "DirecTiVos" - DirecTV DVRs powered by the TiVo software. But not so long ago DirecTV ended their relationship with TiVo and started making their own DVRs. They also launched new satellites to carry HD programming that were not going to be compatible with the TiVo DVRs. So we were going to face a stark choice some day - either switch to Comcast and buy real TiVos, or go with the "can't believe it's not TiVo" DirecTV DVRs.

I'd been watching the various forums for a while and finally decided that the software on their DVRs was ready enough and called them last week to get them to install the new 5 bird dish and a pair of HR20 DVRs. Well, when they came on Saturday, they said that they had HR21s, which do not have an ATSC receiver in them to receive local channels. Well, that ruined the plan, so I told the installer I didn't want them. I then called up DirecTV and spent an hour on the phone with them. Turns out that the HR21 does not have an ATSC tuner, but you can get one as an accessory add-on (the AM21). But you can't just add an AM21 to your order and have the installer bring it, you need to have an HR21 on your account first before their computers will let you buy one. Stupid. So, fine, I had them come out Monday.

The next problem is that we have two RG6 lines running to the living room. Since one of them is going to be dedicated to terrestrial signals, that means that if I want the two-tuner functionality, I will need to use the new SWM technology. When I explained that to the installer that came Monday, he said that they could not do an SWM installation except for new customers with more than 5 tuners. Grumble. So I told him to just install it with one tuner and I would do the SWM thing myself. So I've placed an order for the two AM21s and an SWM-8. The good news is that the cost of all the stuff I need to buy to make it right is about the same as the cost that I expected to pay for the new receivers and the installation (which it turns out was free).

The installer left before the software updates were complete. Of course, the receiver in the living room got stuck. My brother-in-law called DirecTV up and read them the riot act, and they said they'd send the installer back, but he never showed. I finally power-cycled the thing and that fixed it.

Now that it's all in (except for the AM21s), I have to say I'm reasonably happy with the functionality. I don't really miss TiVo's menu system. Time will tell, but I may miss the suggestions (the HR21s don't save anything you don't actually request), but it's nice to see Discovery channel programming in HD.

More later.

CSI:Miami's DX4 "vaporizer" isn't entirely vaporware

The latest episode of CSI: Miami featured a plot that revolved around a weapon they called the DX4 or the "vaporizer." In the opening scene, three gun smugglers are blown into tiny pieces my a mystery weapon later revealed to be an electronically fired multi-barrel gun. Though lots of folks may have thought it a flight of Hollywood writer fancy, there is a grain of truth to be found.

The technology behind the DX4 is, in fact, been in development by an Australian company called Metal Storm for some time now. The animated technology demo given on the show to illustrate how the gun worked was wrong. They had a single shot per barrel, making the DX4 the biggest single-shot blunderbuss I've ever seen. The real Metal Storm system uses stacks of ammunition in each barrel.

But after getting the technology wrong, which is de rigueur for Hollywood, you have to look at more basic plausibility issues. And if you do, you won't like what you see. For one, it's unclear why the perpetrators of the three opening scene murders resorted to such ridiculous over-kill when a double-tap would have been just as effective (and given the victims' line of work would have raised far fewer eyebrows). Then there's the problem with assassins moving swiftly and silently through the shadows lugging a giant sedan-chair sized weapon around - never mind aiming it properly at 3 armed stooges who presumably are trying not to be shot. Lastly, if you were to set off all the barrels in such a gun at once, with the purpose being to vaporize a human target, the recoil would be, well, memorable. Do we even need to mention the ever present exploding gas tank myth?

But despite all that, the episode was rescued at the last minute by Horatio Caine shooting the perp in the forehead in mid sentence. In that one instant, I was transported back to "The Good, The Bad and The Ugly," and Tuco's memorable advice to all would-be villains who find themselves with the upper hand on their nemesis: "When you have to shoot, shoot. Don't talk."

The Price is Right - mastering the wheel

Scarlet and I want to see if we can't go see The Prices Is Right (TPIR) at some point. The overwhelming factor as to whether you get to actually play a game or not - the opinion of the audience interviewers - is largely out of your control. The fight to escape Contestant's Row depends - like poker - largely on position. The individual pricing games vary pretty wildly, but there is one aspect of the experience that potentially could be mastered - the Showcase Showdown wheel.

The wheel is, more or less, just like a Wheel of Fortune turned on its end. There are 20 sectors on the wheel numbered in multiples of 5 cents up to a dollar. Your goal is, in one spin or two, to get closest to a dollar without going over. Get a dollar exactly and you win $1000.

While this may seem random, the important difference between this wheel of fortune and the ones in Nevada is that you get to spin it, rather than a croupier. That means that the velocity of the wheel is under your direct control. And the velocity of the wheel and its decay function are the only things that control where it is going to land.

First question's first: Where do you want it to land? Obviously you'd like to land it on the dollar on your first spin and be done with it, but the reality of the situation is that perfect control is going to be almost impossible. If you actually graph the wheel's positions, you'll see that they were not chaotically arranged.



You can see that they alternate high and low numbers to some extent, but there's an even more important pattern. It emerges somewhat better if you graph the average of each spot's value with its two neighbors:





That's pretty evil. Assuming you don't win the dollar on your first spin, you want to either spin a very high number or a very low number. The "death zone" is in the 40-60 or so range. On the low end, you're forced to spin again where you have almost an even money chance of going over, and on the high end you're forced to stand with an excellent chance that your following opponents will beat you. But you can see from both curves that the sweet spots are separated into two pieces near the beginning and end of the wheel. The "back" of the wheel is particularly dangerous territory for the first spin, as it has a high average, which is dangerous for a potential second spin.

So the ideal strategy is to aim for the front half of the wheel for your first spin, as you'll have a shot at the dollar spot, but more importantly you'll be more likely to land on something big or small. Then if you hit low on the first spin, aim for the back half of the wheel where there are only a couple of potentially dangerous numbers and lots of medium sized numbers that will boost your total to a safe range.

Well, that begs the question - If you know exactly how many sectors you must move the wheel from its current spot, how hard do you spin it so that it lands where you want? For that, we need to work out the decay function of the wheel and do a little math and figuring. The first half of that assignment will require a bit of time with a few TiVo'd episodes and some audio capture software. I'll get back to you...