One thousand miles (and Griffin iTrip Autopilot review)

One thousand miles. To be a prisoner inside a steel cage for 14 hours with a singular focus on piling up the miles, listening to tunes.

Driving from Tucson to Boston back in January took me just over 4 days. I averaged a very comfortable 650 miles a day.
(See my blog entry and mile/fuel stats here.)

So why a thousand miles?

Well, on my return from Boston to Tucson, I lost a rear tire to debris and a travel day due to I-81 southbound being completely closed.

With the beginning of the semester approaching, I had to make up time. Heading west from just east of Little Rock AR after breakfast I managed to make it all the way to Las Cruces NM in 14 hours for an average of nearly 72 mph including stops.

Yup. A cool thousand, including all the way across Texas:

1000 miles and 14 hours wouldn't have been realistic parameters in the crowded Northeast but in the vast emptiness that is Texas, one can just set the cruise control and listen to music. Well, there was heavy stop-and-go traffic going through Dallas but that was the only trouble spot I encountered.

Speaking of music, I used my iPhone 3G for both iPod functionality and GPS navigation on this trip. Mounting options include simply placing the phone sideways in the instrument binnacle (displaying GPS-enabled Google maps):

or using a generic vent mount (from aWalmart Supercenter) - here in iPod mode:

Compare this to what I did with my Garmin Etrex back in January here.)

To interface with the aux input-free Harman Kardon sound system in my car and to feed the battery-hungry beast that is the iPhone 3G, I used a Griffin iTrip Autopilot FM radio transmitter and charger that I purchased at the Cambridgeside Apple store for this purpose. A vital accessory on a 14 hour day.

I was pretty happy with the FM transmitter part because the iTrip Autopilot can be set in extended FM frequency range (76.0-108.0MHz) for international (i.e. non-US) use. Furthermore, my car was sold in multiple markets with the same radio/cd player. This means the radio can be rebooted in Japan FM mode (76.0-90.0 MHz) via the service menu and tuned down to an empty 76.0MHz here in the US. The sound quality is markedly better than in the regular noisy FM band here.
(For those of you who are not familiar with car radio FM transmitters, settling on an unoccupied, i.e. interference-free, frequency on FM can be a rather frustrating experience.)

BMW Business CD service menu access: turn radio off then on. Hold down the m button for ten seconds, +/- buttons to find Area, preset 1 to flip through the areas, select Japan, then +/- reboots.
Griffin iTrip Autopilot extended frequency range: hold down center key until logo shifts position.

Unfortunately, I was less happy with the charging function of the iTrip Autopilot. To my dismay, my iPhone actually discharged despite being plugged in!

I opened a ticket with Griffin Tech Support:

[ME] Unfortunately, I've discovered there is a big problem with the itrip autopilot. Sometimes it doesn't give enough power to the iPhone 3G, esp. when the maps/gps is running and the ipod functions are playing to charge the iphone 3g. Worse still, when these functions are running, the iphone 3g actually discharges! As a result, i get warnings that it's down to 20% power etc. when I started with a full charge before plugging it into the itrip autopilot.

The reply?

[Technical Support]This will happen if the iPhone is running multiple applications like you are on your trip. If you dim the iPhone screen a little, this will help. A good analogy would be... you're burning gas faster than you can fill up your tank. Does that make sense?

Follow-up:

[ME]but I thought you'd have a version with a beefier power supply for the iphone 3g. It's wierd to plug it in and end up with a discharged battery. Like if I plug in my macbook and run lots of applications, I don't expect the batttery to run down.

I gave up after the next reply:

[Technical Support]True, but its much different when you're talking about AC compared to DC. Thank you.

Well,in my opinion this is a product defect. All I have to say is watch out if you buy the iTrip Autopilot: you may end up with a discharged iPhone 3G because the power supply is too wimpy and there is no warning of this anywhere in the product packaging.

the imprecision of measuring devices

Question: you have multiple measuring devices, which do you trust?
(Answer is none.)

Here's the story. Today was a beautiful day. 70F and sunshine.

I just ran the Charles River loop between the Museum of Science and River St bridges fully instrumented.

Full image here

This is the route recorded by my Garmin Etrex Vista Cx in my back pocket. I also had my Apple iPod Nano with the Nike+ kit.

The Nano computes speed/distance by measuring foot strike time. It overestimates my distance by about 5% usually. But I don't bother to recalibrate it because it would depend on the running surface: treadmill, grass, hard mud, gravel, tarmac, concrete all affect the foot strike time differently.

Clearly, there are some issues with the GPS data points recorded. I'm pretty sure I can't run at nearly 30 mph.

Zooming in at the Museum of Science reveals some oddities:

According to the tracklog, I've been doing some impossible zipping around. Of course, we need to delete those outlier points. Google Earth then reports:

The Nike+ kit doesn't record every footfall. It saves a reading every 2 seconds and performs lots of smoothing:

Finally, there is a well-known reference guide to this course (probably obtained by someone with a measuring wheel):

Summarizing, we have:

Source	Distance (miles)
Garmin tracklog	9.66
Google Earth	8.9
iPod Nano Nike+	8.13
My best estimate	7.6
Reference table	7.0

I didn't run the exact reference course, which is a good lower bound.

Additional mileage included running from the MIT Stata Center out to Memorial Drive. (Plus I had to double back at one point since a gate was locked.)

So I can't rely solely on the reference table.

Lesson? The GPS isn't too reliable in this urban environment. As it turns out, the lower tech device (Nike+ kit @ $30 + iPod Nano) is closer to the ground truth.

The possibility of bad track points (e.g. from interference) means that on a short run you have to inspect the GPS tracklog that's recorded. Wish there was filtering software built into the Garmin.

Springtime in New England

It really felt like Spring today in Boston. In the fifties (F) with sunny blue skies.

A quick opportunity to get a short and leisurely 28 mile loop before temperatures plummet again and the rain moves in.

Unlike out west (Arizona), New England has the advantage of having a dense network of backroads. Given local knowledge, it's possible to put together a beautiful and relatively traffic-free ride in a major metropolitan area. A friend, Pete Hausner, showed me one such route from his place in Newton.

With a Garmin etrex Vista GPS receiver in my jersey pocket, I recorded the route for posterity (here mapped on Goggle Earth):

(Click here for a larger view.)

The satellite imagery really gives a nice idea of the surrounding urban density and green areas. (Notice how we skirted around Needham.)

And despite near total unfamiliarity, I can use the recorded tracklog again. With the street level mapping capabilities of the Etrex Vista, I can now re-ride the loop and not miss a turn anytime I want:

Thanks Pete!

crosscountry by car this time

I went crosscountry again last week. This time by car.
(Last summer I rode my bicycle.)

Wedged my Garmin Etrex Vista with street maps between the windshield and the dashboard. Same exact GPS as the one I had on the handlebars of my bike while crossing the continental US in summer.

Bike crossing from San Diego CA to Savannah GA took 17 days. In the car it was a tiring but comfortable 4.5 days (43 hours of driving time not including pit stop/meal times) from Tucson AZ to Boston MA for about the same number of miles (2800) and climbing (84000 ft). Basically, around 12 hours a day from motel to motel.

Stats below:

Yes, it is cold in January! Fuel economy was good though. Almost 30.5 mpg. No speeding tickets. And averaging nearly 65 mph is a pretty sensible average for a multiday drive.
(My friend Jim shadowed me in his Dodge Grand Caravan the whole way. I wonder what mileage he got.)

The Etrex switches to night mode automatically as it gets to dusk. Some of the driving ended up after dark (up to 9pm one day). Never saw it switch on the bike, on the PacTour Elite Transcontinental, the daily miles always finished before dark.

Cost of this trip is around $800 for gas and hotel. Cost of the bike trip was $3000.

Back on the bike

Tomorrow, I'm doing 200km brevet ride from Marana to the top of Mt Lemmon and back. 125 miles.

So today, I put the bike back together again. It has been lying in my living room in pieces for months. I've been so busy since the start of the semester in mid-August, I can't believe it's November before I'm actually riding again.

• First, I degreased and washed it. Charged the dead SRM PC V controller while I did all this.

• Threaded in a shiny new Shimano Dura-Ace 9-speed chain, my last one. Push the pin in. Break it off carefully. No more pins left, gotta get some spares.

• Installed new rear Michelin Pro Race2 tire (old one ruined on too-fresh tarmac in Delaware). New rear brake pads (Swissstop yellow) for the Reynolds Stratus carbon clincher rear wheel. Adjust the rear brake and pads.

• Swap the touring seatpost/saddle for the regular one (Selle Italia SLR and Bold Precision Ti seatpost). It's actually identical to the touring one except for the Moots Ti seatrack. Mount the underseat Blackburn bag with tools, 2 CO2 cartridges, Park patches and inflator.

• Put the fork back in. Adjust headset preload. Line up saddle nose, stem and fork. Put the Keywin pedals back in. Tighten cleat bolts on my shoes. Tighten waterbottle bolts.

• New stem mount system for the Garmin Vista Cx. Reset ascent, tracklog, and trip on the Garmin. It has been a while. Almost forgot how to do it.

• Connect PC V to Windows XP. Set the new date/time. Mount it on the bike. Hit Set + Mode to set the offset. So much stuff to remember. Get dressed.

It has been four hours. Finally, I'm ready for a shake-down ride. 12.6 mile loop around Rancho Vistoso. Nice sunny day and no creaks from the bike. About 533 ft of climbing.

SRM:

I see I pushed the wattage close to 400W near the end. Couldn't resist. It's good to be back on the bike.

Garmin Etrex Vista Cx

Tried my almost new but nearly obsolete Garmin Etrex Vista Cx on a flight to PHX today.

The Vista Cx is being replaced by a more sensitive model with poorer battery life by Garmin.
(See May 31st 2007 press release titled Garmin Adds High Sensitivity GPS Receiver to eTrex® Series here.)

I can confirm it cannot pick up satellites inside the aircraft (A-320) unless it's placed right next to the window, as shown above. The window shade and the rubberized case cooperate nicely. Then it happily tracks the flight. I wonder how much better the model with the newer chipset performs.

[I turned on the GPS somewhere before the plane got near Chicago and turned it off shortly before landing at Phoenix.]

Since the Vista Cx also has a barometer, it is fooled by the cabin pressure to report (incorrectly) merely a mile-high altitude. However, the location seems correct, as the map features seem to match up perfectly with what I saw outside the window.