Choose a Race Weather Station

How Should You Choose a Race Weather Station?

General Race Weather Station Questions

Software and Prediction Questions

General Race Weather Station Questions

How Should I Choose a Race Weather Station?

Choose a weather station that is specifically designed for racing. An off the shelf instrument, no matter how accurate may not perform well in the racing environment. Gauges you buy from a department store are probably designed for indoor use, and will only be accurate during a narrow temperature and humidity range.

What kind of warranty is offered? Many companies are satisfied to offer 90 days as a warranty. After all, racing is a hard environment. Altalab offers a 3 year warranty. We have many weather stations that are still performing excellently after 12-15 years. You might want to choose a race weather station with a robust warranty.

Choose a race weather station that offers some immunity from IR Heat through its design. For example, in Altalab weather stations we put our temperature and humidity sensors inside the case, not sticking out in plain air. We shield our sensors from direct sunlight. We chose a light colored case, which is slower to gain solar radiation than a dark case. Altalab pioneered fan-aspiration in racing weather stations in 1995, and continue to make fan-aspiration standard, so the movement of air will both prevent the sensors and case from heating up in the sun, and promote responsiveness to ambient air changes.

Who are you are buying from? Can you get information if you need it? Is the sales staff knowledgeable? Do they take time to answer your questions, or are they too busy to listen? If they don’t talk to you now, don’t expect them to work with you if you have questions later. Can you reach out from a race on the weekend and get tech help? Altalab offers a dedicated after hours tech email so you can get help when you need it.

What kind of tech support is offered? What kind of manuals come with the weather station or software? Are they written for the average reader, or do you need to be a rocket scientist to make sense of the material? Or worse, is the manual useless instead of being chock full of tips and techniques you can use? Altalab writes manuals with easy step by-step instructions, comprehensive information for advanced users, and maintains individual troubleshooting guides for help on our website.

How Did Early Drag Racers Measure the Air?

Bob Hoffa, Altalab Instrument’s President, interviewed “Big Daddy” Don Garlits.

While researching the origins of air and racing, Don Garlits told me what he did back in ’59 or ’60 with his early nitro efforts. He had a pack of birthday candles and a fishbowl for a weather station . Say what? It’s true, he’d light a candle and placed a fair sized fishbowl over it. As we all remember from science class or Mr. Wizard, the candle burned out after a period of time because it consumed all the available oxygen. If the candle could produce a flame of the same rate of fuel consumption every time, the quantity of oxygen could be determined by measuring the amount of time elapsed until the flame was snuffed. Very elegant technique. Mr Garlits is an innovator and genius and this story set the tone for gathering other interesting techniques. What he did is the same every racer has tried to determine in one way or another. You have the fuel and the machine, how much oxygen is available to oxidize that fuel and produce power?

Do I need fan aspiration?

The benefits of fan-aspiration cannot be overstated, therefore you should choose a race weather station with fan-aspiration. We pioneered fan-aspiration for motorsports weather stations because the benefits are so important. The fan pulls air across the sensors so they can measure the ambient air, and the fan also prevents the case and sensors from overheating in direct sunlight. All our weather stations have fan-aspiration as standard.

How does your race weather station compare to others?

Isn’t this the sixty four thousand dollar question! If you are hoping we will trash our competition, ‘fraid not. Read our answers to questions in this FAQ and talk to racers. That will give you a sense of who we are and how we build our products. You can also compare our warranty and service to decide who you want on your team.

What information does your weather station provide?

Temperature, Relative Humidity, and Absolute Barometric Pressure are measured by sensors. Adjusted Altitude, Density Altitude, Absolute Humidity,  Vapor Pressure, Air Density Ratio, Dew Point, Pressure Altitude, and Grains of H20/Lb dry air are calculated from the sensors. Altalab displays both measured and calculated readings in a variety of ways to make your racing easier.

Altalab’s Merlin Software displays:

  • Trend Weather on Screen updating and accumulating every 5 minutes
  • Live Weather on Screen updating every 20 seconds

Merlin Texts and Pages weather every 5 minutes

Merlin allows you to download logged weather data that is recorded every minute. You can also save trend weather for keeping a 5 minute record or your race weather.

Why doesn’t Altalab Instrument use an O2 sensor?

Altalab Instrument tested the use of the O2 sensor when we released the 02 ALTA in the Fall of 1994, but gave it up after 1 year because it had more problems than could be justified by the value of information gained. The four main reasons for our decision are listed here.

1) Current technology 02 sensors function like a battery, and slowly drain down over their lifespan. They need annual calibration in order to remain accurate, particularly if the racer wants to build upon previous performance. Also, they have non-linear output, so to compensate we calibrated each sensor individually and generated from 6 to 10 calibration points per sensor. Most racers do not want to be bothered with an annual calibration, and their ability to relate current information to past references thus degrades over time.

2) The current technology O2 sensor contains an electrolye, and poor temperature compensation. When overheated the readings could go haywire and could take HOURS to settle.

3) The O2 sensor currently available has a 1% accuracy rating which sounds pretty good until you realize that this means 1% from 0-100%, not 1% of 20.94 (standard O2 %). You could have an arbitrary fluctuation from 20.54% to 21.54% and still be within spec. This is NOT useful or reliable information.

4) Perhaps the most important reason – In all the testing and weather logging with the 02 sensor over a 2 yr. period, and after studying data from more than 20 different weather stations we did not find significant correlation between 02 measurement changes and performance changes. The biggest changes in 02 measurement were caused by temperature fluctuations.

 Do you have to re-calibrate the barometer at each different track?

Altalab weather stations use an absolute barometer instead of a sea level corrected barometer. By using absolute, you do not need to re-calibrate at every new location, and you don’t need to know the elevation of the track. A sea level corrected barometer has limited range compared to an absolute barometer. The reading from a sea level corrected barometer will match the weather forecast, but you also need to know your elevation to correctly use the information.

Can I run the weather station from a 12 volt supply?

Yes. Included with your Altalab weather station are both a 110 adapter and separate 12 volt power cord.

Where do you mount the Remote Sensor?

Four to five feet above the trailer roof is high enough to prevent picking up heat off the roof. Mount the sensor housing away from generator exhaust.

Do you supply mounting hardware for the remote?

We supply a T-shaped mounting mast that fits over a 7/8″ outside diameter pole. The optional wind sensor fits easily on top of this also.

Can I get extra pagers? 4xR and AC2


What if someone else has another Altalab paging weather station at the same race? Will it mess up my transmissions?

Altalab weather stations have carrier detect to keep transmissions separate. Your pager and console are matched up to each other so you will only receive transmissions from your weather station. In the event there are many weather station in the area that share a frequency, we can switch you to a different frequency to reduce conflict.

Software and Prediction Questions

This information will help you choose a race weather station that supports you in your racing efforts.

What operating systems does Merlin run on?

Merlin 8.2 is compatible with Windows XP, Win7 and Win8, 10, and 11. (AC2 Your usb to serial adapter needs to have a driver that is also compatible with your PC’s operating system.)

How does Merlin handle alcohol cars?

Altalab’s prediction calculations can predict lean, rich, and alcohol vehicles through the use of our Performance Factor (PF). You can use the PF to tweak the predictions to match your vehicle, and even predict ET and TS from a single reference run with confidence. If you are using the program to predict more than one vehicle you can set the PF for each vehicle separately.

In addition to the PF, Altalab’s program provides information about moisture in the air which is most critical to alcohol racers.

Does Altalab have special software for Junior Dragsters?

No, not a separate program, but our Merlin software can effectively predict a Jr. Dragster. We offer several features to help the junior driver or crew chief. Run graphing, Performance Factor calculation and multi-vehicle/situation predictions enable you to handle even the most unusual vehicle characteristics. The predicted 60′ function can also help juniors standardize their 60′ times.

Can your programs predict more than one vehicle?

Merlin Software, which comes free with our weather stations, allows the racer to create up to 5 separate, simultaneous predictions of ET and/or TS. Each prediction setup can be customized separately for jetting, rich and lean conditions and alcohol.

I like to run the car lean, will Merlin still predict it?

Altalab’s prediction programs are designed to predict lean, rich and alcohol vehicles through the use of our Performance Factor (PF). If you choose to run lean, you can use the PF to tweak the predictions to match your vehicle, and even predict ET from a single reference run with confidence. Let’s look at why you are running lean.

Some racers without a weather station like to run lean because their ET doesn’t change much and is easier for them to predict. But running lean has its hazards. For example, a big improvement in the air during a race can cause the lean vehicle to slow down instead of pick up, and the driver may not know when this will happen. A slightly rich vehicle is easier and more reliable to predict . If you have a good weather station (and of course we can suggest one, LOL) you should consider fattening up to take advantage of this.

If you are running lean by accident, as can happen when you go to a new track, Merlin can help you either by suggesting a jetting change or by suggesting a PF that will match the predictions to your vehicle’s lean condition.

Do I have to use a PC?

The Merlin software allows you to text weather and predictions to your cell phone, change the time and date, customize pager display, make live drag racing predictions, graph and download logged weather data, and interface with a Racepak data logger.

The 4x and the 4xR require your PC to display weather and prediction information on screen, and to control texting of weather and prediction data. The 4xR also uses Merlin to control paging.

Both the Alta and AltaCom2 function stand alone as weather stations, and you can view weather data on the LCD. Additionally the AC2 pages weather without a PC. You do need a PC for predictions. These weather stations are discontinued although Altalab continues to service and maintain them bot in and after warranty.

Can I predict more than one car?

Yes, if you choose a weather station from Altalab Merlin supports live ET and TS transmissions for up to five vehicles/users.

Is wind speed factored into the live predictions?

No, but wind data is available on text and pager so you can make your own adjustments.

How many runs are needed for predictions?

Merlin can predict both ET or TS from a single reference run. You need to do some work with your data first to understand your vehicle and determine the Performance factor (and TSR for index racers), but after that, barring major weather and setup changes a single reference run is sufficient for TS prediction.

  • What Racers Say:

    "We won the National Open in Cedar Falls Div. 5. Your weatherstation has us dialed in the whole day." Ray Ruggiero SG NHRA Div. 5