Troubleshooting 4x and 4xR

Troubleshooting the legacy AC and AC2

Weather Readings and Calibration

Paging Problems

Computer and Software

Weather Readings and Calibration

Help! My weather readings are off!

The problem is usually NOT a calibration problem. First off determine which sensor or sensors are not reporting correctly. If a calculated value such as Adjusted Altitude or Grains is off, the cause will be found by looking at the Temperature, Relative Humidity or Barometric Pressure readings.

  1. weak battery in your 12 volt supply
  2. broken 110v power supply
  3. (4xR)using the wrong power supply (correct is 12v 3.3A)
  4. (4x)using the wrong power supply (correct is 12v 1A)
  5. mis-calibration

If both Temp and RH are off, or one is slightly off, or if Temp or RH is pegged (Temp at or near 125 degrees and RH at 100%) the most likely problem is in the digital sensor cable or cable connections:

  1. Bent, damaged, or missing connector
  2. using the wrong cable (one not purchased from us or a dealer)
  3. Remote Sensor fan not running. In ACLive > Options > Fan

If you have 2 cables in series with a connector panel, try using just one cable and then the other, or borrow a cable to see if that isolates where the problem is.

Over time, (years) the RH sensor will tend to read high and not read fully down to the low end of its range. It can be replaced and is not expensive.

My weatherstation doesn’t match the other guy’s.

There are many reasons your weatherstation may not match someone else’s. Different weatherstation manufacturers use different formulas to calculate values. A digital instrument may have a different full scale range than analog gauges. Some weatherstations are designed for racing while others are desktop instruments. There are micro climates in any environment, so a weatherstation near the finish line may not read the same as one located elsewhere.

You should expect accuracy in your weatherstation, and if you suspect mis-calibration get it corrected. Keep in mind that some important aspects of weatherstation performance such as repeatability, cannot be determined through comparison. The final test of any racing weatherstation is whether or not it is working for you, allowing accurate predictions and reliable tuning. The most important aspect for racers is repeatability, and minor differences between stations is acceptable.

When comparing your instrument to someone else’s be sure to let the weather stations settle in the same location for 10 minutes or so before checking the readings. If a friend’s weatherstation has been in the in the sun for 5 minutes, and you try to compare it to a weatherstation that’s been in the shade there will be a difference caused by those different conditions.

Be specific about what readings are different. Let’s look first at the measured readings.

A difference in barometer reading could be caused by:

  1. One is absolute and one is sea level.
  2. Some companies scale their digital barometers light by 25% over full scale range. We don’t. You would see more of a difference at higher altitudes.
  3. Some digital barometers may not have adequate temperature compensation, so if you are comparing them at high or low temperatures the uncompensated barometer will read higher.
  4. Note that an analog barometer may have drifted due to vibration or being bumped, but it will still show the same amount of change even it an incorrect setting.

A difference in temperature could be caused by:

  1. The gauges have not settled together long enough. The larger and heavier the instrument, the longer it will take to settle.
  2. Comparing at too extreme a temperature (less than 30 degrees or more than 90). A desktop model will not be accurate at the highs and lows.
  3. Some digital temperature sensors are less linear than other types.

A difference in relative humidity could be caused by:

  1. One point versus multi-point calibration. Altalab provides multi-point calibration to keep the RH sensor accurate full scale, some other instruments are calibrated at only one point. Think of this as trying to keep a long heavy board level. It’s much more reliable to use multiple supports than one.
  2. Difference in sensor accuracy.
  3. Sensor age differences (older sensors will tend to read higher)

If the measured readings are different then it is likely the calculated values will also be different, after all, the measured values are the starting point. The biggest difference us usually between weatherstations that provide Adjusted Altitude and those which provide Density Altitude.

How do I calibrate my weatherstation?

Call us. Mis-calibration is not usually the cause of bad readings, and trying calibration to fix a hardware problem will make things worse. But if you must, you can use ACLive in the Merlin program to adjust calibration.

How can I check barometer calibration?

You can call a local airport and ask for Station Pressure which is the same as absolute. There may be a slight elevation difference between the track and the airport (roughly 1″ Hg per 1000′ of elevation).

Will it hurt the remote to get rained on?

No, but it is not ideal. The worst that can happen is the RH sensor will become saturated and take time to dry out. Turn off the weatherstation if it rains, to prevent the fan from pulling moisture inside. You can turn off the fan (ACLive > Options > Fan) but remember to turn it back on when the weather event is over. If the RH sensor does get saturated, put the remote inside a dry warm place and let the weatherstation run until the sensor reads normally.

Should I build a roof or sunshade for the remote?

Not necessary, the remote comes with an aluminum shield. You would not want to add anything that would trap air, such as a four-sided enclosure.


Help, I am only getting pages close to the trailer, or transmissions are garbled.

Paging draws the most power of any weatherstation function. Check these potential causes:

  1. weak battery in your 12 volt supply
  2. broken 110v power supply
  3. (4xR)using the wrong power supply (correct is 12v 3.3A)
  4. (4x)using the wrong power supply (correct is 12v 1A)
  5. transmitter (in console) is weak and needs repair or replacement
  6. pager needs repair
  7. antenna is damaged or broken
  8. antenna not connected (will damage the transmitter)

If you have trouble only at the track, but not at home testing, and if you receive pages but they are garbled, we can change the frequency on your system to reduce interference.

Help, I am not getting any pages.

In the 4xR paging is controlled by Merlin, (or other vendor’s software). This is unlike the legacy AC2 which automatically pages without software. Read the Merlin manual to make sure you are setting up paging correctly. If your paging worked in the past, any of the causes of weak paging above could be the culprit. In addition:

  1. Transmitter needs repair or replacement
  2. Carrier Detect is continuously ON (red light on console) because of local interference
  3. Carrier Detect is continuously ON (red light on console)because internal radio cable has become detached from the board

If your station is brand new and has never paged we could also look at these possibilities:

  1. pager and console mis-matched (can be fixed over the phone)
  2. internal radio cable disconnected from the board
  3. paging not set up correctly via Merlin
  4. faulty USB

Computer and Software

Help! I can’t connect to Merlin

  • Do you have a compatible Operating System for Merlin? Merlin 8 and later is compatible with Windows XP, 7, 8 and 10. We do not support Windows Vista.
  • Do you have the current version of Merlin? Registered Users can Download Merlin here
  • Does your USB cable (connecting the weatherstation to your PC) show up in Device Manager under Ports as a COM Port (1-20)?
    1. If it shows up as Other Devices, right-click it and choose Update Driver, then Search Automatically.
    2. If it shows up in Ports with a number greater than 20, choose Properties, then Port Settings, then Advanced to find an available COM port 1-20.
    3. If it shows up as Ports (1-20) but you still cannot connect, right-click it and choose Update Driver, the Search Automatically. If this is not successful, you can download an FTDI driver here.
  • What Racers Say:

    "Your weatherstation works wonderful. We've won because of you! Thanks for all your help." Norm Sams