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Fleetwatch FMS · On-Vehicle Hardware
Where Should I Mount the TX55 or TX200 on a Bus?
Mount the TX (TX55 or TX200) behind a non-metal panel or window near the driver’s area, with its flat side facing the side of the bus. Check for hidden metal with a magnet first, keep it away from fluorescent lights, and auto tune the TX (if necessary) with an MR55 when everything else checks out.
Why Location Matters
The TX is the radio (transmitter) part of the vehicle module. It sends vehicle data to the fuel lane reader by low-power 2.4 GHz radio. Metal blocks and absorbs that signal, so the TX needs a clear, non-metal path out the side of the bus. The guidelines here apply to both the TX55 and the TX200.
| TX55 Radio Specs | |
| Main radio | ZigBee-based, IEEE 802.15.4, 2.4 GHz, DSSS spread spectrum |
| Channels | Can use any standard ZigBee channel (2405–2480 MHz, 5 MHz each). It runs on channel 11 (2405 MHz) unless a Fleetwatch receiver tells it otherwise. |
| Transmit power | About 1.25 mW (+1 dBm) typical. Some module families can reach up to 8 mW. |
| Receive sensitivity | −96 dBm |
| Activity | Short bursts every 10–60 seconds, depending on how it’s set up |
| Second radio | 125 kHz, receive only (like a toll tag), so it doesn’t transmit or interfere on that band |
Typical Mounting Locations
Pick one of these, on the driver’s side and typically about 9 ft off the ground:
- A non-metal panel in the equipment cabinet behind the driver’s area. Run the cable to the JX in the same cabinet, or another mounting location.
- The driver’s window, or a non-metal panel in the upper left of the driver’s area. Run the cable to the JX in the equipment cabinet, under the dash, or another mounting location.
Before You Install: Check the Spot
| 1 | Check for hidden metal with a magnet. Many bus walls look like fiberglass but have metal framing or panels underneath. Hold a heavy-duty magnet against the wall where you plan to mount the TX.
Magnet sticks: there’s metal behind it. Metal absorbs RF and weakens the signal. Try another spot.
Magnet doesn’t stick: good spot. Go to the next step.
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| 2 | Stay away from fluorescent lights. Fluorescent light fixtures can interfere with the TX. Don’t mount it next to or behind one. |
Careful with the magnet. Keep it away from the TX and from other electronics on the bus. A strong magnet can interfere with electronic parts and cause malfunctions.
How to Mount the TX
| 3 | Clean the surface. Wipe the spot with the 54190 alcohol wipes and let it dry. |
| 4 | Remove the Dual Lock backing. Always peel the backing off the 3M Dual Lock pads before you apply the adhesive. |
| 5 | Apply the adhesive. Put a bead of Sikaflex-252 on the Dual Lock pads only. Don’t put Sikaflex on the TX box itself. |
| 6 | Mount it facing the side of the bus. Press the TX onto the non-metal panel or window with its largest (flat) side parallel to the side of the vehicle. Then run the cable to the JX. |
| 7 | Auto tune the TX. When the TX is mounted, cabled, and everything else checks out, auto tune it with an MR55 as the last step. See below. |
How to Auto Tune a TX55 or TX200 with the MR55
The TX55 and TX200 tune the same way. Auto tune finds the tuning value that gives the TX its strongest signal.
| 7a | Turn on the MR55 and read the TX first. From the main menu, press 1 (READ) to read the TX. Reading it before tuning is recommended.
**MAIN MENU**
1.READ 2.VIEW RECORDS 3.MORE |
| 7b | Open the technician menu. Press ID, NO, YES. The asterisks around the title mean the MR55 is in tech mode.
**MORE OPTIONS**
1.AUTO TUNE 2.SET BUS # 3.INITIAL VALUES 4.VL55 SETTINGS |
| 7c | Press 1 (AUTO TUNE). Tuning takes about 3–5 seconds.
Hold still. Keep the MR55 still in relation to the TX until tuning finishes. If you move, the TX will be tuned wrong.
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| 7d | Read the result. When it’s done, the MR55 shows a signal strength message. If no message appears, try again.
AUTO TUNING …
AX@2BR01D8 Example result
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How to read the result (format AX@aaRssss). Both numbers are in hexadecimal, so they can include the letters A–F.
| Part | Meaning |
| AX | Auto tuning the X channel. (The TX also has Y and Z channels, but only X is used.) |
| @aa | The tuning value: the setting that gave the strongest signal. Example: 2B (43 in decimal). |
| Rssss | The signal strength received. Bigger is better. Example: 01D8. Expect a value well above 0100, but it depends a lot on how far the MR55 is from the TX. |
| 04 – 3A | Best. Tuning succeeded. |
| 01–03 or 3B–3E | Tuning succeeded, but the value is near the edge of the range. |
| 00 or 3F | Failed. (00 or 63 in decimal.) Something is wrong. Try the auto tune once more. If it fails again, check the mounting location and cable, then contact Fleetwatch Support. |
Weak or Missed Reads?
If a bus reads poorly at the fuel lane, check the same things on an installed TX:
- Is there metal behind or near the TX? Do the magnet test around it, keeping the magnet off the TX itself.
- Is it close to a fluorescent light fixture?
- Is the flat side still parallel to the side of the bus, and is the TX still firmly attached?
- Is the cable to the JX secure? If all of that checks out, auto tune the TX with the MR55.
Need help choosing a location or auto tuning a TX? Contact Fleetwatch Support.