dBcom and AMB, side-by-side

In a nut shell, dBcom is the Volkswagon and AMB is the Cadillac in this comparison.

Price and features always go hand in hand and on the surface, AMB is the clear winner. But not so fast, my friend. dBcom offers up portability that AMB with their embedded timing loops just can't match. I should also mention that over the past few years AMB has been working their way through a change in identity brought about by a change in ownership. Although they are commonly known as AMB, they currently market themselves as MyLaps. I think I'll stick to referring to them as AMB for the time being.

Hardware Overview

dBcom and AMB both use electronic 'black boxes' to decode or decipher radio frequency (RF) signals received from vehicles passing by a particular point on the race track. I've never asked either organization exactly what's in the decoders but it would make sense that at the core is a digital signal processor (DSP) that examines the signal strength of the RF coming from the vehicle as it passes by the timing point and assigns a time stamp value to the identifying information received when the signal is strongest.

dBcom Hardware

dBcom transmitter

dBcom uses a small transmitter about the size of a cigarette package mounted on the vehicle that sends out a RF signal with a unique identifying number. This RF signal is received by an antenna located track-side. This received signal is then sent on to the decoder for processing. If the distance from the antenna to the decoder is 30' (feet) or less, the connection is made with a 30' length of RG-6 coaxial cable. If the distance is greater than 30' then dBcom can provide an amplifier to boost the signal strength from the antenna to the decoder and (very important) a 300' length of RG-6 coax must be used between the amplifier and the decoder. More on this later.

The transmitter is a single circuit board mounted inside a plastic case with room to connect a 9 volt battery. The transmitter operates with a 9 volt battery or can be hard wired to a 12 volt DC power source (i.e. 12 volt car or motorcycle battery). I've seen the result of one falling off a motorcycle and it wasn't pretty although I don't know if it was run over by another motorcycle while it was laying on the track.

I've been using the same decoder for 10 years now and I don't think the basic technology has been upgraded since it's inception. The output from the decoder is a RS232 DB9 serial connection which is then expected to be connected to a computer (and/or an optional serial interface printer). Computers these days just don't come with RS232 inputs so a RS232 to USB adapter must be employed to make the connection. The information from the decoder makes it's way to the computer where a software package processes the information for determining timing and scoring results. The manufacturer states accuracy to within 3/10 of a second and the receiver can handle up to 10 'simultaneous' crossings. Personal experience shows if a transmitter is missed on a pass due to a large number of vehicles passing in a short period of time (for example, a standing race start), the next time the field comes by, they will be spread far enough apart that the receiver can process all the passes as necessary. It is a simple matter for the scoring person to manually insert a passing that was missed into the software record.

The dBcom decoder offers some flexibility in that dBcom offers 2 flavors of their system; support for up to 400 unique transmitters (called RaceTime) and support for up to 1,000,000 transmitters (called RaceTime2). Apparently there is enough room inside the decoder enclosure to install circuit boards for both RaceTime and RaceTime2 capabilities. The system I have used is RaceTime2, so things may be a little different using RaceTime.

The antenna is pretty much a flat rectangle about 2 square feet in size. I use it mounted on a tripod beside the track. If it is going to rain (or heaven forbid, snow) I always drape a plastic garbage bag over it and tape the open end of the bag to the legs of the tripod so the wind can't pick it up and blow it away.

The in-line amplifier is used for long runs from the antenna to the decoder (dBcom calls theirs a receiver). The installation I use is about 50-60 feet from the antenna so I asked dBcom for some technical input as to whether I could dispense with the amplifier and/or additional 250' of coax that laid coiled up on the floor of the Race Control building. I figured I could eliminate the extra coax and use an RF attenuator to lower the signal strength to an acceptable level. Their answer was to go ahead and try it without the amplifier and extra coax. Any sensitivity setting from the 10 o'clock position to the 3 o'clock position is acceptable. It worked for me.

AMB Hardware

AMB transmitter

Similar to dBcom, AMB uses transmitters mounted on the race vehicles, a decoder and software. The major difference lies in how the signal gets from the transmitter to the decoder. AMB uses loops of wire embedded in the track surface to detect the magnetic induction coming from the vehicles and here lies the most obvious difference between AMB and dBcom. You can pick up the dBcom antenna and take it home with you. Not so much with a loop of wire embedded in the track. On a positive note, the AMB transmitters are much, much more rugged than the dBcom transmitters; they are essentially a solid block of epoxy resin with electronic components securely embedded within the epoxy. The AMB transmitters are also waterproof; the dBcom transmitters need you to put them inside a Ziplock sandwich bag to waterproof them. There are different models available for different types of vehicles and although I've heard that some can be interchanged in order to save money, it could be an exercise in false economy.

AMB decoder

The AMB decoder supports 3 timing loops and a maximum track width of 60 feet. Typical accuracy is within 2/1000 of a second for the transmitters. AMB has embraced newer technology and uses Internet Protocol (IP) to communicate with the scoring computer. You also have USB and good ol' RS232 connections available if you want. They also use GPS technology to determine the physical location of a decoder because... wait for it ... AMB supports multiple timing points. That translates to more timing loops embedded in the track surface but it also means you can record entry and exit on and off of Pit Lane, Start/Finish (of course), create speed traps and record sector times. The track can be divided into sectors to allow the racers to more accurately determine where they may be faster (or slower) than their competitors. All these extra timing points do not come cheap, however. The wire for the timing loops themselves is cheap. It's the cost of the additional decoders, power sources, network infrastructure and additional software modules that can really add up.