Airwire by CVP

Note well: CVP makes two DIFFERENT types of systems:

  1. "EasyDCC", A "traditional" DCC track powered system throttles and wireless throttles that communicate back to a base station, to a command station and booster and feed the DCC signal to the rails. This system uses standard DCC decoders in the locos.
  2. "AirWire 900", A wireless "throttle to loco" wireless system with a proprietary "DCC over the air" wireless communication from a wireless throttle to a wireless receiver in the loco.

The "traditional" CVP DCC track powered system uses the same throttles, so be sure which system you are working with, you cannot be sure just looking at the throttle.

This page is only about the wireless 900 MHz R/C system where the throttle transmits directly to the loco, independent of any other locos and throttles, i.e. the one to one relationship with no central station function, and no shared knowledge of other locos and throttles.

Overview:

While this is basically DCC commands, over the air, it is not strictly DCC, and CVP's implementation removes some DCC features, and adds some unique problems.

The NMRA definition of DCC requires power over the rails. Most people say "so what". Keep reading.

Impact of wireless/lossy communication:

True DCC protocol and architecture was intended for a "lossless" communication medium (hardwired through the track), and basically unlimited transmissions over the rails to the locos. There several orders of magnitude in the increase of errors transmitted wirelessly, especially since AirWire does not employ any modern error correction technicques like Wi-Fi, Bluetooth, and indeed even Ethernet.

Since DCC was designed so long ago, there is a certain redundancy in commands, where commands are often repeated several times to avoid loss or the decoder not decoding for some reason. This is usually good enough for AirWire to function most of the time, but it's marginal.

Impact of battery operation:

Being an older technology/modulation, the 900 MHz airwire throttle does not do what most DCC command stations do, is send commands "round robin" on a continuous basis. The concept of DCC is a central command station, whick "knows" all the throttles, and thus all the commands to all the decoders. After sending new commands, the command station typically then sends the last speed command to every loco in "round robin". So, if a loco "loses" the signal (dirty track, derailment), once that is corrected, that loco will resume at the correct speed.

The limitation of battery life forced AirWire to only transmit when a new speed is commanded. This is compensated for with the "cruise control", which tells the loco to keep going at the last speed it received. On the surface, this was a great idea, when the loco went into a tunnel, if it lost signal, it kept going. Unfortunately, if there is signal loss, you also cannot STOP the loco! I still have the image of Dennis Serrine on his million dollar layout chasing an out of control loco running into his garage.

Impact of one way communications:

There are 2 impacts: the first is that if the throttle could receive (and the loco transmit), then you could guarantee that a command was delivered to the loco. One common issue is the horn/whistle. In the DCC standard, this is not a "toggle", but there is a horn on and a horn off command. Many a time I have seen (heard) a horn sounding and really hard to turn off, the loco going out of range or some other issue.

The other impact is that NMRA "service mode" is crippled, you cannot read back CV values, you are operating in the blind. There should be a better solution, or at least any solution.

  The essentially Airwire must make some changes, that work with the lossy communications system, lack of any additional error correction over the air, and factors like battery life.

AirWire Products, CVP & other manufacturers

 

Throttles:

Airwire has made a number of throttles over the years.

The first wireless throttle was introduced in 1999

As of December 2020, there are 2 throttles: The T1300E and the T5000E

T1300E

This low cost throttle now has a rechargeable battery. It is intended for general use.

Here is a link to the manual: http://cvpusa.com/doc_center/r2_T1300_Usr_Gd_EzDCC_Jan017_web.pdf

 

The T5000E

The T5000 has a sunlight-readable monochrome LCD display:

Here is a link to the manual: http://cvpusa.com/doc_center/r7_EasyDCC_T5000E_web.pdf

Discontinued: T9000

The T9000 is a metal plate with the electronics attached and in a Radio Shack project box. The fit into the box is not great, the front plate sticks above and has gaps. This is cosmetic, but I'm comparing it to other throttles that cost the same, that have custom plastic molded.

There is a small "shipping screw" that holds the bottom of the front panel in place, and threading the antenna on the top holds the guts in place. The manual recommends removing and discarding the "shipping screw". DON'T !

link to manual: http://www.cvpusa.com/doc_center/t9k.pdf

t9000 size   Copy

Discontinued: NCE throttle for CVP AirWire

Recently, NCE modified their wireless throttle to work with the AirWire system, and it's great. Some people like the controller as small as possible, but the large screen and non-slip shape is tried and true. For all the things you can do with DCC, I recommend this throttle to get the most from your system, and it has a greater ease of use.

 

CVP also finally makes the equivalent of an accessory decoder, most often used to control switch machines. It takes 2 boxes to do this, one is basically the receiver, and the other is the accessory controller, which has no receiver. Clunky, and much more expensive than track powered DCC, but it's good to have the product finally. 

In summary, you have the choice of 3 different throttles, and 2 different motor decoders, one without sound (but can be added) and one with integrated sound.

The new drop in decoders have another twist, it seems that the DCC "output" used for the sound card is not the standard "bipolar" DCC but unipolar (ground to positive only). Apparently this limits the choice of sound cards that may be used, in particular, the very popular Phoenix line of sound decoders, only the P8 seems to be supported, not the pure DCC P5, which is lower cost. I need to double check this information, but please verify for yourself before purchasing.

NCE modified their very successful "Procab" to work with the Airwire protocol, called the "Gwire" throttle

In my opinion an excellent alternative, easier to use, backlit (with a simple mod).

 

There are some operational "gotchas" with the GWire.

First, the original AirWire system only supported 8 channels, but the newer ones support 16. The GWire throttle from NCE only supports the first 8.

Another is some programming restrictions. Here is a tip from Richard Eberwein:

Push PROG/ESC ... 4 Times
Push ENTER .......... 2 Times
Push #5 ..................1 Time

That will get you to PROG TRK Screen

That is the only way I could program the G2 with the GWIRE
The G2 Manual said that the G2 will only program in Service Mode Programming.
The only way I could program it was in Direct Programming mode.
The 3rd party motor/sound decoders I used I used Program on main mode.

 

Receivers:

Overview:

AirWire motor only:

AirWire plug and play

airwire drop in

QSI receiver

 

The original decoder / motor driver from CVP worked OK, but had some strange quirks.  The idea was a high power unit (rated 10 amps and maximum 120 watts) with a "DCC output" to "pass through" DCC commands to a DCC sound card. So a typical combination was the receiver with a Phoenix sound cars.

The first thing you learned was that if running with power input over 18 volts, you have to split the power and provide lower power to the electronics. The output transistors that drive the motor will run up to 28 volts.

There is also VERY confusing information about the power output capabilities. 10 amps max is specified, but it's in relation to the total power handling in watts. 120 watts is listed as maximum. I have seen CVP literature where a graph titled "Select Your Power Level" shows completely impossible combinations of motor current and voltage, i.e. shows 15 amps at 6 volts (90 watts, but over the 10 amp maximum of the transistors), and about 6 amps at 28 volts (within the 10 amp limit of the transistors, but 168 watts, over the power dissipation capability of the unit)

So a word to the wise: make sure your load is UNDER 10 amps AND UNDER 120 watts, and then you will probably be safe. I have heard stories that even these limits are beyond what the electronics can handle, so I would advise not pushing it to the limit.

6 volts is the minimum and 12 volts if running split power is usually optimal. Not that running higher voltage or reversing the input polarity will DESTROY (their words) the decoder and there is no warranty coverage for these situations. Be careful!

Now, with the new G2 receiver, the split power supply requirement is gone. Also the output to the DCC sound decoder is raised to a maximum of 3 amps. There are also a few feature improvements. The warnings about max current and power stand.

 QSI has also made an add on receiver to fit their successful all in one motor and sound decoder.

 

2 throttles and there is a new decoder/receiver in 2009. The older decoder had limitations in operating voltage, sometimes requiring a regulator or "split battery supply". That's a thing of the past with the new receiver/decoder.

The latest "receiver" is the "Convrtr", which has no motor control, but outputs DCC signal, like a normal track based system, up to 5 amps. Then you connect a stock DCC decoder to this and away you go. Took a while to realize that the motor and light control on the Airwire receiver was redundant at best.

 


On the comparison between the Airwire Receiver + Phoenix vs. the QSI, I would say the major points are

  • higher max current on the Airwire (helps if you want to run 2 locos from the receiver)
  • more complete sound library with the Phoenix (an edge now, but that will probably change to be equal)
  • more realistic "sounds under load" with the QSI (huge advantage in realism)
  • more controllable sounds with the QSI
  • single board, less wiring with the QSI (big advantage when room is at a premium)
  • cruise control feature with the Airwire (lots of people like this)
  • more lighting output on the Airwire (I believe it is 6 with effects, QSI only headlight and backup light)
 

Below is a diagram of Airwire receiver connections for running higher voltage batteries.

 

Can the decoder pick up power from the track?

This is not recommended or supported. But, yes it can be wired to do this. However, do not assume the batteries can be charged - lithium cells will not allow intermittent charging and doing so will damage the battery. However, 12 volt lead-acid gel cells can be used in this way. But, not only do you have to keep the track and wheels clean, but now you have to worry about electrical safety and reversing loops too. Thus, we don't recommend doing this since it negates all the advantages of battery operation.

Accessory decoders:

 

 

 

What should I buy?

I do not recommend buying the one with no display for your first throttle, it's difficult enough to program sound boards and CV's already.

A common problem with these throttles is the sudden lack of range.

For the CVP units with external antennas, the thickness of the plastic case makes it so often the center contact of the antenna does not touch the socket. Also using the antenna to clamp the guts in place is not a good design, it's easy to overstress this connection. (The NCE throttles are also sensitive to this, same connector).

I recommend that you enlarge the hole in the case to just allow the antenna body to pass through, and use the "shipping screw" to hold it together. IMPORTANT! Gently tighten the antenna, only light tightening is necessary, the center pin contact does NOT work any better being tighter. 

Follow these suggestions and you will not break anything and always have a reliable antenna connection.

QUIRKS

Recently (2012) someone had a problem running a Tsunami from a CVP  AW9D10SS decoder.

It did not work until the tsunami leads were reversed. That tells us two things: The Tsunami only "looks" at one half of the DCC signal... (probably the positive half)... AND this particular CVP decoder only OUTPUTS a "unipolar" DCC signal, i.e only from zero to plus volts (or the reverse).

So if your DCC sound decoder does not work from an Airwire decoder, try reversing the track input leads on your sound decoder.

 

Eliminating the "programmed sounds" from Phoenix installations.

Paul Burch suggests you set the programmed sounds to level 1, not zero. Setting them to zero often shuts off all sounds.

 

CV Programming on AirWire

So there are some fundamental issues here, since AirWire is not strictly DCC by the NMRA definition.

The big issue is that service mode programming cannot read back the value stored in the CV, because AirWire only transmits from the throttle to the decoder, it cannot receive anything.

So, you really never know if something was programmed or not.