# Gwire receiver to generic decoder



## alfischer (Mar 8, 2010)

Looking at the info on QSI site they show connecting the Gwire rcvr to a generic decoder. It appears to handle only functions - no motor. Other than hacking into the uP directly is there any way to run a full function-(off the shelf)-decoder and have motor control? 

I would like a cheap way to do R/C without sound for a couple of engines. Sound is nice but not worth the price in some locos.

Or would it be practical to run the Gwire into a booster and use track powered DCC?


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## lownote (Jan 3, 2008)

I asked about this a while ago and could not get an answer I could understand--my limitations. Since then I've switched to straight DCC on the rails. 

It seems to me that since the G-Wire receiver receives and relays DCC commands, it ought to be possible to run any DCC decoder using the G wire. It also ought to be theoretically possible to send the signal from the Q-Wire reciever to a booster and run dcc on the rails. Someone is doing that--a member here was kind enough to send me some pictures, but I could not make sense of them


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## alfischer (Mar 8, 2010)

Can you send me the pictures so I can try to understand it? The problem I see is the Linx chip output is VERY limited in current handling ability. (.230ma) I figure a driver and opto isolator to the boosted should work. If it has allready been done, I don't want to have to reinvent the wheel! Most decoders I am seeing are just to tiny to hack! 

My email is al at alfischer dot net


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## blueregal (Jan 3, 2008)

You might get ahold of Bob Roberts on the Airwire Group looks like he may have done what you want to do already!! Here is the link to his picture page take a look. 

AirWire: Photos: Bob Roberts' Pix: Thumbnails


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## Bill Swindell (Jan 2, 2008)

Why not just buy an AirWire receiver. If you don't want sound, it's not a very expensive solution.


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## alfischer (Mar 8, 2010)

Bill, isn't the Airwire and Gwire the same receiver?


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## Road Foreman (Jan 2, 2008)

Al, 

The QSI people say that the connection for the ground wire has no connection to the black & red wires.. If that is true then the cathode side of the other bridge diodes ( where the cathodes are tied together ) should have no connection to the black & red wires either.. If that is true then you can hook the plus side of the battery there.. That will give you full voltage & current to the decoder, that will run all the functions & motor outputs.. Do not forget the 5 volt regulator for the GWire receiver.. Hope this helps.. 

BulletBob


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## blueregal (Jan 3, 2008)

I know you are never supposed to assume, but I believe he doesn't want to go with the OEM Airwire at $150+ when the g-wire is only $97+ big difference in price unless you are different from the gen public which is looking for a less expensive way to go on everything. You know "more bang for yer buck" philosophy!! Regal


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## alfischer (Mar 8, 2010)

BLUEREGAL: 

YOU GOT IT! What I am looking at is the cheapest R/C DCC for a small, cheap engine. Like a Critter, Eggliner or an older Bachman. Also R/C added to go into a booster to be able to run any DCC equipped loco or stationary decoder for the cheapest solution. Like ONE handpiece that can run the whole shootin match. My GOOD engines will have battery and sound with QSI Magnums. I went with the QSI because they appear to be trying to be COMPATIBLE with others, admit it is DCC and provide very good support. Compatibility is important to me and this industry needs to become more so. I will not spend one red cent on any proprietary product.


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## Cougar Rock Rail (Jan 2, 2008)

Another option if you're willing to wait is to use the new Massoth DRC-300 receiver, along with the wireless navigator. The Navigator acts as the central station, DRC-300 receives and can interface with anybodys decoder, and you can use either battery or track power. That way you can run multiple engines from the Navigator without a booster etc. It will also be great for running live steam with the DRC-300/function decoder (like the 8FL) running servos. The nice thing about the massoth decoders for servos is they can run them proportionally with the throttle setting, not just end to end. 
Zimo also makes a self-contained handheld that acts as a central station but I don't believe it is wireless. 

Keith


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## alfischer (Mar 8, 2010)

Not really an option for me. I just dropped almost $1k into this project and doubt that my CFO would buy into that! 

I picked the QSI because it appears to be as 'standard' as most others and their support quite good. Of course like everything in DCC ther is a real steep learning curve. Electronics is my background and interfacing things will not be difficult, once I get DCC down. So far, got one engine going pretty well with QSI and am about to embark on the next. AFTER I get the weeds undercontrol for the year! (I'm talking about 5 acres of NASTY weeds!) My RDC is next. (right after the weeds!)


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## Bill Swindell (Jan 2, 2008)

AirWire & Gwire are not the same. AirWire is a complete receiver & motor decoder. Gwire is an RF addon to the QSI board that gives you wireless capability and sound.

An AirWire receiver & a set of batteries are all that is needed in your engine.


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## K27_463 (Jan 2, 2008)

Al: Regal's numbers are a bit off. I sell Airwire g2 all day for less than 140, not 150+ as he indicated. 
With recent price increase of the gwire reciever from QSi the 97.00 he noted is also not realistic unless you can find old stock, which could be hard as they were backordered on these for many months- up until late Feb/early march. So, for the extra 25.00 or 30.00 cost of the g2, you get a fully protected and buffered 
DCC aux output that can drive any external decoder, lighting control outputs, 2 extra dcc programmable outputs, and a waranty and fully tested design, all nicely integrated onto a single board. I understand if you want to develop things yourself, that is part of the hobby for electronics folks, but your parts cost is likely to exceed the number differential listed above. 
jonathan/EMW


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## Road Foreman (Jan 2, 2008)

Al, 

Most if not all decoders use a resistor around the bridge rectifier to feed the DCC signal to the processor.. 
Lift the end that hooks to the bridge rectifier & hook 1 of the Gwire tx lines there, also hook the Gwire ground to the negative side of the bridge rectifier.. Put power to the Gwire & hook the red & black wires to the track or a battery.. If you need more info go here to Marks site.. http://www.siliconvalleylines.com/dcc/presentations.html 

BulletBob


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## blueregal (Jan 3, 2008)

Posted By K27_463 on 06 Apr 2010 04:59 PM 
Al: Regal's numbers are a bit off. I sell Airwire g2 all day for less than 140, not 150+ as he indicated. 
With recent price increase of the gwire reciever from QSi the 97.00 he noted is also not realistic unless you can find old stock, which could be hard as they were backordered on these for many months- up until late Feb/early march. So, for the extra 25.00 or 30.00 cost of the g2, you get a fully protected and buffered 
DCC aux output that can drive any external decoder, lighting control outputs, 2 extra dcc programmable outputs, and a waranty and fully tested design, all nicely integrated onto a single board. I understand if you want to develop things yourself, that is part of the hobby for electronics folks, but your parts cost is likely to exceed the number differential listed above. 
jonathan/EMW 

Uh UM nope numbers still up to date,and not a bit off on the g-wire! Just checked em out, and I don't use the OEM Airwire either so if its off the $150 mark, so be it! Regal


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## alfischer (Mar 8, 2010)

I ordered 3 Gwire rcvrs last month and paid $97 ea. I don't think they are 'old' units because the vendor backordered 2 and shipped them abt 3 weeks later. I doubt he was losing money on the transaction. 

I didn't realize that when Bill mentioned the Airwire rcvr That he was referring to a rcvr with decoder. I was thinking just the rcvr. He showed me his working Airwire setup and I was really impressed with it. I opted for the QSI because several vendors explained the greater functions available. (they didn't mention that the aux lighting board did not and probably would not exist) Also from what I have heard Airwire support is on a par with cable TV support. That's not good. I have no first hand experience with Airwire support but one of the QSI decoders was defective and their support was wonderful. Called, they answerd on the 2nd ring and immediately transferred me to a tech and withing 5 min he stated that it was defective. Back for an RMA and they stated they would sip as soon as they receive it. I mailed (from Calif) on a Friday. It was in my mail the next Saturday. THATS EXCELLENT SERVICE!!! I am impressed. 

Both the QSI and Airwire have advantages. I will probably end up with a mix. No doubt I will also end up with some flavor of track powered DCC, not sure which manufacturer, but operated wireless. With my existing NCE transmitter. 

Airwire seems intent on using on-board battery only. That's ridiculous. Their statement about safety being compromised when using track power is stupid. Thousands of LS folks run trains with track power and while any outside (or inside) use of 110V requires common sense, I havn't heard of anyone being electrocuted from their train track. Both power methods have advantages and disadvantages. I plan to use both where appropriate. 

Take for example several small locos that I have draw much less than 1 amp. My Hartland Dutchess draws about 350 ma running with 6 cars fom on board batteries with the QSI sound up full. Don't need a 10AMP Airwire (questionable rating) that costs close to $150. A $29 HO decoder can handle 1.5 AMP and do 6 functions. Putting a $150 recvr/decoder and a $150 sound card in a $100 loco does not make fiscal sense. (I am not the Fed Government!) I realize there are folks that have what appears to be unlimited financial resources. I am happy for them. I certainly do not. A lot of my enjoyment come from doing things myself - my way. I don't enjoy plugging black boxes together. 

It appears at this point that my solution to a decoder is one of the DIY designs that can be SEEN with normal vision. And can have MosFets that csn handle any amperage desired. Every off the shelf decoder seems to be too small to work on without a binocular microscope! Yes, I can make a board and program a PIC. The programs for operating the units are available. Pretty simple devices. I have a Linx chip. $46 from Mouser and it looks like about $20 to build a decent decoder. Add a few components and for about $80 I can have R/C and DCC in a loco. Don't need or even want sound in everything. But right now I am going to attack my RDC install. Right after the weeds!


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## Greg Elmassian (Jan 3, 2008)

Last time I checked, the 10 amp rating of the AirWire was a bit deceiving, it was 10 amps at 12 volts. At 24 volts it would be 5 amps, which is about where the QSI maxes out, although that's not really a fair comparision, because the QSI is rated at 2.5 to 3.5 amps by the manufacturer. 

From all the people I have talked to, the AirWire is robust on it's output, and can handle roughly twice the current as the QSI. But the QSI was never intended to be shared among multiple locos, after all the entire idea is independent remote control of locomotives, not tying them together with cables and wires. 

Advantages and disadvantages on both sides. 

On prices, I typically choose one vendor that carries both products, to get an apples to apples comparison, although MAP pricing has messed this up some. 

RLD Hobbies has the Airwire G2 for $140 & a Phoenix P9b for $220, total is $360 
RLD Hobbies has the QSI for $170 and the Gwire for $115, total is $285 

So, I see a difference of $75.... that would probably come down a few dollars if you add the $17 screw terminal board, and if you could buy a phoenix P5. 

I did not compare the P5 (not available), the P8 (not available)... when stuff becomes actually available for purchase I would look at it. 

So, are they close? You figure it out for yourself. For one or 2 locos, it's really no difference. 

If you had to use today's numbers and availability for 10 locos, well that could be $750 difference... 

In terms of features, it's a personal choice. I like things only the QSI provides, but others may not care about these features, and there are some features of the Phoenix that the QSI does not have (although you CAN program the volumes and the repetition frequencies of the random sounds in the QSI Jonathan, so it's not as clear cut as we discussed before) 

So it depends on your situation, your tastes, and in some instances, your pocketbook. 

Regards, Greg


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## alfischer (Mar 8, 2010)

Also, interestingly enough, look at the MosFets in the QSI. Then pull the data on them. They are rated at 42 AMPS. I doubt the leads would handle that amount of current and I KNOW the board can't! This seems common with newer MosFets. However, with proper heat syncing and probably water cooling or a tornado producing fan they could handle much more than 3 AMPS. (don't plan on doing that)


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## Greg Elmassian (Jan 3, 2008)

Yeah, power rating does not mean much without heatsinks. 

Aristo uses a heat sink on the Revo, but there is foam between the FETs and the heat sink, so not sure how much heat they can shed. They have an overcurrent shutdown, and people have hit the limit with running 2 locos from them (they are not designed to run more than one loco) 

Problem with heatsink is that the unit is normally in an enclosed space, so once the air is hot, then you are stuck. Fan cooling and some vents in the loco and an "airflow path" is needed. 

Anyway, I guess I'm derailing the thread... bad Greg bad Greg....


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