Duplex or not to Duplex (Digitrax)

[mfm37]

alco_fan

The only reason not to have duplex was that Digitrax was years behind the other manufacturers in developing it. It is dumb to me to keep using simplex now

Actually, Digitrax had simplex long before anyone had duplex radio because their system doesn't need duplex radio. Others used polled systems so the command station must query each device. Two way communication required.Tthat also tends to swamp the bandwidth. Ever see two NCE radio layouts running in the same room? That's why we banned NCE radio from the building at the 2008 N Scale convention. Little did we know that Digitrax was going to let us play with a bunch of their not yet released duplex throttles.

i remember back when NCE first introduced their radio system. Reception was not reliable. There were numerous discussions on the NCE Yahoo group about tin foil arrangements to improve reception. They did get the bugs out.. Discussion can be found in the archives.

Digitrax throttles send the info to the command station. Command station puts it on the track. One way is all that's needed to run trains and functions and accessories. Plus each device doesn't require a unique I.D. like other duplex systems. Command stations never needed a firmware up grade to implement duplex. In fact there has only been one firmware change to the Chief command station. That was to increase functions above F5. The change allows more functions to be added without upgrading.

Quite frankly, I like simplex. I have a Duplex throttle to use at train shows. Why?  Because we are always near an NCE radio layout and their radio system jams the band. Digitrax duplex solved the interference problem because it's on a different frequency.. Wi throttles work well too. I use simplex at home because there is no outside interference.

Martin Myers

[cmrproducts]

alco_fan

The only reason not to have duplex was that Digitrax was years behind the other manufacturers in developing it. It is dumb to me to keep using simplex now

That was one of the main reasons I went with Digitrax as they had RADIO and my current layout was being designed as a Walk Around Operations Layout back in 1999.

I did not like the Wired Throttles as that was what we had with the DC Momentum Throttles and the old Keller Onboard Analogue Command Control.

No one else had a really good Radio system.

I have both the Simplex and Duplex on my layout and had the Duplex working great before the Upgrades started - I was one of the few that made it work when other were having problems.

We finally fixed the Duplex Radios and my layout works great with both systems as I usually have 15 to 20  Radios on any given OPs night!

BOB H - Clarion, PA

[jrbernier]

alco_fan

The only reason not to have duplex was that Digitrax was years behind the other manufacturers in developing it. It is dumb to me to keep using simplex now

  Research your facts!  Digitrax had the simplex radio system out well before most DCC manufacturers even had a wireless radio system to sell.  I remember a 'wireless' phone  throttle system that was available for Lenz about the same time.  When the NCE system came out, it was full of radio signal loss issues(that NCE addressed quite well).  That is one of the reasons the RB02 base unit replaced the RB01

  I have both simplex and duplex on my layout.  One of the advantages of the simplex throttles is that I plug them into a UP5 port when I am done so I can 'dispatch' a loco assignment.  I know where I left the throttle. With the duplex throttles, I can 'dispatch' the duplex throttles without plugging in, and they sometimes get left 'somewhere'(like your TV Remote')

I have both a DT400R & a DT402D 'Super Throttle', and a pair of DT200R throttles that refuse to 'die'.   I will replace them with utility throttles if they ever die(Digitrax cannot get parts for them any more).  If the 900mhz radio stuff becomes unavailable in the future, I can always 'factory upgrade' it from Digitrax.  Right now, have both throttles is good when 'visiting' another layout.

Jim

[alco_fan]

The only reason not to have duplex was that Digitrax was years behind the other manufacturers in developing it. It is dumb to me to keep using simplex now

[fmilhaupt]

If I were getting into radio right now, I'd go duplex.

Electronic components aren't manufactured forever, and at some point Digitrax won't be able to get parts for the simplex radio system any more.

The duplex radio system is based on 2.4GHz radio components, which are in much wider use commercially than the 916MHz parts used in the simplex system. If I had to bet, I'd bet on the 2.4GHz duplex components being available longer and in greater quantity to manufacturers than the 916MHz simplex parts.

On the Operations Road Show layout, we mostly use simplex radios, since we got into it when Digitrax first released it in the late 1990s. We started with DT100Rs and eventually replaced them with the simpler UT4Rs. We've added duplex to the layout and are now running a DT402D and some UT4Ds alongside the simplex UT4Rs.

[fmilhaupt]

Paul3

BTW, if you have a bad DT300, it's probably due to "capacitor plague".  It happened to a DT300 of mine, and one at our club.  There was a huge bad batch of caps made a while back, and they got into everything.  The DT300's were made during that time period, and it's a common problem as they age.  Send it into Digitrax and they'll fix it for a small fee.

Paul A. Cutler III

Quite a few DT300s were affected by this. The worst part is that it didn't show up immediately.

Two of my DT300Rs started showing symptoms after about two years of use, while my third didn't until I'd been using it for six years. I sent them in and Digitrax took care of them quickly for me.

I had to deal with this at work, too- the company I work for bought several thousand PCs that had motherboards built with the same bad capacitors. They started getting flaky before our usual three-year lease was up.

[Paul3]

Don,
I have a 25' x 50' layout myself with Digitrax simplex DCC (three DT400R's, one UR91).  My club (half a 6300 sq. ft. room so far) has Digitrax as well with both simplex and duplex radio receivers.

IMHO, if you can live with plugging in to acquire locos & make MU's, then I would not upgrade.  I don't think it's worth the money.  I mean it's handy and all, but is it worth the extra cash?  Not to me.  The other issue with the duplex throttles is that they are harder on batteries.  My simplex radios will still work reliably down to 7vdc.  The duplex radios stop working below 8vdc.  It's got to the point where the guys at the club are buying rechargable "super 9 volts" that charge up to 10vdc or better so they'll last longer.

BTW, if you have a bad DT300, it's probably due to "capacitor plague".  It happened to a DT300 of mine, and one at our club.  There was a huge bad batch of caps made a while back, and they got into everything.  The DT300's were made during that time period, and it's a common problem as they age.  Send it into Digitrax and they'll fix it for a small fee.

Paul A. Cutler III

[jrbernier]

  Both simplex and duplex throttles can work on the same Digitrax DCC layout.  Our club has both a UR91(simplex) receiver and a UR92(duplex) receiver on the LocoNet.  Both types of throttles can be used on the layout

  I am having problems understanding why you have three UR91 receivers.  My layout area is 25' by 20' and I have NO problems with the single UR91 that is fascia mounted on the layout.  Our club has a double deck layout that fills a 27' by 27' room, and has a single UR91 and a UR92..  The biggest problem is 'batteries' - Typically a fresh battery may last 3-4 hours.  The 'rechargeable' ones from R/S, Walmart, etc only put out 8.4v, and you will loose radio contact at the 8 v mark(within 2 hours).  I use POWER-EX rechargeable batteries that put out 9.6v - They need a special charger.  We are using the 230ma batteries as they 'fit' in the Digitrax throttles better.  The 300ma batteries are a tight fit, you just have to be careful extracting them!  You can buy the batteries at Batteries Plus, but I do not think they have the chargers.  Do not try to use these batteries in a typical 'wall wart' charger - they need a 'trickle' charger.

Jim

  We have a 10 position charger at the club and 10 of the 230ma batteries.  Since going to these batteries, we have rarely 'lost' control of a train.

[TwinZephyr]

To get full duplex functionality you will need duplex throttles and at least one UR92 duplex receiver.  Being able to select and program locomotives without plugging in the throttle is a very nice feature.

[simon1966]

The two, Simplex (R Throttles) and Duplex (D throttles with a UR92) will coexist quite happily.  We use both at the same time on the huge K-10 layout.  You could upgrade the UT4R to a D throttle, but the DT300's can not be upgraded. 

[conrail079]

I am building a larger basement layout with 3 power districts and need to get a few more throttles... So the question is, should I stick with the radio throttles or switch to the duplex? Throttles I have now are UT4R (newer), DT300 and a DT300R that doesn't seem to work, That's why I'm looking to get more throttles. Plan for the layout is to use most of my basement 24x28' and I currently have 3 of the UR91 radio receivers. Thanks for your input....

Don

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