Quick overview of 2 cheap decoders that can come quite handy in N-scale cars: the Tams FD-R basic and DH FH05A.
DCC Function decoders operate functions only, and don’t have any motor output. They can be used for example in coaches (for interior lighting) or in dummy locomotives (headlights). Some advanced models can control servo motors (e.g. for opening doors), but that’s not really useful in N-scale.
To some, installing a DCC decoder in each and single train car is exaggerated. That is a matter of taste. One thing is for sure, many coaches with a driving cabin are equipped with dual-color lamps or LEDs, that tend to all stay on in DCC (instead of changing red/white depending on the train direction). In all cases, a function decoder is a better solution.
In fact, with a bit of time for DIY, you can equip all your cars with function decoders. This allows you to control interior lighting remotely., turning it off during “daylight” on your layout. All this for about the same price (€14-€18) as a “dumb” light stick from the major brand, that would always stay on.
Here are the 2 cheapest function decoders that I know of, and that I use in my trains.
- The FD-R Basic from Tams Elektronik
Is perfect for basic coach lighting (2 function outputs), and costs less than €11!
- The FH05A from Doehler & Haass (often written “D&H” or “DH”)
Is probably better for coaches with driving cabs (4 function outputs), less than €17.
(prices are as of Jan. 2014, from online retailers in Germany or Europe)
There are many small & medium manufacturers in Germany, that make excellent model train/DCC products. Unfortunately, they are not well distributed abroad, or aren’t really marketing oriented.
Tams Elektronik has been around from some time now. They make many DCC products (decoders, command station, modules). I learned about them because they are distributed by Conrad Electronics. That means they are available in many brick and mortar stores in Germany, and also for European and International customers through all local Conrad websites.
As for Doehler & Haass, you can look them up online. They are actually the company behind Trix’s selectrix protocol (an ancestor/competitor of DCC). They still manufacture most of the decoders in Minitrix products. Suffice to say, they know what they are doing.
More importantly, both those manufacturers haven’t totally forgotten international customers:
- Tams Elektronik
Seems to deliver all products with a full printed manual in German, English, Dutch & French.
Unfortunately, their website is in German only, and the download page for manuals in English hasn’t been updated in years (as of writing this post). I had however written an email once, and received an answer quickly with a PDF of the manual that I had lost.
- Doehler & Haass
Doesn’t seem to deliver manuals with their decoders. However, full PDFs are available in German, French, English and Italian on their website (itself also unfortunately just in German).
Here is a quick comparison of the models:
|D&H FH05A||Tams FD-R basic|
|Size||13.7 x 7.8 x 1.5 mm||12.5 x 9.5 x 3.3 mm|
|Connector||FH05A-0: none (solder pads)|
FH05A-1: Flat Cable (=NEM651)
FH05A-3: Free cables
|SUSI (for ext.|
|Ready for anti-|
|Max power per|
|AUX 1/2: 150mA|
AUX 3/4: 300mA
(300mA for versions
|Total max power||500mA||300mA|
(as of 2014/01)
As you can see, there is only one version of the Tams FD-R Basic. The D&H FH05A can be bought in 3 different versions.
Those decoders are actually quite different, so I use them in 2 different situations:
- The Tams FD-R basic, has 2 outputs. It is perfect for passenger cars (1x interior lighting, and optionally 1x rear red lights at one end of the coach)
- The D&H has 4 outputs. This is good for passenger cars with driving cab (1x interior lighting, 1x yellow headlights, 1x read headlights, 1x maybe driver’s cabin light?).
There are other functions decoders that fit in N-scale, from other brands. This includes ESU (Lokpilot Fx Micro) or Zimo. Those are excellent decoder manufacturers with surely excellent products. Unfortunately, they start at €22+, which makes a big difference if you are planning on fitting them in many cars!
What needs to be said: in most cases, you will need to know how to use a soldering iron with an acceptably small point. Both decoders have clean soldering pads, large enough to not be missed. But it still requires a bit of patience at the risk of destroying the precious small device!
Strengths & limitations
Both Tams FD-R basic and DH FH05A are fully NMRA compatible (including function mapping), and offer several functions. Refer to the product manuals to know more!
Here are some important points, in my experience, for each decoder:
I like the FD-R Basic for its very low price. I have more than 10 on my layout, and they work perfectly.
One big plus for this decoder: there are solder pads for an external support capacitor. This capacitor (to be bought separately) can used to avoid flickering. This is very useful in coaches with poor contact with the track. In my case, just adding a 220uF capacitor provides totally flicker-free results.
The FD-R Basic has 2 caveats though:
- If you use Railcom, the FD-R Basic has a weird (but powerful) implementation of it
RailCom (Train ID recognition) usually is a setting in CV29. It can be on or off, whether or not the decoder will broadcast its address. The Tams FD-R basic goes one step further: RailCom feedback information can be different from the actual decoder address. In other terms, you can program the decoder to respond to functions on address 78, while having the decoder pretend “I am train number 22”. This can be useful for some power users (e.g. giving a coach with a driving cab the same address as the main locomotive).
Because of this dual system, to actually program the Tams FD-R Basic decoder, you need to turn off RailCom in CV29 first. When turning RailCom back on, it will copy the address from the “decoder section” as a default, to broadcast it. Then, optionally, you can give the decoder a separate RailCom address to report to the command station. People get confused because of that (seen in forums), so beware!
- It can be hard to program
Many people only connect LEDs to the function outputs (I do as well). Unfortunately, as already mentioned on this blog, DCC programming is an old system. To confirm a programming order has been accepted, the decoder speaks back to the command station by “consuming power”. This is why locomotives make little jumps during programming.
The FD-R Basic is notoriously known on German forums for requiring a very big load to be able to acknowledge a programming order to the command station, which is unfortunately rarely the case with LED lighting boards. However, even if the command station shows an error after sending a CV value, it doesn’t mean the decoder hasn’t been programmed: it just means the decoder wasn’t able to speak back to the command station. What this means is that you may need to program the decoder “blindly”: without being able to read the values. Sometimes, you may need to send a programming order 2 or 3 times just to be sure.
If you are aware of those 2 points, the Tams FD-R is an excellent low cost decoder, probably the cheapest out there. I particularly the option to easily connect an anti-flickering capacitor, ideal for car lighting.
For about 17€, and with 4 function outputs, you get a lot.
This decoder also has a SUSI output. That means you can latter attach a small sound module to the decoder for a low cost (unfortunately, there aren’t so many SUSI modules/sound projects available out there).
The FH05A is actually much thiner than the FD-R Basic, and it seems to be easy to program even with LEDs.
However, there is one problem. On most D&H decoders, you can connect a capacitor to the decoder using 2 of the 4 SUSI connectors.
It would seem that on this function decoder, this method does not work (see a German forum thread here). There may be a way to attach a capacitor to another part of the board, but I haven’t tested it seriously yet. In any case, that means you might have to limit the FH05A to coaches with reasonably good power contact to the track, to avoid flickering.
Update (June 2014): How to use a capacitor with a FH05-A
Starting with firmware 1.10 (from January 15th 2014), the FH05 can be used with a capacitor to reduce flickering. Here is how.
How to connect:
The capacitor can be connected to the SUSI solder pads (ZVS for +, GND for -).
How to configure:
Then you need to change the CV# 137, bit 1: “deactivate the energy saving mode” by adding 2 to the CV 137 value (bit 1 = on). Deactivating the energy saving mode seems counter-intuitive, it actually isn’t.
By default, energy saving is activated: when the decoder looses power, it directs all the remaining power (very little) to the internal processor. Until then, outputs are deactivated to save power. This way, the decoder “remembers” the functions that are on/off until getting power back.
By deactivating this power saving mode, you are telling the decoder to KEEP the outputs on during power losses (dirty tracks, crossings…).
Check that you can:
If you do not have a firmware from January 2014 or later, connecting a capacitor to a FH05 will likely remain without effect. To check if you can connect a capacitor, simply try to read CV#137. If it exists (no error while reading), then you can follow the procedure above.
This explanation should be valid for other D&H decoders.
Examples & where to shop
For the Tams-FD-R basic, you can look at 2 full examples installations I did in a car with driving cab or in a dummy EMU unit from dapol. Below are just 2 FD-R Basics ready to be installed on a LED board:
I will post tests on the FH05-A in the future, here is one to which I just soldered the wires:
I have mentioned those 2 decoders, because you can get them easily anywhere in Europe (or elsewhere).
The Tams FD-R basic for example, is available globally at Conrad.com (direct link, part no. 246917), and on all local Conrad websites in the EU.
The Doehler & Haass products are available for example at Modellbahnshop-Lippe (direct link) or DM-Toys (direct link). Those are two well known German online retailers that ship worldwide.
If you are not afraid of a bit of DIY, next time you’re thinking about buying a coach lighting kit from Minitrix of Fleischmann for €20, think that for about the same price and a few minutes of soldering, you could get the ability to switch the lighting on and off with a fancy function decoder instead.
I have found both Tams FD-R basic and DH FH05A are good and cheap options for this.
Last note: Of course, you need to attach LED boards or LED stripes to those decoders if you want light! Refer to other posts on this blog or elsewhere!
April 2015 Update:
Tams Elektronik has released the “FD-R Basic 2” decoder. Similar to the FD-R Basic, it has a 3rd (100mA) output.
I always try to be fair and square when giving grades, see the details about the evaluation criteria here !
Reminder: I am a hobbyist and these articles only represent my personal views. I am not receiving any compensation, in any form, from the brands or stores mentioned here. The product names, marketing names, and brands mentioned here are the property of their respective owners.