# 2.4Ghz antenna mods in live steamers ?



## Pete Thornton (Jan 2, 2008)

OK, so I now have multiple Spektrum-compatible receivers to be installed in my live steam locos. Does anyone have any experience playing with the antenna on these receivers?

My first install in the FWRR/Ruby has been fine, but I was able to pull the antenna wires out of the wooden top cover and leave them dangling in the breeze. (One day I'll cover them with a coal or wood load.)

The next loco will be an Accucraft C-19 with a C-16 tender. The tender already is rigged for r/c, as it was used with my C-16 for years. Cables, power switch, and antenna are already installed - the latter is a long wire wrapped around a piece of card and covered with real coal. (It was an old 27Mhz radio) There's a pic around here somewhere from 2006 . . Ah Yes:










So the receiver I'm using has a short wire, suitable for a 2.4Ghz signal. [If I remember correctly, optimum antenna length has something to do with multiples of wavelength, so a very short radio wave would need a very short antenna. Am I on the right track?] 

Here's the rx and the antenna is that 1" stub on top.











If I enclose the rx inside that brass tender, it's unlikely to get any signal. So how about your opinions on the following:

1. I connect that antenna to the wire under the coal (pictured above) so there is now a 3' long antenna outside the brass tender box.

2. I connect the antenna to a short wire sticking out of the tender (probably using the wire that connects the coal load to the tender - it has a plug on it as the gas tank is under the coal and thus it has to be removed frequently.) How long should the outside piece be? How long should the whole cable be? 
_Any thoughts? I guess it wouldn't be too hard to test some hypothesis, as Rog's track is very large (great for range tests) and the wiring is already installed so it will be easy to mess with._


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## Del Tapparo (Jan 4, 2008)

Yes. Don't mess with the antenna! Give it a try inside the tender. It may work fine. If not, you should use an AR500 receiver that has both a short and a long antenna. The long antenna can be routed outside. The actual antenna is the last 1" of the wire, which is about 9" long. 

I think Tony has experience with this.


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## TonyWalsham (Jan 2, 2008)

Gordon Watson of Argyle Locomotive has done quite a bit of experimenting with 2.4 GHz radios. 
To date the best system has proven to be the Planet Twister 5 channel FHSS radio. 
The Planet RX has a very short antenna just like Pete has shown in the pic above. There has been no need to take special measures to maximise range. Gordon has even put the RX inside a metal dummy water tank with no loss of effective range. 
Gordon has also tried the Spektrum DX5e and Hobby King (Exceed) brand radios. 
The Spektrum works OK but is expensive when compared to the HK system. 
The HK system works just fine but is hampered by requiring 8 AA size batteries for the TX instead of 4 as used in other brands, and the complication of having to plug the TX into a computer to reverse the servos.


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## Pete Thornton (Jan 2, 2008)

Many thanks, Tony. Guess I'll leave it short inside the tender - I can always clip a wire to it to get it outside the tank.


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## Wesley Furman (Jan 2, 2008)

Pete,
You could always mount the Rx so that the antena wire is sticking out a "discreat" hole drilled in the tender. Like at front near the foot plate or rear above the coupler. 

Tony,
What do you think of an antenna's reception if RX is in the tender and the antenna passes thru a hole downward toward the track, it would be exposed to the open?

Wesley
SA #212


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## TonyWalsham (Jan 2, 2008)

No. 
You must not change the length of the wire that is the actual antenna. 
Some are very short, as in about 1.2". Others look longer but only the last 1.2" is the actual antenna. 
Changing the antenna length will screw up the range. 
If you need to have the antenna outside, mount the whole RX under the tender floor.


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## Pete Thornton (Jan 2, 2008)

If you need to have the antenna outside, mount the whole RX under the tender floor.
Now there's a thought. The side frames of the tender are about the same depth, but the frames and trucks are in the way. Might be easier to mount it on top under a pile of coal ! 

I could also stick the antenna up through the coal load - it covers the area where my rx is fitted. 

Further interesting info: I set it up this am and plugged in a couple of servos, then I left it switched on for 3 hours. The tx has some cheap NiMH rechargeable AAs in it. I periodically waggled the tx levers and watched the servos turn. Nothing went wrong (except it took one new servo abut 10 tries to finally start turning reliably.) After about an hour, (when I read Tony's first post here,) I picked up the tender shell and dropped it over the rx and battery. Made no difference, but I'm indoors so it's not clear how much range I'll get on an open layout. I'll let you know.


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## Andre Anderson (Jan 3, 2008)

Greetings, 

I work in a hobby shop so for my 2 cents worth on this subject, and how I am planning to install mine on my 4-4-0 is to mount the whole thing under the wood load on the tender with the antenna sticking out of the load. So I would go for hiding it under the coal load and what ever you do DO NOT CUT THE ANTENNA they have to be the length that the manufacture made them to work. 

Andre Anderson 
Portland Oregon


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## placitassteam (Jan 2, 2008)

I control three locos with a Spektrum DX6 and have used a different RX mounting on each one. My Forney has the entire RX (including the antenna) inside the tender which is all brass except for the top which is wood with a coal load on top. The C16 has the RX in the wood cab. The Mason Bogie has the entire RX inside the tender which is ALL brass. I cannot detect any difference in the reception, they all work at distances over 100 feet. If you want you could run the antenna through a hole in the tender deck and under the coal load but that doesn't seem to be necessary at least with the DX6. Hope this helps.


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## TonyWalsham (Jan 2, 2008)

I have found both Spektrum (DSSS) and Planet Twister (FHSS) RX's will work inside the metal boxes such as tenders and dummy water tanks.


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## Tom Lapointe (Jan 2, 2008)

I'll second Tony's comments on the Spektrum receivers - on my Accucraft Mich-Cal # 2 Shay, the Spektrum receiver is completely inside the tender water tank; "theoretically"







, the only way for the 2.4 GHz. signal to get to it through the relatively small air gap (maybe 1/8"







) between the "fuel" & "water" tanks - *and that's enough!







*NO range issues at all around my 160-foot long mainline.







Tom


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## Dwight Ennis (Jan 2, 2008)

I have the Spektrun Rx in the brass cab of #21 Pete - never had any range or control issues. I wouldn't worry about it if I were you until and unless you have issues.


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