# Rails as TX antenna?



## DKRickman (Mar 25, 2008)

OK, I'm sure this has been brought up before, but here goes anyway... 

It seems to me that one of the biggest complaints about R/C (other than cost) is range. It also seems that even the folks using battery power and R/c are still using metal rails. Would it be possible and/or practical to use the rails as a broadcast antenna for a system that otherwise has relatively poor range? Since the rails are horizontal, the antenna in the loco could be mounted hoizontally, running longitudinally. Conveniently, that's where most models have the longest straight run. Also, having the track be the antenna would prevent loss of signal in tunnels, behind buildings, etc. 

The rail joints would of course need to be bonded, but there would be no need to keep the rails clean or otherwise conductive. I would think that using a single rail would work as well as, or better than, both rails. I can imagine that if the antenna were not perfectly equidistant to both rails, some sort of interesting parallax would develop. 

As an alternative to using the rails, what about using a single wire burried beneath the track? That has the advantage of being simple, free from the problems with rail joints, and allows any type of rail (wood, metal, plastic, none at all...). The big downside I see would be the expense of the extra wire. 

And the final question.... Is there an R/C system that is significantly less expensice that others and that works well, except for a lack of range? It seems that if such a system exists (Aristo TC? I don't know much about R/C yet), then it would be a great candidate for this use.


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## Guest (Aug 28, 2008)

I connect my receiver(RX) antenna to one side of the rail (via unused pickups)to be used to further reception..works great (the RCS Brand of control) for me! 
not sure about your idea though?


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## DKRickman (Mar 25, 2008)

Posted By calenelson on 08/28/2008 2:51 PM
I connect my receiver(RX) antenna to one side of the rail (via unused pickups)to be used to further reception..works great (the RCS Brand of control) for me!



Thanks for the comment. Have you noticed a difference in reception compared to _not_ using the rail as an antenna? 

Also, does it matter that the transmitter antenna is vertical (I'm assuming) and the recieving antenna is horizontal? I thought the antennae should be parallel in order to get the best signal strength.


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## Paul Norton (Jan 8, 2008)

The new Aristo-Craft battery/control car also has the TE antenna linked to one rail to improve radio range. There is a capacitor in the link to suppress unwanted radio noise from the rails. This may work well for a railway that has good continuity through throughout the track. 

Most people who run battery power and radio control cars however, are not concerned about maintaining the electrical continuity of their track. That, along with being able to independently control several locomotives on the same track, are the two main reasons people adopt battery power and radio control. 

There are other ways to accomplish the same thing. 

With 27 MHz systems, radio noise from the motors is not usually a problem, but range can still be limited. That can be improved by using the M-27-L micro-lite antenna from E Cubed R/C on the receiver. As usual, the higher and longer it can be installed, the better it will function. If the Aristo-Craft TE system is being used, a telescoping antenna on the transmitter makes a dramatic difference. Tony should be in bed at this time, but he should have other ideas on how to get the best out the RCS systems when the sun rises over Australia. 

The Aristo-Craft 75 MHz system works well if the receiver is mounted in a tender or trailing car away from the motor(s). If it installed in a diesel, the radio range and slow button response suffer terribly from radio noise generated by the motors. Noise suppression components, like the RCS RF-CHK, are a must. The telescoping antenna on the transmitter also makes a dramatic difference. 

I have not yet installed my 900 MHz AirWire/QSI Gwire/QSI DCC decoder and sound board, so I can not comment other than to say people who posted here seem very pleased with them. Perhaps they can comment of the reliable and responsive radio range of the system. 

I am not sure what the Aristo TC is? If it is the Basic TE, it has very limited range. If it is the HO model, it has very limited power handling capability and range. 

If you plan to use radio control, invest in quality equipment so you can continue to enjoy it.


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## TonyWalsham (Jan 2, 2008)

Hello Kenneth. 

I have been using the rail as antenna connection for many years. 

Is it my first choice method? 
Not always. Sometimes it is the only option such as in all metal locos where an external antenna would be obvious. Such as live steam locos. 
Dave Goodson nearly always uses the rail as he has found it to be the best all round method. 
There are some rules you need to follow but generally using the rail as an antenna will provide good "reach" around a layout when standing beside the layout, rather than "range" when standing away from the layout. 

For the best range, my first choice is to have an onboard antenna. 
However running the antenna wire past a speaker magnet & batteries can many times create range destroying interference because of the magnetic fields. Likewise placing an antenna anywhere near the pwm generators powering the lights and smoke units in many AC and USAT locos. 

I have finally found the best way. Best way for me that is. 
I have today just finished an installation using the new RCS PnP-3AC with Phoenix P5 + P5T sound. This loco started out as an AC RS3 and is now a longer wheelbase NSW 40 class Alco diesel that is being kitbashed by a customer. 
After a couple of less than satisfactory antenna placements I mounted the RCS RX-8 metal cased receiver on the back of the cab wall. I drilled a small hole through to the cab and mounted the AZARR 27 Lite antenna vertically up one corner and around the top of the roof. 
I have just range tested the loco and I could reliably control the loco and blow the horn wihtout it dropping in and out, up to at least *300'*. I couldn't get any further away because I came up against an electrified fence for keeping horses away from the garden. 
To say the least, I was astounded. The only other locos I have tested to get anywhere near that range were an USA F3 and an AC E8. Both of which allow an antenna to be stretched out up really high. 

The really interesting part is I had no extra motor "noise" suppression components on the AC motor blocks. Just the suppression fitted by the factory. 

I have a friend with an SD-45 that has reasonable range and shortly I will try the install method on it. 
I will report back on what happens.


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## DKRickman (Mar 25, 2008)

Tony, I was especially keen to hear your thoughts on this. It seems that most people who've used the rails as antannae are using them to recieve. Why not to transmit? I would think that using the rails as a recieving antenna would require good electrical contact between the wheel and rail - hence rail cleaning is still required. Using the rail to transmit would allow the use of track so dirty and corroded, painted, etc. that there's no way electricity could flow between the rail and wheels. 

In fact, painting the rails might be a good thing, to keep the signal from falling out of any open spots along the track. /DesktopModules/NTForums/themes/mls/emoticons/hehe.gif


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## TonyWalsham (Jan 2, 2008)

Sure the rail could be a transmitting antenna. 
It sort of is anyway. The signal is inducted and partially radiated up into the loco. It can jump smallish gaps and does not need perfectly clean track to work, as long as you stand close to the track itself. 

The whole point of R/C is freedom of movement and no cables connecting the operator and the controller. 
How would you propose connecting the transmitter handpiece (the RCS one is very tiny) and still have it cordless? 

I still prefer the antenna *not* connected to the track unless I really have to.


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## DKRickman (Mar 25, 2008)

Posted By TonyWalsham on 08/29/2008 7:26 AM
Sure the rail could be a transmitting antenna. 

How would you propose connecting the transmitter handpiece (the RCS one is very tiny) and still have it cordless?


You know, that seems like a perfectly simple, obvious question, and well worth asking. I suppose I should have thought of that one myself, huh? You're right, of course. 

Guess I was thinking of a stationary transmitter, but that would require some sort of signal relay, to recieve from the controller and re-broadcast via the rails. Waaaay too much extra complication. 

I hope I'm permitted to suggest an obviously dumb idea from time to time. /DesktopModules/NTForums/themes/mls/emoticons/blush.gif


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## Paul Norton (Jan 8, 2008)

Wow, 300 feet in an RS-3! Nice install Tony! I knew you would have some good news for us. 

I will pass this information on to our members, as a number of them use RCS receivers with Phoenix sound in their A-C and USAT diesels. 

I just bought 3 more M-27-Ls from Azarr, two of them were black instead of yellow. He said there were specially made for another customer. Hmmm? Is the roof on cab of your new locomotive black?


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## Curmudgeon (Jan 11, 2008)

I use the rails in 98% of the instances during installs. 
Have for 14 or so years, I think. 
I am gladdened that Aristo has "discovered" what we have been doing all along. 

That said, the higher the frequency, the more critical the antenna length. 

27MC is by far the most "forgiving", and it works on induction, clean track not necessary. 

LocoLinc folks told me years ago they had not so good success with 75MC. 

For "trouble" spots, I have folks strip out scrap Romex, use an insulated section, strip 1/2" off the end, put a 90 degree bend in the end, and clamp it to the outside of a rail, then run up a fencepost, tree, side of house. 

Fixes those "dead" spots.


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## Guest (Aug 29, 2008)

Posted By DKRickman on 08/28/2008 3:19 PM 
Posted By calenelson on 08/28/2008 2:51 PM 
I connect my receiver(RX) antenna to one side of the rail (via unused pickups)to be used to further reception..works great (the RCS Brand of control) for me!

Thanks for the comment. Have you noticed a difference in reception compared to _not_ using the rail as an antenna? 
Also, does it matter that the transmitter antenna is vertical (I'm assuming) and the recieving antenna is horizontal? I thought the antennae should be parallel in order to get the best signal strength.

I've done it both ways...seems the rail connection works better, maybe an extra 15-20' or so (but 2 totally different installs)...I get excellent range either way....no idea on the 2nd part of the question...sry!...I will step back out of the way for the experts to continue the education... 
cale


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## TonyWalsham (Jan 2, 2008)

Posted By Paul Norton on 08/29/2008 11:11 AM 
Wow, 300 feet in an RS-3! Nice install Tony! I knew you would have some good news for us. 
I will pass this information on to our members, as a number of them use RCS receivers with Phoenix sound in their A-C and USAT diesels. 
I just bought 3 more M-27-Ls from Azarr, two of them were black instead of yellow. He said there were specially made for another customer. Hmmm? Is the roof on cab of your new locomotive black? 


Hello Paul. 
It is not my model. 
Also It is not exactly an RS3. 
After WW 2 the NSW State Government owned railways ordered a bunch of these:







They were also used in SA, Tasmania and WA running on 3'6" gauge. 
My customer is kitbashing the loco from two RS-3's to roughly 1:24 scale so it will be the correct 3'6" on 45 mm # 1 gauge track. 
The cab was scratchbuilt and has plenty of room to fit the antenna. 
The secret is to have the RF part separate from the controller part so you can place it anywhere you like such as the back of the cab. 
AZARR started making the 27 Lite antennas in black for me. I always use them in every install I do.


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## John J (Dec 29, 2007)

I don't know if this is of any value. But I have increased the range of my TRACK SIDE mounted in a box car by touching the Antena to the rails. The engine responded better at greater distances.


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## Greg Elmassian (Jan 3, 2008)

by the way, the official Aristo method (as shown on their forum) is to use the ground of the receiver through a .1 mfd disc cap to one rail, so in this case it's technically not the antenna but the counterpoise connected to the rails. 

Regards, Greg


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