Installing Aerials

How and where to place aerials

Installing Aerials

Installing aerials in easy, providing you follow a few basic rules, and will result in detection of rolling stock easily.
When installing a system for the first time, please follow the Out-of-Box testing advice first (press button below to go to Testing page).
Once you have installed one or two aerials, then it becomes much easier - remember extra aerials are available if required, or if you find you have placed them in the wrong place.  Attaching with masking tape to start with is probably a good idea, as this can be removed - the sticky back on the aerial is more or less permanent.

Placing Aerials

Aerials need to be placed reasonably accurately with respect to the track, to give the best performance.  The aerials are rectangular, 25mm long and 15mm wide, with a little tag at one end where the wires connect.  On one side there is a pull-off strip, which exposes a sticky surface.  This sticky strip is permanent - once stuck you will almost certainly not be able to remove the aerial without damaging it. The aerial is very thin, but actually quite robust.  The aerial must be kept flat, but the tag on which the wires are attached can be bent through 90 degrees, if you are mounting the aerial under the track, rather than under the baseboard.
The RF field of the aerial is quite small, it only extends around 5mm outside all around, so aerials can be fitted very close to one another without interfering.  This does, however, mean that the aerial need to be placed correctly with respect to the track.  The aerials should be placed "in-line" with the track, with the long edge parallel to the rails.
You can mount the aerials without using the sticky back - just tape the aerial to the bottom of the baseboard using masking tape - this will enable you to reposition the aerial if you need to.
The aerials come fitted with a 0.1" housing, which can be plugged directly into the reader board.  However, you can extract the crimped cables from the housing, if you are installing the aerials above the baseboard, which will make it easier to thread the wires through the baseboard, and then put the housing back on.

Gauge considerations

There are two sizes of aerials - Small at 25mm by 15mm, and Large at 45mm by 35mm.The small aerials have a read distance of 30mm, the large aerials have a read distance of 42mm.
For Z gauge, use the small aerials - with the StaRFIshrail tags you will get 30mm read distance, but the smaller Murata tags (3mm square) you will get 15mm.
For N-gauge, use the small aerials and the StaRFIshrail tags, for a read distance of 30mm.
For HO/OO gauge use the small aerials if your baseboard and track bed are less than 18mm.  If, however, you have the North American preferred 1/2" Homasote over 1/2" ply, then you should use the large aerials.  Use the StaRFIshrail tags with either aerial type.
For O gauge, use the large aerials - though you can use the small aerials if your baseboard and track bed are less than 12mm. Use the StaRFIshrail tags.

In general, you should try and place the aerials beneath the baseboard, providing your baseboard is not too thick - most model railways are on a 9mm (3/8") baseboard, but if you have a thicker baseboard, then you will need to work out the distance between the aerial and the tag, to make sure that there is less than 30mm between the two, or 42mm if you are using the Large aerials.  

Aerial Types

The Small aerials have three length options.AERS13 has 13cm (5") long wires, and will be used with readers RD1S13, RD2S13 and RD4S13.
AERS23 has 23cm (9") long wires, and will be used with readers RD1S23, RD2S23 and RD4S23.
AERS43 has 43cm (17") long wires, and will be used with readers RD1S43, RD2S43 and RD4S43.

The Large aerials have two length options
AERL09 has 9cm (3.6") long wires, and will be used with readers RD1L09 and RD2L09.
AERL33 has 33cm (11") long wires, and will be used with readers RD1L33, RD2L33 and RD4L33.

The aerial type (S or L) and the aerial length (09,13,23,33,43) must be matched with the reader, otherwise the read distance will be much reduced. 

Aerial positioning

You MUST mount the aerial centrally to the track - this will give the best pickup, especially at high speed.  One way to do this is to drill two small holes (maybe 1mm) centrally between sleepers at around 30mm apart, and then use these as the positioning point when installing the aerial under the baseboard.  A mm or two either way won't make much difference. If you are using the 3mm tags for Z or N gauge, the aerials MUST be placed under the track or under the track bed - unless you have an extremely thin baseboard, as the read distance is only 15mm.  If you have a baseboard thicker than 13mm (1/2") then you will need to use the Large aerials.
The illustrations below show you how close aerials may be positioned in order to get the maximum read distance.


In general, you should use Large aerials for O-gauge, as these will give a larger read distance, and also pick up data at scale speeds to at least 100mph (160kph). Because of the spacing of the 0-gauge tracks compared to the aerial size, you can place aerials on adjacent tracks in a line.  If you have aerials in places where you know the speeds will be slow, such as sidings, then you can use Small aerials.

OO/HO 50mm Track spacing,
thin baseboard

With the NMRA minimum track spacing in HO of 50mm (2"), you can place Small aerials in line across parallel tracks as shown, providing your baseboard is 13mm (1/2") or less.

OO/HO 50mm Track spacing,
thick baseboard

With NMRA minimum track spacing of 50mm (2"), and a baseboard thickness of up to 25mm (1"), you should use Large aerials.  These will need to be staggered as shown in order to keep the read distance of 42mm.

OO/HO 67mm track spacing,
thin baseboard

With 67mm OO/HO track spacing, Small aerials can be mounted in line across the tracks, and there is even space for an aerial between the tracks to monitor points or crossovers.

OO/HO 67mm track spacing, thick baseboard

With 67mm track spacing, and a thick baseboard, the aerials must be staggered as shown.  You can also monitor points or crossovers as in the diagram above, providing that the aerials are spaced 90mm away from any aerials on adjacent tracks.

N-gauge, 33mm track spacing

Small aerials can be placed in line across parallel tracks as shown. If the N-gauge tracks are closer than 33mm, then the staggered system should be used, keeping the 50mm stagger distance.

N-gauge, transverse aerials

Aerials can be mounted across the tracks, rather than in-line with the tracks.  A stagger system must be used, as shown.


Z-gauge aerials need to be mounted in line with the track.  If the track spacing is less than 22mm, increase the stagger distance from 45mm to 50mm.

Aerial Questions

The picture shows a dual reader with 13cm small aerials, spaced at 33mm for N-gauge dual line working.
If you have any questions about how to place aerials, or what aerial sizes and lengths you may need, please contact us before placing an order - we are always willing to discuss your requirements and to answer any queries.

Under the baseboard

This is the easiest way to install aerials, especially on an existing layout.  However, you need to make sure that the read distance is kept less than 30mm - ideally, a few millimetres less than this will give some overhead.
You should centre the aerial in the middle between the tracks, and use the aerial in-line, that is the 25mm length in the direction of travel.  The easiest way to do this is to drill two small holes (1mm) in the centre of the track, about 30mm apart, and then align the aerial between these holes from the underneath.
With a 9mm(3/8") baseboard, a 3mm track bed, and a normal HO/OO track, the distance to the running rail top will be around 18mm.  With wheels of 12mm diameter, this means that the tag should be placed a couple of millimetres above the line of the axle.

Above the Baseboard

If you have a thick baseboard, you can install the aerial immediately under the sleepers, or under a trackbed such as cork.  If you are doing this on a new layout, then there is little problem .  You can either drill a 8mm hole and feed the aerial wire with housing through it, or a 6mm by 3mm slot hole - done by removing the aerial crimps from the housing, feeding the wires through the baseboard, and then re-assembling the housing.  The aerial can then be stuck to the baseboard, the track laid on top, and then landscaped. 
For existing layouts, you will need to make the hole, remove the landscaping, fit the aerial, lay the track back and then re-landscape.
If you are running N-gauge or below, and want to use the smallest 3mm tags, then you will need to put the aerials under the track. You may put the aerials across the track for N-gauge, but for HO/OO and O gauge, the aerials must be in-line with the track.
For O-gauge, use the 45mm by 30mm aerials - this is an ordering option.
The picture shows a 25mm by 15mm aerial mounted below the sleepers on HO/OO gauge - you could also mount it below the trackbed.

Running Aerial Wires

Aerial wires should be taped to the bottom of the baseboard.  They should not be coiled or bundled, and where there is extra length, they should be snaked.  They should be kept 10mm away from other aerials wires.  If you have crossing aerial wires, consider how you could re-route the wires to stop the crossing - it may mean putting the aerials in a different order on a dual or quad reader, or even moving the reader board.
Note that some aerials may have a red stripe on one wire - this is because the aerial wires have been unzipped from a multi-way flat cable - there is absolutely no difference between aerials have a red stripe and those that do not.

DOs and DO NOTs in Pictures


Where aerial cables are longer than required, snake the cables.


Keep aerial cables 10mm apart.


Tape over the point at which the aerial wires meet the aerial - this will give strain relief, and will make the wiring more robust.


DO NOT coil aerial cables when they are too long, this will result in degraded performance - always snake longer cables. Keep aerial cables 10mm apart.


DO NOT bundle aerial cables, always keep them 10mm minimum apart.


Cables should be attached to the bottom of the baseboard, not allowed to hang. Although this won't affect performance, damage could easily occur to the aerial.


Keep the cabling neat by taping the aerial cables to the underside of the baseboard.


Where aerial cables need to cross other cables, try and do it a 90 degrees - this will stop interference.


The reader board and the cable length MUST be matched - if not, read distance is severely compromised.


Aerial cable should not run over other aerials - route the cable around.


If aerial cables cross, try changing the order of plugging the cables to a multiple reader, or changing the positions of the readers.


Reader boards MUST have all their aerials connected - otherwise the reader chip could overheat.