There are three types of reader, Single, Dual and Quad.
There are two types of aerial, small and large.
The small aerial is suitable for OO/HO, N and Z. The large aerial is suitable for OO/HO and O.
When you purchase a reader board, it comes with a matched length aerial. There are various options of reader boards, which have to be matched with the aerials.
The reading distance is the distance between the Tag and the Aerial, when the Tag is immediately above the centre of the aerial. The distance depends on the type of tag used. StaRFIshrail tags will give a read distance of slightly over 30mm, as will the Murata 8mm tags. The smaller 3mm Murata tags will only give a 15mm read distance, so the aerial would need to be place under the track or trackbed - and this would only apply to N-gauge. It is recommended that you use the StaRFIshrail tags for N, OO/HO and O gauges.
The reading distance does not depend on the reader used - the single, dual and quad readers all have the same reading distance, and it doesn't matter if the aerial wire length is 13cm, 23cm or 43cm (providing the aerial is matched to the reader board).
With the larger aerials of 45mm by 30mm, the read distance increases to 40mm - but these should only be used with OO/HO and O gauges, due to lateral spill. However, this means that for OO/HO, aerials can be placed under a baseboard 25mm (1 inch) thick, as favoured by North American modellers.
This board contains a single reader, a switched mode power supply, an aerial connector, power LED, RFID present LED, and two RJ45 connectors. There is also an address switch to set the address to one of 4.
Picture shows Single reader and N-gauge track.
There are 5 options for this board.
RD1S43 - 43cm long aerial wire, small aerial.
RD1S23 - 23cm long aerial wire, small aerial.
RD1S13 - 13cm long aerial wire, small aerial.
RD1S33 - 33cm long aerial wire, large aerial.
RD1S09 - 9cm long aerial wire, large aerial.
This board contains two readers, and thus has two aerials, As with the single reader, there is a switched mode power supply, power LED and two RJ45 connectors. On the Dual reader, there are two aerial connectors and two RFID present LEDs. The address switch selects a pair of addresses, either 1 & 2, or 3 & 4.
Picture shows Dual reader and N-gauge track.
There are 5 options for this board.
RD2S43 - 43cm long aerial wire, small aerial.
RD2S23 - 23cm long aerial wire, small aerial.
RD2S13 - 13cm long aerial wire, small aerial.
RD2S33 - 33cm long aerial wire, large aerial.
RD2S09 - 9cm long aerial wire, large aerial.
The quad reader board has 4 readers on the board. There is no address switching, and only one RJ45 connector. As with other readers, there is a switched mode power supply, and a power LED. There are 4 aerial connectors, and 4 RFID present LEDs. This is the simplest board to install, as you do not need to do anything about addressing, and it is also the most cost effective.
Picture shows Quad reader and N-gauge track.
There are 4 options for this board.
RD4S43 - 43cm long aerial wire, small aerial.
RD4S23 - 23cm long aerial wire, small aerial.
RD4S13 - 13cm long aerial wire, small aerial.
RD4S33 - 33cm long aerial wire, large aerial.
When the readers are powered up, ALL aerials must be connected, otherwise the reader chip will heat up, and failure could occur.
The aerials are unlike any other system, in that they are not part of a complete reader (such as the IDLA12 or IDLA20), or a pcb, such as the RC522 and Traintraxx system.
The aerials are flat and thin and flexible, and are connected with a pair of linked wires to the aerial connector, and hence to the reader.
The aerial comes with a self adhesive backing, covered with a backing sheet, which can be peeled off. Thin means thin - the aerial on it's own is only 0.07mm thick, and even with the backing sheet is only 0.15mm thick.
The aerial itself is 25mm by 15mm, with a connector area for the wires of 6mm by 6mm. The aerial is also very flexible, in that the connector area can be bent at right angles to the actual aerial - extremely useful if installing the aerial immediately under the tracks.
Because the aerial size is so small, the RF field is kept small as well, so there is no spill between aerials, even when mounted close together. Aerials for HO/OO gauge should normally be mounted in-line with the track, as this gives a better pickup for trains travelling at high speed, but for areas such as fiddle yards, the aerials can be mounted across the tracks. For N-gauge, where the real speed is slower, aerials can be mounted either in-line or across, and do not interfere with one another on adjacent tracks. Aerials are not affected by dc or DCC signals on the rails.
Depending on the tags used, and therefore the read distance, the aerials can be placed either beneath the baseboard, beneath track bed such as cork matting , or immediately under the track - or any combination.
Picture shows 25mm by 15mm aerial, with OO/HO and N-gauge track.
The lateral spill of the aerial is very small, so it can be used on adjacent tracks in OO/HO (67mm), N (33mm) and even Z (22mm).
The aerials for O-gauge are larger, 45mm by 30mm, but work exactly the same as the smaller aerials. They are available with 9cm and 33cm wires.
The picture shows the 45mm by 30mm aerial with O-gauge track.
The read distance of the larger aerials increases to 40mm, which is suitable for thicker baseboards with OO/HO, but should not be used for N or Z gauges.