Among FrSky receivers, the XM receiver from FrSky is one of the tiniest receivers and is suitable for a lot of smaller sized crafts and drones. In this how-to guide we will dive a bit into the receiver and also look at the In this article/how-to guide, we will take a look into the XM receiver, its specs and an how to replace the FrSky XM Antenna.

FrSky XM Receiver

The FrSky XM receiver is a great tiny receiver which has full-range capability unlike some 3rd party receivers, which only provides limited range than FrSky original 1st party receivers and so you can be assured that you will get enough range for whoops and all. But do keep in mind that this is not a diversity receiver and hence only has a single antenna for reception.

 

Specifications:

 

Compatibility

FrSky D16 mode

Dimension

15*10*3.5(L x W xH)

Weight

1g

Operating Range

>600m

Operating Voltage Range

3.5~10V

Operating Current

[email protected]

Number of Channels

Up to 16CH from SBUS; CH16 for RSSI

The XM was the first tiny receiver from FrSky and it is still being used today for whoops and other tiny crafts but is mostly replaced by its successor the FrSky XM+. The XM+ is basically the same receiver but with antenna diversity so if you can spend the extra dollar or two, I would suggest getting that receiver instead.

Construction of FrSky XM Antenna

The antenna we usually refer to would be the black colour wire(s) from the receiver but the actual radiating part of the antenna often referred to as the “active element” is the part that actually sends and receives the signal!

These antennas are made up a special cable known as a coaxial cable (or coax for short). This is similar to the type of cable found on your TV connection and is usually made up of 4 parts out of which 2 are insulation and the other 2 for the signal.

The first casing/covering is usually a black plastic to protect the delicate insides from physical stress and damage.

The second layer is a ground layer composed of thin intertwined wire strands whose purpose is to protect against noise and disturbance to the signal and also to stop the signal from being transmitted till the particular antenna region - the part where no grounding wire is preset.

The third layer is used as another insulation layer and is directly on the active element/main wire to prevent shorting with the ground layer.

The final fourth layer is that the actual wire where the signal travels from the device it's connected to. This is the actual “antenna” part which as previously explained is also called the active part.

In case you strip your antennas active element(the transparent part where the black plastic shielding is not present), the easiest way to revive and reuse the antenna is just to strip some of that shielding to show 23.5mm of the active element which is different from the usual 31.2mm we see in other receivers.

Make a clean cut right on the antenna right before the area where it got stripped.

Measure 23mm from that end and strip the insulation until you are left with the active element. This length of 23mm is special for the FrSky XM antenna because FrSky has “tuned” their antennas in the PCB board.

Replacing the FrSky XM Antenna

In the worst case where you lost the whole antenna and, you'll need to order a replacement FrSky antenna from HorusRC. Replacing the antenna is quite. Just unplug it from the receiver and attach the new antenna. While antenna replacement is being done, make sure you are grounded properly as static discharge from your body can damage the ESD sensitive RF chips on the receiver.

Conclusion

In this article, we have seen about the FrSky XM and the FrSky XM antenna and what needs to be done to replace it on your quad for happy flying. This article is not necessarily particularly for the XM/XM+ but can be applicable for other mini receivers as well but with the change that the active elements total length is 31.23mm instead of the 23mm for the XM as shown in this article.