Recently i replaced antenna of my old FS-R6B receiver which came with FS-CT6B 6 channel radio system. This receiver was collecting dust from long time. I damaged antenna of R6B during hard crash. I had no plan to repair that rx because radio link is an important part RC aircraft and any mod or repairing done on that might directly affect the range and reliability of radio link. But when i saw some videos and topics regarding antenna replacement i decided to give it a try, atleast it can be useful for RC cars or any other project where losing radio link won't create any major issues.
I bought replacement antenna from QuadKopters.com. Special thanks to Satya Gupta to bring and keep such good diy items in shop inventory. Below you can see the exact pic of replacement antenna.
Before going any further i would like to share information that i found from various sources, i just summarised them here for better understanding.
2.4 Ghz antenna is actually called coaxial wire, which means wire inside wire. Check below snap of coaxial wire.
Please note main parts of wire shown in above two pics. Outer part is an insulation layer which protects wire from wear and tear and stops any short circuit from nearby cables. Copper mesh acts as ground. Then again an insulation layer comes to separate ground and main wire to prevent short. This assembly is called antenna however only top bare part acts as an active antenna. Check below snap of active antenna
Length of active antenna is crucial. If it's not maintained properly it will affect the range and reliability of your radio. After quick search i found formula on internet to calculate antenna length. The length can vary from 28.8mm to 32mm for 2.4GHz frequency which is 1/4 of the wavelength. And same formula can be used to calculate antenna length of 5.8GHz receiver.
1. Velocity = Frequency * Wavelength
2. Wavelength = Velocity / Frequency
Take an example of 2.4GHz radio. To calculate antenna length follow below steps
Wavelength = 300/2.4
= 125mm
Wavelength = 125mm
Antenna length = 1/4 * Wavelength
= 1/4 * 125
= 31.25mm
Rest shielded wire is grounded on the rx circuit, so you can increase or decrease that part as per your need but bare active antenna part length must be as per above calculations.
Lets take an example of FS-CT6B radio set. As per specification RF range of radio is 2.4055 - 2.475 GHz. From above formula antenna length will be 30.30mm to 31.17mm.
Another example is RCB6i radio which is between 2.4GHz - 2.483GHz. Again from above formula antenna length will be 30.20mm to 31.25mm.
R6B has slightly different antenna, top part is covered by heat shrink tube and ground wire mesh is soldered to one hollow cylinder. Check attached snap of stock receiver
I don't know why they made such complicated design but i decided to repair my rx with replacement antenna that i bought from QK. I just unscrewed 4 screws from bottom part and unsoldered damaged antenna. New replacement antenna had female connector which we generally see on mobile circuit boards and wifi routers check below pic
however mine has to solder directly on the pads so i cut that portion and stripped the antenna as per below snap
and soldered it as per old antenna pattern.
here is the final soldered rx close snaps.
I just spent few bucks to replace damaged antenna wire which is definitely better solution than buying whole new receiver, however i will check the range before using it on project. Please share your comments and write us if any information needs to be corrected.
I bought replacement antenna from QuadKopters.com. Special thanks to Satya Gupta to bring and keep such good diy items in shop inventory. Below you can see the exact pic of replacement antenna.
Before going any further i would like to share information that i found from various sources, i just summarised them here for better understanding.
2.4 Ghz antenna is actually called coaxial wire, which means wire inside wire. Check below snap of coaxial wire.
Please note main parts of wire shown in above two pics. Outer part is an insulation layer which protects wire from wear and tear and stops any short circuit from nearby cables. Copper mesh acts as ground. Then again an insulation layer comes to separate ground and main wire to prevent short. This assembly is called antenna however only top bare part acts as an active antenna. Check below snap of active antenna
Length of active antenna is crucial. If it's not maintained properly it will affect the range and reliability of your radio. After quick search i found formula on internet to calculate antenna length. The length can vary from 28.8mm to 32mm for 2.4GHz frequency which is 1/4 of the wavelength. And same formula can be used to calculate antenna length of 5.8GHz receiver.
1. Velocity = Frequency * Wavelength
2. Wavelength = Velocity / Frequency
Take an example of 2.4GHz radio. To calculate antenna length follow below steps
Wavelength = 300/2.4
= 125mm
Wavelength = 125mm
Antenna length = 1/4 * Wavelength
= 1/4 * 125
= 31.25mm
Rest shielded wire is grounded on the rx circuit, so you can increase or decrease that part as per your need but bare active antenna part length must be as per above calculations.
Lets take an example of FS-CT6B radio set. As per specification RF range of radio is 2.4055 - 2.475 GHz. From above formula antenna length will be 30.30mm to 31.17mm.
Another example is RCB6i radio which is between 2.4GHz - 2.483GHz. Again from above formula antenna length will be 30.20mm to 31.25mm.
R6B has slightly different antenna, top part is covered by heat shrink tube and ground wire mesh is soldered to one hollow cylinder. Check attached snap of stock receiver
I don't know why they made such complicated design but i decided to repair my rx with replacement antenna that i bought from QK. I just unscrewed 4 screws from bottom part and unsoldered damaged antenna. New replacement antenna had female connector which we generally see on mobile circuit boards and wifi routers check below pic
however mine has to solder directly on the pads so i cut that portion and stripped the antenna as per below snap
and soldered it as per old antenna pattern.
here is the final soldered rx close snaps.
I just spent few bucks to replace damaged antenna wire which is definitely better solution than buying whole new receiver, however i will check the range before using it on project. Please share your comments and write us if any information needs to be corrected.