What is this thing and can I cut it off?

[dure16]

I ordered some longer antenna wires for my RadioLink R7FG receiver. But there is a thick piece near the end of the wire that prevents me from a protective sleeve over the antenna wire.

What is the thick part? Can I cut it off and then strip the antenna insulation to the proper length? Or do I need a different antenna wire?

 

[Jerold]

Remember that an antenna is more than just a wire. It's tuned for specific frequencies and performance. Modifying it might be an issue.

It's hard say exactly what that is, but it could be some sort of inductive coil, tension spring, protective tube or maybe a ferrite? If that is just heat shrink you can probably cut/peel the heat shrink to see what inside.

However, pulling it apart means you cannot send it back if it doesn't work. I would contact the seller an ask them about it. Or just send it back and get the right antennas.

So to answer you question, you can cut off anything you like. But will it work is a different question.

 

[LibertyMKiii]

I have seen these come in 2 flavors.

1. There is a metal part in side.
2. Its hollow in the black shielding.

For either one, you can cut the antenna and expose 31.25 mm of the internal antenna. I have done this many times and works great.

 

[FPVkabina]

I ordered some longer antenna wires for my RadioLink R7FG receiver. But there is a thick piece near the end of the wire that prevents me from a protective sleeve over the antenna wire.

What is the thick part? Can I cut it off and then strip the antenna insulation to the proper length? Or do I need a different antenna wire?




View attachment 307996

Oh wow so those Frysky antenna's fit Radiolink Rx's?

 

[LibertyMKiii]

Oh wow so those Frysky antenna's fit Radiolink Rx's?

As long as you have the same futaba jr iPex port any will fit, but frsky seems to be one of the biggest sellers of them.

 

[Bustedaw11]

This is a sleeve dipole antenna.

It is one way to produce a half wave length antenna.

You cannot remove it and have it work.

You need to buy the proper antenna for the application.

 

[LibertyMKiii]

This is a sleeve dipole antenna.

It is one way to produce a half wave length antenna.

You cannot remove it and have it work.

You need to buy the proper antenna for the application.

Sorry man that is just not true,

Skip to 4:35 in the video. I went 1700+ ft distance away from myself after this mod

 

[Bustedaw11]

Sorry man that is just not true,

Skip to 4:35 in the video. I went 1700+ ft distance away from myself after this mod

That is interesting.
You didn't cut the exposed wire/shielding to the specified length and it worked out that well for you?


I will just leave this here and we can all learn from it (including me)

https://www.rchelicopterfun.com/rc-antenna.html

 

[LibertyMKiii]

That is interesting.
You didn't cut the exposed wire/shielding to the specified length and it worked out that well for you?


I may stand corrected on being able to modify the antenna though. I think if the small center wire is cut to the correct length it will still produce what you need.


I went to edit my post about being able to mod it and was quoted so no point

It got lucky that the total exposed part is 31.25 mm after ripping it off, but you can basically cut it anywhere along the wire and expose 30mm and have similar results.
Thanks @Bustedaw11
I went back and edited my posts to say 31.25mm instead of 30mm. I imagine the difference is minimal, but still want it to be accurate for any future readers looking for info via searching.

I think ditching that piece has to do with the 2way comms. My radio will start saying signal lost and I still have another 300-500 ft range left in it.
I don't take my eye off the car at those distances or high speeds so I could care less what data is sent back to the radio.

 

[Bustedaw11]

It got lucky that the total exposed part is 31.25 mm after ripping it off, but you can basically cut it anywhere along the wire and expose 30mm and have similar results.
Thanks @Bustedaw11
I went back and edited my posts to say 31.25mm instead of 30mm. I imagine the difference is minimal, but still want it to be accurate for any future readers looking for info via searching.

I think ditching that piece has to do with the 2way comms. My radio will start saying signal lost and I still have another 300-500 ft range left in it.
I don't take my eye off the car at those distances or high speeds so I could care less what data is sent back to the radio.

I'm no expert.. I read a ton on it when I got into drones 6-7 years ago and most of that info has been lost by now.
I know in a crash I clipped a wire with a prop and it didn't work for crap after so I know if you just cut them it drastically effects range.

Your fast to respond so me going back to edit mistakes or something I wasn't happy with didn't work out well for me in this post

What im still lost on is how the transmitter doesn't have an antenna at all on some apps...... there is clearly some for me to learn.

 

[Cereal_killer]

Didn’t bother to read everyone’s replies. Pubut don’t cut it. Yank it off. Never had any problems

 

[LibertyMKiii]

I'm no expert.. I read a ton on it when I got into drones 6-7 years ago and most of that info has been lost by now.
I know in a crash I clipped a wire with a prop and it didn't work for crap after so I know if you just cut them it drastically effects range.

Your fast to respond so me going back to edit mistakes or something I wasn't happy with didn't work out well for me in this post

What im still lost on is how the transmitter doesn't have an antenna at all on some apps...... there is clearly some for me to learn.

It was a collaboration effort to get good info to the OP

 

[Jerold]

It got lucky that the total exposed part is 31.25 mm after ripping it off, but you can basically cut it anywhere along the wire and expose 30mm and have similar results.
Thanks @Bustedaw11
I went back and edited my posts to say 31.25mm instead of 30mm. I imagine the difference is minimal, but still want it to be accurate for any future readers looking for info via searching.

I think ditching that piece has to do with the 2way comms. My radio will start saying signal lost and I still have another 300-500 ft range left in it.
I don't take my eye off the car at those distances or high speeds so I could care less what data is sent back to the radio.

+1

I would aim for 31mm but I wouldn't sweat it too much. If it's cut and measured by hand, 30mm is close enough because it's not going to be exactly 30.00mm nor 31.22mm either way. Also the radio system is frequency hopping, meaning it's not at exactly 2.4 GHz all the time. The frequency is between 2400–2483.5 MHz, which is 31.22-30.18mm antenna.

So yeah 30mm or 31mm is good enough. I would bet it would work at 29mm or 33mm too, but at a reduced distance

With two antennas (64.44 mm total) that would be a like a 1/2 wave dipole antenna, assuming that's how it works. I'm wondering if anyone has tried cutting each side to 64.44mm? In theroy it would be like a full wave antenna and have more gain and more distance.

 

[dure16]

I summoned my inner Hercules and yanked the damn thing off. It looks like heat shrink with a piece of metal inside.

It came off clean. All set. Thanks everyone.

 

[SrC]

Sorry man that is just not true,

Skip to 4:35 in the video. I went 1700+ ft distance away from myself after this mod

I thought these 2.4 ghz antennas were pretuned for best maximum range, as is, already??? They look to be Air RC antennas, you would place within the Fuselage or the wings of RC planes.
Why cut them?
Just curious.

 

[SirCrashALot]

+1

I would aim for 31mm but I wouldn't sweat it too much. If it's cut and measured by hand, 30mm is close enough because it's not going to be exactly 30.00mm nor 31.22mm either way. Also the radio system is frequency hopping, meaning it's not at exactly 2.4 GHz all the time. The frequency is between 2400–2483.5 MHz, which is 31.22-30.18mm antenna.

So yeah 30mm or 31mm is good enough. I would bet it would work at 29mm or 33mm too, but at a reduced distance

With two antennas (64.44 mm total) that would be a like a 1/2 wave dipole antenna, assuming that's how it works. I'm wondering if anyone has tried cutting each side to 64.44mm? In theroy it would be like a full wave antenna and have more gain and more distance.

Stick with the antenna length that corresponds with the middle of said frequency range. The frequency we use is high enough for a few millimeter difference ,to throw your antenna into another band.
Also antennas are half wave because of the alternating of waves: Plus-Minus.
A full wave antenna length will work on half the frequency, not on ours. If it still does, at least performance will be poop.

 

[SrC]

Signals react way differently when running Surface RC's compared to Air RC's. Mostly because surface RC's signals are low on the ground ( ground plane deflecting) vs Air RC, which are not. Signal gets shortened with Surface RC's, for the most part.
It's why range always fairs better with Air RC's.
Line of sightsignal transmission works best up high off the ground.

 

[LibertyMKiii]

I thought these 2.4 ghz antennas were pretuned for best maximum range, as is, already??? They look to be Air RC antennas, you would place within the Fuselage or the wings of RC planes.
Why cut them?
Just curious.

Because you cannot fit this thing through an antenna tube to get the antenna up above the body.

 

[SrC]

Obviously will not fit inside a tube.
My point being, these antennas are for Air Rc's.Tubes not used in that application.
I have seen many use these types for speed running without tubes/uncut. Excellent range. But maybe the OP should have chosen different antennas. I guess they can be hacked up... shortened.....with success and will work. But ultimately were not the correct antennas. Uniformed purchase pehaps? Using ant. tubes was not considered, from the start.
Its not easy to cut them perfect.

 

[LibertyMKiii]

Obviously will not fit inside a tube.
My point being, these antennas are for Air Rc's.Tubes not used in that application.
I have seen many use these types for speed running without tubes/uncut. Excellent range. But maybe the OP should have chosen different antennas. I guess they can be hacked up... shortened.....with success and will work. But ultimately were not the correct antennas. Uniformed purchase pehaps? Using ant. tubes was not considered, from the start.
Its not easy to cut them perfect.

The problem has been for me... product availability. Finding long antennas is easy at times and then other times there seems to be none for 6 months.
That often drives me to grab the ones intended for airplanes and as noted in my video and by others it works just fine.... Even if not perfectly cut.