RC India

RC Equipments => Radios and Receivers => Topic started by: khan007 on May 09, 2016, 12:05:58 PM

Title: Fixing a 2.4ghz transmitter antenna
Post by: khan007 on May 09, 2016, 12:05:58 PM
Guys i own a flysky t6 transmitter.  recently i found that the range has reduced to a couple of meters.  when checked inside by multi meter i found that the inner element in antenna has been  shorted. I found same type of wire from my damaged laptop.  but i have no idea about.  the length needed for antenna wire and length needed for the part where no shielding is needed.  antenna got a metal round base shield which i recovered  from antenna. I watched a lot of videos on YouTube  for dimensions and non describe about the dimensions  required  for transmitter antenna.  i an really confused.  if anyone know the dimensions  pls replay. I am willing  someone  got the real idea about what i am talking. Pls help. I think stock antenna is 3db. And dimensions  of lower and higher gain can be shared
Title: Re: Fixing a 2.4ghz transmitter antenna
Post by: Dipanjan on May 09, 2016, 12:25:37 PM
theory says that antenna length must be at least lambda/4
lambda being the wavelength.
Now for a freq of 2.4 GHz, lambda =0.125 m
that brings antenna length to =0.031 m or 3.1cm approximately.


and I THINK that this must be the unshielded length.

Title: Re:
Post by: a3ruz on May 09, 2016, 05:44:28 PM
Same type of wire ?
If it's the WiFi's antenna use it ,  no mods or need of removing shield ! WiFi's frequency is same ,
Or you can get replacement antenna wire from some one ,
Title: Re: Fixing a 2.4ghz transmitter antenna
Post by: khan007 on May 15, 2016, 04:23:19 PM
Bro. I made the antenna by 3.1 cm (length of unshielded  portion). But the problem now face is when i checked(multi meter on circuit check mode)the ground and main connection  where i have to solder the antenna  the multimeter is showing that there is connection  between them(multi meter  is buzzing). Is that normal???
Or is ther any problem with internal connection  of transmitter????
Title: Re: Fixing a 2.4ghz transmitter antenna
Post by: khan007 on May 15, 2016, 08:08:27 PM
Does anyone  have any idea???  please  help. I am stranded.
Title: Re: Fixing a 2.4ghz transmitter antenna
Post by: v2 eagle on May 16, 2016, 09:30:44 PM
post a pic of what exactly is your issue, its much easier to understand.
Title: Re: Fixing a 2.4ghz transmitter antenna
Post by: sooraj.palakkad on May 18, 2016, 09:26:05 AM
Quote from: khan007 on May 15, 2016, 04:23:19 PM
Bro. I made the antenna by 3.1 cm (length of unshielded  portion). But the problem now face is when i checked(multi meter on circuit check mode)the ground and main connection  where i have to solder the antenna  the multimeter is showing that there is connection  between them(multi meter  is buzzing). Is that normal???
Or is ther any problem with internal connection  of transmitter????

That is perfectly normal. - using a DC meter , it will read low resistances b/w the gnd and antenna pad of a rf module , close to few ohms.

But actually it's the measuring method which is wrong , an RF or antenna feed is AC. DC measurement systems are of no use here .

The same ground and antenna pads that your multimeter thought are short circuited , might read 10's of ohms of impedance at 2.4Ghz (that is when measured with the proper equipments! , Your DC resistance measuring device will still show a short circuit !! ).

So don't worry about it , put it back , make sure to solder properly and do a range test (ground and air) before you fly out in the open .
Title: Re: Fixing a 2.4ghz transmitter antenna
Post by: khan007 on May 23, 2016, 08:06:03 PM
Done the soldering and had put it back like stock one. But still no range. I still dont know whtas the real problem  is???. Thankz for reply  bro. Its a great  relief  that the tx is good in shape.
Title: Re: Fixing a 2.4ghz transmitter antenna
Post by: khan007 on May 23, 2016, 08:08:32 PM
Again  a simple doubt. Is the antenna unshielded  portion  length same for  tx and rx