I was intrigued by one of my favorite LHS throwing challenge that its only he who could provide replacement Antenna for 2.4Ghz Receivers. Now since they were selling the Antenna only for the Radio system they sell(just kididng), being a Futaba user, i had to find ways for myself and other lesser like me!

Well these antennas are not something special. These are just omni directional Whip antenna made up of U.FL connector (http://www.scribd.com/doc/7185751/UFL-Connector) , which goes to Rx Board, attached to a Coaxial cable. You just remove the Outer shield (Ground) at the other end and expose Lamda/4 (Wavelength/4) of the inner core which acts like the antenna (the shielded part acts like a ground plane).

For 2.4Ghz, Lamda =  12.491cm = 124.91mm
So Lamda/4 = 31.2275mm.

So all you need is a short 4-6 inch long Coax wire with the U.Fl connector on one side. You can get in single or bulk on e-bay (if someone knows local supply, please update)

5x  $12
http://cgi.ebay.com/5pcs-Pigtail-cable-U-fl-U-fl-1-13-cable-IPX-pigtail-/380080679564?pt=LH_DefaultDomain_0&hash=item587e92ea8c#ht_2761wt_905

1x: $4
http://cgi.ebay.com/RF-Pigtail-cable-U-fl-U-fl-1-13-cable-IPX-/150543280616?pt=LH_DefaultDomain_0&hash=item230d1429e8#ht_1256wt_1139

I am ordering few cable for myself to try....
Cheers!

I tried to fix a case for a friend where the antenna had come out of the connector... it was an absolute nightmare, and I was an utter failure (probably I am fat fingered, or did not have the right tools).  The little tabs which are bent into place break away real easy.

Decided that it was time to buy a new one after the connector broke off, although it was expensive.

Wonder if these work (although backordered now).

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16666

i guess you need an SMD soldering iron to do that...
I use a Spektrum AR6200...its an Rx with a Satellite/Remote Rx..


Do you think it will help if i increase the length of the antenna ??

Quote from: Samanth on May 04, 2011, 07:20:05 PM
i guess you need an SMD soldering iron to do that...

Guess you have not seen it in person. It is more like "crimping".  At least that is the part which was difficult, and there is a 90degree bend.

Quote from: anwar on May 04, 2011, 06:10:31 PM
I tried to fix a case for a friend where the antenna had come out of the connector... it was an absolute nightmare

Wonder if these work (although backordered now).
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16666

Anwar, the U. Fl connector are really small and you need a pair of twezers to put them. I have remove-insert on my Orangne FASST Rx and confess they are too delicate and have too less mating cycle.

I would not speak about few of HK's back ordered items. Sometime they look like 'Chor - Bazar' item, come once only.

By Crimping if you mean buying the U.FL connector and Coax, I would rather suggest to get a ready made cable as the proper crimping tool would cost more than 50 of such cables! Hand crimping near-Micro wave connector is a big no-no.

Quote from: Samanth on May 04, 2011, 07:20:05 PM
i guess you need an SMD soldering iron to do that...
I use a Spektrum AR6200...its an Rx with a Satellite/Remote Rx..

Samanth, Different kind of Rx put this Antenna in different ways. most of 'Full range' Rx have  the U.FL connectors, other like DSM ones are directly soldered. You dont only need SMD iron, but good SDM soldering skill as you can easily mess the PCB and even fry static sensitive components if  the iron is not properly grounded to the board.

Quote from: ujjwaana on May 04, 2011, 09:22:26 PM
Anwar, the U. Fl connector are really small and you need a pair of twezers to put them.

By Crimping if you mean buying the U.FL connector and Coax, I would rather suggest to get a ready made cable as the proper crimping tool would cost more than 50 of such cables! Hand crimping near-Micro wave connector is a big no-no.

Yes, only the wire had come out of the coax connector, and I tried with needle nose pliers.  It was a tough task, I guess tweezers would have worked better.

Quote from: anwar on May 04, 2011, 09:26:11 PM

Yes, only the wire had come out of the coax connector, and I tried with needle nose pliers.  It was a tough task, I guess tweezers would have worked better.

Wire out of the connector is good as discarded. One could re-use the wire, not the connector. What I meant above was inserting the U FL connector on the wire to the opposite gender connector on the Rx Board with a Tweezer.

Here is case where I was helping a friend repair his similar case of broken 2.4Ghz antenna of a DX6i.

He gave the Tx with a binding problem. Outwardly everything looked ok. But the antenna was fixed straight. On closer inspection it appeared as if the antenna had broken and it was fixed with adhesive.

I doubted it was a case of broken antenna since was having binding problem.

On opening the tx, it was a found to be a case of broken antena at the ufl connector.

Since it was very difficult to get a replacement antena. it has now been replaced with wifi router antena. Wifi routers are also 2.4 Ghz.

Now it is working perfectly.

See the photographs please.

Some more photographs please.

The Connector used here is a Pig tail connector UFL to SMA Male. The antenna is a Wifi antenna with SMA female connector.

Total cost of replacement of antenna is Rs 200 for UFL Connector and Rs 500 for the antenna. Total cost was Rs 700/- Cool !!!

Well, if it cost 700 then better to buy a original one from some internationa website, will cost all inclusive about 700. In case of resale of the transmitter, this (non original looking) antinna will be a hurdle to get a fair price  ...

If you can source a new replacement antenna nothing like it. you should go for it. Here is one available on ebay international

http://cgi.ebay.com/SPEKTRUM-ANTENNA-SPMR7500-DX2-DX3-DX6-DX6i-DX7-/200627056914?pt=UK_ToysGames_RadioControlled_JN&hash=item2eb64df112#ht_500wt_922

but Sad it is not available to India.

Friends it is available in India and also cheap on other international website. I faced same problem here it goes
http://www.rcindia.org/radios-and-receivers/help-needed-with-broken-antenna/msg34744/#msg34744

Hey I saw your post. You bought it for Rs 850 the original replacement. You were lucky I must say, you got the second one free by mistake and it worked out much cheaper for you for the original replacement at Rs 400.

Saw the rotor zone one for Rs 1350/- .

My friend is also a friend in need.  Any chance you can pass the second antenna this side. My wifi antenna can go back to where it belongs 

Anyhow the price of antenna qouted by me was for a higher gain wifi antenna from ebay. The original rubber ducky stock antenna should not be more than Rs 200/-. Overall it will not cost you more than Rs 400/-.

Further till now it has not cost me a penny for this modification, since like you, I also got two such pigtails free since it came as wrong product despatch for which I have already taken replacement. Further the the antenna used is from an unused router.

If it can be sourced even I would prefer original antenna as you have bought out it maintains the value of the radio.

So how about passing the second antenna this way. 

I would love to share that with you but my son (now 3 yr old) loves my transmitter and specially the tilting and moving rod (antenna). He took pride in breaking the original antenna and now he already broke the second one..... ,  I have the final antenna installed on it.  Infact until he become little more sensible, I may have to purchase another one soon...

But yeah 850 was the total cost from Heliproz (I bought it about 7 months back) for one piece which is still much lower than available locally and you don't mind spending that to keep its original shape.

PS: For you it may be just one time investment remember for me it may be 3rd time investment  all credits to my little one..

A very naughty brat you got there I must say