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[John.B]

Ihave a 2.4GHz RX intended originally for aircraft which I am hoping t o use in my Amati Riva. The antenna emerge directly from the RX and I want to extend them so I can position the higher above the waterline.  In place of the existing antenna I plan to connect RF coax from receiver, grounding the screen to the RX ground and paring back the screening for the last 50mm.  Can anyone advise on the impedance of the coax I should use and would making these mods affect the tuning of the receiver.

[mrlownotes]

https://www.modelboatmayhem.co.uk/forum/index.php?topic=69201.0

[dodgy geezer]

Ihave a 2.4GHz RX intended originally for aircraft which I am hoping t o use in my Amati Riva. The antenna emerge directly from the RX and I want to extend them so I can position the higher above the waterline.  In place of the existing antenna I plan to connect RF coax from receiver, grounding the screen to the RX ground and paring back the screening for the last 50mm.  Can anyone advise on the impedance of the coax I should use and would making these mods affect the tuning of the receiver.

Quite possible if your receiver has an aerial socket. Here is a pre-cut 2.4 Gb aerial extender on eBay  [size=78%]https://www.ebay.co.uk/itm/186420453215?_skw=2.4+AERIAL+EXTEND&itmmeta=01K7CNN5X93J88JBV9MFSWC1MA&hash=item2b67865f5f:g:EdoAAOSwmvlmLzbh&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1cUNRar0Lot%2BAPx91vExp8yxJSXJK5OULfnbDajheBti1FmRugDyXMIHvWyPczIfa8ELxAbwwDNabeMwC5PFe9lzwcZLYdWSJSkKklOwmdiFB4rNZFdZ2OayielDNi2y%2Fl2GHBpbY7vfda3mvdWDwcMR2tK%2BXDqBmrg1BvDRKFhr%2F8kEpooMZb2pcy0JRoeawSU2evnqWF1Qjz7phJcpgobGXKAjIjy%2FI%2FldPyfWb2%2FJBC%2FiZhcdcasOED2eaBWFklIPVFHVP6Qjm8HEJL880mahBrTQJdxlnWGyWbKqg%2FNDw%3D%3D%7Ctkp%3ABk9SR_je1JW7Zg[/size]


If you haven't got a socket you could simply buy this, cut the socket off and solder it direct to the PCB. I hope you have a small soldering iron and good eyesight...

[Akira]

If you happen to be trying to extend an antenna on a FrSky receiver,  then FrSky has longer antennas already available. They simple snap onto the board within the case.

[John.B]

I have ordered some arial extenders from Amazon.  My Detrum reciever has the arial soldered directly to the board, does anyone know where I can get matching female connectors that I can solder to the board.

[dodgy geezer]

I have ordered some arial extenders from Amazon.  My Detrum reciever has the arial soldered directly to the board, does anyone know where I can get matching female connectors that I can solder to the board.

The board connectors are usually male. IPX is probably the word you are looking for. This sort of thing: [size=78%]https://www.ebay.co.uk/itm/283387214608?_skw=ipx+plug+socket&itmmeta=01K7EGN7CQBGVTE3Z72ZJ0KD85&hash=item41fb31bb10:g:KLoAAOSwR0xZulis&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1dt2CBCGeAENoWTjH3Sujc%2B0KJtGZR0I%2BQJAHVz29PYfSqS5aHs8mRcr04gOOzXGS0XRM782haYxoaE1Y4hZ%2BNJt043pPuclwWg9j5QC%2FZNwoU99LLWxhyOFzobMcu6%2Bs%2BrKFDKgyvkPCIFgi4n7PuKUsW1pJ5VNsCSIQdJz9fhilG95OI%2B%2Fm2aSapMbBnNusGZ%2BMySeiyDKnM7DUhXbjvdH2ZJW%2FG2ctIyreB0Pkr4TlPyCcBzoQXuXsVNPPvZ4JKOQWLLX%2BcDwYnF0SMMGJ4WoQOPcKgdO%2FdeZD6hhtR7AQ%3D%3D%7Ctkp%3ABFBM6vbU0Ltm[/size]


If you are soldering direct to the board you will not need a connector. If you want to put one in then you need to be sure that there is enough room and that the PCB will accept one. A picture would be useful.

[Big Ada]

Ihave a 2.4GHz RX intended originally for aircraft which I am hoping t o use in my Amati Riva. The antenna emerge directly from the RX and I want to extend them so I can position the higher above the waterline.  In place of the existing antenna I plan to connect RF coax from receiver, grounding the screen to the RX ground and paring back the screening for the last 50mm.  Can anyone advise on the impedance of the coax I should use and would making these mods affect the tuning of the receiver.

Are you sure that you need to do this?,  A RC Aircraft is a lot Further away than a RC model Boat.

Len.

[T888]

Correct me if I’m wrong but it sounds like you’re worried about the receiver being below the water line ?
Could you not relocate it to a better location? I’ve always been told not to ever extend a receiver antennas specially with 2.4 systems.

[JimG]

I’ve always been told not to ever extend a receiver antennas specially with 2.4 systems.

That was always the case with 27MHz and 40MHz systems where the aerial was part of a tuned circuit and the length was fixed (except for a few where it was detuned and you could alter it's length wihout much loss of signal) With a 2.4GHz aerial most of what you see is a screened coax connector which should not pick up any signal. Only the bare end actually picks up any signal and must be the correct length. Some manufacturers actually provide alternative aerials which basically plug onto  the circuit board.(FrSky have aerials where the actual receiving end is a printed circuit board) Note that these plugs are only good for a few removals and replacements so you can't keep on swapping aerials around.Lengthening the aerial on a 2.4GHz RX just means increasing the length of the coax and doesn't change the actual exposed end length. (For those of us older modellers just think of how the length of coax between your TV and the actual aerial wasn't important, it was the aerial at the end that had to be the right type and pointing the correct way.)
Jim

[John.B]

Thanks Jim for confirming all my thoughts and to dodgy-geezer for the link to the connector.