openrcforums

I am making a new Multi module, I have two choices I can use:
http://www.ebay.com/itm/291593792701?_t ... EBIDX%3AIT
https://alofthobbies.com/250mm-receiver ... frsky.html
both have uFL connector directly to the module. and both are dipole antenna.
I want to use one of these to avoid a SMA connector to get the max output from the antenna.
Any one knows there is any difference as for the antenna gain using either one of them?
The wifi antenna has the advantage of just taping inside the module box. The other one I have to make an antenna holder somehow.

Yes.

Bob B.

Since you are concerned about maximum output, you obviously want to get the antenna out of the box and into the open. Why are you using a receiver antenna rather than a conventional transmitter type?

deleted, duplicate post

Is there a difference of a Tx antenna and rx antenna? (for a dipole, circular is a different story)
Any realistic difference as for the antenna is inside the box or outside the box?

As far as I know, all the antenna has a plastic outer shell around just for protection except for some rx antenna.
Isn't 9XR has its antenna in the handle?

The point is that a Tx antenna is designed to get clear of the module and other stuff that affects the radiation pattern. The difference is mechanical, not electrical.

The 9XR internal antenna works well, but it's inside a plastic handle specifically designed to keep it away from the works.

If you don't mind losing some output, you can use a receiver antenna inside the module case. This is what people often do for transmitters to be used at short range. For maximum radiated signal, however, the antenna should be located more traditionally, preferably on top of the transmitter. You could do this with a receiver antenna, but you would have to make a rigid support, whereas Tx antennas have this already.

Here is some more RF info: (https://www.youtube.com/watch?v=xCVd3QGQhKU),
(https://www.youtube.com/watch?v=AuGBgTC6ph4),
(https://www.youtube.com/watch?v=mWs36MUpHec),
(https://www.youtube.com/watch?v=aZGcyuezMik),
(https://www.youtube.com/watch?v=DHnV6hGH108),
(https://www.youtube.com/watch?v=UlexW9awtfo).

Bob B,

Self made dipole from a RX antenna.

João

Bob195558:
Thx for the link, very interesting videos.

Daedalus66 wrote:The point is that a Tx antenna is designed to get clear of the module and other stuff that affects the radiation pattern. The difference is mechanical, not electrical.

The 9XR internal antenna works well, but it's inside a plastic handle specifically designed to keep it away from the works.

If you don't mind losing some output, you can use a receiver antenna inside the module case. This is what people often do for transmitters to be used at short range. For maximum radiated signal, however, the antenna should be located more traditionally, preferably on top of the transmitter. You could do this with a receiver antenna, but you would have to make a rigid support, whereas Tx antennas have this already.

do you know the db difference when the antenna is on top of the tx and at the back of Tx where the module box is?
Seems to me the general rule isfor each added connector you loose about 2-4db signal. if the loss of signal putting it at the module box without a SMA connector is less than putting on top of the tx with a SMA connector, then it is better to use a ufl connector and put the antenna at where the module box is than adding a SMA connector and extends it up to the top of the Tx.

kaos wrote: Seems to me the general rule isfor each added connector you loose about 2-4db signal.

Noo, more like about 0.1dB for an SMA at 2GHz for example. Might be a bit more like 0.5 for an u.FL, but never 2-4. You must have missed a dot.