Single-Board Universal Module

Well hope next week or so I'll have my tools out and should doing something useful.
Which switch are you using now?

Good news !

Maybe off topic, out of curiosity, but more and more radios seem to get two tx antennas on the Tx module. I am wondering how it works? Is it diversity, for reception of telemetry back from model?

and if you designing new state of the art concepts, must it also contain 2 antenna?

Here example the cheap flysky i10 opened.

In Case of the Spektrum DX18 transmitter the manual says:

Dual Diversity Antenna
The DX18 is the first Spektrum transmitter with a “dual diversity” fixed antenna. Aside from being incredibly durable, it’s the first pro-class transmitter antenna to employ the use of both vertical and horizontal antenna arrays. The horizontal array is cleverly housed in the handle on the back of the transmitter and, with the vertical array, virtually eliminates the possibility of polarization blackouts.

FDR wrote: I was talking about the code change, but I don't know if it is in the trunk...

I know we got at least one such mod into the team trunk.

It's in there. Was putting an "ifdef EMULATOR" around it when working on SymaX.

Seems like a good time to finish my multimodule.

2.4GHz antennas can be very small and the TX cases are usually RF-transparent, if not loaded with carbon-black, or metalization, so internal antennas should be OK.

Adding a second antenna for receiving RX in full duplex makes sense, but as these chips alternate between TX and RX (TDD) the use of separate RX and TX antennas makes no sense unless separate RF and TX chips are used, which of course would be OK, but is probably not the case.
This leaves the use of two antennae for diversity, which could be OK, especially if the model transmits an RSSI message, which could be used by the TX to decide which antenna to be used.

(Reportedly, external antennae is marketing "requirement" as most people will not buy a TX without something pointy sticking out.)

A 25x25mm ceramic patch antenna (WLP.2450.25.4.A.02) on a 50x50mm ground-plane could also work.
A little bit of gain won't hurt as most people will be facing the model under control.

Myself I use with good succes PCB J-pole antenna at TX.
This antenna has a good wideband match, I have it aligned horizontally.

Many of the small NRF modules use a "folded" j-pole, I use just the non folded.

like this one;
www.dx.com/p/repair-parts-replacement-in...i-32562#.VQ7oHsstFtY

Should be no reason not to implement pcb antenna, as long as the pcb antenna stays clear, un obstructed.

So goes product development! Never easy or a straight line, surprises etc happen.
Thanks for the update.

PB: Your progress reports are exciting, and as many others on the forum, I am following your progress with great anticipation.

A thought has been kicking around since your post a week ago (#29717) in regards to potential sale/purchase of a universal transmitter once development and testing is complete. Referencing your comments about FCC regulations, and the fairly strict rules against selling ‘unlicensed transmitters’, I’m wondering where that line exactly is... In other words, how much of a ‘mostly assembled’ board could be sold, purely as a ‘hobby item’, before it becomes an ‘unlicensed transmitter’? Could enough of a board be manufactured and sold as a ‘hobbyist kit’ where a marginally (and I do mean marginally) skilled person could complete the final assembly?

I’m hoping there is some middle ground between a low likelihood of success if I were to attempt to place and solder all of the components, and the complete pain of FCC certification of a commercial product.

Either way, whether my thoughts are completely off track or not, your progress and success is definitely awe inspiring!

Cheers,
Paul