multiple simple rf link mystery

I have been using Hope 433 MHz ASK simplex radio modules, with the VirtualWire Library, for several years now with no hassles.

I used to have one receiver driving up to 19 display panels, using Shiftout, with 16 way ribbon cable between the decoder and each display " tile " ( they are sports scoreboards )

I have had no problems, apart from the fact that the ribbon cable is easily damaged if it is pulled through a hole in the wall or metal front panel on the scoreboard.

So now I have moved on to having a receiver and decoder ( a “barebones” 328 ) in each " tile" and just have a red/black rugged DC cable to run from the power supply to each tile.

With the current project though, I have a problem that I can press the “standby” button on the remote control, and sometimes one or two of the tiles will not respond on the first push of the button, and sometimes will hang up for 3 or 4 pushes of the button.

It is not a range thing, it can happen with the remote 50 meters away. or 3 meters away.
It is also not the same tile each time.

It seemed like the receive buffer wasn’t getting the right data ?

I don’t understand the part of the library ( VirtualWire or Radiohead ASK for v1,5) where it says :-

 if (vw_get_message(buf, &buflen)) // Non-blocking   
 {	int i;
	// Message with a good checksum received, dump it.
	Serial.print("Got: ");
		for (i = 0; i < buflen; i++)

Where does the dump it come in ?

I have tried setting all the buffers and buflen to 0 after reading them, but it still has the same erratic problem.

attached is the remote sketch, it scans 12 bcd switches and 2 pushbuttons ( update and standby ) when a button is pressed , and send it then goes back to sleep :-

and the receiver sketch is also attached

RX3betterbufferandblank.pde (4.74 KB)

remote2definateoffassent.pde (8.83 KB)

I got a clue when I saw that the displays in the bright sunlight were responding OK, but those in a shadow of a tree for instance were playing up.

I had the antenna too near the LEDs, and the PWM noise of the autodimming was interfering a bit with reception, the tiles in the sun had the PWM set to 0 so were not affected.

Luckily I have space in these enclosures to move the antenna a few inches away and now its fine and the range is better. Its working fine at 80 meters away ( which is the dead-end of my road )