Testing/troubleshooting my RF transmitter and receiver pair

Hello all, back again asking for more help, maybe one day i'll know enough to be able to help other people eh?

Anyway, I've got an RF solutions AM transmitter and receiver pair (data sheets on the links below)
Transmitter: https://www.bitsbox.co.uk/index.php...ucts_id=2112&zenid=he0v7e59g7lhp80lt921c6aai4
Receiver: https://www.bitsbox.co.uk/index.php...ucts_id=2113&zenid=he0v7e59g7lhp80lt921c6aai4

They don't seem to be communicating with each other (They are hooked up to the output and input of HT12e and HT12d chips respectively). I know the HT chip side of everything is working fine because if I connect a wire between the output of the HT12e and the input of the HT12d everything works fine. When I try to communicate via the RF components however nothing happens.

I've tried to test the receiver by connecting an LED between it's output pin and ground. When I put my mobile phone near the receiver the LED flashes on and off so the receiver certainly seems to be able to receive what it thinks is a signal and put it through to the output. Is that a good way to test the receiver? Is there another way to test it?

I think the issue may be with the transmitter. Here is part of the data sheet:

My chip is the RT4.

If I connect pin 1 (VCC) to 5v and an LED between pin 4 (antenna) and ground then the LED comes on i.e pin 4 is at 5v. This is with no connection between pin 2 and ground so that seems odd to me for a start.

If I connect the transmitter up as per the pin descriptions the LED between pin 4 and ground remains lit and this does not change even if I bring pin 3 (signal in) to 5v. It seems to me that perhaps the transmitter module is broken? I would have expected the antenna no to have any voltage when pin 3 was low i.e for the transmitter not to be transmitting? Maybe i'm just confused? How would you recommend I could test the transmitter?

Any help much appreciated.
Thanks,

 

Hi KTW, thank you for your response. Could you expand on how you would use the frequency tester to test the transmitter?