Help me with Addlink 112 RF transceivers from RFsolutions

[Alvin81]

RF Transceivers

Hi.

I'm not sure anyone here have used transceivers called Addlink112 from RFsolutions (www.rfsolutions.co.uk).
I'm kinda having trouble sending multiple data from 2 transceivers to 1 transceiver. The problem is only 1 transceiver's data is received on the other end. If I were to switch on the second transceiver, the first transceiver gets cut off and only data from the second one is received.( If the second transceiver is switched off, the data from first transceiver is resumed).
Now, all the transceivers are operating on the same radio frequency. I'm trying to send about 15 packets of data per second, each packet is 7 bytes long. Transmission is 19200,N,8,1. I've tried using different time intervals for transmission, but to avail.
Anyone can help?

Thanx
Alvin81

 

[Humber555]

Re: RF Transceivers

Hi Alvin81,

I'm trying to send about 15 packets of data per second, each packet is 7 bytes long. Transmission is 19200,N,8,1. I've tried using different time intervals for transmission, but to avail.

The receivers are not the problem. You are trying to modulate with unbalanced code like ASCII chars, wich create an undesiderable pole bias in the receiver demodulator side.
Also check if the band pass of the Addlink112 support 19200 bauds.

Workaround: use a balanced modulation in your Tx side like Manchester codding and of course you will need a Manchester decoder in the receivers too.

The key is keep the same amount of binary '1' and '0' in the whole packet string.

To confirm my assumption just make a small test sending the following string:

"0x55, 0x55, 0x55 ....... 0x55" // Binary 0b01010101
"0xAA, 0xAA, 0xAA...... 0xAA" // Binary 0b10101010

regards,

humber555

 

[Humber555]

Re: RF Transceivers

Hi Alvin81,

I'm trying to send about 15 packets of data per second, each packet is 7 bytes long. Transmission is 19200,N,8,1. I've tried using different time intervals for transmission, but to avail.

The receivers are not the problem. You are trying to modulate with unbalanced code like ASCII chars, wich create an undesiderable pole bias in the receiver demodulator side.
Also check if the band pass of the Addlink112 support 19200 bauds.

Workaround: use a balanced modulation in your Tx side like Manchester codding and of course you will need a Manchester decoder in the receivers too.

The key is keep the same amount of binary '1' and '0' in the whole packet string.

To confirm my assumption just make a small test sending the following string:

"0x55, 0x55, 0x55 ....... 0x55" // Binary 0b01010101
"0xAA, 0xAA, 0xAA...... 0xAA" // Binary 0b10101010

regards,

humber555

 

[pva]

RF Transceivers

Hi
if transceivers are very close it's possible to have interference between them.