Where is your software listing. I suspect your serin command may be locking up on noise without the use of the squelch circuit from the data sheet. Also are you aware that the es series transmitters have a maximum recommended operating voltage of 4 volts. There are some typos in both manuals which make this unclear.

I use the ES for voice and data and I find the range is limited to around 75 feet max with 1/4 wave whip antennas.


Your software, if you post it, could also provide some insight into whats going on.


Mike