General :: Push Command To The Background In A Cron Script?

I'm writing a script that performs backups from partitions on remote servers. I used to do this with ssh, but that seems to be somewhat slow, so I switched to netcat.I start a listener on the receiving server (which runs the script) like this:netcat -l -p 7000 | dd of=imagefile &and then I make the remote and start a dd piped to netcat. This works quite well started manually and the listener is waiting in the background. However, when I have cron run the same script to automate it, the netcat listener is not started, probably because the "&" thing does not work (or there is something with the piping that behaves differently then)