Quick answer: yes.
A full Synthetic backup is in essence a consolidated duplication of last full and subsequent incrementals.
The need for original backup copies is a show-stopper for users who send tapes off-site on a daily basis.

Thank you very much Marianne, So you mean I need to have full+Incremental backup Media's Onsite to run a Synthetic Full

Correct.

make two copies

If you have to send one off site, you will need to make two copies and keep one on site - suggest you use disk or VTL for that.

If you can make both copies at once, you will save some time...

I'm new to Netbackup, and I could do with some advice on how to set up the policy for my companies backup please.
The company has asked me to setup a backup to cover the following.

We have 1 Netbackup Master backup/Media Server, with a standalone Storagetek drive which used HCART LTO tapes, we have 2 Netbackup clients that require backups, I cant put in the same policy because the directories that require backups on each server are in different. 

Incremental on three tapes to cover 6 days
Monday  - Saturday
1) Daily 1 Tape to be used on Monday's and Thursday
2) Daily 2 Tape to be used on Tuesday and Friday
3) Daily 3 Tape to be used on Wednesday and Saturday

Weekly Full Backups will use 3 tapes on the following a number of writes Weekly 1tape will be removed an put in a Volt for Archives a new tape will be introduced to the tape Pool.

1) Weekly 1
2) Weekly 2
3) Weekly

Thanks in advance.

Regards.

John.