Why use a script. You can set up auto-enter calculations for this.
The From field seems to always get "VMR466", you can simply set up the From field to auto enter that text. The field can be edited after the fact to enter or select different text in cases where this is not the desired value.
The To field can use an auto-enter calculation with the case function:
Case ( FrequencyField = "Open Station" ; "All Ships" ;
FrequencyField = "107.5 FM" ; FrequencyField ;
FrequncyField = "TOLW" ; "VTS Gladstone "
Remarks can be set up the same way.
A much more flexible approach would be to set up a table where you have one record for each value in the frequency field where you want such data to appear automatically. Add fields as needed for From, To, and Remarks. You can then relate your main table to this table by their "frequency" fields and either use Looked up value field options to copy the data into matching fields, (a "static" link) or you can just place the fields from this related table (a "dynamic" link).
To better choose between dynamic and static links to data in a related table, see this thread: Auto Fill
The FROM field dose not always have VMR466 in it only for certain entries, will this still work if set to auto-enter calculation for different entries, where FROM may contain a vessel registration number.
Any auto-entered data may still be edited by the user. The one auto-enter feature that can prevent that is when you clear the "do not replace existing value..." option for an auto-entered calculation. Then you can edit the values, but the calculation will kick in and modify the data after you exit--potentially changing the value back again.
If VMR466 is the value entered most of the time, you can enter it in the data box on the auto enter tab and you'll see this as the default value in any new record, but you can always change the value in cases where you need a different value. It's your call as to whether this is a good interface design option for your particular solution.
Please keep in mind that auto-entered calculations and/or auto entered data may well NOT be the best option for you. If you set up a look up table like I suggested at the end of my first post, you can adjust what data appears when circumstances change just by editing the data in the look up table instead of having to redefine your auto-enter calculations--something that's a much more user friendly operation.
I think i will set up a look up table like you have suggested, thanks for your time once again.