Sorry to hijack the discussion, but I was looking for something like that, I'm using the Zoom F3, and apparently the only way to to record a specified time period would be to control it with a computer, which defeats most advantages of a field recorder.
Now the Tascam DR-60DMK2 is already a big baby compared to the F3, and you'd need a powerbank if used for more than a few hours... but maybe you know about another device (in these prices) that could do that?
Presumably, if you are looking to set time periods, you are looking for unattended recordings.
WildLife Acoustics are one company that produces passive recorders and I have used these quite a lot for unattended recordings - either nocmigging or 'dusk-1 to dawn+1', to capture any evening activity, nocturnal birds and the dawn chorus. Their recorders are not at all similar to the F3, as they are standalone units with built-in omni mics, and the recorders are only 16 bit. They are designed for bird survey and monitoring, and therefore are not really field recorders as such.
That said, If you are doing unattended recordings then getting your directional mic to work is always going to be a game of chance (unless you really know a bird well and where it is likely to perch), so an omni is more likely to get results. I have raised this issue before with regards to nocmigging and the use of parabolas, but alas, I have yet to prove my suspicion that a lot of captures are probably from outside the parabola focus and therefore without added gain. That said Birding Beijing used a mini without parabola for nocmigging (
See this link) and seemed happy with results, and on another site they actually came up with a nifty idea to house the device in a parabola
(See this link) in any case.
Whereas 16 bit has a higher noise floor, if the bird is close enough and you have a good enough signal to noise ratio, the results are not bad. The problem is that you have to guess the gain settings in advance, so some trial and error is required, and you are still likely to loose some recordings through clipping if birds come too close. It would be great if there was a 32bit float version of these recorders, but alas Wildlife Acoustics have said to me that this is not in the development plan.
Birds too close can also create some unnatural recordings - particularly if they are mobile, and you get a series of calls, with one very close and loud and other calls much quieter.
The mini and micro are programmed through your phone and pick up time signal and location. The timing functions cover pretty much every possibility - so not just hard time triggers, but triggers around sun-rise and sunset (calculated based on the location).
The units are weatherproof, and the devices can (kind of) be secured in place with a cable lock. The batteries last an awful long time. On one holiday, I set up non stop recording on an SM mini and dumped the recorder in a clump of bushes for a week - the batteries were still fine when I picked it up later!
I think there are other companies that make passive recorders for survey purposes that do a similar thing.
