I was always told when silk at the top is brown,or open one if kernels are plump.

My husband's family always sold sweet corn, so they all can just zip through the field, feel the ears in the husks, and tell for sure if it's ripe or not. I usually have to peek. The kernels should be filled out to the end.
I like corn when it is young and more tender, some people like it more mature. Just don't let it go too far or it will get "tough" and starchy. Probably trial and error works best.

we also do this pull the husk back where you can see some kernels,prick the corn with your nail if its still creamy its ok otherwise its pass eating.

Its sweeter in late afternoon like 7 pm test bit into ear taste milk you know right day pick. Cut each end ear off with meat clever on board leave shuck on and freeze in bag it last 2 years in freezer with shuck on loose none fresh flavor. The bag can be paper sack open top or folded over.

"1 or 2 days after the racoons get it. "

I burst out laughing when I read this as I had those exact words on my lips (at the tip of my typing fingers) and that is a very accurate way to tell. The racoons just found my garden this week and the destruction has begun. Last year my husband had complained because I was picking the ears just a tad on the immature side and that is why. They also can tell you when a peach or persimmon crop is nearly ready. I find broken tree branches when the fruit is nearly ripeness where they'd been up sampling like a taster of fine wines.

I've heard that interplanting corn with pumpkins or some sort of vining crop can keep the varmints away, not sure if it works but it doesn't stop digging cats.

Found out that yes, it's when the silks turn brown. Nice to know at least the seeds aren't GMO's, they aren't as sweet as the modified hybrids, but they have a nice 'real corn' taste.

No...........interplanting vining crops does not help. Been there and done that. The groundhogs are busy nipping holes in the pumpkins and muskmelons when the racoons are up the stalks, or bringing them down to ground level. Once when out by the back forty around sunset, I wished so I had a camera with me. There ahead of me about thirty feet were a racoon and immediately to its side a groundhog not two feet away walking off into the sunset toward the field behind me.

I've used a 4 foot fence and this year tried one of those ultrasonic/supersonic devices, it seems to keep the deer and varmints away (except for moles, which we now have!! Aarrrrgh!!). Though it does not keep crows away, I had to string fishing line up to keep them out. It seems to work, but the animals will not stay away 100 percent if they are out of the perimeter of the device, it seems to have a 15 foot long range (sideways), and it triggers about 30 feet away.