I'm thinking about getting Voom and I really would like to watch local channels with HD. I went to AntennaWeb (http://www.antennaweb.org) to see how far I was. I'm about 31 miles from the stations. Is this considered too far or it's okay?

It came up, so that's a good sign.

But the violet means you're gonna need a grande antenna ;)

Any links to see how big the antennas are and will I able to connect it to my dish the way Directv has it?

From my experience, once you enter your zipcode, any channels that appear on the website, you will be able to get.

Go to http://www.winegard.com/offair/chartselector.htm and look at the chart. You will need a bigger antenna than the default Voom provides. You are just past the edge of reliability with the GS2000A antenna which is the default. Try to get Voom to simply approve an upgrade of the antenna before the first visit. It will save a lot of hassle. Stay with one that gets both VHF and UHF.

I'm further than you (closer to 40 miles), and have never had a problem with the 'standard' Voom antenna. I typically have an OTA signal strength of 90+.

Im 76 miles away from my stations using a rather small Channel Master 4228 Antenna and a RS Preamp. I get all my stations fine.

It's not just about the milage folks. Pulling a station 30 miles a way from one place can be totally different at another place 30 miles from a tower.

as they say, your mileage may vary :) It depends on the contour of the land and what's standing between you and the towers. I'm farther away than you are and was able to get reception using a silver sensor (set top antenna). But I got tired of having to fiddle around with it to get ALL channels consistently, so I went to radioshack and bought the cheapest rooftop antenna they had and now I get 100% on almost all channels.

as they say, your mileage may vary :) It depends on the contour of the land and what's standing between you and the towers.
That is absolutely correct.

The question that was asked is "is 31 miles too far away?" The general answer is no, as some of us have mentioned we're further than that away. However that doesn't mean 31 miles is a lock for everyone. And even though you may not be too far away, which antenna you need is very much dependent on your specific terain, etc.