Very cool. I want to try this. I have the RTL-SDR and the software, so all I need is the antenna. I may try to resurrect the 5 element 2 Meter Quad from my 90’s adventures in the Dominican Republic (I still have the copper tube elements!). I know the Graves radar is out of range, but there must be a suitable North American signal for this kind of thing. Any ideas?
For more info:
http://hackaday.com/2017/08/27/sorry-us-europeans-listen-to-space-with-graves/#more-270298
https://dk8ok.org/2017/08/23/graves-reflections-out-of-the-blue/

Pick any analog TV station working ch.2 or 3 as your source. There are a few still left in Canada
Bill, Not sure if the post without the link made it or not, but here’s a link (http://www.livemeteors.com/) to a site from the DC area that’s streaming live meteor pings from an analog TV station in Canada, believed to be in Timmins, ON. Maybe that’ll also work for you as a signal source since it’s already working in the Metro DC area. Larry K8MU
I saw a demo of this. He used a 6 meter antenna and was pinging off a Canadian TV station. I’m sorry but I can’t remember the Freq. I know he had a website so it might be worth a Google search. If I find it I will post it here. Mark KC4GIA
I did not d find the site but did find this : http://livemeteors.com/Detecting%20meteor%20radio%20echoes%20using%20the%20RTL-SDR.pdf Hope it helps.