Radar Gun Fraud?

What is the name of your state? Vermont

I was stopped for speeding 40/mph in a 25/mph zone. Cop said he clocked me at 40/mph and gave me a $125 ticket. I asked to see his radar gun and he let me but it said 38/mph. He said "thats just where I locked you in because you were slowing down." After that he tried to show me how the radar gun worked by placing tuning forks in fron of it, however it took several tries with inaccurate readings before he got it right.
So, first he gave me a a ticket for going 40 when the gun said 38, and finally it took him several times, at least 3 to get the tuning forks to work.
I am going to contest the ticket, any advice. should i supboena anything like the videotape or the calibration records, how do I do that.
any help appreciated

Look here.

[url]http://law.freeadvice.com/general_practice/traffic_law/speeding_radar.htm[/url]

[url]http://www.uspeeding.com/[/url]