[TowerTalk] field strength meter recommendation?

[Gary Slagel]

Hi all,
 
Can anyone recommend a field strength meter?  I'm putting up a 3 el yagi on a 51' tower.   I'd also like to add a 40/80/160 dipole hung just below it but I'd like to do some field strength measurements on the yagi before and after I hang the dipole to make sure the dipole doesn't impact performance of the yagi.  Of course... I'd like to keep the cost reasonable... less the $200?? 
 
Thanks for any help!

Gary Slagel/N0SXX
Hot Springs, SD
http://marina.fortunecity.com/sanpedro/351