[TowerTalk] DIY conduit locator?

[Grant Saviers]

Trying to find a design for a empty conduit tracer.  We've dug at a 
couple of places at the 501c3 where it was "supposed to go", NG.  Seems 
to me this is a simple widget for energizing a test wire in the conduit 
or some sort of mouse - LF or magnetic placed on the end of a snake.

Some googling hasn't found a design so hoping a towertalkian has a 
design or link to one that works.  This 2" conduit was installed some 
time ago at 24" depth but where it routes is now lost.

The commercial tracers are $3000.  My budget is more like $20.  The 
usual AM radio and dongle SDR's are available.

Also interested for when I need it to exactly locate my coax conduits 
before digging.

Grant KZ1W