Hey, I just thought I'd post a couple of pics of my Drone Mods and Marco Polo RC mounted to my quad.  I have been super happy with the tracking ability of both.  I have yet to need them to find my quad (knock on wood), but they have tracked my kids all over the place and both do EXACTLY as advertised.  The Drone Mods is spot on if there is a clear view to the sky and somewhat close if the tracker is inside the house.  The Marco Polo seems to echo locate  best when the reciever is moving.  Both are a must have!  Both are velcroed to the quad and due to the small size of the Marco Polo, I used kevlar thread to tie a loop to the rear name plate and screw it down.  

Well, following one of Murphy's laws, the machine will not make flyaways anymore. Just by the fact of having the Tracker installed.

has anybody checked to ensure standalone gps does not interfere with the onboard gps?

Drone Mods only locks on gps when triggered by my call.  So far I have not had any interference.

nice! i am waiting for them to arrive in the mail as well.

It would be better if you can mount the Marco Polo tag so the antenna is vertical to match the polarization of the antennas in the locator. While it's true that you could land in any orientation, it is more likely that you will come to rest either right-side-up or upside-down so having the antenna vertical in the normal flight position would be the best bet.

Having the tag antenna horizontal is not the end of the world and will make little difference if the antenna is close to the ground and you are far from the tag,  since the polarization of the RF wave flips when bouncing off the ground anyway. The effect of a horizontal tag  antenna is seen more in the close-in direction finding which suffers because reflected signals will couple more efficiently with the locator antennas than direct signals. This may cause bearing display offsets when getting close. Try it for yourself - you can just bend the antenna to experiment.

so what are the best positions to mount these?