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Old Jul 28, 2010, 03:33 PM
theothercliff is offline
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Much happier at LibrePilot!
Temple, GA, USA
Joined Jun 2009
3,156 Posts
Quote:
Originally Posted by Derek_S View Post
The BOB fades at 1000' for me very badly, as it did for him. I get a lot of interference here in the city, too, which is not entirely the BOBs fault but could be intensified by a presumed poor receiver sensitivity of the BOB. I have not yet dared to find the limit of my 900 sytem, but I have gone at least 2000' on 500mw.
Try a pair of known good antennas on the frequency you need. Borrow them for a test if you can.

My BOB FOX-700 goes farther than my old Century VII PCM (0.85 miles). It was really pleased from the start. I run both stock antennas vertically, and put the receiver 2.5m up on a PVC pole.

I ordered a couple 912mhz FOX-800 systems and had horrible problems. They would work to about 1000 feet and would go completely out when I banked to come back from 1000 feet. To make a long story short, it was the antennas. I confirmed that they were 1.3G antennas that came with my new 912mhz systems because they worked well on my 1280mhz system. I spent some time looking on eBay and found some bazooka dipoles on 915mhz and now the 912mhz systems work perfectly. I would borrow some known good antennas and retry you BOB system with those (and the setup I described above). If you buy antennas, make sure they are bazooka dipoles; that is the kind with a thicker tube bottom half and a thinner tube top half and a taper in between.

Quote:
Originally Posted by Derek_S View Post
Another discussion on BOB is that it has an F type RF connector, 75ohm, where most of use use SMA.
Only the receiver has an F connector. I think all receivers of this type have an F connector? My stock BOB came with two identical antennas except that one had an F connector for the receiver and the other had an SMA for the transmitter. For my 912mhz systems I got a good deal on 2 SMA antennas on 915mhz so I bought an SMA to F adapter for my F receiver. It seems to work fine.

Turn down your audio before watching this video...

Cliff

Perfect video on BOB with stock antennas to limit of RC range at 0.85 miles = 1.4km
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Last edited by theothercliff; Jul 28, 2010 at 03:46 PM.
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