common causes of short range
- interferrence (check different channels, try different locations)
- incorrect antenna (needs SMA - the one with the center pin)
- incorrect antenna placement (must be vertical and clear of craft)
- supply noise from RC vehicle
- using linear polarized antenna when circular polarity is a must (quads)
- unrealistic expectations (maximum 300m for FCC TX, 500m for 25mW TX, 1.6km for 250mW TX)
- not flying line of sight (5.8Ghz does not penetrate objects)