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Full Version: [DG] AIS 700 - AIS Antenna problem
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I keep getting an error with my AIS 700. on the diagnostic page of the proAIS2 software i keep seeing a red X by the AIS antenna list. I'm wondering what this means and if there are other diagnostic tools to help me solve the problem. (though i realize its prob an issue with my VHF antenna)
Hi nachothecat

Thankyou for your enquiry.

The key diagnostics to check in PRO AIS2 is the VSWR reading . . ideally it should be between 1.0 :1 and 2.0 : 1, VSWR is a ratio of how efficient the antenna (and cable) is, the higher the ratio the poorer the performance.

check out this FAQ found here for more information, ( it refers to AIS 650, but the antenna issues will be the same)

So if the VSWR is high, then either the antenna is at fault or the cable/ connections to the antenna. Please also bear in mind that some antennae are not suitable for AIS transmissions, most antenna are specified for a range of frequency and AIS operates circa 162MHz, this needs to be in the middle of the range for the antenna selected.

Make sure the antenna, if on a ratchet mount, is not laying down horizontal. High VSWR can result and give you a bad antenna indication.
Thankyou - also good advice
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