Garmin HD radar antenna versus non HD???

[Alchemy]

I'm curious to know the advantages of the GMR18HD radar antenna over the GMR18? If I was to buy either it would be connected to a Garmin 4010.

[Muddy Toes]

Even though it's got nothing to do with your actual question....I used to have my 18hd hooked up to a 4010 and it was a pretty sweet little unit. Could see everything that was out there including small boats, birds and markers with a bit of tuning so no complaints here with the 18hd. I've now got it hooked up to a 7012 and with the bigger screen and better resolution it's got just that bit better and more 'trustworthy' in times of low visibility.

[mull dog]

I have the non hd connected to a 4210 and it performs the same as muddy describes. I have a feeling but not 100% that the 4000 series do not support hd. It is a great feature that gives that you that extra confidence.