Which one is better on a depth finder. What have been the down side of the Internals. Is there that big of a difference.

I have the internal and never had a problem getting a signal or anything else..I can't see where you would have a problem unless you parked under a BIG bridge for a while, but I've never tried that so I really don't know..
I know with the internal, there are less parts..I just took my old one off and used the same wires and mount and was running in 5 minutes..

I have both. My big HB is external and small Low 522 up front is internal. When I get the new HB for the front it will run off of the external. I have never had an issue with either yet.

The down side of external is that it is exposed to stumps if you fish around them and could get damaged.

my thoughts were he was talking about the antenna for the GPS...

He was.

I have had both. I noticed my internal dropped signal quite often, I went external.

I really dont think there will be a BIG difference though.

I have had both. One problem I had with the internal was to remember to not rest my hand on top while operating buttons with my thumb. My hand ould block the antenna and that was the only negetive I encountered. Positives are no hole in the boat to mount an antenna. Get or make a power adapter for use in a lighter or accessory outlet and you can carry the head unit anyhwere and have GPS like fishing in someone elses boat to make waypoints, that is if they do not object.

I have both internal and external Humminbird but also put the transducer in the back right over my transducer location so that I get the most accurate waypoint placement. An internal is good for the front deck but will put some additional error in the waypoint placement when mounted in the dash. Either works fine 99% of the time.

It's only a guess which one will work better or longer but for sure the external is easier to fix- I have seen some boats with both

Unless things have changed, the US Military intentionally degrades the accuracy of GPS to the public by about 10 meters so it won't work as well for missile targeting from our enemies. That means to me that the accuracy of whery you antena sits on the boat is probably not that important.

Two reasons I like an internal: 1. If something breaks the troubleshooting is easier, you send the box in. I've seen my budy have to first send the antena in and when that wasn'tt the problem he had to send the unit. 2. No drilling, extra wires, etc. for an internal.

I have never had a problem picking-up a signal with an internal either.

The military only degrades the signal when there is a possible crisis brewing. Otherwise, the data are spot on.

Roger that -- I heard what I said years ago -- I stand corrected.

Depends weather or not your wanting to have kids!!