Originally Posted by richardhula
Interesting results posted here
regarding test of 9 & 12dB gain omni antenna's on a Bullet installation.
Too much emphasis seems to be placed on the number of AP's a particular installation can "see", but what's the point if they are too weak to connect to.
That is my test. I hadn't gotten to posting
it here yet. I usually post to the 3 forums
I frequent (anything-sailing.com, sailnet.com and cruisersforum.com) as a practice. Thanks for linking it.
CruisersForum has strict rules on how long you can edit your posts. I got hit with that time limit on this reply just now. (Mods, please delete my previous short reply to Richard.) The test results took me hours to post and I actually took them down and reposted them when I needed to change some of the analysis. I also find that I tweak grammar even a day later. So I typically post to CF last. (That, and not having any time limit is just more freedom.)
It may seem like too much emphasis simply because listing 50 access points takes up a few graphics. There are 3 reasons to show the access points that you can't currently connect to, during an antenna
1) signal strength isn't the only factor. In a lower noise environment
(away from suburbia) a weaker signal will get you connected. And there were/are a lot of access points transmitting/interfering on the same channels. I mentioned that -75db was my arbitrary cut-off for determining if you can connect to an access point. The needed signal strength could be higher or lower depending on where you are.
2) so people can get an idea of just how many wifi
access points are "out there" to connect to. Coupled with the capability to move the boat if you need better connectivity, knowing there are 36 more access points nearby gives you some confidence that if the first 14 don't work, you have some options. In my case, I already pay for service
from one of the cable companies that have access points scattered about. When hurricane
Earl passed close by, I moved the boat to the upwind side of the lake (and deployed a ton of anchors) and happily connected through that access point. It is nice to know they are there.
But most importantly, 3) it is the only good measure of the affect of the antenna's beamwidth during the test, and beamwidth is a major factor when choosing an antenna
. Some of the weaker signals were within the 9db antenna's beamwidth and outside of the 12db antenna's beamwidth -- that affect would be more prominent if you are in hilly terrain or in an anchorage with some swell. The access points I couldn't "see" with the 12db antenna (but could see with the 9db antenna) are a clear demonstration of that beamwidth effect. When choosing, you'll want to think about how much rolling and pitching you do at anchor
. And when you are rolling the most is perhaps when you want to connect the most -- to see where that storm is going on NexRad radar
, or because it's poor weather
for a shore excursion (or trip to the cafe to get urgent work done), or because you want to check-in on CF.
That's not to say those see-but-can't-connect metrics are the most important in an antenna comparison test. They are simply a big part of the decision on what to get. For me, where rolling/pitching at anchor
are not a big factor, the 12db antenna let's me connect to access points that are 58% farther away. For others that have any consistent rolling, beamwidth would be a more important factor. And you just wouldn't get a sense of that part of the decision with a simple signal-strength test.