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Old 28-10-2009, 15:45   #301
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Quote:
Originally Posted by CarlF View Post
I was getting set to buy a Ubiquiti 2HP when I stumbled across the PicoStation2HP

...The disadvantage is only a 6DBi omni antenna. Am I likely to notice the difference compared to a slighly more directional antenna?Carl
The PicoStation2HP is the same electronics package as the other ubiquiti a/b/g products except with more memory for customizing firmware. The 6dbi rubber ducky antenna is not on par with a commercial grade 8 dbi but you will certainly get your money's worth with the PicoStation, at least up to a couple of miles. You always have the option of adding a better antenna by using a short pigtail if you aren't satisfied with the stock setup.
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Old 29-10-2009, 08:06   #302
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One consideration on a sailboat is the rocking (and heeling, if you want to use wireless while actually sailing). This is one reason that very high gain antennas are specifically NOT recommended for sailboat VHFs. As such, the lower gain antenna might, in some cases, actually work better. More so the higher you mount the antenna.
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Old 10-11-2009, 06:51   #303
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has anyone used the alfa 1000mW.....amazon has the whole set up for 65.00$
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Old 20-11-2009, 17:58   #304
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From the folks who keep the standard, usb.org:

Q1: How long of a cable can I use to connect my device?
A1: In practice, the USB specification limits the length of a cable between full speed devices to 5 meters (a little under 16 feet 5 inches). For a low speed device the limit is 3 meters (9 feet 10 inches).
Q2: Why can't I use a cable longer than 3 or 5m?
A2: USB's electrical design doesn't allow it. When USB was designed, a decision was made to handle the propagation of electromagnetic fields on USB data lines in a way that limited the maximum length of a USB cable to something in the range of 4m. This method has a number of advantages and, since USB is intended for a desktop environment, the range limitations were deemed acceptable. If you're familiar with transmission line theory and want more detail on this topic, take a look at the USB signals section of the developers FAQ.
Q3: How far away from a PC can I put a USB device?
A3: With the maximum of 5 hubs connected with 5m cables and a 5m cable going to your full speed device, this will give you 30m of cable (see section 7.1.19 for details). With a low speed device, you will be able to get a range up to 27m, depending on how long the device's cable is. With a straightforward cable route, you will probably be able to reach out 25m or so from the PC.

So, the alfa would be a very good deal IF you bear in mind that you will suffer signal loss by using antenna cable, and you'd want to locate the alfa box itself on a longer USB cord. Either a maximum of 5 meters away from your computer (enough to get up on deck) or a bit longer--if you start chaining repeating hubs, which could be a bad idea for several reasons including water intrusion and ugliness.

Maybe put the antenna at the mast base, or on the rail, and with five meters there's enough to run inside to the nav station? Or just use it on a pole, pop it out in the cockpit or hatch when you are at anchor.
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Old 20-11-2009, 22:32   #305
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Regular CAT5 cable will work but for a boat I would recommend a gel filled direct burial CAT5 to eliminate moisture problems. The only complicated part is that you have to thread the cable through the rubber seal and screw on cap before installing the RJ45 plug. You can buy an RJ-45 crimp tool at Radoi Shack for $10-$12.
Is this the right stuff and is this a good price (when they get some in stock)?
Also I notice there are two different types, Black for Outdoor Flooded and Black for Outdoor Flooded (Mylar Foil & Water Proof Tape).
Is one better than the other?

Thanks,
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Old 21-11-2009, 03:47   #306
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On my CSY 44 W/o the nav station is right at the rear companion way door, so 15 ft would put me at least 12 ft in the air. As an X-CATV Engineer, i do understand antenna (db) Loss. that's why i wanted to do the active USB cable......Thanks for the info.....Extemp: if you go with the flooded Cat 5 cable, make sure your ends are sealed really good. in the some times hot weather in a boat the flooded compound will ooze out of the ends....Very sticky and messy.....Ed
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Old 21-11-2009, 04:52   #307
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Extemp: Either will do. I believe the foil shielding is really not necessary in this application. As mentioned, the goop inside is rather unplesant to deal with. Reminds me of that silicone grease divers use on mustaches. Be sure the ends get sealed. Make sure the inner jacket fits under the clamp on the RJ45 plug.
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Old 21-11-2009, 05:07   #308
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Is this the right stuff and is this a good price (when they get some in stock)?
Also I notice there are two different types, Black for Outdoor Flooded and Black for Outdoor Flooded (Mylar Foil & Water Proof Tape).
Is one better than the other?

Thanks,
Extemp.
Opps
I see I didn't put the link in my post last night.
Cat 5 Network Cable - 1000ft Bulk Cable
Further to my questions in my original post, I see there is Solid and Stranded Cat5 cable. The gel filled is solid, I would think standed would be better on a boat. Is that a problem?
Also any comments on price?

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Old 21-11-2009, 05:44   #309
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I would stick with solid. MUCH easier to make up reliable end connectors. 24 gauge wire is thin enough that you really don't have to worry about fatigue. $110-$120/1,000' is about average but 1,000' is enough to do a small marina and the shipping will hit you. You might check this guy: http://www.cat5ecableguy.com/inc/sdetail/14224 He is selling it in 100' increments for $22/100'.
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Old 21-11-2009, 19:30   #310
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I would stick with solid. MUCH easier to make up reliable end connectors. 24 gauge wire is thin enough that you really don't have to worry about fatigue. $110-$120/1,000' is about average but 1,000' is enough to do a small marina and the shipping will hit you. You might check this guy: http://www.cat5ecableguy.com/inc/sdetail/14224 He is selling it in 100' increments for $22/100'.
Okay,
Thanks Gashmore.

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Old 22-11-2009, 05:48   #311
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Just remember that the weak point will be at the ends. I have never seen any Cat5 with tinned conductors. Not a problem with gel filled in the standing part but the RJ45 connectors are vulnerable. Boots don't help much and don't fit in many waterproof devices. Once you install the RJ45s carefully wrap them with self amalgamating tape.
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Old 24-11-2009, 05:58   #312
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Here's an antenna question for Bob Stewart and the other network guys. I see uptilt and downtilt omni antennas on the market. I'm about to put our Bullet 2HP up at the mast head (or maybe a new Bullet 2MHP) and I'm wondering about a best all around antenna for up there. Elevation will be about 50 feet above sea level.

George
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Old 24-11-2009, 06:56   #313
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Down tilts are generally used for access points where the antenna is elevated to give clear coverage to a defined area below it. That is not what you want on a moving client. A normal 8 or 9 db gain omni has the greatest gain about 8 degrees above and below horizontal. At 120 yards an antenna 50' high will cover from the shore line to 100' up and has enough spread to maintain a good signal with normal rocking. That will handle 99% of the access points you will find when cruising. A 12 db antenna has a beam width about 5 degrees above and below horizontal. That will be sufficient on a cat but can cause signal fading on a mono. An up tilt might be useful if you are anchored off Saba but that is about the only place I can thing of.
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Old 24-11-2009, 09:49   #314
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"Not a problem with gel filled in the standing part but the RJ45 connectors are vulnerable."
Very true, but wrapping the connections may not help since you can't get a vapor-proof seal over the entire connection inside and out.
What you need for this is a good quality RJ45 to begin with, a brand name not "generic Chinese". All RJ45 connectors that I have seen are gold flashed to prevent corrosion but I've seen moist air eat through that in semi-exposed (i.e. patio) locations. So pick the good stuff, and then ADD SILICON JELLY (silicon grease, high temperature dieelctric grease, brake grease, whatever your prefer to call it) before you pop in the RJ45 plug. That's really the key ingredient, the silicon jelly will give you the 100% waterproofing that you need on the actual connections. Put it in the fitting before you make the crimp as well.
Something like $8 for an ounce Ancor brand at West, or $4 for six ounces at an auto parts shop, as "brake grease". Which is probably not quite the same high spec--but appears to be perfectly good for the job.
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Old 24-11-2009, 12:24   #315
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I see uptilt and downtilt omni antennas on the market. I'm about to put our Bullet 2HP up at the mast head (or maybe a new Bullet 2MHP) and I'm wondering about a best all around antenna for up there. Elevation will be about 50 feet above sea level.
George
+1 for Gashmores advice.
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