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Old 08-11-2019, 06:22   #1
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Iridium Go Reception

Well- I took the leap and purchased an Iridium GO.

To get familiar with it before heading out on some deliveries, it is being tested on my personal boat. Reception appears to be wonky. On a calm day, below decks I can have 5 bars of strength, then two and then it is searching for satellites.

Thinking it was an issue with being below decks, I moved the device up on deck. Clear view of sky, light clouds- same results. I then purchased what was supposed to be a "Good" portable antenna, the stubby black one (see below). There appears to be no significant improvement.

https://www.bluecosmo.com/iridium-po...RoCBPgQAvD_BwE



Any tips from you guys running GO devices? The mast mounted antenna on an upcoming delivery will likely be better. But for now I am working on getting the portable package that will be used for deliveries more efficient.

thanks
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Old 08-11-2019, 06:29   #2
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Re: Iridium Go Reception

Sounds like a faulty unit.

We donít have a GO, but use our inreach below decks.
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Old 08-11-2019, 06:49   #3
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Re: Iridium Go Reception

We used Iridium based phones in the field and I remember having issues with them doing this. It seemed that you had about 15 minutes of really good quality signal, so we would try and get our conversations in then. The issue was the call connection to the satellite and then to the land based phone took a few minutes so we really only had like 13-12 minutes to get what we needed said said. I remember talking to tech about this and it was blamed on the orbit of the satellites and how the handoffs occured or didn't occur. Supposedly the closer you are to the poles the better your chances are of getting good handoffs from one satellite to the next.

This info may not be very helpful, but maybe this will help you not chase performance that may not be there. Also, this was several years ago, so things may have changed.

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Old 08-11-2019, 06:54   #4
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Re: Iridium Go Reception

FWIW, I used a Go! all summer last year, up to 300 miles above the Arctic Circle. I had an external antenna for it, but I found the reception was flawless with the built-in antenna provided there was a reasonable view of the sky (NOT below decks), and ended up never using the external antenna (which I should get around to selling off).



So based on this limited experience, and take it for what little it may be worth, it sounds to me like you may have a faulty unit.


One caveat: I found the phone connections via the Go! to be crap. But the data and text connections were so extremely useful, we just forgot about using the phone, and never used our included minutes. I was very pleased with it -- it exceeded all my expectations and was exceptionally useful.
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Old 08-11-2019, 07:52   #5
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Re: Iridium Go Reception

Thanks guys.

The moving satellites makes perfect sense. @Dockhead- I did a short test call and wifey heard me fine. Call quality is likely related to satellite signal.

Definitely like on-demand GRIBS.
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Old 08-11-2019, 08:11   #6
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Re: Iridium Go Reception

Quote:
Originally Posted by Snore View Post
Well- I took the leap and purchased an Iridium GO.

To get familiar with it before heading out on some deliveries, it is being tested on my personal boat. Reception appears to be wonky. On a calm day, below decks I can have 5 bars of strength, then two and then it is searching for satellites.

Thinking it was an issue with being below decks, I moved the device up on deck. Clear view of sky, light clouds- same results. I then purchased what was supposed to be a "Good" portable antenna, the stubby black one (see below). There appears to be no significant improvement.

https://www.bluecosmo.com/iridium-po...RoCBPgQAvD_BwE



Any tips from you guys running GO devices? The mast mounted antenna on an upcoming delivery will likely be better. But for now I am working on getting the portable package that will be used for deliveries more efficient.

thanks
============================
been using a brand new unit for the last 4 months sailing from Halifax to MoreheadCity.
My unit seems to work on deck as well as inside, in fact lately leave it down below, some places below seem better than others.
Both in or out the reception measured by the rating from 0 to 5 varies constantly, I just leave the unit alone connected to my tablet for download grib files from Predictwind, and eventually does the job and have all done, do the same sending emails and voice.
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Old 08-11-2019, 10:48   #7
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Re: Iridium Go Reception

Quote:
Originally Posted by Snore View Post
Thanks guys.

The moving satellites makes perfect sense. @Dockhead- I did a short test call and wifey heard me fine. Call quality is likely related to satellite signal.

Definitely like on-demand GRIBS.

OK, that makes sense.


It was fabulous getting NOAA gribs (via SailDocs) 4 times a day, hot off the press, also ice charts, wefax, text weather forecasts, all kinds of other stuff. The Go! works brilliantly for this. It's a very slow but very reliable connection and if you keep your GRIB files down to 100kb or so, it is just no problem getting them downloaded.



You can get the same stuff over SSB but the Go! is just like 10x easier and without the propagation blackouts and all the faffing around.



Also text email works brilliantly so you could keep up a quite active email correspondence if you wanted to. I even sent and received low res images on occasion, and even managed to extract information from web pages using the ingenious SailDocs web page fetch function. We are off grid for almost 3 months and it was cool to read the New York Times once in a while while the icebergs floated by.


I've always been a big big fan of SailDocs; the Iridium Go! is now in the same place of honor in my list of favorite devices and services. $139/month for three months for unlimited data and unlimited SMS messages is actually cheaper than I would have paid for a SailMail subscription for a year (I think the minimum period) in order to be able to use SailDocs over marine SSB.


I actually missed having it this summer even though my longest passages were only 4 days.
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Old Today, 02:27   #8
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Re: Iridium Go Reception

Quote:
Originally Posted by Snore View Post
Well- I took the leap and purchased an Iridium GO.
Hi Bill,

I'm not familiar with the antenna you bought so can't speak to the specs. I've installed these https://www.sea-tech.com/product/63-165/ or the mast mount version.

There are three things going on: r≤ spreading losses, gain, and attenuation.

The Iridium satellites are in low earth orbit with an orbital period (once around the planet) in 100 minutes. They move pretty fast - from horizon to horizon each one is in view something like eighteen minutes. The signal strength is reduced by the square (r≤) of the distance so that means that signal received from a satellite twice as far away is one-quarter the strength. That means satellites near the horizon have much weaker signals than the same satellite overhead. On the horizon signal could easily be 10% or less of the signal overhead. This is why people report connect times of 8, 10, 12, or 15 minutes per pass; there isn't enough signal strength to connect at low angles.

What is supposed to happen is that your signal is handed off from the satellite you connect through to the next one in the same orbital plane in a seamless manner. If you don't have a strong enough signal to the following satellite the connection drops.

The external antennas are up higher so have better line of sight than you'll have below. They also are designed to exhibit signal gain, higher off to the sides than the top. This improves signals at low angles nearer the horizon much more than those overhead. It isn't magic and can't make a signal from nothing and can't overcome noise already on a signal. They do make a huge improvement. This is all consistent with the first law of thermodynamics: you can't come out ahead (conservation of energy, or enthalpy).

I agree that external antennas don't improve performance much when a satellite is directly overhead. They aren't meant to. They are meant to improve the low angle performance and greatly increase the chances of a clean handoff from one satellite to the next.

That brings us to attenuation. There are many things that reduce the strength of a signal other than distance. Water is a big one. Anything other than vacuum, even air, reduces signal. Air isn't significant. Many materials, including fiberglass, are not particularly significant although thicker deck layups have an effect. Water is worst. In a path link analysis even clouds show up. Heavy cloud--coverage and water content--is bad. Rain is horrible. Water on deck (we've all seen that offshore and probably don't even notice it half the time) causes a big hit without an external antenna. Herein the second law of thermodynamics: you can't even break even (entropy).

Don't you wish I was in your study group in school? *grin*

There are other elements, mostly implementation we have no control over: software on the satellites, software at the ground stations, software in the GO!, and software on your device. Your trying to get data through a 2400 bps connection. Data compression helps but in a weak signal environment (those pesky low angles) needs to downshift (less aggressive compression) to get through. Remember that your data is routed from satellite to satellite until it gets to a satellite that is in the field of view of a ground station. THAT is a massively dynamic mesh network, changing constantly as the satellites move along their orbits. The overhead is high. All of that is anchored by digitization (for voice) and packetization (for data and voice) in your device (phone or tablet). There are a lot of moving parts and an update to Android or iOS can take a while for Iridium to catch up. The guy who wrote a lot of the fundamental software (a cruiser by the way) is getting older. I hope Iridium has a succession plan.

In my experience voice is mediocre through the GO! Data is slow. Shared text messaging is sometimes awkward. The email interface is clunky. Support for real computers is poor. APIs to external services (e.g. Facebook) are a moving target and often don't work (Facebook changed their API two years ago and Iridium hasn't caught up).

I had my hands on yet another GO! yesterday. They certainly are popular. For a permanent installation the monthly charges quickly add up to an HF/SSB radio and SCS modem with Pactor IV (which is four times faster than Iridium). For portable applications like deliveries satellite or nothing are our options. I'm sticking with my portable weather fax kit for now.
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