As promised in my post on 15 July, here are the results of the comparative test conducted aboard "Prince d'Oc" for our trip from Port Leucate to Dubrovnik.
Thanks to the loan of a complete IsatPhone Pro, with docking station and outdoor antenna (a big thank you to PYG @voilier_xhosa, who sent me all this from Belgium), and the presence of a similar facility Iridium on board Olivier's boat : Iridium 9575 with Sailor outdoor fixed antenna, We were able to carry out tests in real use situations.
Prince d'Oc on his way to Croatia
Principle of implementation
Two types of tests were carried out :
- MacBook USB connection with Iridium and IsatPhone through GMN XGate application.
- iPad 1 WiFi connection via GMN Redport Optimizer, featured onboard.
Three identical GRIB file queries have been made, a file of 32 KB compressed in all cases 27 KB by the same algorithm (bz2). In each case XGate application was used (MaxGate with MacBook and XGate with iPad). Two tests were carried out at anchor (in the Strait of Bonifacio) and a sailing test. In all cases, the tests are relatively similar.
The competitors
Results
The tests confirm GMN's assertions in my previous post (¹) while specifying the real times of communication. The IsatPhone is penalized by the fact that the establishment of each connection requires 50 seconds up to 1 minute for the wedging, probably the time it takes for the satellite to receive the GPS position of the mobile to lock its antennas, before you can transmit data. Then the transfer times are relatively similar.
We noted that the Iridium external antenna, Sailor brand, was particularly effective. Throughout the course, Most of the connections were made successfully without using the satellite passage prediction tool (²) in Weather4D PRO.
Calculating the costs of the IsatPhone (³) was confirmed by the invoice received in July by the owner of the device. This shows, As mentioned in my previous post, that communication costs are significantly higher with Inmarsat than with Iridium. Especially since the connection times, such as receiving the 27 KB, seems to vary greatly with the IsatPhone depending on the movements of the boat.
We can only hope, for IsatPhone Owners, that prices will fall in the future through competition.
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(¹) IsatPhone Pro versus Iridium, which one to choose ?
(²) Iridium Mail & Web app : GRIB weather files on iPhone and iPad in open sea
(³) The prices per minute are those of a prepaid card from 500 minutes for both operators.
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Hello
In your tests with Macs at anchor and en route you tell us about units (in fact 2), This means that the Iridium or ISAT units are different ?
In the’ example in Data (in iridium), with a card of 500 Prepaid minutes, after your tests at anchor and at sea, will have been debited from 4,40 Minutes on his 500 (2 times 2m20s) therefore 4,40 minutes for 54Kb of effective transfer (2*27KB), That's right?
Could you tell us in a few words (me) Explain iridium billing in Data and Voice ? THANK YOU
In the end a 10Kb skyfile mail, 50KB, 100Kb how much do you cost? ?
According to you, what is the way to optimize the Kb/price ratio in our emails? ?
Do you have a comparison of your tests with those done under Windows PC and skyfile?
The answer to the majority of your questions can be found in Previous post regarding the choice of Iridium/Isatphone. About Skyfile, I am not in a position to answer you, I only deal with Mac or iPad/iPhone solutions.
Je peux seulement dire que tout fichier > 45/50Ko nécessitera plus d’un passage satellite Iridium, therefore an additional cost for each transfer resumption.