Duplicat's Diary

by Rick at 02:48:57, 2023-02-17 (day 3211)

We were having increasing difficulties with the Iridium Pilot system we used mostly for email onboard Duplicat. It was an old system but the aerial was showing signs of failing - and this had happened before. However, last time it was in warranty and Iridium replaced it (despite the claim by Mailasail that the warranty did not apply to us, just to the service provider). This time, Iridium have their new satellites and would prefer you to be on their Certus system. Which means new kit (roughly £5k) and more expensive plans. No thanks!

As we’re not faced with going offshore at the moment, but do want some reasonably fast internet access - I got a Starlink system. By default, this works in ‘bent-pipe’ mode - where the satellite has to see the user and the ground station at the same time. For us around New Zealand this is fine. Offshore, it won’t work - though they do have a system using inter-satellite lasers but at the moment this is priced outside the reach of the typical cruiser. There’s hope they may allow access but I doubt it will be covered by the normal monthly fee as the inter-satellite links are a constrained resource.

I took the old Iridium kit off and had a look at it. Its nicely designed, with multiple aerials, gps on top etc - but it was pretty clear what was dying - as usual, its a capacitor

The starlink unit has flat phased array aerial which can steer its transmissions electronically. It also has a motor system to angle it slightly towards the best view of the satellites. This is a pain at anchor, as you swing and end up with it pointing the wrong way. So I’ve modified it (by drilling into it and using tweezers to disconnect the motors). This leaves ‘dishy’ (as it’s called) flat which works surprisingly well. In fact, we’re regularly seeing download speeds of over 200Mb/s. Its been a revelation.

Dishy has, for now, been lashed into the old mast for the Iridium Pilot. I’ve left it with a tilt to help it shed rainwater. As it’s working so well, it may turn out to be the permanent home. Whilst sailing over from Whangarei, we had a couple of spots where it lots data, but mostly it was fine.