I splurged on my last hotel on this trip – complete with all the trappings and a rooftop swimming pool. Today’s breakfast, however, was quite muted and did not live up to the expectations. This didn’t have anything to do with the hotel, though – local health regulations reduced the offering dramatically. I’ve definitely had enough restrictions by this current situation.
Let’s hope that it will not last too much longer until we can get back to ‘normal’. I’m not an advocate of going back to the good old way of doing things for everything… but: let’s do it at least for the breakfast buffets!
Why did I choose this hotel? The credentials were good – sustainability, access to jobs by the less fortunate etc.
Shortly after breakfast, I pack up the TWIKE and make my way to the ferry terminal. I’ve always liked taking ferries and this one is a treat – long duration, huge vessel and the added bonus of maximum mobile network cell edge geekery – more on that later.
I saved €3 for another day pass for my TWIKE by cleverly avoiding 2 red lights with installed number plate readers and was left wondered if it would be possible to cross Barcelona and avoid detection with clever routing?
Anyway, this year, without having to drive around looking for the correct port entry gate, I get to the queuing zone without any problems. As always, I’m immediately surrounded by lots of people who want to know more about the TWIKE. After the first 30 minutes, I ask them to keep an eye on my TWIKE whilst I go and get the ‘real’ ticket required to board the ferry…as the one downloaded from the internet isn’t considered a ticket but just a ‘travel voucher’.
Thanks to the current situation and massively reduced amounts of travelers, the queue at the one ticket office taking care of all tickets issued (it took me >1 hour last time) my line was just 3 people deep and I was able to get my tickets within 10 minutes. Most of the process is manual and analog. Also, if you don’t speak Italian, it’s going to be an interesting experience language-wise.
With the ticket in hand, I head back to the holding queue and continue my conversations with the people there until it’s time to show the ticket and get in line to board the ferry.
Videos and images from the loading bay are forbidden, we get told whilst waiting in-line. Reason: Terrorism.
I really wanted to show how small TW560 is in relation to the loading bay. This time, I park on the smaller C-level as the complete B-level seems to be locked and empty.
Nevertheless, I sneaked a pic to let you see how it looked like and how low occupancy was.
Entering the ship, I’m – as last time – impressed by the sheer size of the vessel. At least this time, there are much, much less people on board which makes walking around and exploring it much easier.
I’m looking forward to the cabin I’ve allowed myself to have this time. My cabin, thankfully, is on the upper-most deck on the left side of the vessel which gives me the best possible starting point for my mobile network challenge later on.
The cabin is spacious and quiet. Pure luxury for the next 22 hours.
Exploring the ferry is a déjà-vu from last time. Men are playing cards and drinking tea whilst the women congregate outside. The bar is completely overwhelmed and long lines form to get a slice of pizza or a drink.f
Not being hungry and having took some bottles of water to drink with me, I head to the upper deck and just relax in the sun and breeze. There is nothing to do and I intend to consciously enjoy having nothing to do.
Two hours in, the coastline slowly starts to fade in the distance – this is when things get interesting and most people lose their mobile phone connections to the shore. It’s amazing to see how quickly everyone starts to put away their phones and start looking and speaking to each other! Even the older kids join the younger ones playing catch on the main deck.
[geek talk]
For me, however, it’s time for some ‘fun’.
Increasing the distance to the shore for the first 15 or so km raises the noise and lowers the ability to connect as more and more cells become visible and frequency re-use overlays disturb any channel on any band. I would have expected these cells to somehow limit access by refusing attach requests by UE’s with a too high TA.
Again, I’m not a mobile phone network specialist – my interest is in RF propagation and optimization.
When the shore dips below the horizon, things suddenly get markedly better as my modem only sees the macro-cells on the higher hills.
Below, I show a typical setup with which I usually work when observing and working with cell-edge setups:
noping – a fancy ping variant
gtkterm – serial port monitor to display AT!GSTATUS with a plethora of useful information.
qmicli – QMI is another way to speak to the modem and get advanced status outputs such as LTE TA
mmcli – ability to set lots of lower-level settings, one of which is manipulating the band-bitmap and thus heavily optimizing cell seek times
In the image above I’m connected to a band 7 – 2600Mhz cell twice with a total bandwidth of 35Mhz. CA is not yet active. The cell itself is already at a distance of around 28.5km.
My goal for today is to see how far from the shore I can maintain a connection – regardless of the connection, latency etc.
However, before I’m completely out of touch for any kind of reliable voice link, I decide to call my wife and have a quick chat with her…at ~34km from the shore, very close to the theoretical maximum cell size of 35.2km. Link quality with only about 2% bit error rate at -88dBm on the TCH is a very reliable and good link (during which I obviously wasn’t holding the phone in my hand and the phone was propped up in the ‘just right’ angle). We phone until the link stops working due to me moving out of TA range.
The further away I get, the more interesting things get. I’m amazed how resilient the signals are and how far I can maintain double-digit mBit throughputs.
To cut a very long story short: My last reliable link was at around 82km from shore. This means that the antenna I was in contact with must have been at least 700+ metres above sea level. Given that I’m transmitting with 125mW e-utran and 200mW for utran, it’s amazing, how far you can keep a LOS link going.
Beyond this point, I was able to periodically see an attach but no data could be transferred…until I went past the max LTE cell size and even my modem went silent.
[geek talk]
On board there is an option for voice calls – TIM offers a satellite based GSM service – which is exorbitantly expensive.
With my geekery over, it’s time to go back to the deck and admire nature.
A few pieces of pizza and some beers later, I head back to my cabin for some well-deserved sleep.
