NewerTech Macbook Pro Battery Replacement

After 4 years and 624 charge cycles, my MacBookPro11,3’s (15” Mid 2014) battery wasn’t quite functioning as well as it used to. At first, occasionally, during high CPU load the machine would decide the battery was flat, and refuse to switch on again until placed on the charger briefly. Then the shutdowns just started happening at random times when the battery was anywhere below 50%. Then the OS started throwing warnings to replace the battery.

After spending an entire day at a tech event without a working laptop, I decided to do something. Apple weren’t sure they had parts to do it, and quoted a cost that was approximately the same as the value of the laptop.

I ordered the NewerTech NuPower replacement kit from Macfixit. Unfortunately it was out of stock for about six weeks, but despite being given the opportunity to cancel the order and receive a full refund, I kept waiting.

CoconutBattery shows there’s some sort of issue here.

Replacing it, sadly, is not just a matter of wielding a screwdriver. The battery is glued into the top case. NewerTech on their page rates this “DIFFICULTY LEVEL: 5 OF 5: Recommended for experienced technicians.“. iFixit rates it as “difficult” with a full three red bars of difficulty.

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80s Amateur Radio Fun - Icom 3200A

I was at a local hamfest looking for a cheap radio to sit on the workbench to work a few of the local repeaters - especially the ones where you want a little more power than a 5 watt handheld. Locating an Icom 3200A, I purchased it. 25 watts on 2 and 70, and as many as 8 memory channels!

Yes it’s a little on the “vintage” side but not much has exactly changed about FM Phone in 30 years…

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Building a Multiband Inverted-V Dipole

Even if I had the space to put up an HF antenna where I live, the noise floor being a constant S9+20 would make actually using it quite difficult. But you can always drive out to a far away place, set up an antenna and get on the air…

The inverted-V dipole is a good choice for this - you need a pole, a balun and a lot of wire.

(more guy ropes will make it less bendy when the wind blows…)

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A Radiosonde Chase in Two Acts

It started when Mark Jessop sent me a message notifying me that there was a sonde down not far from where I work. The ill-fated RS41 launch RS_N3940146 reached an altitude of only 2083m before descending again. Unlike all the other sondes launched that day that ended up in far eastern Victoria this one came down comparatively close to the launch site.

An opportunity too good to pass up, I decided, after some encouragement from my colleagues, to “go out and get a coffee”. I grabbed my bike and went for a short ride to the landing zone. But a not so infrequent problem occurred…

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Radiosonde Chase Semi Success 2018-03-10

The story starts much like any other chase. The landing location looks good, “only” 45km out of suburbia this time. We grab our stuff, get in the car and watch it ascend from the ground station while driving out to somewhere near the landing zone. We’re eager to catch it, hoping it will be our first recovery of a Melbourne-launched RS41 - up until quite recently they were still launching RS92 sondes.

This was only made a little more interesting by the fact that I was working on the receiver code to allow two concurrent instances to run - under the impression that I could always git stash in the event that I needed it running right now. Turns out that was wrong, as some un-committed local changes had been made - should have checked, but wasn’t on my machine…

That proved to be no problem as I got the feature working by the time the balloon was at about 17km altitude. The code change meant we could simultaneously run the vertical and the cross-dipole on two different rtl-sdr receivers at the same time. Mark Jessop initially suggested switching between them with a coaxial relay - however looking for a suitable candidate revealed that buying a second rtl-sdr was actually the cheaper option.

The descent was still relatively uneventful - aside from the prediction being fairly off as the weather was in the process of changing. The balloon burst and began to freefall - and thanks to the newly implemented feature, I could see exactly how much better the cross-dipole was at picking it up in this phase of flight. But something interesting happened next…

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Kogan Smart Tv Hacking

I recently purchased a Kogan 43” Smart TV (KALED43KU8000SZA), and I’m not entirely happy with it. Since the invention of the instant-on CRT in the 1960s, TVs have been able to switch on in mere seconds. Nearly 60 years on from that, I hit the power button, wait for Android to boot, and 30 seconds later, this:

It’s displaying input from my OSMC Vero 4k - and yes, then I have to use the menu controls to select the input, before it displays fullscreen - every time. It’s a small annoyance, but it’s a significant one - the TV has one job…

I wanted the “smart” features to play with, but it appears I’m being forced to. This just won’t do, so Michael Wheeler and I took a look and we fixed it. Read on to find out how.

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LTE Gateway - the build

“In theory, there is no difference between theory and practice. But, in practice, there is.”overheard at a CS conference by Walter Savitch

In the previous post, we went over the theory of building a LTE gateway.

In the build phase, I obtained a Mikrotik RB2011, a 9AH SLA battery, a PicoUPS, a Sierra Wireless MC7430 in a miniPCIe to USB converter, two RFI XG884 antennas and some patch leads.

And here’s the finished product.

The build process began with getting the router to talk to the modem.

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Ozonesonde RS92 Hunt 2018-01-15

The “normal” radiosondes are launched twice a day from capital city airports at the international standard of 45 minutes before 00Z and 12Z (midnight and noon UTC time).

However, on occasion we’ve received some interesting signals from sondes that appear to have been launched from the general area of a location in Broadmeadows - which a bit of judicious Google Street View stalking reveals to be BoM’s training facility.

These appeared to be a mixture of the old fashioned RS92s and the new, much more desirable RS41s. While RS41s are quite nice, further decoding of the RS92 signal revealed something even more interesting - it had an auxillary payload to measure ozone.

Noticing one launched early Monday afternoon (a surprise because we’d previously only seen launches from that facility on Wednesdays and Fridays), Michael Wheeler and I decided to attempt a retrieval mission. Due to work commitments, we couldn’t just drop everything and run, so we decided to head out after work and hope it was still sitting where it landed.

The signal was received down to about 1500m altitude - an encouragingly good result leaving us with a search radius of about 1km. The plan was to drive out there then drive around until we receive the signal, get GPS coordinates then find it.

We drove two hours out there, we received the signal but then there was one small problem.

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Good News From 10Gbit Land

Previously in 10Gbit Land…

Browsing through Mikrotik’s RouterOS changelog I noticed something.

6.42rc6 includes this (Yes, this was a while ago - I’ve been busy):

*) crs317 - improved transmit performance between 10G and 1G ports;

Is this what I was after? Let’s try it out…

Connecting to host 172.16.1.20, port 5201
Reverse mode, remote host 172.16.1.20 is sending
[  5] local 172.16.1.19 port 55268 connected to 172.16.1.20 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  78.5 MBytes   659 Mbits/sec                  
[  5]   1.00-2.00   sec  75.9 MBytes   636 Mbits/sec                  
[  5]   2.00-3.00   sec  77.8 MBytes   653 Mbits/sec                  
[  5]   3.00-4.00   sec  79.3 MBytes   666 Mbits/sec                  
[  5]   4.00-5.00   sec  77.7 MBytes   652 Mbits/sec                  
[  5]   5.00-6.00   sec  76.9 MBytes   645 Mbits/sec                  
[  5]   6.00-7.00   sec  77.2 MBytes   647 Mbits/sec                  
[  5]   7.00-8.00   sec  75.9 MBytes   637 Mbits/sec                  
[  5]   8.00-9.00   sec  77.0 MBytes   646 Mbits/sec                  
[  5]   9.00-10.00  sec  76.5 MBytes   642 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec   774 MBytes   649 Mbits/sec  6065             sender
[  5]   0.00-10.00  sec   773 MBytes   648 Mbits/sec                  receiver

iperf Done.

Still a few (hundred) megabits short, and a rather high retry count, but certainly better than what we were seeing before - so I’m happy to go back to bridging rather than routing.

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LTE Gateway - the theory

I’m building a LTE to WiFi modem for the car. There are many existing devices to do this, including your mobile phone, so why build one?

I’d like something that can receive a better signal than a mobile phone - especially as our newfound hobby of radiosonde hunting takes us further afield even more than before. And most phones these days are no longer fitted with external antenna sockets. I’d also like it to be permanently fitted into the car, so it’s just “there”. Decent WiFi that extends out of the car would be a plus too.

Here are just a few of the commercially available options for doing this that I’ve collected over the years:

On the left we have the Huawei E585, one of the first such devices. On the right, the ZTE MF70. In the middle, from top to bottom, the Huawei E3872, the Netgear Aircard 785S and the Netgear AirCard AC790S. The E585, 785S and AC790S have internal batteries, and all except the E585 have external antenna sockets.

In this post, we’ll look at why I didn’t just use one of these devices (to be fair, the AC790S still gets a bit of use outside the car) and what hardware I’m planning to build my own with.

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