Stratux is good enough for a student starting off, that doesn't own a plane. My instructor has a Sentry and we have gotten 2 false alarms for Carbon Monoxide which we acted on. And in the past 3 weeks it's been turning off mid flight. So now my instructor has just been connecting to my Stratux and keeping his Sentry off and only using it in case the stratux acts odd.
My recommendation are these with it:
https://www.amazon.com/gp/product/B00CJG2ZYM/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B01EROIUEW/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
and you will have to use something like makexyz to print a suction cup mounted antenna holder.
https://www.thingiverse.com/thing:1720290
SuctioncupmountVK162only.STL
makexyz.com
you'll need to get it made with ABS & make sure you select 100% infill.
you can find suction cups that fit it at Lowes, but not home depot or staples. I tried both.
the advantage of the external GPS is you keep the unit out of the direct sunlight, and way better reception. To use the external GPS you'll have to unplug the internal GPS, if you use that USB extender. It will just stick out of the case through the provided hole.
I had two internal GPS's perform very poorly. I have one of them sitting on my desk right now. It's the Stratux GPYes 2.0.
The internal GPS would never get better than 10M accuracy, but on 5 straight flights the best it was connecting was 100+M accuracy.
With the external GPS I've been getting 3M accuracy at the worst.
I did have it lose connection the other day, which resulted in me having to assign a new static IP and then it started working.
The advantage of the static IP with the Stratux is your device iphone, ipad, etc will keep its LTE data connection active if it has one. If you use the automatic IP option you'll lose LTE, which sucks for sitting on the ground.
Let me know if you need any more info.
It is just an antenna. If you look on the backside of the GPYes there's a beige square thing. That's the antenna. The external kit just moves that antenna outside the case so you can remotely mount it to have a better view of the satellites. The VK-162 (https://smile.amazon.com/dp/B01EROIUEW/) is a different story. It basically is a GPYes with a long USB cable on it and is more what you're thinking. That moves the entire GPS module (antenna and everything) outside the Stratux. You can do the same thing by taking your GPYes and putting it on a USB A to A extension cable, but it doesn't have a nice housing around it like a VK-162. 2 different ways to do pretty much the same thing. Get the antenna away from the noisy electronics in the Stratux case and give it a better view of the sky.
Metal materials scatter and reflect radio frequencies (like Wi-Fi, bluetooth, analog radio & television, GPS, radar, etc.). Since your GPS antenna is inside the aluminum case, it is not going to receive very much signal, and the signal it will receive won't be very good quality.
If you want to keep the metal case you could get the external GPS antenna:
https://www.amazon.com/gp/product/B01EROIUEW
Or, you could buy the plastic case as you mentioned. I have the plastic case for my Stratux and it's definitely a lot sturdier than it looks!