What ever you do make sure you could do a career in it.
As a reservist ACISS (Army Communication and information Systems Specialist) I love my job. That being said I only do my job, 1 or 2 nights a week and 1 - 3 weekends a month.
What I like about my job is the variety. While the end goal is always to provide communication support for the army this can be done in a variety of ways. Sometimes I'm dismounted and running around with the infantry (which can be fun when it doesn't rain
). Other times we will set up a cp sometimes we operate out of the truck, other times it is literally an antenna out of a window. Or I can I be doing 8 on 8 off in the TOC. I even got lucky and managed to get to participate in an amphibious assault which was pretty fucking cool. I've also been on shift while an amphibious assault was happening , not quite as cool as being on the boat, but nevertheless ;D. One other time I was told that if I wasn't out of an area by a certain time I was going to die as they were going to live fire artillery in the area. Sometimes I sit on a hill for the weekend and relay messages while watching movies on tablet. I've worked with Service, Engineers, Infantry, MPs and soon will be working with the artillery. Throughout my time with the infantry I've had various roles. I've been the a platoon sig, an OC's sig, a duty sig in an infantry Cp, a duty sig in a TBG Toc. I've literally experienced every piece in the puzzle and it has made me a better signaler as a result.
I also like the early opportunity of leadership in the trade. I'm currently a detachment commander and I am responsible for up to three people, thousands of dollars of equipment and I am responsible to liaise with senior officers from other units and at time provides guidance and suggestions with regards to communications. It truly is a lot of a fun.
There some things I hate and sometimes I'm bored (especially on the midnight - 6pm shift), but it is what is and the good outweighs the bad otherwise I would of left the reserves.
Now I know the reg force is a whole other can of worms but if this sounds remotely interesting check out the video.
http://www.forces.ca/en/job/armycommunicationandinformationsystemsspecialist-171
edit:
What you should do is go here
http://www.forces.ca/en/jobexplorer/browsejobs-70
And filter the jobs by a category that sounds interesting to you, read the descriptions and watch the videos. After read some threads on here and after if you still have questions ask them and someone will answer them.
Best of luck