Over the years I've developed some requirements for my portable and mobile stations. I operate in a variety of conditions (e.g. weather, time, elevation, etc). In tougher environments I don't want to waste time fiddling with my rig, antenna, or computer. I either want to make the needed contacts in as short a time as possible or maximize my time on the air. In short I prefer to have a tactical setup. The requirements I'm presenting are based on personal experiences with a variety of gear and conditions. Additionally, I'll provide my reasoning for each requirement.
I don't have too many requirements for a rig. Most important is having multiband HF capability. Honestly 40m/20/15/10m is good enough to use JS8Call, Winlink, WSJT-X, and FlDigi.
My second most important is having a radio with USB sound card and CAT control. This makes it incredibly easy to setup and teardown, both in terms of having a single cable to plug into my computer and making it easy to reproduce software-wise. When having a USB sound card and CAT control, I can reproducibly connect each application to the rig. I have simple scripts for each rig with the correct device id's and sound card devices for said rig. Launching Winlink is as easy as starting Direwolf or ARDOPC (with rig specific configs) and launching PAT Winlink. I don't have to fiddle finding the correct device under /dev/ or finding the correct ALSA device.
For antennas I require something that's multi-band, requires no tuner, and requires very little fiddling when switching bands. I prefer having an antenna that supports 40m through 10m so I can operate day or night. I have these requirements to ensure my portable station can be tactical.
Starting off, a tuner is an additional component that I prefer not to rely on. Most of my rigs don't have one and I prefer not to have an additional component which can break or run out of batteries. Additionally, antennas that don't match, but are forced to with a tuner may radiate in an unpredictable way.
Next I want an antenna that requires little or no tuning by hand. In my experience EFHWs can be thrown on a mast or in a tree and require no additional fiddling to reach an acceptable SWR. Some coil based verticals or dipoles are fine too, assuming I can quickly and reproducibly hand tune to the desired band/frequency. For my mobile I use the SuperAntenna MP1 which I can quickly tune to the desired band using the provided ruler.
In regards to power I stick with 12V LiFePO4 batteries for several reasons. This battery chemistry is much safer than Li-on, can be stored longer, supports a large amount of charge cycles, and can delivery the high current needed for even my 100 watt HF rigs.
To add further, 12V is an absolute requirement because I can support 12V USB-C PD which is the minimum needed voltage to charge my laptops. I have numerous devices that also optionally support USB-C PD such as my phone and GoPro. I can also step down to 5V for traditional USB and charge the rest of my devices.
All 12V devices and supplies are equipped with Anderson Powerpole connectors for easy interoperability and because these connectors can support high current (20A+). Various other aspects of my off grid and portable operations support 12V such as my water kettle. Finally, my batteries are usually charged beforehand or in the field with solar.
I have two major requirements for the laptops I use. First of which is that the machine can be charged with 12V USB-C PD and the other that it run Linux.
I use a Linux distro to stay consistent. I can install a variety of Linux distributions without additional cost and most of the Linux software I use is open source so I'm not at the mercy of closed source developers. This ensures the software I train on stays around. Finally, having open source OS and ham radio applications allows me to contribute and modify functionality.