A FPV ground station can be as simple or complicated as one wants or needs it to be. In the simplest sense, a ground station consists of three distinct items:
The receiver at your ground station is used to receive the RF video transmission from your aircraft.
It then sends the signal to the video
display through standard RCA analog video and perhaps an audio cable if you are
also transmitting audio from your aircraft.
You have 3 basic options here...
The frequency decision is the easy one of the three. You already
decided that when choosing what frequency your video transmitter would be using
so you have to get the same frequency receiver. In other words, if you get a
5.8GHz transmitter for your aircraft, you must get a 5.8GHz receiver for your
ground station. As I also mentioned in the FPV transmitter write-up, most
transmitters allow you to select several channels within the band and so do
most receivers allowing you to fine tune your system for the best video
transmission if one or two channels happen to be a little nosier than the others.
Deciding on getting an external/stand alone or built-in
receiver is also a pretty straight forward decision and in most cases it's
going to be an external. This really only applies if you use video goggles that
have an option to have a built in receiver such as the Fat Shark Dominators that I started out with.
I decided on the built-in option again for simple, easy, and portable first person view fun but that certainly doesn't make them the better choice. External FPV receivers definitely give you more connectivity & placement options and as a general rule of thumb give better overall performance. Going external/stand alone also give you diversity options.
If you already fly with a 2.4 GHz radio system, chances are you know about diversity or have at least read about it, even if you didn't know what it did. Most 2.4 GHz radio system receivers have 2 antenna leads for example and having two antennas to "listen" improves diversity so if the radio signal is weak at one antenna because of being in a bad position in relation to the incoming RF signal, the idea is the other one that is positioned along a different axis will still be receiving fine allowing the receiver to use the best/strongest signal.
Anyways, the same idea applies to FPV receivers and antennas. To improve RF signal reception quality, having more than one antenna positioned along a different axis can give you a better RF link as the receiver automatically switches back and forth between antennas constantly selecting the one that is receiving the best overall video signal.
Another dual diversity example would be if you used a circular polarized
directional antenna in combination with a circular polarized omni directional
antenna at your ground station. This particular dual diversity antenna example
will give you good long range out in front of the directional antenna, but will
still allow you to fly behind the directional antenna a fair ways because the
omni antenna will now "hear" the signal better.
This "antenna switching" can be done either within
a receiver that supports multiple diversity (generally dual diversity - two
antennas), or it can be done though something called a diversity box/controller
where two or more single diversity receivers are hooked into the diversity box/controller
and it chooses the best video signal to send out to the video display.
When first starting out, you are likely not going to need a dual or multiple diversity FPV receiver, especially if using a good circular polarized antenna set, but I at least wanted to mention the diversity topic.
I've covered FPV RX antennas in depth on the FPV antenna
On that page I make mention of something called an "antenna tracker". This is an advanced and rather costly FPV ground station add-on where directional ground station receiver antennas are used in conjunction with aircraft trackers.
The directional antenna is on a motorized tracking mount and
it will follow the aircraft around in the sky so the high gain directional
antenna is always pointed at the aircraft. Now you won't have to worry about
straying outside of the directional "listening" zone which would
knock out your video image. Again, this is a very advanced FPV option that you
won't be considering for your beginning steps into FPV, but I did at least want
to mention it.
A better and simpler solution in my opinion if you are looking for long range using higher gain directional antennas is to use a diversity setup. Multi diversity is usually going to be less expensive and simpler to use with multiple long range directional antennas looking out over a larger area of the sky over an antenna tracker system that has to follow the aircraft around in the sky. Both systems (antenna trackers, and multi diversity) in other words give similar reception results by using very different means.
Below is my "simple" FPV ground station. A pair of Fat Shark Dominator FPV goggles with the optional plug in 5.8GHz video receiver module, and an omni directional circular polarized IBCrazy Bluebeam antenna set. That's it! When first starting out in FPV, something as basic as this is honestly all you need to have lots of fun.
Below is my "slightly" more advanced FPV ground station setup. I now have an extra 7" monitor that I mount on a tripod that is plugged into the FPV goggle's receiver output so a buddy can also watch the flight. If I'm feeling really generous, I'll give him/her the FPV goggles to be immersed in the FPV experience while I pilot and view the flight using the monitor.
Lastly, here is my FPV ground station recording setup. I use my laptop plugged into the video goggle's receiver output through a USB to RCA audio/video capture device to record the FPV flight in a digital format while I fly and view through the goggles. Any conversion delay at the laptop is not an issue because the image delay occurs after the goggles. In other words, I'm still viewing the flight through the goggles in real time.