Take this with a grain of salt because I've not tried it myself but back when ZWO introduced the ASIAir Pro, a number of users complained about poor WiFi range as the ASIAir box had no external antenna. A number of people set a wireless WiFi range extender (go to your favorite internet store and search for WiFi extender, WiFi range extender, WiFi signal booster, etc) next to the ASIAir Pro to boost the signal. As long as you have a way to power the WiFi extender, you should be good to go. WiFi range extenders don't draw very much power so, assuming you're only powering that and nothing else, even a small power pack with an AC outlet built in should supply power for quite a while. For instance, I'm seeing several 30 to 40 Ah power supplies for $60-$70 US. Range extenders typically aren't going to draw much more than 10 watts so a 30 Ah power pack should keep your range extender running for a number of nights w/o recharge. That's under ideal conditions, of course ... you're going to lose a lot of power going from DC to AC and a cold night can substantially decrease a battery's capacity but, still you should be fine for a weekend's use. If you want to be safe, double the capacity (i.e., something more like a 60-100 Ah pack). Any electrical engineers or anyone more familiar with WiFi extenders running off batteries feel free to unmercifully correct me.

WiFi extenders are usually not a good idea for regular use.

But in urban areas where there usually are no other network this could work very good.

But to get best coverage it should be in the middle of both devices. But you get less bandwidth using an extender but not a big issue if you just want to use your seestar.

I have tried to find information on how to open the seestar so that I could replace the original antenna. It really don't have to be on the outside. But a better antenna with more gain on the innside should also give a little more range.

I do use a range extender.
I use the TP-Link AC1200 WiFi Extender which is A/C powered, so I lug around a portable battery bank with A/C outputs and power it off that (using a 12 inch extension cable), and can of course power the S50 as well.
Looks like the GL.iNet GL-AR300M16-Ext is USB-C powered so that may be a better option

Anyway, I just set it up so its upstream Wifi network is the ZWO Seestar wifi itself, and it mirrors the name of that network with an extra bit at the end that I can connect to. Out in the field I can set up the Seestar some distance away (usually trying to get it out of the wind, and maybe block the city lights) and connect to the wifi extender from a hundred feet or more away while inside my car. Everything works better when you have a strong connection.

LA3QMA They only want to be at the midway point if both ends have similar performance capability. In this case we can assume the scope's is worse so the range extender should be closer to that.

Roger Pittock Yes i know but my point was that it could be further away from the scope and the phone/tablet. If all clients have a bad signal your back to step one. Anyhow modern WiFi extenders that are actually repeaters are a better choise compared to the devices that many use that increase the transmit power of the unit. And i.e TP-Link also have P2P with directional antennas. And i guess this is better than modify the seestar with an external antenna.

7NL4E3J2 If your device supports it, try switching the station mode WiFi to use the 5GHz band, as this can avoid interference from the 2.4GHz channel and may provide a more stable connection.

Daemn42
Can you please give more info as to how you attached the tplink to the seestar? Like what password and security type you used. I tried 1234568 but it didn't work.