I've got this guy on my roof and has pretty good results. Note that it is directional.
https://www.amazon.com/gp/product/B073WQ8DXD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
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I do not have this one but am considering it for other miners I have:
Technically you can buy an external antenna like this and use extension cable to connect it to your router.
The router has MCX connectors so you may do a little bit DIY.