Like this:
https://www.amazon.com/3-5-Wood-Screw-Standoff-Insulators/dp/B006558WAE
If you're able to screw something into the deck, maybe something like these would work?
​
https://www.amazon.com/3-5-Wood-Screw-Standoff-Insulators/dp/B006558WAE/ref=sr_1_15?dchild=1&keywords=antenna+insulators&qid=1615247341&sr=8-15