I have a Diamond X50 that I use for the 2m and 70cm ham bands mounted on a pole. When I needed to mount a discone for my SDR I used one of these to put it on the same pole:

https://smile.amazon.com/gp/product/B00068YUN4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1