A few things to check (just in case). Have you set the input and output on the Xiegu to Line, adjusted the levels, enabled the VOX, and turned the volume up on the tablet?
Hi Derek. I think this is the one I've got: www.aliexpress.com/item/1005004347472864.html?spm=a2g0o.productlist.main.1.117dsgvgsgvgBC&algo_pvid=19e5402f-c4a2-4ad4-bd6b-063602d00868&algo_exp_id=19e5402f-c4a2-4ad4-bd6b-063602d00868-0&pdp_npi=3%40dis%21GBP%2116.4%2110.67%21%21%21%21%21%40212243c016813019452133064d06cc%2112000028849467921%21sea%21UK%212367807122&curPageLogUid=C3I5JUq2kfA7
Hi. It's hard to say without knowing what car you have, but I'm assuming you can get a mount installed - on the gutter, boot or other. It depends which bands you want to work, but a mono-band will typically be more efficient. Diamond do a range of mono-band whips that might do the job, search for Diamond HF Whip (for 20M, the model is HF20FX). Hope that helps :)