Empty radio Button Doesn't Show in the Crystal Report

Dear All

I have a Crystal Report with a string field (ATD) in Query (TendersCurrent) which I want to be shown as radio button , I made a formula field and added this code to it

Code:

if {TendersCurrent.ATD} = "ATD" then CHR(164) ELSE CHR(161);

The problem is the radio button is shown only when it achieves the condition but why it does not show when it does not achieve the condition ,
and is the chr(161) is correct or not?

Thanks your cooperation

Moheb Labib