Clicked field says to me that this Redirector is living under a chart or table? And thus that this is a chart or table drilldown config?
In that case, yes the key that you're looking for wont be just $host$. Look in the Sideview Utils docs (inside the app itself), for the docs around linking, and also the docs around Table and Chart drilldown.
Here's also a quick summary for you below:
If the field displayed in the table is "host":
If you're using Table you want $row.fields.host$. And if you have multiple nested clickable Tables, you can use the "name" param to change the "row" part to something else, ie "row" is just the default value of the optional "name" param.
If you're using SimpleResultsTable you want $click.fields.host$ (Note that Sideview Utils patches SimpleResultsTable to add this key) and you can likewise use the "drilldownPrefix" param to change the "click" part if you need to.
And if you're using Chart drilldown, either JSChart or FlashChart, most often you want the "split by" field, aka the field in the legend, which is always $click.name2$. If you want the pie wedge or a bar in a simple bar chart, you'll want $click.value$. As an advanced topic, if you're plugging this back into a search, especially if it's a complex chart where you don't know the fields in advance, you might prefer to use $click.searchTerms$. Sideview Utils has a lot of fancy code to parse out exactly what the searchterms for the click should be and to quote things appropriately. (It can even figure out and unwind OTHER and NULL for you)