REST Query no results

Hello,

I'm trying to do a simple query the rest service with a filter of system.hoststatus = normal using the following parameter:

systemProperties:"{'name':'system.hoststatus','value':'normal'}"

so my entire post string looks like this: 

https://me.logicmonitor.com/santaba/rest/device/devices?filter=systemProperties:"{'name':'system.hoststatus','value':'normal'}"

I'm getting a response, but its always empty:

{
  "status" : 200,
  "errmsg" : "OK",
  "data" : {
    "total" : 0,
    "items" : [ ],
    "searchId" : null,
    "isMin" : false
  }
}

Am I fundamentally mis-understanding the syntax for the query?

Thanks!