PostGres ODBC -- Multiple ordinal parameters ?

$DB1ConnString = "Driver={PostgreSQL ANSI};Server=192.168.0.1;Database=dbname;"

$DB1Conn = New-Object System.Data.Odbc.OdbcConnection

$DB1Conn.ConnectionString = $DB1ConnString

$DBCmd = $DB1Conn.CreateCommand()

$DBCmd.Parameters.Add("@Param", [System.Data.SqlDbType]'VarChar')

$DBCmd.Parameters["@Param"].Value = "fieldval"

$DBCmd.CommandText = "select count(*) from tablename where fieldname=`$1"

$DBCmd.Connection.Open()

$DB1Results = $DBCmd.ExecuteReader()

while ($DB1Results.Read()){

       write-host $DB1Results.GetString(0);

}

$DBCmd.Connection.Close()