derby and which other station are the only ones to not have a frequency?
ulverstone
col : callsign | area served | frequency | band | fate | freq currently | purpose row 1 : 7cae | hobart | 092.1 | fm | changed call to 7the ca. 1980 | 7the | community row 2 : 7dy | derby |  | am | moved to scottsdale and changed call to 7sd in 1954 | 7sd | commercial row 3 : 7ex | launceston | 1008 | am | moved to fm in 2008 as 7exx | silent | commercial row 4 : 7ho | hobart | 0864 | am | moved to fm in 1990 as 7hho | 7rph | commercial row 5 : 7ht | hobart | 1080 | am | moved to fm in 1998 as 7xxx | 7tab (hpon) | commercial row 6 : 7la | launceston | 1098 | am | moved to fm in 2008 as 7laa | silent | commercial row 7 : 7nt | launceston | 0711 | am | moved to fm in 2006, retained call | silent | national row 8 : 7qn | queenstown | 0630 | am | moved to fm in 1991, retained call | 7rn | national row 9 : 7qt | queenstown | 0837 | am | changed call to 7xs in 1988 | 7xs | commercial row 10 : 7uv | ulverstone |  | am | moved to devonport and changed call to 7ad in 1940 | 7ad | commercial row 11 : 7zl | hobart | 0603 | am | changed call to 7rn in 1991 | 7rn | national
derby and which other station are the only ones to not have a frequency?
Callsign Area served Frequency Band Fate Freq currently Purpose
7CAE Hobart 092.1 FM Changed call to 7THE ca. 1980 7THE Community
7DY Derby AM Moved to Scottsdale and changed call to 7SD in 1954 7SD Commercial
7EX Launceston 1008 AM Moved to FM in 2008 as 7EXX silent Commercial
7HO Hobart 0864 AM Moved to FM in 1990 as 7HHO 7RPH Commercial
7HT Hobart 1080 AM Moved to FM in 1998 as 7XXX 7TAB (HPON) Commercial
7LA Launceston 1098 AM Moved to FM in 2008 as 7LAA silent Commercial
7NT Launceston 0711 AM Moved to FM in 2006, retained call silent National
7QN Queenstown 0630 AM Moved to FM in 1991, retained call 7RN National
7QT Queenstown 0837 AM Changed call to 7XS in 1988 7XS Commercial
7UV Ulverstone AM Moved to Devonport and changed call to 7AD in 1940 7AD Commercial
7ZL Hobart 0603 AM Changed call to 7RN in 1991 7RN National
Ulverstone