Old tv, 1 channel only. Why?

I has a tv (sharp-lc20s1). I think it is an old one. I plug that tv in the provided tv-antenna in my apartment wall.
I searched the channel an only get 1 channel. It said that there are at least 5 channel for hiroahima.
Do I need a digital terrestrial tunner to get the other channel?
What type of tunner and how to set it up?

Thank you.

You should ask to house owner/estate agent/realtor first.
BC if using "Cable-TV" no need digital tuner.

If not you have to buy a digital tuner (not so expensive)
https://itunews.itu.int/en/1537-Switching-to-digital-television.note.a...
http://buffalo.jp/pqa/category/110_multimedia/faq2095/images/001.jpg
or buy a new recorder. (include digital tunner)
But also recieving digital TV（地デジ/chi-deji）needs UHF antenna.(No VHF)
http://www.urbanc.jp/img/img_uhf.gif
(Don't forget asking to house owner/estate agent/realtor)

Cheapest way is USB 1(one)seg tuner for PC or.
http://www.redspyce.com/db01/wp-content/uploads/2013/07/lt-dt306_w1.jp...
http://shopping.c.yimg.jp/lib/sanwadirect/400-1sg003_740_250.gif
Usb full seg tuner exist but not cheapest.
http://wm.netprice.co.jp/@0_img/goodsimg/P83355/m_01.jpg
(no realated that TV monitor)

full seg vs 1(one)seg :
https://en.wikipedia.org/wiki/1seg
http://i.gzn.jp/img/2014/05/14/aquos-pad-sh-06f-dcm2014sm/P2000532.jpg

this model is not digital.