Some really basic first checks…
What receiver antenna are you using ? (this receiver is not supplied with one by HK so you need to add your own)
Check the polarity of the RX antenna connections ( SMA or RPSMA) It is possible to fit both halves which have inner sockets and there is then no connection, one side should have a pin.
Is the TV set to the correct AV input source for ‘composite’ video ?
Is yellow plug in video, with red & black plugs in the two audio channels ?
Do you have sound but no video or nothing at all ?
What power source are you using for the reciver ?
Maybe this will put you in the right direction