[Premium-Rx] Preselector for HF Receiver

[Enrique Fernandez García]

 Hello all,
 
    I am quite confused about what preselector to choose for my Racal 1772 receiver.   Single pole or four pole?
 
   Recently, I have read an article about preselectors and says that one pole provides outstanding protection against out of band interferences.
 
   Harris RF 551 A could be a good election but it start to work from 2 Mhz and I am interested in a full coverage of HF spectrum.
 
  Any recommendation or advice would be greatly appreciate.
 
  Thank you very much.
 
  Regards