[Premium-Rx] WJ8718A i.f. filters

[Les Locklear]

Massimo and Group,

The Government, both Military and Civilian Agencies operate on frequencies that are usually allocated and in the clear. That is one reason they usually have 3.0 khz ssb filters etc. Most amateur radio tranceivers have far better if filter shapes from that era. Many general coverage shortwave receivers also have filters that surpass those used in Government contracts.

Les Locklear
Gulfport, Ms.
Dx'ing since '57
Drake R8B
Hammarlund HQ-150
Hammarlund HQ-180A
Hammarlund SP-600 Re-Engineered by John R. Leary
Ten Tec RX-350



  ----- Original Message ----- 
  From: Massimo Corinaldesi 
  To: Premium-Rx at mailman.qth.net 
  Sent: Thursday, June 17, 2010 9:26 AM
  Subject: [Premium-Rx] WJ8718A i.f. filters


  I read the data sheet of the WJ-8718A hf receiver, and I was surprised 
  to see the shape factors of the i.f. filters are very high.
  I think in the years the 8718A was conceived - I suppose first half of 
  '80 -, the technology allowed i.f. filters having better shape factors.
  Why they did so ?

  That's just a technical curiosity.

  Thanks.

     Massimo Corinaldesi  I0MCF
     Roma
     Italy

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