[Premium-Rx] Collins 51J4 filter needed

[w3jn]

Fred, you can just use a 100 pF cap or so across the filter terminals (input to output) with 2.5 mH RF chokes across the two inputs terminals and the two outputs terminals.  This will give about 8KHz BW due to the fairly sharp L/C chain.  I built this on a small piece of plexiglass and just plugged it in with one a those grey panel 51J-4s some years ago and it worked fine.

73 John
  ----- Original Message ----- 
  From: premiumreceiver 
  To: premium-rx at ml.skirrow.org 
  Sent: Wednesday, October 20, 2004 8:56 PM
  Subject: [Premium-Rx] Collins 51J4 filter needed


  Hello list. 

  While this may be slightly off the topic of modern premium receivers, I have aquired another old receiver to add to the stable. It's a late grey Collins 51J4, supposed to have come from the Collins lab.

  I'm looking for either a 9 kHz filter (or other wide BW) OR a bad filter of any BW. The defective one would be used for the housing.

  Anyone have something in their junkbox? Please contact me off list.....

  Fred   k2dx



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