[TenTec] When did Ten-tec switch to Schottky diode ring mixers?

[Steve Hunt]

Kevin,

I have a Corsair II purchased new from the UK distributor on 3rd October 1986. The serial number is 580 - 01861

The schematic shows a single component, D13, for the mixer diode quad; its part number is given as 87C2 K38

Hope this helps.

Steve G3TXQ
  ----- Original Message ----- 
  From: Kevin Purcell 
  To: Discussion of Ten-Tec Equipment 
  Cc: Kevin Purcell 
  Sent: Saturday, May 19, 2007 7:01 PM
  Subject: [TenTec] When did Ten-tec switch to Schottky diode ring mixers?


  When did Ten-tec switch to Schottky diode ring mixers?

  If you have a Corsair or Corsair II you can help by looking at the  
  schematic in the manual for the RX mixer in your TT rig. Let me know  
  the diode type.

  Why ... I've been trying to interpret some performance numbers from  
  Sherwood and trying to find comparable measurements for 1n4148 and  
  Schottky diode ring mixers to answer the question "how much worse is  
  a PN diode mixer?".

  <http://www.sherweng.com/table.html>

  Looking at the data I have it seems to be sometime in the first half  
  1980s

  The TT 546 Omni C from 1981 has four 1n4148 in the primary RX mixer  
  (1981).

  The second version (after serial 822?) of the TT 525 Argosy  
  (analogue) has four 1n4148 in the primary RX mixer (early 1980s).

  The TT 525D Argosy (digital) had a Schottky diode ring mixer  
  (1982-1986?)

   From W8KC's lineage
  <http://mywebpages.comcast.net/w8kc/lineage.htm>
  Omni C -- 1981

  Corsair -- 1983

  Corsair II -- 1987? (8/87) (production 1987 to 1990)

  Paragon I 585 -- 1988? (5/88)
  Omni V -- 1990?  (11/90)

  So I think one can be pretty sure that the Paragon and the Omni V  
  have Schottky diode ring mixers so that leaves the Corsair's as the  
  point of the design change. But if I'm wrong let me know.

  Thanks.
  --
  Kevin Purcell
  kevinpurcell at pobox.com


  _______________________________________________
  TenTec mailing list
  TenTec at contesting.com
  http://lists.contesting.com/mailman/listinfo/tentec