====== Argosy Model 525 / 525D Identification ======
**From the Ten-Tec Reflector - October 1, 2007**

The current list with contributions from: VE7BGP, WA3FIY, N4NT, NN8B  
and NS1W. Thanks too all.

^  Model  ^  S/N  ^  RX Mixer  ^  Front Panel  ^  Contributor  ^
|  525  |  00721 |  1496  |  Argosy  |  VE7BGP  |
|  525  |  00748  |  1496  |  Argosy  |  NS1W  |
|  525  |  00895  |  4 diode mixer MBD-101  |  Argosy  |  NN8B  |
|  525  |  ?????  |  4 diode mixer  |  Argosy  |  KW7CD  |
|  525  |  01096  |  4 diode mixer (TO-92 diodes not marked: probably MBD101)  | |  WA3FIY  |
|  525  |  01188  |  4 diode mixer MBD101  | |  WA3FIY  |
|  525D  |  01611  |  diode quad ND487C1  |  Argosy  |  N7WIM  |
|  525D  |  01810  |  diode quad ND487C1  |  Argosy II  |  WA3FIY  |
|  525D  |01892  |  diode quad 87clk32  |  Argosy II  |  N4NT  |
|  525D  |02497  |  diode quad ND487C1  |  Argosy II  |  N7WIM  |
|  525D  |02591  |  diode quad ND487C1  |  Argosy II  |  WA3FIY  |

So the conclusions are:

  -525 Argosy with serial number 0823 or less has a 1496 for rx mixer.
  -525 Argosy with serial number 0824 or greater has a discrete 4 diode ring (most likley using MBD101 schottky diodes) in the rx mixer. They didn't use PN diodes unlike say the 546 Omni series.
  -All 525D Argosy have a schottky diode quad ring (even though they may have either an Argosy or Argosy II front panel they all have a digital display).
  -Somewhere between serial numbers 01611 and 01810 the 525D got a new plastic front panel with a different name plate (Argosy II).

The serial number 0823 comes from the change in noise blanker design hypothesized to match the mixer type: Model 223 for 0823 or less; Model 223A for 0824 or more.

73 DE N7WIM / G8UDP\\
Kevin Purcell\\
[[kevinpurcell@pobox.com]]