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

[Kevin Purcell]

I know that feeling!

Another question:  Is it still a MOSFET (like the Omni C) or did they  
make the change to a higher emitter current BJT such as the 2N3886  
(like the Argosy 1 second revision) or 2N5109 (like the Argosy 2)?

It seems like TT were fiddling with the designs in the early 1980s  
making incremental improvements.

73
Kevin

On May 20, 2007, at 1:21 PM, Duane - N9DG wrote:

>
> Oooopsie, I miss read my schematic. They are actually MBD
> 101's too. I'm road weary from the long drive back from
> Dayton. The take away lesson is: Don't read schematics when
> tired.
>
> Duane
> N9DG
>
> --- Duane - N9DG <n9dg at yahoo.com> wrote:
>
>>
>> Looking at the orignal Corsair mamual I have it shows the
>> first mixer being made from 4 discrete MPN 3404's. As far
>> as
>> I know the CII's all used the monolithic quad.
>>
>> Duane
>> N9DG
>>
>> --- Kevin Purcell <kevinpurcell at pobox.com> wrote:
>>
>>> Excellent. Thanks Steve for that data point. And Don,
>> NN8B,
>>> who
>>> replied too. Both have the Corsair 2.
>>>
>>> So they had switched by 1986.
>>>
>>> Anyone with an original Corsair (Corsair 1, so to speak)?
>> I
>>> think
>>> that might be the rig they made the switch to schottky
>>> diodes.
>>>
>>> It would just take a second to check the schematic in the
>>> manual on
>>> the RF Mixer board :-)
>>>
>>> They won't be MPN-3404 PIN diodes (which appear in fours
>> in
>>> the
>>> Corsair too) but something else.
>>>
>>> I'm sorry I didn't mention the quad option too (so people
>>> go hunting
>>> for 4 diodes) as it is similar to the digital Argosy RX
>>> mixer.
>>>
>>>> TT will use either four discrete diodes (probably
>>> switching diodes
>>>> if they were still using them but they may be discrete
>>> schottky
>>>> didoes) or, more likley, a single quad schottky
>> package,
>>> as they do
>>>> in the 525D Argosy digital which is an ND487CI.
>>>>
>>>> Does the RF mixer board have a ND487CI on it?
>>>>
>>>> Or a similar 4 legged package between a pair of
>>> transformers and
>>>> taking signal from the LO via a driver?
>>
>>
>>
>>
>>
>>
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--
N7WIM / G8UDP
Kevin Purcell
kevinpurcell at pobox.com