On Mon, 2009-01-12 at 22:42 -0600, Bob McGraw - K4TAX wrote:
> Easy solution, build a 50 ohm 10 dB pad or attenuator and use it between the
> transmitter output and the transverter TX input. For the input resistor use
> 10 pieces of 2W carbon 1000 ohm resistors connected parallel, the output R
> should be 100 ohms 2 watt and the series resistor of about 75 ohms. This
> will make a pi pad design.
With 2 watt carbon resistors being hard to buy, and having a pronounced
tendency to drift in value from heat, I'd prefer the 3 watt tin oxide
film type resistor. I've tested them to ten times rated power without
permanent damage or shift in resistance. Though they did tend to ignite
their environment from the radiated heat. True the resistive film has a
spiral cut in it. I've been unable to detect (measuring at 144 MHz) more
inductance than that of a rod the size of the resistor.
>
> You will need to bring the IF output separate from the transverter to the
> AUX RX input on the Corsair.
>
> As to the input of the transverter hit with excessive power, yep, you get
> one shot to blow the input mixer.
The mixer is fairly tough and since it needs less than a milliwatt of RF
drive there is a lot more attenuation on the transverter board, at least
30 dB, maybe as much as 37 dB, which knocks 100 watts down to 20
milliwatts at the mixer.
>
> 73
> Bob, K4TAX
>
73, Jerry, K0CQ
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