G'day

Could someone please help me out with the resistor values/wattages for the Microwave Modules MMT 1296 15 db attenuator pad please. I will be driving it with an FT-480R using 10 watts output.

A link to the MMT 1296 manual is at www.g4fre.com/mm1296.zip!

Best 73

Ross Anderson VK4AQ
Innisfail, Queensland
Australia

I guess you are refferring to the pg11.gif of your files, where a resistor pi-attenuator is used?
A very usefull calculator for calculating the values is here: www.microwaves101.com/encyclopedia/calcattenuator.cfm
and here:
chemandy.com/calculators/pi_attenuator_calculator.htm
Although as far as I can see the values of the resistors in your schematic are different than the ones given in the calculators. For the shunt resistors I think they are 100ohm and for the series 50ohm. Maybe the I/O impedance in your circuit is different.
About the wattage of the resistors, to be sure, I would use ones with the rating of the output of the FT-480R, thus about 10W. I guess you must not use wire resistors there (such as dummy loads) for low inductance, so you can create your values using multiple five x 2W resistors in parallel, each one five times the value of the desired final resistor.