[Elecraft] CP1 coupler query

Don Wilhelm w3fpr at embarqmail.com
Wed May 20 08:13:54 EDT 2009


Chris,

I would think the input levels of whatever instrumentation you will 
connect to the coupler as well as the power levels that you will have at 
the input will dictate whether you build it for -20 dB or -30 dB.

I have both and use them on the test bench with a Tandem Match power/SWR 
meter.  For better accuracy at lower powers, I use the -20 dB coupler 
and my Tandem Match gives good results from about 2 mW up to 200 Watts.  
If I have need to measure above 200 watts, I switch to the -30 dB 
coupler which gives me a range from 20 mW to 2000 Watts.

My application is just one example - look at your highest power level 
and the sensitivity of your instrumentation.  That will tell you which 
range you need.

73,
Don W3FPR

Chris Meagher wrote:
> I have a CP1 dual directional coupler kit.
> Debating whether to make it -20dB or -30dB.
> If I were to make it for -20dB, could I then add Elecraft step attenuator
> to extend the range without causing problems at higher wattage (like core 
> saturation with the 20dB toroids).
> Thanks for any help.
> Chris VK2LCD  K2#3666, K3#685 
>
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