[Collins] 312B-4/5 wattmeter coupler query

[Dr. Gerald N. Johnson]

On Fri, 2008-08-01 at 12:51 +0900, Yong Surk Lee wrote:
> Hello;
>     I own a new coupler(rf pick up for wattmeter) which I am planning to use in a 312B-4/5.
> This coupler looks exactly the same as the one in 312B-4/5 but internal component values are different.
>  This one has 
> R3=  6810 
> R4 = 7320
> R5 = 619
> R6 = 681 ohms which are different from the old one in the 312B-4/5.

How much are they different? The resistor values were selected to adjust
for diode variations so probably vary from unit to unit by more than
20%, but are 1% resistors for long term stability. They seem to be in
the 10:1 ratio for 10:1 power indications.

I know the same coupler design was used in several pieces of equipment.
I don't seem to have a 321B4 manual on my computer.

> Can this coupler be used with 312B-4/5? 
> Or was this coupler made for different equipment?

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer