[Elecraft] 1N5711 diodes in directional coupler

[Jack Brindle]

I agree with Lyle's discussion on this. The reason for using 1N5711s is 
to get low power accuracy. If you are running high power only, then you 
probably could get by with 1N4148s in the directional coupler, 
sacrificing low power operation.

If you really want to replace them today, you could probably get away 
with using the 1N4148s temporarily, replacing them with real 1N5711s 
when you get them. 1N5711s are relatively easy to get (here in Silicon 
Valley, at least), obtainable from Mouser, DigiKey or even Scott at 
Elecraft...

The original Breune bridge circuits favored by many (including DeMaw) 
used germanium 1N34 diodes because of their low forward voltage drop. 
They are no longer manufactured, and hard to obtain. If you have some 
in your junk box, they might be a better selection for temporary (and 
maybe longer) use.

On Aug 8, 2004, at 8:14 AM, Indy wrote:

> These are used in the directional coupler of the K2, KPA, and KAT-100. 
>  I have lost these to ESD more than once.  Several questions;
>
> Gary says that 1N5711's give more accurate readings than lessor diodes 
> such as the 1N4148... question; how much more accurate, and how 
> critical is this accuracy?  Would the 1N4148 be more, less, or the 
> same susceptability to ESD?
>
> I don't have any 1n5711's in my stock, but I do have some very fine 
> PIN diodes, labeled, MA 47 266.  Are these acceptable substitutes for 
> 1N5711's?  Would they be more or less accurate in the directional 
> coupler?  Would they be more or less susceptable to ESD damage?