[Elecraft] K2 - signal loss in band-pass filter

[David Lankshear]

>From postings on the reflector, it would seem that more than a few of K2 8v regulators are on the low side, including mine.

I've just ordered a couple from a local supplier to see if they are any better, but if they are not, I will "jack up" the ground lead of the 8v regulator by connecting a diode in series with it - i.e. interposed between the regulator's ground lead and the ground it was connected to.  A silicon diode like a 4148 (or 4001 to 4007) will effect about a 0v6 increase in output voltage and a schottky or germanium diode will give about 0v2 to 0v3 increase.

Of course, this "jacking up" compromises the regulator's inbuilt short circuit protection but in a stable environment like the K2 it can either be accepted that it is unlikely to ever be called to work into a short circuit, or a reverse connected diode can be introduced between output and ground as protection. 

73   DaveL  G3TJP