Re: VK4PP uBitx LPF BANK add-on Board

Jerry Gaffke
 

I interpret this measurement from Glenn:
    "-32dB from one set of contacts to the other. (common terminal)"
as being from KT1 pin 14 to pin 16 as seen in the uBitx schematic.

Also, interpret his -39 and -41 dB numbers to be from one relay section to the other,
which I averaged as -40dB.    For example, KT1 pin 12 to pin 5.

I now suspect those assumptions are incorrect, but the analysis could easily be adjusted to for any change to those two numbers.

Jerry


On Fri, Aug 31, 2018 at 03:40 AM, Glenn wrote:
All good points Warren.   I did some checks of isolation using a typical DIP relay, type HK19F. DPDT

I made a small jig to hold the relays and measure isolation across contacts etc.
Typically it was -34dB across open contacts,
-32dB from one set of contacts to the other. (common terminal)
-41dB from open terminals on each side
-39dB from common of one pole to open on the other pole.
-48db from common to coil.
 At 30MHz.  Better as freq drops of course.
That's without effects of a PCB and various other traces.

glenn

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