[Skimmertalk] CW Skimmer + RTTY Skimmer running simultaneously on Red Pitaya - Success!

[Bob Wilson, N6TV]

On Tue, Jul 4, 2017 at 2:53 PM, kazeringue--- via Skimmertalk <
skimmertalk at contesting.com> wrote:

> This may be a simple issue of finding the right transformer ratio for use
> on 6m. (RP input impedance goes down with rising input frequency, if I
> recall correctly)
>
> My RP skimmer is using a K9AY and a full sized "fan"
> vertical(20m/15m/10m/6m).  The vertical has 2 radials for each band. This
> goes into a combiner, W7IUV style pre-amp, and a compound step up
> transformer(3:1 into 4:1).  These are the same antennas used with previous
> softrock skimmer system.
>

The prototype 14:1 transformer (kindly sent to me by the Red Pitaya company
mounted on a small board with M/F SMA connectors) appears to be a MiniCircuits
T14-1+ <https://www.minicircuits.com/pdfs/T14-1.pdf> with approximately 1
dB or less of insertion loss from 1.8 to 54 MHz.  Perhaps your step-up
transformer combination has more loss at 54 MHz?

I have not tested the sensitivity of the RP on 6m. Does the W7IUV preamp
work up to 54 MHz?

73,
Bob, N6TV