Hello ,
While I was waiting for my K3 to arrive, I have been doing some experiments
with the Softrock Lite .
The softrock lite is an amazingly good rx for its 11 $.
I was interested in a panoramic display, so I tried it out on the TS-850 . With
a 35.362 Mhz Xtal and Rocky software that was not much of a problem. It worked
just fine.
For the K3 , I ordered a 32.812 Mhz Xtal .
I read here that more isolation is needed to prevent the oscilator signal (
8.204 Mhz in my case) to go back to the K3.
Someone suggested the use of a HCPL-4562 .
First I measured at the input of the Softrock, with the TS-850 and found a
strong S9 carrier at 8.204 Mhz
With the HCPL-4562 in front of the Softrock, I was able to hear the carrier on
the input, but no indication on the S-meter. That should be enough isolation, I
think.
Then I added an extra stage . I copied the schematic from the K2 preamp with a
2N5109 to give the signal from the IF an extra 14 db or so and extra isolation.
I still could hear the carrier , somewhat quieter, and see nothing on the
S-meter.
The whole thing is built into a metal box and shielded between the different
stages, and an extra shield between the HCPL-4562 input and output. The
connection between the K3 and the adapter is a short coax cable with two bnc
plugs.
When changing from xfil1 to xfil2 and xfil3 on the K3, I noticed a shift in the
display, so I made three different entries in the rocky.ini file: in the [Band]
section I added :
FL1=8625
FL2=9700
FL3=9630
I had to experiment with these values until the signal was at the zero mark on
the scale .
One important thing I overlooked was the fact that you need the KXV3 interface.
It was only when I was building the K3 that I realised that... :)
I have no special soundcard, I use the on-board soundcard of my pc.
It works fine with Rocky, I haven't tried any other software ( yet ).
73 de on5ao
K2 #5237
K3 #0324
jo benoit
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