Joe, First off, I can't thank you enough for the time you're taking
for me. It's very enlightening and informative, and I appreciate it!
However, I'm not sure I've explained my issue in enough detail.
I have no problem decoding in a general sense. For example, on a
busy 20M JT9 band segment, if there are 12 stations all transmitting
at once, chances are excellent that I'll decode every one of them -
even down to levels of -25, sometimes even -28 dB.
It's only when I engage a station in QSO that I see a problem. It
works either of two ways:
1. Station calls CQ
I answer the CQ
He replies to my call and he is not decoded
2. I call CQ
Station responds to my CQ and is not decoded
It's almost always that first transmission from the other station after
I have transmitted
that is not decoded.
What really makes it difficult to diagnose is the fact that while
his signal was not decoded, every other signal on the waterfall IS
While it doesn't happen every time, I would guess that it occurs
around 60 to 65 % of the time. It is more prevalent on the higher
bands (30 thru 10M) and not nearly as much on the lower bands (160
I have recorded these using the WSJT-X audio recorder, and when
played back, the same thing happens. Other stations decode just
fine, but the one I'm in QSO with loses that first decode. Almost
always, the rest of the QSO is fine, and unless I'm working a very
weak station, the rest of his transmissions decode fine.
I have to conclude, that while you may very well be right about the
sound card in the SignaLink being quite noisy, that it is very
unlikely that this would affect only one signal out of many on a
waterfall - or that the only one it would affect would happen to be
the one I'm trying to work at that moment, repeatedly.
This problem has been going on for months, and is not limited to
WSJT-X. It also happened with previous versions of WSJT as well as
JT65-HF. However, I have had no problems with any other digital
software such as DXLabs, MultiPSK, MMSSTV, EasyPal, and so on. It's
only JT65 and JT-9 that seem to have an issue.
Tnx es 73
On 8/29/2013 11:50 PM, Joe Subich, W4TV
> The SignaLink USB, at least with Windows 7 does not
have a "line"
> input - only "microphone".
"microphone" vs. "Line" is only a matter of the USB CODEC
one would assume the hardware designer chose the
input voltage level (and internal gain settings in the
for the device being used.
> The first thing I noticed was that to bring the audio
level from the
> SignaLink (step 7) up to 20 or 25 dB I had to turn it
all the way up.
> May very well be due to the fact that I turned the
Windows input from
> 100% down to 65%.
Then increase the Windows input. In theory increasing the
the sound card driver would make it easier to overdrive
the CODEC but
perhaps your device is gain limited (or the transceiver is
> Does the position of the cursor in the waterfall have
any bearing on
> what is decoded?