All,

I have a new WinSDR release available on my web site. You can download it
from here http://www.seismicnet.com/winsdr/. The release version number is
2.0.7. There are two new features in WinSDR. The first one is the ability to
filter the data used to produce the GIF images. In the GIF Settings dialog
box you will see a new group box called Filter Control. You can enable or
display lowpass and highpass filters, set the cutoff frequency and the
number of poles for each channel using the controls in this group box.

A note about digital filtering. The process of digital filtering can take a
lot of CPU time to filter the data used to produce the GIF images. You need
to make sure your system is fast enough to had the extra load on the system
when you filter the GIF images. One way of monitoring how well your system
is running, is to open the Status Viewer (use the View / Status Viewer menu
items to open this dialog box) in WinSDR and keep an eye on the Max Input
Queue number on the bottom right hand side of the dialog box. The first
number is the maximum number of RS-232 input characters seen in the input
queue. The second number is the size of the queue. This is currently set to
32678. If the system is very busy doing other things, like creating GIF
images, then reading the input data, the input max input queue number will
get larger. If WinSDR cannot keep up with the data coming from the A/D
board, the input queue will fill up to 32768 and you will start seeing data
errors do to the loss of data. If this happens, you either need to turn off
filtering or get a faster system.


The other thing new with WinSDR is the support for a new GPS receiver. I was
looking around for other GPS options other then the Motorola ONCORE receiver
and came across the Garmin GPS 16 Sensor. This receiver has the antenna
built in and it has the all important 1 pulse per second output signal
needed for accurate time keeping. More info on the receiver can be found
here http://www.garmin.com/products/gps16/index.html. This is a very nice
receiver. Since the receiver and antenna are mounted together, extending the
data cable length between your datalogger system and the receiver can be
done with a standard 9-pin to 9-pin RS-232 cable. I have tried 50 feet (~16
me) of cable without any problems. The receivers I have been getting run on
~5 VDC, higher voltage models are also available. What I have been doing is
adding two jumpers on my serial output A/D board that supply +5 volts to the
receiver and a ground signal through the RS-232 cable. Since the receiver
inputs/outputs standard RS-232 signal levels (except the 1 PPS signal, it's
0 to 5 v) there is no need for a interface board like what's needed for the
ONCORE receiver.

To use this new GPS receiver you must upgrade your A/D board firmware to
version 2.0. The new firmware version is included in the install package. In
the System Settings dialog box in WinSDR you will see a new Time Reference
Type called GPS Garmin. If you are using the Oncore receiver, make sure you
select the GPS ONCORE item. An adapter is needed to covert the RJ45 8 pin
connector to a 9-pin RS-232 connector. I have information on this page on
how to do this http://www.seismicnet.com/winsdr/gps.html.

The Garmin GPS 16 also supports a new differential GPS system called WAAS.
Currently it's only available here in the States. More info on WAAS can be
found on the Garmin site. If the receiver can see one of the two WAAS
geostationary satellites, the position information can be improved to less
the 5 meters. The WAAS signal is not needed for accurate time keeping.

That's it....

Larry Cochrane
Redwood City, PSN


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