WebSDR "URL" Parameters:
There are a number of parameters that may be added to the URL when accessing the KFS WebSDR:
- ?tune=[freq kHz][mode] - Specify tuned frequency and mode which may be any of am, lsb, usb or cw - as in "?tune=7200lsb" which sets the WebSDR to 7200 kHz and the mode to LSB. The mode is optional. This works ONLY if the WebSDR actually covers the frequency specified! The available modes are LSB, USB, AM, FM, SAM-L lower and SAM-U for upper sideband synchronous AM reception.
- ?zoom=[n] - Zoom waterfall "n" times on the tuned frequency when loading the page, as in "?zoom=2" which zooms 2 times. "n" can be 0 through 9, but it will zoom only the number of steps available.
- ?squelch=[n] - If "n" = 1, squelch is enabled (e.g. "?squelch=1") just as it would be if the "squelch" checkbox were selected. Squelch is not enabled if "n" = 0.
- ?smsquelch=[n] - Where "n" - which is always a negative number and is the S-meter reading for the squelch threshold, which is usually between -110 and -80, depending on the band and the amount of receiver background noise. Because of this, this parameter is most useful for VHF/UHF FM receivers where the no-signal S-meter reading is pretty constant - but it often works well with AM activity when signals are reasonably strong. If "n" = 0, the S-meter squelch is disabled. Example: "?smsquelch=-88" sets the S-meter squelch threshold to trigger when signals are above -88 dBm.
- ?nolabels=[n] - If "n" = 1, the "DX labels" (the labels under the waterfall/frequency display) are disabled and will not appear unless manually turned on with the checkbox. A setting of "n" = 0 is the default and the labels will be displayed. Example: "?nolabels=1" which hides the DX labels is the same as checking the "Hide Labels" box.
- ?altagc=[n] - If "n" = 1, the "Alternate" AGC system - which is primarily designed for AM reception - is enabled. If "n" = 0, the normal AGC operation is selected. Example: "?altagc=1" enables the alternate AGC, which is the same as selecting the Alt AGC button.
- ?10hz - This forces 10 Hz frequency display resolution. This may be necessary if you are running the CatSync software, which appears to parse the frequency as a string of characters rather than as a number and cannot seem to deal with the extra digit (representing 1 Hz) to the right of the decimal.
- ?usbcw - This causes the WebSDR to use USB for CW reception rather than the default, LSB.
- ?allow_kbd - This is the same as checking the "allow keyboard" box to permit many WebSDR functions (tuning, frequency entry, mode selection, etc.) to be done via keyboard rather than just a mouse.
- ?chan=X - This sets the audio channel to "X", which may be "left" or "right". Example: "?chan=left" causes audio from the WebSDR to come only from the left channel.
http://websdr1.kfsdr.com:8901/?tune=3900lsb - Tune KFS to 3900 kHz, LSB
http://websdr1.kfsdr.com:8901/?tune=7200lsb?10hz - Tune KFS to 7200 kHz LSB with 10 Hz display resolution
http://websdr1.kfsdr.com:8901/?tune=14155usb?smsquelch=-80?altagc=1?10hz - Tune KFS to 14155 kHz USB with the S-meter squelch set to -80, alternate AGC and 10 Hz display resolution