jks

Fixed in v1.272
From the CHANGE_LOG file:

v1.272  March 14, 2019
    Added URL parameters "p", "prot" and "protected" (they are all equivalent) to force a
        password protected channel to be used when connecting. This is for the case of a Kiwi with
        a mix of password protected channels and publicly available channels without a password. 
        And you want to connect without decreasing the pool of public channels.
        
        Note that if you are connecting from the same local network as the Kiwi, and admin auto-login
        has been setup, this is counted as a connection from the password protected pool and you
        do not need to specify this parameter. So you would not need to specify the "prot"
        parameter for a Kiwi on your local network but you would need it for a Kiwi installed at
        a remote location. Or it would be needed by a group of users to access the private channel(s)
        without impacting the availability of the public pool.

More information about URL parameters: http://kiwisdr.com/quickstart/index.html#id-user-tune
kiwiclient.py needs to be modified to take advantage of this change.

There seems to be a couple of issues here. Take a look at the 0 - 250 kHz band segment below. There is a terrible -60 dBm (S9+10) switcher starting at about 37 or 38 kHz. And it is very wide at the fundamental which will make the harmonics even wider. There is also this funny frequency-switching (square wave looking) signal at 67 kHz.



Now look at this 17 - 19 MHz segment. Harmonics of the square wave looking thing are clearly there as well as what sound like harmonics of the 38 kHz switcher (particularly above 18 MHz). Now you might ask why are there no harmonics of these things in the 1 - 15 MHz range (or why they are so much more heavily attenuated). But I have seen this behavior before where there seems to be selective attenuation of the harmonics. It is extremely interesting that two sources of LF RFI seem to have the same attenuation pattern.



Does it happen at all hours of the day? I'm wondering if a street light (electronic or otherwise) has gone bad. Does the signal strength change (or even null) if you rotate the loop?

I can reproduce this error by putting invalid input in some of the configuration fields, e.g. making the "photo maximum height" field blank rather than a number on the admin webpage tab (it's set to 350 by default). So look at all the field values carefully.

You can also cause the default kiwi.config file to be reinstalled by doing:

cdp
mst        // stops server
cdk
mv kiwi.config kiwi.config.save
cdp
mi         // make install       
ku         // restart

So the problem here is that FT8 has a much greater time synchronization requirement (i.e. "wall clock" time) than WSPR does. The timing of the audio hitting FT8 must match what time the FT8 program is getting from the host operating system within a second or two at most.

The Kiwi produces a delay in the audio stream because it has some buffering. Buffering is required because it is the only defense against latency/interruption issues in the network, particularly when the audio is being delivered by the Internet over long distances with lots of potential points of interruption. So you are already being disadvantaged by the time delay of this buffering to begin with. Any additional cumulative delay by other software behaving badly (e.g. sample rate compensation by the VAC) may push the total timing over the FT8 limit.

One thing you could try is reducing the Kiwi buffer size to reduce the fixed delay. The penalty for doing this is that you will have much less immunity to short-term network interruptions. That means it's important to make sure there are no highly variable latency devices in the path between the Kiwi and computer running the browser, like a WiFi router or a cheap Ethernet switch that might behave badly with heavy traffic on the other ports.

Add "abuf=n.nn" to the URL where n.nn is a number in seconds of the minimum audio buffer size. Start with 0.5 and experiment with a range from 0.3 to 0.8

It would also be interesting to know on the control panel "Stats" tab what the value of the Audio "Qlen" (queue length) is when you are having problems versus what the value is when starting (this value will vary when the abuf= value is changed)

That's the sound the computer program makes to try and wake up the late-night board op who's fallen asleep and let the programming run out..