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G8JNJ
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How do you use your SDR
Hi All,Mine is fully public 99% of the time.I don't think the bandwidth used is excessive, but I'm on a VDSL service with no user cap (as far as I'm aware).However it does get very high usage and sometime I have to kick users off so that I can log in and use it myself.I have a particular problem in that a lot of Dutch music pirates use my SDR all day long to monitor their own transmissions around 6MHz.What I really need to be able to do is to be able lock out certain frequency ranges or restrict the amount of time individual users can stay on the SDR before getting automatically kicked off. I currently have the inactivity time out set at 15mins but I may have to reduce this still further.I now have a second Kiwi on order, so it would be good if I could link them in some way so that they both appear as one Kiwi but with eight possible connections.I previously raised this suggestion in this link https://github.com/jks-prv/Beagle_SDR_GPS/issues/48I know that there is at least one other station running multiple Kiwis on different ports so I don't think I'm the only Admin who may be interested in this idea.Most of the time (when I can log in) I use my Kiwi for general short wave listening and enjoy spotting 'unusual' activity on the waterfall. I also enjoy listening to NDB's, BC stations and Amateur stations. Quite a few of my users seem to listen to HF Aero traffic as well.I note that quite a few folks use the WSPR extension (logged as SWUKSDR) especially on the 472KHz band. I've also got antenna switching and this gets used some of the time mainly by the BC listeners in order to try and reduce interference or other stations that are co-channel.I think the KiWi has been an excellent purchase and It's certainly re-awakened my interest in Short Wave Listening.Well done John, and thanks for all the ongoing support and rapid resolution of any problems that may occasionally arise :-)Regards,Martin - G8JNJ -
How do you use your SDR
Hi All,Mine is fully public 99% of the time.I don't think the bandwidth used is excessive, but I'm on a VDSL service with no user cap (as far as I'm aware).However it does get very high usage and sometime I have to kick users off so that I can log in and use it myself.I have a particular problem in that a lot of Dutch music pirates use my SDR all day long to monitor their own transmissions around 6MHz.What I really need to be able to do is to be able lock out certain frequency ranges or restrict the amount of time individual users can stay on the SDR before getting automatically kicked off. I currently have the inactivity time out set at 15mins but I may have to reduce this still further.I now have a second Kiwi on order, so it would be good if I could link them in some way so that they both appear as one Kiwi but with eight possible connections.I previously raised this suggestion in this link https://github.com/jks-prv/Beagle_SDR_GPS/issues/48I know that there is at least one other station running multiple Kiwis on different ports so I don't think I'm the only Admin who may be interested in this idea.Most of the time (when I can log in) I use my Kiwi for general short wave listening and enjoy spotting 'unusual' activity on the waterfall. I also enjoy listening to NDB's, BC stations and Amateur stations. Quite a few of my users seem to listen to HF Aero traffic as well.I note that quite a few folks use the WSPR extension (logged as SWUKSDR) especially on the 472KHz band. I've also got antenna switching and this gets used some of the time mainly by the BC listeners in order to try and reduce interference or other stations that are co-channel.I think the KiWi has been an excellent purchase and It's certainly re-awakened my interest in Short Wave Listening.Well done John, and thanks for all the ongoing support and rapid resolution of any problems that may occasionally arise :-)Regards,Martin - G8JNJ -
internet lag and decoding JT65
On my local connection I'd estimate that the KiWi lag is only about 200-500mS maximum.Just about a long enough a delay to cause you to hesitate whilst speaking if you are monitoring your own transmission.Over the internet the delay can be much longer, one user has reported a delay of around 2 seconds.I think a lot depends upon variables in the users ISP and network routing, all of which are outside the Admins control.Regards,Martin - G8JNJ -
AM Overload Solved
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GPS Admin screen
Hi,The patch antenna supplied with the KiWi doesn't seem to be as good as some other GPS antennas.A lot of modern double glazing uses a metalised film to provide additional heat retention, but this also has the effect of greatly reducing the strength of GPS signals.I rarely used to get two satellites at any time with the supplied patch, but this week I ran in some more cables so that I could split the feed from an existing Trimble GPS antenna and now I'm typically seeing six at any moment with four or more at good strength most of the time.Regards,Martin - G8JNJ -
External Functions
Hi All,I would like to be able to switch antenna ports directly from the BB GPIO pins via the web interface and also change some text on the web interface if some of the BB GPIO pins are switched externally.Kari, OH1KK, has done a great job in writing the Kiwi extension to drive a MS-S7-WEB antenna switch . But I really don't want to be tied to specific hardware as I've already got a number of different peripherals that I'd like to control & monitor directly from the KiWi.Is there an easy way (I'm not a coder) to modify Kari's extension to drive and receive commands from the BB ?Regards,Martin - G8JNJ -
Local Timeout
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Strong local signal overloading - any suggestion?
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ADC Overload
Hi All,I notice that one or two KiWi SDR's which are using good antennas (myself included) are suffering from ADC overload due to strong Broadcast stations, especially during the night on the short wave bands.I have built a very simple filter that I use to place a very narrow 10dB deep notch on frequencies where I have problems with strong broadcast stations.It simply consists of a number of series tuned resonant circuits connected in parallel (shunt) with the KiWi SDR input. The frequencies and number of tuned circuits can be varied in order to suit your own RF environment.I used Elsie http://www.tonnesoftware.com/elsie.html and RF Sim 99 http://www.electroschematics.com/835/rfsim99-download/ (both free) to help design and fine tune the values.22uH inductors are used in order to provide the required bandwidth and attenuation for each frequency, but you can change the values as required.Fixed value capacitors with trimmer capacitors connected in parallel were used to fine tune the circuits to the required frequencies.The filters are built into a small metal box with BNC connectors that simply fits in line with the antenna feed.You can tune two or more notches to the same frequency if you have a really strong signal.The following diagram shows the circuit and frequency response curves.By adding a simple filter like this, it's possible to reduce the level of very strong stations to below -20dB on the spectrum display, which is usually the point at which ADC overload starts to become problematic.Regards,Martin - G8JNJ