G8JNJ
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- G8JNJ
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Broadcast database application with control of WEB SDR
Hi John,I recently found a broadcast database application that allows control of various receivers (including the Twente WEB SDR).Although it's a bit of a pain to setup, it does have some 'interesting' features that may be of interest for KiWi admins and users.Regards,Martin - G8JNJ
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Some things I have noticed [problems with a large DX/label database]
Hi John,The change has made a huge difference no sign of any audio 'stuttering' and a very fast and smooth scroll up and down in frequency at all zoom levels.Thanks for that :-)Regards,Martin - G8JNJ
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v1.161: FSK/RTTY extension
Hi John,Quite a few 170Hz / 100bd FSK signals I've heard (but not decoded) turn out to be "Digital selective-calling system for use in the maritime mobile service" using a ten-bit error-detecting code.All of the code structure is defined in https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.493-14-201509-I!!PDF-E.pdfDSC calling frequencies- 2.1875 kHz
- 4.2075 kHz
- 6.312 kHz
- 8.4145 kHz
- 12.577 kHz
- 16.8045 kHz
Regards,Martin - G8JNJ - 2.1875 kHz
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Home Brew Broadband Magnetic Loop
Hi Ron,I think that the problem is almost certainly loop imbalance.You can check this by rotating the loop to peak a known station. Note the signal level then rotate the loop 180 degrees and note the signal level of the peak in that direction.If the loop is properly balanced the signal levels should be the same. If it isn't the peaks will be different as the imbalance means that it is now configured as an Aperiodic loop.Which are often used for phased receive arrays like this commercial version.I found that the LZ1AQ design was easier to build than the 'Wellgood' (Wellbrook copy) and performed slightly better.I fed mine with coax and left out the input filter network and voltage regulator (works OK on 13.8v)The Wellgood and ZL1AQ work OK up to about 10MHz then run out of steam. if you want better performance on the HF bands the only solution is to make a 'fatter' loop or connect multiple loops in parallel in order to reduce the loop inductance.Lots of notes here http://www.lz1aq.signacor.com/ and here http://active-antenna.eu/amplifier-kit/technical-documentation/More stuff about loops etc. on my active antennas webpage http://www.g8jnj.net/activeantennas.htmRegards,Martin - G8JNJ -
v1.154 released: New user interface, Navtex extension
Hi,Three other signals I've decoded (so far)6322.5 CW FSK 170Hz shift 100bd, Murmansk, Russia12603.5 CW FSK SVO, 170Hz shift 100bd, Athens, Greece12622.5 CW FSK XSQ, 170Hz shift 100bd, ChinaRegards,Martin - G8JNJ -
Direction Finding and linking existing KiwiSDRs
Hi,Take a look at this thread.Although it's not available in real time, this may be a step towards it. By processing time stamped off-air recordings and then determining the time difference between each, it may be possible to perform a hyperbolic fix (or similar) on the transmitter location.However my maths and coding are not up to the task :-(Regards,Martin - G8JNJ
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What is this huge signal?
Hi Ron,It's probably Super Darn. I normally see it around 12MHz but your screen grabs look very similar.Regards,Martin - G8JNJ -
Demo of new user interface [now available in v1.154]
Hi John,The LMS "denoiser" and "autonotch" filters work quite well and are a very welcome addition, so thanks for that.However I can't open any of the three test sites on my iPad running Chrome. The URL resolves OK but I just get a blank white screen.A few other minor observations:-The purpose of the 'Slow Dev' button isn't obvious - I think it needs to be called something elseI'd prefer the 'Slow Dev' waterfall to be white rather than a 'strange' green colour, so that it is a higher contrast display that can be more easily be seen outdoors.Should the 'rainbow' spectrum amplitude display bar also be in black and white when the 'Slow Dev' option is enabled.The mute button needs to be either on the main pane or the audio panel needs to open by default rather than the waterfall when the browser session opens.Why is it WFO rather than WF - what does the 'O' stand for ?Should the spectrum display button now be on the WFO pane ?If the spectrum display button is moved could a second mute button be added in it's place ?Should the green arrow URL button be aligned under the up and down arrow buttons ?I'd still prefer the S-Meter scale to be at the top of the control paneI still think that the new dBm reading needs to be differentiated from the rest of the S meter scaleCould the waterfall contrast schemes be better named ? I think they correspond to:-- Normal Linear
- 1. Square law
- 2. Square law between 21% and 50% spectrum range
- 3. Square law between 31% and 60% spectrum range
- 4. Square law between 41% and 70% spectrum range
Regards,Martin - G8JNJ - Normal Linear
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add DTG to Log
Hi,I'd also like to add the KiWi ID to the time and date, so that it makes it easier to use the data at some later date if a centralised database is ever established.Covered in these previous threads.Regards,Martin - G8JNJ -
Contact: causes issues [universal browser issue, can't be fixed]
Hi,This is a known issue in the bugs list.- Javascript stops on "sendto:" email links. This is a browser problem that may never be fixed according to stackoverflow.com
Regards,Martin - G8JNJ
