Category: Amateur radio

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How does FT8 work?

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FT8 is unfortunately impacting amateur radio negatively. CW and SSB activity goes down and the modes that require serious skills to operate are not practiced. FT8 can today run fully automated QSOs. However FT8 is interesting from a technical view. Advanced techniques such as FFT, correlation, 7×7 Costas matrixes are used to synchronize, error correct and decode data. Here is an interesting presentation that gives you a lot of the the technical details. (Reference / Full credit to WB2FKO Mike Hasselbeck)

ft_8_how_it_works_TechFest_2019_WB2FKO_revisedDownload
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Finn posisjonen til masten som ditt 4G / LTE modem er koplet til med Celle ID! (4G / LTE Cell ID database with position info., Norway)

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Lurer du på hvor masten som ditt 4G / LTE modem er koplet til er lokalisert? (LTE Cell ID database with locations, Norway). 

Maybe this can help: I found a comprehensive database that contains approx 147000 lines at https://opencellid.org/ This dataset is made publicly available by Opencellid for download.

Here is the cell id data I downloaded for Norway:

 242.csv

Rename the file to 242.csv (it has a txt extension) and open it or import it in Excel.

You can then find lat and long position from the Excel cheet

Then enter that lat / long (with decimals and add E and N after the numbers) into the search field of Google maps

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How to adjust your parabolic antenna for QO-100 / Es’Hail amateur radio geostationary satellite

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VIDEO. How to adjust your dish for QO-100 geostationary satellite:

  • Find Astra 28,2 degrees (strong signals in Northern Europe and Central Europe) with a low cost satfinder with sound / analog meter
  • This is one of the most eastern TV satellites that are very strong, so you can start east and move towards south until you find the first strong satellite on your satfinder (you should find Astra 28,2)
  • Now move a slight bit more to the south until you are out of the strong Ku band lobe of the Astra 28,2
  • You should point in the correct direction (elevation is the same in practice)
  • If you have a generic LNB the IF should be on 739,7 MHz. Your SDR should be able to tune to that QRG

Join our FB group (exclusively for licenced radio amateurs by the respective government administrations) https://www.facebook.com/groups/252645695661305/members/

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Quatar Oscar 100 Geostationary Satellite / QO-100, Es’Hailsat, new Facebook Group for licensed radio amateurs

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There is a new Facebook group for Quatar Oscar 100 Geostationary Satellite. (QO-100, Es’Hailsat). Licensed radio amateurs are welcome to join via the link below! (Exclusively for licenced radio amateurs by the respective government administrations).
Members typically discuss equipment, design of equipment, antenna designs, post QSO videos and sound recordings etc.   https://www.facebook.com/groups/252645695661305/

cover photo, No photo description available.

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ZUMspot + Pi-Star setup guide

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If you are looking for a Zumstar + PiSpot setup guide for DMR, then KC6N has made a great tutorial that is available here as a .PDF: https://www.hamdigitaal.nl/download/algemene-informatie/ZumSpot_Pistar_KC6N_20180605.pdf Full credit goes to KC6N, I have taken the liberty to link to the site where this document is available to help other amateur radio ops get on the air with their hotspot setup.

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LDG AT-100PROII max C / max L

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LDG does not specify either max C or max L of their antenna tuners in the “pro” series. They specify a vague “it can tune 1000 ohms”. This basically means nothing as no frequency is given and it is not given if they mean R or X or Z by “1000 ohms”. There is also no service manual or schematic available. Very disappointing from a serious (?) supplier.

Well, since LDG doent specify anything, I have measured it.

The LDG AT-100PROII is a series L, shunt C configuration.

Min L is 3uH, max L is 11,8uH
Min C is 85pF, max C is 250 pF
This is measured at 2MHz.

This shows that the capability of tuning an 2x20m doublet via “10-12m” of 590 ohm ladder line on 80m seems to be limited, and that tuning on 160m is very difficult.This is mainly due to limited Lmax. Also the limited Lmax gives limitations on other bands as well. Having the proper length of transmission line is important to overcome this limitations. You MAY also use a 4:1 or 9:1 balun. However it is important that the balun does have a very low loss. (Otherwise you you end up with a good SWR but poor efficiency).