Δευτέρα, 31 Ιουλίου 2017

Digital Mode FT8

New Digital Mode from K1JT – FT8

 Here’s a short demonstration on the new digital mode FT-8 developed by K1JT & K9AN. Part of the WSJT-X software suite. We’ll go over how to call CQ, and a basic QSO of this mode.

 NEW FEATURES IN WSJT-X Version 1.8.0

1.  New mode called FT8: sensitivity down to -20 dB on the AWGN
    channel; QSOs 4 times faster than JT65 or JT9; auto-sequencing
    includes an option to respond automatically to first decoded reply
    to your CQ.

2.  New mode for accurate Frequency Calibration of your radio.

3.  Improved performance of decoders for JT65, QRA64, and MSK144.
    MSK144 includes facilities for amplitide and phase equalization
    and an "SWL" mode for short-format messages.
    
4.  Options to minimize screen space used by Main and Wide Graph
    windows.
    
5.  Enhanced management scheme for table of operating frequencies, and
    a new set of default frequencies specific to the three IARU
    Regions.
    
6.  Improved CAT control for many rigs, including those controlled
    through Commander or OmniRig.
    
7.  New keyboard shortcuts to set "Tx even/1st" ON or OFF.

8.  A number of (mostly minor) bug fixes and tweaks to the user
    interface.  For example: new behavior for the audio level slider;
    correctly logged QSO start times in certain situations; correct
    control of FT-891/991 and some other radios via rigctld.

Download here:  http://www.physics.princeton.edu/pulsar/K1JT/wsjtx.html the
Candidate Release for WSJT-X Version 1.8.0-rc1.

Παρασκευή, 14 Απριλίου 2017

How to work FM satellites

Simon 2E0HTS has released a video that shows him making contacts via the amateur radio satellite SO-50.
This satellite carries an FM transponder that receives signals on 145.850 MHz and retransmits them on 436.800 MHz (+/- 9 kHz Doppler shift). Operation is a little more complex that some other satellites since the transponder needs to initially be activated by a CTCSS (PL) tone of 74.4 Hz which starts a 10 minute timer and then a 67 Hz tone is used for the contact.
Note: If your radio has selectable FM filters use the wider filter designed for 5 kHz deviation FM which is sometimes referred to as a 25 kHz channel spacing filter.

 MORE: https://amsat-uk.org/beginners/how-to-work-fm-satellites/