Yesterday, Dave Moore Vk2DVM and I got FreeDV loaded and running on 6m
, between sydney and canberra (260km path)
We used a variety of modes, but 700D and 2020 are really the only modes
you might as well use, other modes are either legacy, or designed for
specific jobs (es-hail satellite etc) .
Changing modes (like 700D>>2020) I recommend you restart after changing
the setting.
you have to be within +/-60Hz to auto acquire, although on strong
signals, its easy to tune.
700D is a good simple place to start with interleaver set at 1
(default). Restart program if changing the interleaver.
For 700D mode, Very approximately, performance is good at about the
same signal as when weak SSB in headphones in copyable.
for 2020 mode, you need about 6dB more.
There is a large peak to average ratio of 12dB that can be reduced to
7dB using the clip function, IE 100W radio will make about 20W RMS.
Over the slow fading 260km tropo path, signals varied about 10-12dB (10
minute ish fading period) . 20WRMS was not enough to get through the fades
so I got out Mr Freescale and 50W RMS (roughly 300 W PEP) was entirely
reliable through the fade, and up to 200W RMS (1kW PEP) was solid copy.
Actually at 700W , FM was S5.....:-)
I suggest you try it
ideally you need a USB headset-microphone --- $20-$30 on email or
computer store as you'll need the program to communicate with the radio
and ALSO communite with you.
If you dont have that right away, just keying down will generate the
bitstream, and also you can run an automatic voice keyer by recording a
8kHz sample rate PCM16 file.
https://freedv.org/
that link page, at the bottom has all the code, programs, documentation,
how to etc.....
windows and linux. and mac. here is the 64bit windows link
http://rowetel.com/downloads/freedv/FreeDV-1.4.1-devel-20200305-d60b0f0-win64.exe
manual :
https://github.com/drowe67/freedv-gui/blob/master/USER_MANUAL.md
My IC7300 on 6m drifted a little too much on TX, Dave had to follow it,
so I will put a lock board in it shortly.
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