Shortwave
Radiogram, 11-16 May 2023: EasyDRF special (you will need to install
software)
I am sending this preview of program 304 (11-16 May 2023) a few days early
to give you time to download, install, and practice decoding the EasyDRF we
will be using.
EasyDRF is a version of HamDRM which can be decoded using software developed
by Daz Man in Australia.
Program 304 is a repeat of Shortwave Radiogram 300, but in EasyDRF. Details
of program 300 are here.
The EasyDRF software works in Windows and under Wine in Linux. See Daz’s
downloading and operating instructions below.
The sound is different from MFSK. Easy DRF is more of a constant buzz.
Shortly after the buzz starts, the file SWRG-300-00.html will appear in the
Rx Files subfolder. Open that html file and watch the images populate it,
one by one, during the half hour – reception permitting!
If you want to practice decoding EasyDRF before actual radio reception, the
audio file is available here:
https://storage.googleapis.com/dazman/misc/2023-05-06-EasyDRF_Radiogram-v06-ODC-EQ12.wav
Important: If you decode from the
downloaded audio file, delete or move the files from the Rx Files subfolder
before decoding from actual radio reception.
Questions about EasyDRF can be addressed to Daz via Twitter: @DazDude4000,
or email: dazdude(at)hotmail.com
Here are Daz’s instructions to
install and use EasyDRF:
This EasyDRF version of Shortwave Radiogram program 300 can only be decoded
with the EasyDRF Windows application program.
SOFTWARE
Website:
http://homepages.ihug.com.au/~daz2002/tech/EasyDRF/
Installation: Download the executable file from the GitHub release
directory. Create a new folder on the PC hard drive named “EasyDRF”, and
move the downloaded “EasyDRF.exe” file to it. That’s all. (Do not create the
installation folder in “Downloads”, as this can cause security issues.)
AUDIO
Feed the audio into your PC the same way as for normal Radiogram broadcasts.
Options are: VB-Cable (SDRs), line input or microphone (analog radios).
NOTE: If using SDR# (SDRSharp), disable “antifading” as it can severely
degrade data signals.
After installation into its own folder, start EasyDRF by double-clicking on
the EasyDRF.exe file and select the correct input device in the Soundcard ->
RX Input menu setting.
Check audio level using the Display -> Input Level menu setting. Adjust the
receiver audio level to be near mid-scale on the Input Level graph. If the
graph turns red, the level is too high.
Set the Waterfall display under Display -> Waterfall menu setting. Signals
and noise from the receiver should appear on the waterfall display.
It’s a good idea to make a recording of the broadcast in case of decoding
problems.
AM-Sync demodulation is recommended, to reduce carrier fade distortion that
can severely degrade data decoding.
DISPLAY
This Shortwave Radiogram program consists of a series of files, sent using
EasyDRF. The entire program is intended for web browser display, for easy
viewing. The HTML file is sent first. When the HTML file saves, open a new
web browser window. Click the “RxFiles” button on EasyDRF to open the file
save folder, then drag and drop the “SWRG-300-00.html” file into the web
browser to display it. (You can also right-click on the “SWRG-300-00.html”
file, then “Open with” browser of choice.)
The HTML page will open, and it will display stats on the received files in
the top right corner. The page can be browsed while the files are still
decoding.
Please include the stats in your reports (a screenshot), as the image
quality does not change with radio conditions.
The images will automatically load into the page as they progressively
decode and save. Automatic image loading stops after image 12 is loaded, or
after 30 minutes. Images are enhanced for display using a custom SVG filter.
In most cases, only 51% of good data is needed for each file, due to RS4
error correction. If any files fail to decode, some images will be missing
from the page.
Thanks for decoding the Shortwave
Radiogram program 300 EasyDRF special broadcast!
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