Hi Domenico, EbNaut
Thank you for the good news ! :-)
Yes, I was transmiting the message, so this decodes are genuine. It is amazing to get a decode with
so little power. I could not measure the power with antenna connected, but the mosfet driver output was about
4Vrms over 50ohm load when tested in the lab. So it must be around 320mW
You can guess which was the radiated power ;-)
This afternoon I have made some transmissions with the PA at low power, about 20w, using the U3S.
Tried some Op32 and WSPR-2. Got decodes from Chris, 2E0ILY both in Opera and WSPR in daylight being just 13:30 UTC
There are also some decodes at Markus Op32 grabber
Storm forecast for the next couple of days. Will keep testing later this week
Thanks again Domenico
73 de Luis
EA5DOM
Hello Luis and all,
there are good news for you. I was investigating in your transmissions and, just for my error, i set, in the decoder routine, the wrong date of 23rd september. I catch your message at 00.00 and 00.30 !
initial reference phase 54.1 amplitude 1.763e+00
phase 0 0 0 0 0
carrier phase: -2.8 deg
carrier Eb/N0: 9.9 dB
carrier Es/N0: -7.26 dB
carrier S/N: 22.26 dB in 558.0 uHz, -10.27 dB in 1Hz, -44.25 dB in 2.5kHz
elapsed 33
phase 1 180 180 180 180
found rank 0 ber 2.9799e-01 Eb/N0 8.7 M -4.760565567e+01 ph 0 0,0,0,0 [DOM]
initial reference phase 78.1 amplitude 1.387e+00
phase 0 0 0 0 0
carrier phase: -6.1 deg
carrier Eb/N0: 8.6 dB
carrier Es/N0: -8.56 dB
carrier S/N: 20.96 dB in 558.0 uHz, -11.57 dB in 1Hz, -45.55 dB in 2.5kHz
elapsed 33
found rank 0 ber 3.2478e-01 Eb/N0 7.4 M -3.836220932e+01 ph 0 0,0,0,0 [DOM]
Do you confirm the transmissions at that time ? Can you tell the power used ?
If confirmed, seems that your setup now is ok. Many compliments. I have programmed again my autodecoder with your last parameters (3 ch, 2s, CRC18,16K21A 136485 Hz).
Hope to catch you 'live' !
73, Domenico IZ7SLZ
Ciao Domenico
Thank you for the message and extended explanations
Big SORRY :(
Yes, the CRC was 18, not 19 as wrongly indicated in my email, and the time lenght is about 28 minutes
Please check again last night files to see if there is a decode
73 de Luis
EA5DOM
Hello Luis and all,
returned home today and now it's time to 'play' a little bit with our fantastic 'hobby' !
I have tried to search for your signal in the recordings.
This is very easy to do with linux and vlfrx-tools. In fact i'm recording the audio from the LF receiver with the program 'vtwrite'. This program creates its proper files in a dedicated hard disk (used only for the storage) . I setted vtwrite to create
one file each 24 hour. It is very confortable to retry the raw data by using 'vtread' program, just specify the date, the duration and the location of the storage directory. In this way, it is possible to post-processings any possible transmissions in the
audio band recordered. You can 'play' anytime the raw file and change the parameters, offsets or NB settings.
Nice tools, thanks again to Paul Nicholson.
But, sorry to say that, till now, the search of your 'DOM' message is without results.
Maybe one of the parameters you have announced is different from that you have really used. That's becouse the duration for
16K21A, CRC=19, 3 Chars, 2 (total 912 bits) is more than 30 minutes for T=2s and maybe some symbols were not transmitted due to your 'half hour beaconing'.
There is also a lack of sensitivity on LF on my receiver. Noise floor, also during nightime, is very high (one week ago was less) and i suspect some hardware trouble here (groundings or a new local 'macoomba' noise). Investigation is started.
Dear Luis, can i suggest you (or other operators) to try an EbNaut transmission on that MF band ?
Autodecoder webpage is setted for R3RWR transmissions now, but it's easy to change parameters. You can transmitt anytime, since also MF band is recordered in a separate storage media.
Waiting for your comment.
73, Domenico IZ7SLZ
Hi EbNaut
Yesterday installed the PA and my intention was to transmit with the lowest possible power (about 24W at 12V in LOW mode)
but Murphy confirmed that the lowest possible power …..is always zero. Something went wrong
L
Anyway cound trim the antenna to resonance. It was a couple of KHz down. And using the mosfet driver at 14V
could see some improvements in output level and the device clearly heating. No Vrms meter available so I can’t
confirm the output power or current for this transmissions
Trying to check if there could be a decode at Domenico’s EbNaut decoder I transmitted all night
with the usual parameters for weak signal in a less than half an hour message. May be Stefan can
use the files he is recording and check for the transmission
f = 137485.000 Hz
Start time: 20.SEP.2018 19:00:00 UTC up to 05:30:00 UTC (message starting at minute 00 and 30 every hour)
Symbol period: 2s
Characters: 3
CRC bits: 19
Coding 16K21A
The message is “DOM”, so if anyone wants to correlate the received signal and get some extra dBs. This is extremely
weak signal. The input power to the antenna must be well under 1W, so the ERP must be very low
There was no decode at Domenico’s grabber
https://www.qsl.net/iz7slz/EBNAUT/DECODED.TXT
Just for measurement of signal I can run a permanent carrier tonight if this can help
73 de Luis
EA5DOM
|
|
