Re: LF: EA5DOM EbNaut Tx test in 137.485

[DK7FC <selberdenken@posteo.de>]

Hi Luis,

I tried to decode your message and almost got a decode. But i have QRM on that frequency a mixing product in the front end of my RX antenna. I should work on it, i know...
The best SNR was 11.3 dB for the 04:30 message. But this only tells that it was the best compromise between my QRM which disappears when the day begins and your signal which was still theer at that time.
 I  found an unexpected time offset of 0.5 seconds.

On a different frequency it would be no problem at all. That's how my local situation looks on that frequency: http://www.iup.uni-heidelberg.de/schaefer_vlf/LF/opds32.jpg

73, Stefan

Am 21.09.2018 10:24, schrieb VIGILANT Luis Fernández:

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