AW: LF: EA5DOM EbNaut Tx test in 137.485

[markusvester@aol.com <markusvester@aol.com>]

I think that the 1 Hz spaced lines are 2nd order intermodulation from two time signals in the active antenna, 77.5 + 60 = 137.5 kHz. Moving by 0.5 Hz between two lines would solve the problem.

73, Markus (DF6NM)

------ Originalnachricht------

Von: DK7FC

Datum: So., 23. Sep. 2018 23:39

An: rsgb_lf_group@blacksheep.org;

Betreff:Re: LF: EA5DOM EbNaut Tx test in 137.485

Hi Luis,

I tried to decode your message and almost got a decode. But i have QRMon that frequency a mixing product in the front end of my RX antenna. Ishould work on it, i know...
The best SNR was 11.3 dB for the 04:30 message. But this only tellsthat it was the best compromise between my QRM which disappears whenthe 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 mylocal 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 PAand my intention was to transmit with the lowest possible power (about24W at 12V in LOW mode)

but Murphy confirmed that thelowest possible power â?¦..is always zero. Something went wrong L

 

Anyway cound trim the antennato resonance. It was a couple of KHz down. And using the mosfet driverat 14V

could see some improvementsin output level and the device clearly heating. No Vrms meter availableso I canâ??t

confirm the output power orcurrent for this transmissions

 

Trying to check if therecould be a decode at Domenicoâ??s EbNaut decoder I transmitted all night

with the usual parameters forweak signal in a less than half an hour message. May be Stefan can

use the files he is recordingand check for the transmission

 

f = 137485.000 Hz
Start time: 20.SEP.2018  19:00:00 UTC up to 05:30:00 UTC (messagestarting at minute 00 and 30 every hour)
Symbol period: 2s
Characters: 3
CRC bits: 19
Coding 16K21A

The message is â??DOMâ??, so ifanyone wants to correlate the received signal and get some extra dBs.This is extremely

weak signal. The input powerto the antenna must be well under 1W, so the ERP must be very low

 

There was no decode atDomenicoâ??s grabber

https://www.qsl.net/iz7slz/EBNAUT/DECODED.TXT

 

Just for measurement ofsignal I can run a permanent carrier tonight if this can help

 

73 de Luis

EA5DOM