NB passband monitoring

this issue is getting worse.. can someone tell this OM to fix this ?

I told him in voice, not sure he listened

Kind regards

Matthias

http://www.dd1us.de

I have been observing a series of squiggles on the NB transponder. What would be the cause?

Hello to the group,

What are these cyclic white lines on the waterfall (see attachment) and this cyclic signal just aside the digital beacon ?

73

renaud on4kvi

Hi Renaud,

the somewhat cyclic white lines are most likely from an unknown radar source. Today it is especially bad but it has been present for quite some time.

The pacman picture in the waterfall, which is transmitted cyclically, is to remind people to honor the guard band to the PSK beacon.

Kind regards

Matthias

http://www.dd1us.de

Only to see in the NB transponder, there are no disturbances on the wide band.

Very small for Radar i think ...

Thanks Matthias ;

Zooming in and bingo ! pacman comes ! hihi

Renauld on4kvi

Hi Robert,

of course the radar signal is not stronger than the WB beacon, which you are showing on your screenshot.

Kind regards

Matthias

http://www.dd1us.de

Hi Matthias,

but left and right of the WB beacon ? If there is a weak signal, it must be visible.

73s de Robert

Hi Robert,

left not really as the transponder rolls off quickly.

Right maybe depending on the sensitivity of your system.

Sorry, bit I have not checked myself today the WB tpx for radar interference.

Kind regards

Matthias

http://www.dd1us.de

A new use for text in waterfall.

73s DB8TF

Hallo ...

monitoring somtimes FT4 and FT8 ...

EP4HR was QRV in FT8 today on QO-100 looks a good sig decode +10 and +9dB

picture attached .... but no QSO ?

maybe anyone have more information ?

73 de dg0opk

dg0opk, good morning!

I had similar problems reaching a few stations in FT4 and FT8, despite a good signal. I finally managed a QSO with EP4HR but it took a while.

I believe that the link through QO-100 suffers from the time lag between the transmitted signal and the reception. First of all there is the 250ms path from earth to the satellite and back, second there is the time delay in processing the signal in the reception software. Both, FT4 and FT8 are very time critical what the accuracy of your computer clock is concerned.

What helped for me is a little software that W9MDB has published on his qrz.com page. It is called TimeFudge (https://www.dropbox.com/s/b39x…imeFudgeSetup1_3.exe?dl=1). With this software you can adjust your computer clock in 0.01 seconds steps plus and minus. I have been succesful in reaching FT4 and FT8 stations by playing around with this parameter for a while.

Best 73

Holger 'Geri', DK8KW

I made FT8 QSO's with no issues. When you set your (Windows) time properly with rsNTP (google on it) and you're stable enough, and you have clear audio, it works flawlessly.

Hallo...

i am using MEINBERG NTP for Win10

https://www.meinbergglobal.com/english/sw/ntp.htm

it works like a charm without any correction needed until now (also with SDR)

but interesting to see that there are solutions out to correct the time offset (SDR latency + GEOSAT delay)

DK8KW ...

What helped for me is a little software that W9MDB has published on his qrz.com page. It is called TimeFudge (https://www.dropbox.com/s/b39x…imeFudgeSetup1_3.exe?dl=1). With this software you can adjust your computer clock in 0.01 seconds steps plus and minus. I have been succesful in reaching FT4 and FT8 stations by playing around with this parameter for a while.

TNX for Info

BTW:

i made a number of qsos without problems ... and i can decode my signal in FT8/FT4 every time with 2mW with TX 120cm Dish RX 85/70cm Dish and 8mW TX 60cm and RX 85cm... Level Range is then -12...-17dB WSJTX Scale

so no QRO is needed for FT8/4 ... level over 0dB is QRO in my opinion...

73 de DG0OPK

dg0opk and PA3FYM: these time server tools are great, however, they only work as long as the QSO partner on the other side is as cautious about the accuracy of his computer clock as we are. I realized that a few stations (including for example EP4HR) are off in their computer timing, probably beyond the tolerance that WSJT-X accepts. Thats when those time changing tools become handy.

I first realized this critical timing issue when I tried to receive the Chinese moon satellite DSLWP last year. I was able to pick up the 70cm signal but was unable to decode the It. Then Mike, DK3WN gave me the hint, that for some reason the internal clock of the satellite was off by a couple of hundred ms. I adjusted my computer clock accordingly and there it was: my first reception of a signal from about 400.000 km away!

Have fun, see you on the satellite, vy 73

Holger 'Geri', DK8KW

DK8KW and dg0opk FT8 works exactly the same are on e.g. the shortwave bands. If you can make FT8 QSO's there, you can make them via QO-100 as well. QO-100 does not know or does not react different that/when you are making FT8, it's all up to the uplinker (having a stable enough signal).

PA3FYM:

>it's all up to the uplinker (having a stable enough signal).

Thats perfectly OK, Remco but also on HF I have seen stations who are more than a second off and I was only able to reach them by tweeking my own computer time a little bit.

Best 73

Holge 'Geri' DK8KW

Hallo agn...

thank you for all informations...

I am working many years with wsjt...,wsjtx ... and the timing is mostly the GOAL to get an decode... !

And additionally i will give some information about LINUX systems...

There is an tool on the newer versions of LINUX ...called CHRONY as replacement for NTP ...

It can also make a time correction in positive and negative direction controlled by an ini-File

I am using this since some years on my ARM-mini computer monitoring systems with GNURADIO RX and RTL-SDR to correct the time/sdr delay.

73 de dg0opk