Posts by DB8TF
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PE4WJ you forgot in your description to mention the drift correction method using 2 SDR sticks and locking to engineering beacons many MHz away from the P4A Transponder.
Is far as i know, the first working solution since mid-2018.
VY73 DB8TF
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The size of the code in my little driftcontroller is 676 Bytes
But that is only the part in the external uC which controlls two PCs with Win XP & HDSDR.
VY73
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Hi,
could it be that the frequency marker for Mixed should be at 10,489,640 and the marker for SSB at 10489,690? Or are the below frequencys not showing the actual marker?
The rest seems to be correct.
Vy 73
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Works good 3W uplink power here are enough on the uplink.
Thanks to DD4YR for first my AX25 QSO via sat.
vy73 DB8TF
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TX Freq 2400,130MHz , in the middle of the "digital modes" segment of the bandplan
RX Frq 10489,635MHz
https://amsat-dl.org/p4-a-nb-t…-and-operating-guidelines
Currently short Beacon txt every min.
VY73 DB8TF
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Now i tested UISS and that works fine.
Also the AF linearity is much better with that SW.
You can manually start the "soundmodem" and "easyterm" and there you go.
Someone here who wants to make a AX25 QSO over EH2?
vy73 DB8TF
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Hi DB8TF yes your sw drift corr is a cool idea. However you are dependent on the cw beacon always being available ( they have turned it off one time already as far as I know).
Many times people also transmit (almost) on top of the cw beacon to check their power level and frequency etc. This can cause problems with such a scheme if the FFT peak selector algorithm of yours locks onto the wrong FFT bin because the guy sending almost ontop of the beacon is stronger etc etc etc
(I took a quick look at your .py code. Cool concept for sure). Also not always do we have the possibility for cat control of the receiver.
That's why I at least for now would like a hw based approach.
Hello Mike ,
my reference is either the lower engineering beacon from EH2 or currently i am using the telemetry from Astra 2C (i think). So completely independend from the P4A transponder
The .py is not from me, i am no software engineer
Vy73 DB8TF
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Or you use a software based drift correction
No need to modify the LNB and it even works with DRO LNBs.
vy73 DB8TF
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Hier ein altes Daiwa NS-660P mit U-66S2 Meßkopf. (1,2-2,5GHz)
Geht bis 150W
Aber käuflich wird man den Meßkopf wohl kaum noch bekommen...
vy73 DB8TF
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I found out that the AX25 packets are not linear on AF frequency.
At least on my rig (FT790R). The lower frequencys (ca. 1200Hz) needed to be attenuated abt. 12dB
Vy.73 DB8TF
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PC-ALE looks also very interesting
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Look at those filters: https://www.mouser.de/new/triq…5033-signal-conditioning/
High att out of 2,4GHz and power handling to 31dBm.vy73 DB8TF
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After some Tests with MultiPSK in AX25 1k2 mode it Looks promising.
I can decode my send data without problems on the downlink.
Only the TX via Serial port is not properly working in Win 10 pro 64bit.
You have to run Multipsk in compatility mode for Win 7 an disable all UART Buffers on the port.
vy73 DB8TF
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MultiPSK seams to offer a lot of different modes.
I will give it a try
VY73 DB8TF
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Like the Title states i am searching for a Software (for M$) to chat via EH2.
Similar to Packet Radio but better suited for SSB.
Now i am using the chat funktion from KG-STV but you never know if the recipient has got the message.
Some suggestions?
vy73 DB8TF
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On 1201,5MHz (10951.5MHz) a strong Beacon signal can be found.
Looks like it originates from Astra 2C on 23,7".
I will test if it is stable relative to the EH2 Beacon and can be used as a reference for my software drift correction in the next days.
vy73 DB8TF
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@Mike5000
Look @ DG0OPK's website, he has done it first
http://www.dg0opk.darc.de/Octagon_LNB_mod_March2017.html
vy73 DB8TF
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