Posts by pe1chl

The problem with simplex operators is that they cannot hear that they are at a disadvantage when compared to duplex operators.

E.g. I heard a QSO where I think 4 operators were in a roundtable, and two of them were operating simplex.

Due to the delay (and therefore uncertainty that they transmit on a clear channel) they were constantly doubling with others, and the duplex stations had to backoff all the time (of course they could hear when they are doubling).

This is also apparent when calling to "rare stations" on the satellite. Those simplex stations are all transmitting on top of eachother where a duplex station can hear that it is useless to continue shouting.

I think it is part of the personality of some people to not bother about such things.

It is likely inherited from the (also simplex) world of DX'ing where it only counts to make that "you are 59" QSO. And some people just want to have the microphone all the time and do not want to be bothered with others who want to say something too.

However, those that want to listen to others and want to open themselves up to experiences made by others quickly find the advantages of having duplex capability.

Alas, not all people are like that.

It is not very likely that a WLAN system can accidentally provide such a broad and flat signal at this level. Besides, the lowest WLAN channel is 2412 MHz so quite a lot higher.

Some form of radar is a lot more likely. It would probably be near the edge of the coverage area, so the beam transmitted at low elevation angle still hits the satellite.

Quote from DH2VA

We had to define a minimum ground station for SSB and this was 60-80 cm

Of course I agree with that - my remark was only to indicate that something has changed, not that it was for the worse.

60cm dish is not so bad even for a portable station.

(of course not portable like a handy, but easily transportable and setup to make qso from a rare location or for emergency communications)

Quote from YU7RSX

If I understand right, some QRP stations that could work via TP before gain reduction are not able to work any more?

No, it does not affect "QRP stations". It does affect stations with small receive equipment only.

I can still make the same S/N ratio with my QRP station. However, before this change people reported receiving with only a bare LNB (no dish) and/or with very small dishes, and that will no longer be possible.

Quote from HB9SKA

Look at https://www.amsat.org/?s=phase+4b

Didn't that project come to a halt for some reason?

I wonder if a new option would be to find some satellite that is now in the specification phase and is to be built by MELCO, and try to re-use the knowledge and experience they already gained when building the transponder aboard Es'hail-2.

That could make it easier to convince the operator to do the same thing as well.

It appears to be an improvement, the average station sounds much clearer and with better S/N.

My own signal was very marginal and I cannot make QSO anymore, but that is probably mostly because the uplink antenna is soaked in the continuous rain we had past week (it has started again).

I already noticed before the parameter changes I was becoming weaker and weaker...

And I do not feel like mounting the new feed right now, that will have to wait.

Quote from DB2OS

Keep in mind also, that the beacons are currently send from AMSAT-DL HQ in Bochum and we have a lot of wind and rain at the moment

It is a present we got from the guys in G-land and kindly forwarded to you

At the moment it is a lot more quiet here and clear sky, so it will likely improve for you too.

Back home indeed the level of the noise has decreased by some 5-6dB.

But the S/N ratio on beacons and typical stations is still the same.

Es hängt davon ab, was Ihnen spaß macht.

Lediglich zur Demodulation des Beacons ist eine Softwarelösung (Ao40Rcv usw.) heutzutage viel einfacher ...

Ok!

It is fine now here as well, but I have to leave for work so I cannot listen further.

Be careful when judging things on the BATC WebSDR because it has (or at least, had when I last checked) AGC of its own.

I think the level is now about the same as it was before today, but it is a bit difficult for me to judge as we have heavy rain and wind...

I saw the signal drop for a short period but I think that was a little bit too much...

At the current setting (as was used last week) I still have about 12dB of transponder noise but it dropped by more than the 6dB you indicate, I think.

(not really measured it)

Es handelt sich um einen 400-Baud-BPSK-Demodulator. Sie können das Signal bei 10489.800 trotzdem decodieren, denke ich.

I wonder if it would be possible to fit one of those Serit tuners (NIMs) on a plugin board for the DM8000 and then be able to receive lower symbolrates (and directly receive on lower frequencies)...

I have one of those boxes as well. It is easier to receive via the Dreambox than via my PC because there is not much software available for Linux and the Dreambox is already connected to my TV and satellite LNB...

Maybe you could also consider the smaller WiFi antennas that usually are "panel" type and consist of a circuit board with a lot of stacked dipoles fed in phase.

On the uplink you can always exchange antenna gain for output power.

However, be careful that a WiFi antenna actually can handle the output power you use.

(this is not a problem for that large grid but it could be for the smaller antennas that require more output power)

Of course don't use the well-known small yagi for WiFi "with 25dB gain", it is fake.

Try this website: https://translate.google.com/

It is very helpful when translating forum posts (some people also post in Italian!!) to a language you know.

Just copy the text into the left window on that site and select the languages.

Quote from DJ7WL

on what way you feed the referencing cable into the box to make it waterproof?

Check the above tweet. He sends the reference signal via the same coax as is used for the IF and powersupply.

Both the satellite and the ground stations use state-of-the-art frequency standards so you do not need to worry if the frequency is right. It is very close.

Daniel EA4GPZ is doing doppler observations to the single Hz, see his articles about that.

https://destevez.net/

The transponder adds 8089.500 MHz to all signals.

So the ground station transmits the beacon at 2400.050 MHz.

My LNB is about 220 kHz out (oscillator too high), I would not consider that excessive, the spec is usually +/- 1 MHz.

Remember the crystal itself is off by only about 500 Hz in this case, 22ppm.

The commonly observed variation is like 40 kHz peak/peak or about 4ppm.

All typical values for a crystal oscillator.

"converse" operates as a server where all the users connect. so you would have to have one volunteer that runs the server (and could connect locally) and all the others connect to there via the satellite. and all messages have to be transmitted to and acknowledged by everyone.

something tells me this is less than optimal. a multiuser chat protocol could be devised that allows this operation without having a session with everyone.

maybe an extension of the existing chat modes like contestia or olivia (available in Fldigi).