Posts by DD1US
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Dear Alexandros,
thank you very much for your kind offer.
As the construction obstacles should be removed by tomorrow Monday I do not think it is necessary.
Nevertheless I have forwarded your offer for support to the operators of the groundstation in Bochum.
Kind regards
Matthias
www.dd1us,de
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Hello,
there is some heavy construction work ongoing at the groundstation oinm Bochum.
Some of the equipment is presently shading the dishes for QO-100.
This should be corrected the latest on Monday and all beacons and LEILA back to
nominal operation.Kind regards
Matthias
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Hi George,
I am sure you will be able to optimize the design.
Good luck.
Kind regards
Matthias
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Dear all,
I measured the filter with my HP8753E.
Below please find the results.
Kind regards
Matthias
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Hi George,
you have apparently a calibration issue of your measurement setup.
I do not think the ripple in the passband of your filter is real and so is the S11 curve.
If you do not have the proper measurement setup I can offer to you that you send it to me
and I will characterize the filter for you.Kind regards
Matthias
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Hi Georg,
more than 3dB insertion loss is in my opinion way too high.
Not only close to the cutoff frequency but even down at 1GHz.
Hopefully soldering the contacts will help. Probably clamping the discs
would be better (lower loss) than soldering them but as you have chosen
this path I wish you good luck.Kind regards
Matthias
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Hi Georg,
that looks very professional, it seems you have a very nice workshop.
It will be interesting to see your measurement results.
I got the primer and the glue but have been away from home for the last 2 weeks.
I might get back home next week or the week after and then plan to make some tests.
Kind regards
Matthias
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Hi George,
Kurt DJ0ABR built a very nice 2.4 GHz LPF and documented it here:
https://projects.dj0abr.de/doku.php?id=en:sat:filter2400
I guess it is quite similar to yours.
You may compare your results to his.
Kind regards
Matthias
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Hi Stefan,
I have been using the LimeSDR USB (not mini) for several years with good results.
I also have a Pluto and cannot confirm one or the other is more sensitive / better.
Kind regards
Matthias
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Hello Frank,
I for instance use Hamnet and know quite some people who do. It is also used as a backbone for packet radio links and for access to terrestrial DATV repeaters which are out of range for a direct access.
As Peter pointed out: "... this would be for direct User / Client access only. Gateways or traffic between Gateways will not be permitted and this is not planned by design either."
As Guillaume explained above his concept supports "Multi users: probably one or several dozens of simultaneous users. " and "Full-mesh : client stations communicate directly with each others".
Let us wait for the evaluation and conclusion of the expert team.
I am very excited to see such an additional use of the wideband transponder.
Kind regards
Matthias
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Hallo Georg,
Danke für den Tip.Ich habe mir den Primer und den Kleber mal bestellt und werde es ausprobieren.
Viele Grüße
Matthias
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Hi George,
thanks for the explanations.
I now understand.
Please let me know how you glue teflon.
I have not found a good way to do that thus I am interested if there is a proper way.
So far I have clamped my teflon sheets as a window in front of my feeds
but if there is a way to glue teflon that would be easier.
Kind regards
Matthias
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Hello Pietro,
the selected output of HSModem needs to be an output device. You can use a soundcard output and connect it with a patchcable to the input of a soundcard but you cannot choose the input of the soundcard as the output of HSmodem.
Therefore it easier to use a virtual audio cable (in my experience VAC works best).
Kind regards
Matthias
www.dd1us,de
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I agree. I just wanted to point out, that even with a cumbersome antenna, you will have good results with a dish that diameter. My first antenna was the 4 element yagi pointing into the dish , the 2nd was a linear polarised patch feed without waveguide for the lnb and the one i'm using now is a poty . Learning by doing, improving over time. It is more important to have a clean signal, may it be not so strong. The LEILA triggering signals are for later, and even those are clean, if you overdrive NONE of your gear......
Regards
Martin
P.S. : I don't encourage anyone to trigger LEILA.
Hi Martin,
yes, we should not overpower.Looking at the transmit side for the narrowband transponder a smaller dish is clearly enough.
The big benefit of such a large dish is on the receive side especially for the wideband transponder and for transmitting
DATV signals.See you soon on QO-100.
Kind regards
Matthias
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Ronni,
with the 1.5m dish you will not need more than 500mW transmit power at the dish.
Kind regards
Matthias
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Hi Ronni,
a 1.5m PFD is a nice dish. Go for it. You will then also have a good basis for receiving and eventually transmitting DATV signals via QO-100.
I am using a 1.8m PFD (old Kathrein dish which I refurbished). My dish is quite deep (f/D=0.29) and therefore a POTY feed is fits well. I do not use a lens in front of the 10GHz waveguide, just leave it open.
Do you know what the f/D of your dish is?
Most PFD dishes are between 0.3 and 0.4 and a POTY feed will then still serve you well.
On my website http://www.dd1us.de you can find some information about my setup incl. the feed-holder I built.
If you do not find it plase send me an Email and I will give you more details.
I kindly disagree with Martin: if you setup a 1.5m dish you should try to get out the optimum of it. Otherwise it is a waste of
time and material ...Kind regards
Matthias
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Hello,
there has been some maintenance work ongoing in the last 2 days at AMSAT-DL in Bochum.Kind regards
Matthias
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Hello Wilhelm,
in SDR Console the function "writing text in the spectrum" is already built in.
Kind regards
Matthias
www.dd1us,de
