Hi again,
I just confirmed it with the Cornwall websdr. The lower beacon has about -77dB peak (measuring the "Mark" frequency @ 300 Hz filter width), the upper beacon -80dB.
Not that it really matters, we still can use either beacon as a reference of course ... 
Vy 73 and have a nice evening
Holger 'Geri', DK8KW
Hello Matthias,
>So presently both (CW) beacons can be used as level reference.
That is interesting what you say. I use the RSP1A at an intermediate frequency of around 1100 MHz and, independent of the selected bandwidth, the upper CW beacon is definetely 3 dB weaker here than the lower beacon. This also applies to my own signal, transmitting near the lower and near the upper edge of the transponder.
I will check with a different set up and try to find out the reason for this.
Best 73
Holger 'Geri', DK8KW
Hi,
For me the lower beacon was always the reference. The difference between the "Mark" frequency of the lower and the upper CW beacon is about 3 dB, which probably is due to the reduced sensitivity of the band at 10.490,000 MHz.
So, until we get any other instructions, I try to keep my signal below the level of the lower CW beacon.
But, as DB2OS mentioned in one of his posts, calibration of LEILA is not yet completed and I guess there also might still be some adjustments going on, which means we just have to wait and see how things work out.
Best 73
Holger 'Geri', DK8KW
Hallo Hans,
bisher habe ich noch keine RIT gefunden. Ich habe mir angewöhnt, die Kopplung zwischen Sender und Empfänger für die Dauer des QSOs auszuschalten. Dabei bleibt dann mein Sender auf der ursprünglichen Frequenz und ich kann mit dem Maus-Rad die Empfangsfrequenz beliebig verschieben.
Vy 73
Holger 'Geri', DK8KW
@AMSAT: thanks a lot for the extended transponder bandwidth and the updated bandplan!
I have two questions, just for my orientation:
Thanks, vy 73
Holger 'Geri', DK8KW
>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
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
Hello all,
There were a few activitied this week that required not more activity -- just listening: V55QO had a QSO with two youngsters. Sophie, DO4QB (11) and Simon, DL3QB (14) asked him a lot of questions about Namibia and Africa in general and Charly took his time to answer the questions in great detail. It was almost like a talkshow and it was fun just to listen to them.
A second activity took place the same day. A group of people in Hannover had borrowed a bus, installed a QO-100 ground station in it and invited hams and other interested people, including people from the local press. Highlight of this activity was a QSO with the Antarctica, DP0GVN with Felix at the mike. Felix (DL5XL) is originally from Hannover and also he took his time to talk to everyone in the bus who wanted to have a QSO with him. The press people asked many questions and Felix answered them in the same way as Charly had done from Namibia.
For me personally, it is not the quanity of QSOs on the satellite that is important but the quality. Just listening to these two activities made me enjoy that I am a ham and that we have this wonderful satellite available for us.
Best 73
Holger 'Geri', DK8KW
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
Hi,
I have made the same observation and was told, that if you reduce the gain to 40 - 50 the signal should disappear. In this case, of course, you need to amplify the LimeSDR Mini externally to compensate for the attenuated signal.
For my setup (LimeSDR Mini on 50 MHz to feed a BU500) it also worked to calibrate the TX-section of the LimeSDR Mini. in SDR Console, for example, you need to press the TX button and then, on the left side of the pane, press the „TX Calibrate“ button (be careful, you should disconnect the PA before calibrating to avoid damage).
Best 73
Holger ‚Geri‘, DK8KW
Hello group,
let me give you a short report on my tests with the LimeSDR and FreeDV.
My setup:
- SDR Console 3.0.19
- Windows 10 on an old Q8400 Quad CPU - 2.66 GHz
- LimeSDR Mini on a separate USB3-Card with power from the computer power supply
- FreeDv 1.4
- LimeSDR Mini operates on 50 MHz (replacing a KX3 that I usually use), signal is amplified by 30 dB and fed into a BU500
- Filter between BU500 and PA to avoid that the LO frequencyof 2350 MHz is accidentally transmitted into space(attenuation @2350 MHz: >90 dB)
- SG-Labs PA running at about 3.5 Watt output in the shack
- 15m H-100 cable with a total loss of about 7 dB (including plugs)
- about 650 mW at the antenna feed (5 1/4 turns helical antenna)
- dish: Kathrein CAS 180, diameter 1.8m, offset dish
- reception via Octagon LNB, xtal changed to have output signal on 70cm
After my first LimeSDR Mini proved to be damaged (not recognized by Windows) I got a replacement which worked right away.
My general observation is that my computer is far too weak to operate both, SDR Console wih LimeSDR mini transmitting option and FreeDV.
Reception of FreeDV is not possible due to high frequency variation/jitter. All other digital modes work fine (FT4/8, KGSTV, ect.).
Reception with a separate laptop and WebSDR works up to FreeDV 1600.
FreeDV on the mainframe computer will transmit, SDR Console keeps transmitting but the screen will go black and sometimes will not return to its original state, so the program has to be re-settet.
The LimeSDR Mini has the tendency to freeze, this has also been confirmed by Simon, G4ELI, the author of SDR Console.He has even threatened to stop support for this device.
Conclusions and solutions:
- the chain LimeSDR Mini -> 30 dB broadband amplifier -> BU500 seems to be sufficiently linear to transmit FreeDV
- my computer is absolutely overloaded with the software, so to continue I will need to outsource FreeDV to an external laptop.
- to enable reception, my LNA will be stabilized with an external, GPS controlled 26 MHz oscillator.
- if the LimeSDr Mini keeps freezing I will consider abandoning this device and look for another solution.
By the way: I like the option to transmit waterfall text in the SDR Console. It really helps to announce FreeDV transmissions with the mode used.
Best 73
Holger ‚Geri‘, DK8KW
Hello group,
Here is a practical example on how effective a helix can work.
My antenna is a CAS180 from Kathrein, an offset antenna with a width of 180cm and an f/d ratio of around 0,7.
My LNB is in the focal point of the antenna. The transmitting antenna is a 5 1/4 turn helical antenna just below the LNB (see pictures).
To show how effective this setup is, I made the following calculation:
- according to https://www.everythingrf.com/r…ic-reflector-antenna-gain, the theoretical gain is 31,55 dBi (at 70% effectivity!).
- according to an information that was posted here on the forum a while ago, the EIRP of DL50AMSAT is around 900 Watt.
- to be as strong as the CW beacon I need to have 623 mW (27,9 dBm) at the feed of the helical antenna.
- using that power and the theoretical gain (623mW + 31,55 dBi) I get an EIRP of 890 Watt EIRP.
Conclusions: obviously my setup is very effective; I don’t think I can do any better!
Vy 73
Holger ‘Geri’, DK8KW
@SWL - markro92, good job again, thanks!
Version 2.0.13 works fine here, using a Q8400 processor @ 2.66 GHz. Once I realized that the BB Gain slider was at "zero" in the beginning, I am now able to quickly synchronize almost every station now. Also, the Transponder Overlay is very helpful.
Rig here currently: modified Octagon in 1.8m offset dish made by Kathrein, 20m cable, Nooelec RTL stick.
Best 73
Holger 'Geri', DK8KW
Already back in 1984 there was a software called "Dr. DX" for the Commodore C64, simulating an entire shortwave contest with varying band conditions, greyline dx, pile-ups and rare stations showing up and disappearing again throug out the game. There was not even the need for any other ham station to have fun ...
Vy 73
Holger 'Geri', DK8KW
I am asking because stations calling the the dx station will most likely not be listening on their split tx frequency while calling and therefore not hear the LEILA warnings.
... the good thing with QO-100 is: a rare dx station will create a pile-up at first, but if you are a little bit patient and give it a few days, the dx station will call you in the end. The amount of stations accessing the satellite (currently) simply is too low to create an hour-lasting pile-up.
Best 73
Holger 'Geri', DK8KW
@SWL - markro92: marcel, thanks for the new version. I have been playing around a little bit with it and it seems to be decoding faster with the new version.
>Showing Ku-Band Lo/Hi frequencies next to IF frequency.
What I tried to do is to adjust the frequency offset in the device.ini-file but without success. I use a modified LNB and my L.O. is around 9.500 MHz. I am also missing the readme.txt file that supposidly is explaining on how to set up the parameters.
How can I adjust the L.O. frequency so that the correct receiving frequency is shows?
Best 73
Holger 'Geri', DK8KW
PA3FYM: I got them here, at an online shop in the Czech Republic (thanks to ON1RC, see message above): https://www.hamshop.cz/electro…enzator-1nf-300v-m3-i352/
Delivery time was about 10 days.
Best 73
Holger 'Geri', DK8KW
Hello all,
For those of you who want to equip the SG-Labs 20 Watt PA with the additional voltage outputs to measure input (DRV) and forward (FWD) power and estimated SWR (REF), here are a few pictures showing that it is an easy task.
What is needed is just a 2.5mm drill, a tool to cut the M3 thread and steady hands. Wiring is also easy.
As you can see, I operate the PA with a 12 Volt to 24 Volt up-converter that I found somewhere on the internet. I mounted both devices on the same aluminium heat sink.
Here is a detailed data sheet of the L4030-034N
Vy 73
Holger 'Geri', DK8KW
SWL-JanV: I can confirm what DB8TF writes. I use 50 MHz as an IF, so the 2350 MHz signal of my older type BU500 had the same problem. I ordered an interdigital filter from ID-Elektronik (I am not very good doing precise mechanical work). The filter has a 90dB notch at the L.O. frequency of 2350 MHz and the problem disappeared.
Meanwhile (after mechanically damaging the old-type BU500, trying to drill some holes into the housing) I ordered a new one (Version 6) and the problem disappeared. Nevertheless I keep the interdigital filter in the signal path, between the BU500 and my PA, just in case.
Best 73
Holger ‚Geri‘, DK8KW
