Hi all,
Easy mistake to make I think
plus, I guess, a lot of people don’t even realize how sensitive the QO-100 RX really is. Signals of way less than 1 Watt ERP are still detectable despite the 36.000km uplink distance 
.
Vy 73
Holger ‚Geri‘, DK8KW
Hello Martin,
that is an interesting observation. According to the beacon website https://sk0en.se/ the beacon is not even qrv yet on 2.4 GHz yet. The transmission obviously occurs on 2400,5 MHz. At the moment I can not determine how any of the other listed beacon frequencies could produce such a signal. It is worth to further investigate.
Vy 73
Holger ‚Geri‘, DK8KW
George,
thank you very much, your figures give me a good indication on where I need to try and gain some more dB.
Vy 73
Holger 'Geri', DK8KW
Hello YLs and OMs,
I am looking for some real life MER figures that can be achieved with a certain dish size.
I found this table here on https://wiki.batc.org.uk/Receiving_Oscar_100_DATV_signals:
This table is valid for the old 2 Ms QO-100 DATV beacon A71A. There are also a few discussions on the net. but those I found all discuss the values for the 2 Ms transmission. Have these values changed after the beacon bandwidth has been reduced to 1.5 Ms?
What are typical MER values you get with your own setup?
I need some guidance to optimize my setup and to know what to aim for.
Thanks and vy 73
Holger ‚Geri‘, DK8KW
Hi,
from a veteran EME guy I heard that he was using a video camera fixed to his antenna to adjust his setup to the moon. He wrote that his wife operated the antenna joystick, targeting the moon on a TV screen while he made the QSOs. Of course, that was way before those programs that control the antenna position permanently.
Vy 73
Holger ‚Geri‘, DK8KW
Hi all,
Somehow I managed to get the F5OEO firmware (version August 29th, 2020) to work and maintain the frequency extension active.
What I basically did was to makes sure I had the original ADALM PLUTO firmware 0.31 (not 0.32!) on the device and performed the frequency extension.
After that I loaded the pluto.frm from F5OEO into the Pluto folder (Windows 10) and started the uploading process. Firmware is functioning, frequency extension was tested with SATSAGEN.
I have no idea why it didn't do this the last time I tried it, but now it works (well, I understand it's the digital world: either things work -- or thry don't).
Vy 73
Holger 'Geri', DK8KW
Tnx, Mike,
Well, it is a few messages further down that mentioned it. I had loaded the latest F5OEO firmware the other day and SATSAGEN stopped working and didn't allowe me to proceed du to the inability to perform the frequency hack.
This is the message that got me confused:
RE: Adalm Pluto -New official firmware 0.32
saying I have to use the boot frm from 0.31 to still be able to perform the frequency extension hack. Honestly I haven't been able to dig deep enough into the firmware and operating system of the Pluto to be able to perform that stunt so I was hoping for some advice for the layman.
>Advice - use 0.31
Probably that's what I have to do.
Vy 73
Holger 'Geri', DK8KW
Well, G0MJW,
Thanks for the hint, Mike. Been there, done that. Didn't find what I was looking for, therefore hoping to find some assistance here.
Perhaps the wording of my question was not sufficiently clear enough. My understanding is that when I load the latest F6OEO software I get the 0.32 version of the regular Pluto firmware coming along with it. This one suppositly doesn't allow me to expand the frequency.
Is that right? Is there a workaround? Any assistance is appreciated.
Vy 73
Holger 'Geri', DK8KW, W1KW
Hello folks,
I plan to do some tests with DATV, so I want to install the F5OEO firmware onto the Pluto.
My understanding is that with the latest Analog firmware update 0.32 I lose the ability to extend the frequency extension capability that I need, for example, to run SATSAGEN.
Can someone please point me to some further information/instructions on how to keep the frequency extension (70MHz to 6GHz) while installing the (latest?) firmware of F5OEO?
Thanks, vy 73
Holger 'Geri', DK8KW
Good morning, all,
Here is a chart that shows the approximate EIRP that can be achieved with a given PA output power and a given antenna diameter.
The Bochum AMSAT beacon DK0SB (ex DL50AMSAT) has an EIRP of around 900 Watt.
Vy 73
Holger 'Geri', DK8KW
Hello George,
I had a successful reception of DL0SHF on June 2nd, 2020. The moon passed about 1.5 degrees below the beam of my 1.8m offset dish, so I adjusted the inclination of the antenna before the moon pass.
I used a GPS-controlled LNB and the RSP1A for reception. The DL0SHF signal was audible for a few minutes and I was able to decode the CW signal by ear. Due to the Doppler effect the RX-frequency was about 6 kHz above the transmitting frequency of the beacon.
All in all a very exciting and rewarding experience!. Good luck with your redeption.
Vy 73
Holger ‚Geri‘, DK8KW
Hi folks,
An addition to the software for this device: there is a pogram that can be downloaded for the vendors websites. This, however, allows just changing the basic attenuation value and this is simpler if you do it with the five buttons.
Currently on Ebay there is a guy who wants to sell a software written in Python to control the attenuator (just look for ATT-6000 and Python). I am no expert in Python and, to be honest, that software seems to be a bit overprozed.
Third option: I found a software called PureBasic (see https://www.purebasic.com/). It reminds me of my old C64, HP-Basic and QBASIC times and it is simple enough for me to handle it, and strong enough to write a small control program for the attenuator.
A demo version limited to small programs (about 800 lines) is free of charge.
Vy 73
Holger 'Geri', DK8KW
Hello YLs and OMs,
One thing I learned very early, when I started with QO-100 last year: it’s all about the proper power level!
This resulted in the fact that I today own way more attenuators than amplifiers. You see so many distorted signals on QO-100 where you can see that the amplifiers are driven beyond their linear range. A little attenuator at the right place would be sufficient to adjust the signal.
My latest acquisition is a 60dB 6GHz programmable attenuator called ATT-6000. It is offered by several people on Ebay, for example. On the internet there are a few discussions about this type of equipment, for example on an Amateur Radio Astronomy website: http://cygnusa.blogspot.com/20…at-for-att-6000-step.html. Here, the 31dB-version is discussed.
The ATT-6000 comes with in a machine finished metal housing that looks very well made. The little unit is powered via an USB-cable. This also allows the programming of the device.
Attenuation adjustment range: 0-60dB
Attenuation step: 0.25dB
Max. frequency: 6GHz.
More date can be found on the internet, e.g. on Ebay. Also, some measurement-charts are available, e.g. about the frequency range and the accuracy.
I have put this device directly behind my Pluto. On 2.4GHz, the base attenuation is in the 5dB range. For my applications this is not relevant. What I want to do is to test various modes on QO-100 in order to find out to what level below the beacon level communication is still possible.
Once I adjust my TX output signal to the beacon level I can reduce my output power accordingly. The absolute attenuation seems to be a little bit lower than said. I measured about 4.6 to 4.8 dB per 5dB attenuation step, however, that might be a problem of the accuracy of my measurement setup. The repeatability of each step, however, lays within a few tenth of a dB. The attenuation can be adjusted with the 5 buttons on the housing of the unit.
The ATT-6000 can also be remote controlled. I used a simple terminal program. Once connected, the device is recognized as a Profilic USB to COM adapter. Basic communication characteristics are: 115200 Baud, 8 Bit, 1 Stop-Bit, NoParity.
The attenuation value is sent to the device by the ASCII-string wv0xxxx, whereas xxxx is the value of the attenuation. 1225, for example, represents an attenuation of 12.25dB 8see pictures). I need to find a simple programming language (I am not yet too familiar with all the modern stuff such as Python), the I can make the adjustment of the attenuation even easier.
This attenuation device is definetely somehing I can recommend for the QO-100 operator. It can be used, for example, to find the proper attenuation value between power amplifiers so that the signal quality is improved. Once measured, which value is needed it can then be replaced by a fixed attenuator.
Vy 73
Holger 'Geri', DK8KW
P.S.: Again, I am in no way connected to anyone who offers this device.
Hello folks,
Last year, long before I had a Pluto, I purchased an unknown amplifier from Poland on Ebay, that was just marked "Mikom MLA 901-1459". Pictures of the front cover show a frequency range of 2439-2576 MHz.
In the meantime, I have made some measurements and made this amplifier a regular member of my amplification chain. Especially in combination with the new version of the SG-Lab V3 20Watt amplifier the MLA 901-1459 offers a useful tool to use the full power range of the Pluto to drive the SG-Lab PA to its full potential.
If you enter the "MLA 901-1459" in eBay ou can see that these surplus amplifiers are still available. It is a very well designed and built commercial little amplifier. Perhaps this is a good alternative to the little Chinese amplifiers that usually come without a housing.
Below are two amplification measurements, one with just the pre-amplifier (MLA 901-1495) and one with the entire system (Pre-Amplifier plus SG-Lab V3. Measurements were made with the SATSAGEN-Software and the Adalm-Pluto. Amplification of the MLA-preamplifier is around 25dB.
Vy 73
Holger 'Geri', DK8KW
P.S.: I am in no way connected to the seller of this surplus equipment, I just want to give some useful hint to people looking for such equipment.
Hello Marcel,
I did reception tests with the 2.0.20-version today and they all were very successful. Once I found the right adjustments, I was able to jump to another stations frequency, change the bitracte and wait a few seconds and the signal was there. Sometimes, changing the bitrate up or down by one bit helps to find synchronization quicker. Great job, thanks!
I have two request respectively questions:
1st: would it be possible to allow the L.O. frequency to be entered with a few digits behind the comma? I use a LNB with a 26 MHz GPS-controlled oscillator and my L.O. frequency actuall is 9388.888 MHz. But I can only enter freq_lo0 = 9389.
This would help to quicker enter the right frequency.
2nd: when I try to change the IF frequency with the scroll whee of my mouse it changes the frequency in MHz steps. Is that anything that has to do with my computer or is it something in your software? I would be able to change the frequency in smaller steps, actiually, for example like 100kHz.
Thanks and vy 73
Holger 'Geri', DK8KW
hello Peter. can you use the VOX to trigger the relais-PTT in SDR-Console? if not: it might be worth to ask Simon if this could be implemented.
Vy 73
Holger ‚Geri‘, DK8KW
Hello Thorsten,
I am not familiar with the DX-Patrol up-converter but I assume that it is working as a linear converter. So what you would need is a relatively cheap step attenuator on thw input side of the converter to reduce the output power. This step attenuator only needs to be suitable for the input frequency and not for 2.4Ghz. I have seen those already for around 20 or 30 Euro.
The SG-Lab PA is very linear, even down to very low power, see my report at
Vy 73
Holger ‚Geri‘, DK8KW
Hi Oliver,
I have a different GPDXO, made in Germany by a company named Cartain. It was a bit cheaper than the Bodnar, and it was abvailable at the time I bought it and Bodnar had a longer delivery times.
What I did was to check what peope said about the Bodnar-Voltage at 8mA and I basically use the same voltage with the Cartain. I only need a single GPS controlled frequency of 26MHz. I split the output through a Mini Circuits splitter (so at least losing 3dB) and then put another 3dB attenuator in the line before I feed the signal directly into the Pluto.
The other line goes via a 20m coax cable to the LNB and stabilizes the reception. I am very happy with this entire setup.
Vy 73
Holger 'Geri', DK8KW
HB9SKA: what my equipment is concerned, I don't believe in covers 
... my LNB as well as the helical antenna are in the open environment, so the front end of the LNB surely was wet during the rain. However, when a "normal" rain occurs and the surface of LNB lens is wet I can measure no attenuation.
Vy 73
Holger 'Geri', DK8KW
Hello all,
Yesterday I had the opportunity to record the level of the CW beacon while a heavy rain shower came down.
The nominal value I adjust the beacon to is -73dBm. You can see from the picture that the lowest level during the rain is around -88dBm (only look at the upper values of the curve -- I tried to produce an envelope in Excel but that seems to be a challenge in itself).
So the maximum attenuation is 15dB. My uplink signal, adjusted to the beacon level, also had the same attenuation as the beacon, which means, that the 2.4GHz signal seems to be much lesse affected by the humidity in the air.
Did anyone else took similar measurments?
Best 73
Holger 'Geri', DK8KW
P.S.: I don't really know if this is relevant and if the attenuation is the same for different antenna sizes. My QO-100 antenna is a 1.8 Meter offset dish from Kathrein (CAS 180).
