I would say there is something wrong with your output-power or antenna-gain or cable-connection. In addition as already mentioned before the antenna is not the cheapest. My construction is 15€ and works well for TX and RX with one reflector. I would use this solution if a dish can be mounted in your environment.
Good idea - I will try to be there - depends if i will get vacation in that time periode. If yes, i will be qrv via oscar-100 from the camping place out of the motor-caravan.
see u 73' Kai
can you tell me, where I can get this nice housing ?
Hello, its from ebay:
Halbschalen-Kunststoffgehäuse EURO-BOX, 205x180x70mm, schwarz
Halbschalen-Kunststoffgehäuse (205x180x70 mm) mit schraubenlosem Schnappverschluss und austauschbaren Frontplatten.
Art. Nr at ebay : 322497818759
73 de Kai / DH0SK
Hello, is their a link for the Image? Maybe i overlooked it ? Is the Raspi SW able to correct the drift?
My Raspi QO100 Receiver with same design as the Transmitter is now ready besides the SW Image. Maybe someone can point me to a link.
Pic. 1: new QO100 Raspi SDR Receiver
Pic 2: the Transmit Box LZ5HP with 25W PA same design as SDR Raspi Receiver
Now with the Raspi Image my small Groundstation is ready 😁
73 de Kai
Hallo Kai, thanks for the nice qso yestrday. Have you been using the antenna on that picture? Your signal war pretty good!
Yes i only use this Dualband System. Works really good.
73 de DH0SK Kai
Just another optimized dish to promote OSCAR-100 with my portable station for the next HamRadio meetings at our local club http://www.i57.de
One dish with LNB and Helix for receive and transmit ist. works fine.
73 de DH0SK Kai
I am looking for a DC / DC stepup converter from 12V to 28V. The output current is max. 5A
Does anyone have a suggestion?
Hello, See attachement. This is what I used in my portable Station. With the DC regulation you are able to tune the output power to be below the beacon signal or to attach to different antenna gains for portable use.
some experimental notes on modification. I have successfully modified two GM-201's so far, both used the NXP1017 IF processor and LS7005 intelligent regulator:
thanks for the very good explaination. I have still twenty of the GM201 and will start to modify with your idea.
The only open question ist the bias/triplex er for single cable solution. Do you have a schematic of that part?
Thanks in advance
This is my Dualfeed - but not testet yet. Hopefully it will work for portable activity.
73 de Kai DH0SK
Hast du den LNB umgelötet das er eine ZF im 70cm Band erzeugt ? Ist die stabil ?
Ja ich hab den Quarz getauscht und kann somit mit dem LNB im 70cm Band empfangen. Fuer mich war die Stabilität im ersten Ansatz ausreichend (SSB Betrieb) . Verbesserungen (TCXO, GPS usw.) werde ich spaeter machen.
73 de DH0SK
Hello all, thanks for the answers to my question regarding the 70cm IF. Meanwhile i got a Signal on 70cm with that Pollin LNB but not on the expected frequency. The Quarz from eBay from austria was indicated with 25,788MHz. I expected the beacon on 432MHz but i found the beacon on 430,081MHz. Its difficult to have two parameters wrong (frequency and direction). Maybe the Quarz was wrong or the PLL factor i assumed was wrong?
Btw. I was wondering about the good stability of the Pollin LNB. For SSB it was fine for me. With additional aluminium foil arround its ok.
73 de Kai
Hello, I search for someone with experience on Pollin LNB Golden Media GM201:
I soldered a christal for 432MHz IF (25,788 x 390) but nothing received.
I am not sure if the PLL is locking and/or the IF Filter is blocking the 432MHz IF.
Did someone has experience to use the GM201with a christal for 432MHz IF ??
Very nice Transverter - i ordered in Januar and arrived 3 weeks later. Payed by Paypal. Meanwhile fully mounted as portable Station in a small Box with PA for Outdoor activity with FT897. See picture below as apetizer, hi.
Here my just ready built Transverter (SG Labs) for robust portable use together with FT897. The portable Dualband Antenne needs to be developed now. This will be used out of the Motor Caravan in summer. The output Power can be regulated to adapt to the portable Situation. The small old style instrument shows the output power (forward or return) switchable. 73 de Kai
Congratulation to the whole team to the great success of that project. Nice to hear the beacon sound back which i known from the late 80s when i was a young boy. Nice to learn that this kind of projects in Ham Radio is still feasible. I am sure this project could be a good justification for further projects. Now its time to build my uplink station.
Thanks to all involved in that project - i know how difficult the space business is today.
73 de Kai
Output Back-Off. In my own words: the full capabilities of the TWTA will not be used but (in this case) output is 6 dB down. This is to improve linearity and improve NPR (Noise Power Ratio), so that in the passband there will be less IM (intermodulation) due to other (different) modes and users (very briefly said).
So, O/P of the HPA (TWTA) is 100W (50 dBm) - 6 dB (OBO) = 44 dBm - 1.5 dB losses = 42.5 dBm + 17 dBi (EC horn) = 59.5 dBm (= 29.5 dBW).
Divide this into 50 channels (however ... 50 x 2.5 kHz = 125 kHz) <-- ?
But say ... 50 x 5 kHz channels you've 29.5 - 10log(50) = 12.5 dBW per channel.
The rest follows from the sheet.
Nice, i search for Payload Engineers
73 de Kai
Maybe i can explain in the frame of the discussion regarding 'unwanted signals' the IOT phase:
Before the IOT starts there will be a TRR (test readyness review) in front of the customer. All the testplans and test-specifications will be reviewed. When the test is done there will be a TRB (test readyness board). In the TRB they have to show/present all the measurement results (e.g. inband performance like Gainflatness, Groupdelay... aso.) and compare these results with the specification in the contract. Each unwanted signal makes the measurement difficult and needs to be explained or leads to a so named NCR (non conformance report).
The IOT will be done in shifts/nightshifts and with unwanted signals (if not explain able) some measurements needs to start again and again and leads in addition to a delay for the handover and operation of the satellite.
Maybe that helps to understand why it is really important to have only the IOT uplink signal.
To measure the pattern of each antenna the satellite will be moved east/west by the propulsion system of the DS2000 Bus and the signal level is measured by the IOT station on ground (some cuts) .
The commercial beacon can maybe be switched from LEOP Omni antenna to on station antenna when the satellite is placed in the final slot. This should be the reason for the change of the commercial Ku Band beacon signal level the last days.