MY QO100 SETUP

OE3GBB · Mar 26th 2022

Quote from SV1BDS

Can you explain what exactly you want to do?

A friend asked me to think about an additional repeater at OE3XNK on 23 cm. I did some research on the net how to use SDR for that purpose and found QRadioLink. Have not tested it so far as it seems to be quite complicated for setup. There is also one information on the net how to use a simple script within the Pluto itself to copy a signal from RX to TX. For me GNU-Radio possibly seems to be the best solution.
It should be at least a standard FM Repeater within the 23 cm band. But I think it this works the frequency could be changed easily to other bands or to crossband. I think there will be no need to decode the FM on RX and modulate on TX. Therefore maybe a linear repeater would be best.
73 Gerhard

DD1US · Mar 26th 2022

Hello Gerhard,
what are the requirements in OE-country with respect to spurious emissions of such a repeater (in band, out of band, harmonics)?

Kind regards

Matthias

http://www.dd1us.de

SV1BDS · Mar 26th 2022

Hi,

A SDR based system must use the capabilities of software based solutions in order to do things that can not be done or is very complicated to do with hardware. All of us try to replicate hardware solutions into the software solutions and not think what new features can be implemented.

OE3GBB · Mar 26th 2022

Quote from DD1US

Hello Gerhard,
what are the requirements in OE-country with respect to spurious emissions of such a repeater (in band, out of band, harmonics)?
Kind regards
Matthias
http://www.dd1us.de

If I am right, there is no difference between in band, out band and harmonics:

DD1US · Mar 26th 2022

Hello Gerhard,ok.

I think if you transmit with low power then that might be feasible with a Pluto. I wish you good luck and make sure you are measuring your emissions at a dummy load before transmitting with an antenna.

Kind regards

Matthias

http://www.dd1us.de

DD1US · Mar 26th 2022

Quote from SV1BDS

Hi,
A SDR based system must use the capabilities of software based solutions in order to do things that can not be done or is very complicated to do with hardware. All of us try to replicate hardware solutions into the software solutions and not think what new features can be implemented.

Good point George, but you still have to be compliant with the regulations in your country and according to your license.

Regards

Matthias

http://www.dd1us.de

SV1BDS · Mar 26th 2022

Quote from DD1US

Good point George, but you still have to be compliant with the regulations in your country and according to your license.
Regards
Matthias
http://www.dd1us.de

This is mandatory.

The question is what is the added value of us as ham radio to science and society today. Are we just operators and consumers?

DD1US · Mar 26th 2022

George,

well, we have to acknowledge that not all radio amateurs are able to actively contribute to science and society. This may be due to a lack of technical knowledge or a lack of free time besides the daytime job.

For such people there is still the option to support organizations like AMSAT by money (by membership fees or by donations) and thus enable those organizations to forster contributions to science and society.

But for sure there are also quite some, who do not contribute anything but only benefit from the knowhow, time and money others are spending. As long as they value what they are enjoying it is fine for me but those who are only complaining without contributing are a real PITA.

Kind regards

Matthias

http://www.dd1us.de

SV1BDS · Apr 1st 2022

Hi,

Portable station is completed. Fan added. A LC filter was added in series with FAN to prevent interference to LNB. A series diode and a parell diode eliminate the sparc produced by L when switched on/off by the thermal switch, that will destroy it in the near future.

SV1BDS · Apr 1st 2022

Hi,

Mounting POTY feeder to bracket of a 80 cm dish for portable station.

SV1BDS · Apr 15th 2022

Hi,

50 MHz - 900 MHz & GPS preamplifier is connected to a satellite splitter drived by a discone with a notch filter and a GPS active antenna. At shack drives another amplifier and a passive 4 output splitter with a 5 dB increase in GPS SNR.

SV1BDS · Apr 19th 2022

Hi,

Active GPS 4 way splitter with bias tee for active antenna MMIC preamplifier and active GPS antenna.

SV1BDS · May 6th 2022

Hi,

Rf probe for up to 11 GHz using BAT15 constructed. Usable dynamic range is about -30 to +15 dBm.

SV1BDS · May 7th 2022

Hi,

Some notes regarding RF probe:

The 2*100 ohm alone have less than 1.5 SWR up to 11 GHz. Adding the diode the SWR is affected. A isolation resistance maybe a solution. A second diode providing negative voltage can increase the dynamic range 6 dB more in the lower limit. My thought is that a doubler, as described in application note, stress the second diode at twice the voltage! An op amp circuit has designed to convert symmetrical voltage to half in order to be measured by a microcontroller ATMEGA8 and powered and provide measured voltage to USB serial. Double diode exists in a small extra price.

SV1BDS · May 7th 2022

Hi,

RFprobe improved.

Operation up to 16 GHz archived with relative flat responce. Dynamic range changed to -20 dBm to more than +20 dBm.

SV1BDS · May 8th 2022

Hi,

Two probes has been built with similar results.

SWR is under 1.5 up to 12 GHz and less than 3 at 12-16 GHz. Linearity vs frequency is in a ratio of 1:2 max. It can not compared with an IC one but for such a cost is an interesting solution. I use 1206 for 100 ohm and 0805 for 1K and 1n.

SV1BDS · May 16th 2022

Hi,

A out of topic post of using 2.3 GHz for Simplex QSO between Athens and Chania 270 km using 1W & 5W.YouTube video.

SV1BDS · May 20th 2022

Hi,

POTY feeder was fitted at focal point (1 cm vertically from previous position) and proper operation archived.

SV1BDS · May 20th 2022

Hi,

When active in 2.4&5.5 GHz WLan world I have built a software that says with recorded voice the RSSI (S meter), permiting easy antenna alligment. The SDR console programmer seems that does not accept ideas for implementation. I have start implementing one in gnuradio. Is that of general interest?

SV1BDS · Jul 23rd 2022

Hi,

A 4 way coaxial relay & PTT switch powered by 13.8 V using a knob for selection is build.

MY QO100 SETUP

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