Looking for Advice on SDR

Aloha! We are a high school team from the Big Island, Hawaii. We are upgrading our ground station and want to upgrade our SDR. We’d been using the inexpensive RTL-SDR dongles with limited success. We have …
IC-705 Transceiver
GPredict
50 Ohm System
Computer with Windows 11
UHF & VHF Antennas (AMSAT combo)
Yaesu Rotator
Delta Fox Controller

We are looking for a good (at least better) SDR that is compatible with SDR# and (less important) can be used to transmit. We’ve taken a look at …
Airspy R2 SDR
SDRplay RSP1A
HackRF
2021 PLUTO+ SDR AD9363 2T2R

But we could use some input from experienced users.
Mahalo!
BTW the lava eruption that started yesterday is safely away from our school.

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Frederick,

I run both a SatNOGs ground station and an amateur satellite ground station. The SatNOGs uses RTL-SDR’s and the amateur ground station uses a SDRPlay RSPdx. I use the same type of LNA on both and the RSPdx is much more sensitive by about 20dB. Because the RSPdx has a 12-bit ADC at VHF and above, and the RTL-SDR is only 8-bit, the RSPdx has a much better dynamic range. Basically, it can deal with high levels of nearby interferers (ie pagers, etc) much better than the RTL-SDR. I also have a HackRF One. It is about 10dB better than the RTL-SDR. I also have some LimeSDRs but without a preamp they are pretty deaf at VHF & UHF…plus they don’t have an internal bias-tee.

Since you are using Windows 11, the other thing I would recommend is using the SDR-Console software instead of SDR#. SDR-Console has a Satellite module and an External Radio module as part of the package (as well as some others). The Satellite module replaces Gpredict and controls both the external Az/El rotator via WiSPDDE and the doppler for both the SDR and the External radio (via OmniRig). I use a K3NG/VK4GHZ controller and G-5500 rotator and an IC-9700 or FT-991A for the External Radio so my setup is not at dissimilar to yours.

One other feature of SDR-Console that I like is that you can have multiple receivers running at one time (ie Voice receive, CW beacon and Telemetry). Each can go to a different device……I typically use Voice to headphones, CW beacon to either headphones or speaker and TLM to the UZ7HO soundmodem via a Virtual Audio Cable. There are a few quirks about the SDR-Console software that bug me a bit but generally it is very robust and highly featured.

As for transmit SDR’s. The HackRF One and the LimeSDR’s can both do transmit but at low power so you really need some amplifiers to get the power up to 5-10+ watts…or 25W for GreenCube. The HackRF One is only half duplex so it is not really suitable for satellites if you are used to full duplex (ie for SSB).

The other thing worthy of note at the moment is that SDRPlay have a Christmas special price ($USD 169.95 plus tax & shipping) for the RSPdx……check it out.

Hope this helps.

Regards,
John – VK4JBE.

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You might be interested in https://gitlab.com/librespacefoundation/sdrmakerspace/sdreval/-/raw/master/Report/pdf/Evaluation_of_SDR_Boards-1.0.pdf

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Mahalo, John.
Yes, I think our systems are similar - or will be, when we get up and running.
Thank you for your suggestion about the Airspy RSPdx. We have heard other positive responses about it.
Also, at your suggestion, our “tech guy,” Christian Williams has begun investigating SDR-Console. That might be the way we go. (Is it superior to SDR++ ?)
We may transmit with the IC-705, but I understand that transmitting with SDR is an option, so we are looking at that possibility as well.
Thank you so much! Hopefully, we’ll be training our students how to run a ground station next semester.
Mahalo! - Frederick

This looks good! (We’ve heard great things about the Ettus, but I think it’s out of our price range!) Thank you, we’re going over the info.

  • Frederick

Please share some more information on

We’d been using the inexpensive RTL-SDR dongles with limited success

Then I am better equipped to answer your question.

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SDR console is not superior to SDR++ by any stretch!!

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Hi Jupitersaturn09,

I have not used SDR++ ….and am always on the lookout for good software…especially linux software.

I would be interested in why you think is is a better program….especially given Fredericks original use case is for satellite operations.

Regards,
John – VK4JBE