On Thu, Mar 25, 2021 at 2:57 PM Zach Metzinger [email protected] wrote:
On 03/25/21 12:50, Edson W. R. Pereira wrote:
I have an old IC-821 that recently started having CPU issues and am not sure I will be able to fix it. I am in the process of rewiring the dual PA and front-ends to my PlutoSDR.
With the present availability of SDRs like PlutoSDR, LimeSDR, BladeSDR, etc., it is much easier to use them to receive (and generate) signals, but they lack good filtering and adequate RF power. It would be nice if we could have some commercial solutions.
73, Edson PY2SDR
It seems that an outboard filtering "box", with the appropriate band-select signals from the SDR, would be a good solution.
Indeed. I have rescued some BPF from old equipment and have been using them for RX for some time. Now I am trying to get TX.
It could incorporate RF amplifiers, too, to get the signal up to at least 5W. At that point, a conventional external PA could bring the signal level up to 100W or whatever the user chooses.
I still have to determine the power level needed to excite the IC-821 PAs. It may be necessary to add an RF buffer.
While I like the ADALM-PLUTO, I don't like the USB interface. USB is finicky even under ideal circumstances. I would much prefer a GigE interface into the Zynq inside that box. It could then be placed anywhere on the network, ideally with PoE so that a separate power supply would not be required.
You are absolutely right. USB also tends to generate a lot of RFI on HF. I intend to put the pluto inside the IC-821 cabinet with a USB to Ethernet converter plus a media converter to transport Ethernet via fiber. This way I can galvanically isolate the PC from the SDR and antenna and also mitigate some RFI issues. But I am not sure how stable the USB/Ethernet will be.
It would be really nice to have a low-cost SDR transceiver like the Pluto or Lime with a native SFP port.
The design is open-source, so it could be done.
True. Anyone would be interested in a community front-end and PA project for SDR interfaces?