New user Multiband question

[Max]

Max, it makes some sense, but does not explain the use of 'all at once' and a video showing several bands simultaneously showing live waterfalls on the Multi-Band web page. Please take a look and tellme what I misunderstand there.
Thanks & 73, David G3WGN

Simon shows two multiband screens on that page, one is video, showing simultaneous bands LW band to 4.5MHz (60m band). This requires the SDR bandwidth to be set to around 5 MHz or wider, with centre frequency set to 2.5 MHz.

The other screen is static and show ham bands, 1.8MHz to 7MHz. This requires a hardware bandwidth of at least 7.2 minus 1.8 = 5.4MHz, but you need some at the sides to compensate for lack of sensitivity at the edges, so say 7 MHz.

You can achieve both of these scenarios with your RSPdx (albeit with possible performance issues I referenced earlier).

What I am beginning to wonder is if you have set the bandwidth of your hardware wide enough?

You set it here, if it's anything like similar to the RSP2Pro...... I don't have the dx but I'm pretty sure Simon's hardware interface is the same. Set this to 10 MHz and you are good to go. I have a suspicion that maybe you've missed this and you have it set to a much narrower bandwidth?

Max

[G3WGN]

Many thanks for your patient responses Max. The light is at last starting to dawn.
I'll play with the Bandwidth setting and band selection, but now the boundaries are clear.
73, David G3WGN M6O

[Max]

NP David. Good luck with it and feel free to ask if still not clear.

Just be aware that at 10MHz bandwidth on the RSP you may run into some major image issues at HF. If you want great performance wide bandwidth at HF then you may need to look at other hardware such as Elad S3 or RX888. Not may others that are in any way what I would personally call affordable, and in fact the S3 is not cheap at about £900!

Narrower bandwidth (only 768 kHz) but far better performance on HF compared to RSP, try HF+ from Airspy, but does not have the wide VHF/UHF coverage of the SDR Play:

https://airspy.com/airspy-hf-discovery/

If you fancy great quality direct sampling SDR TX/RX but single band use, the Hermes Lite 2 has 384kHz bandwidth (so no good for multiband like in this thread - although it can multiband "skim" with other software) but superb direct sampling performance to match rigs costing many thousands. 5 Watts out so ideally for use with linear but cheap as chips and works brilliantly with SDRC. Cost about £300 direct from factory and maybe 45 mins to put together (semi-kit of PCBs and enclosure):

https://youtu.be/RCa-wd3Xb_k

Have fun!

Max

[Max]

If you fancy great quality direct sampling SDR TX/RX but single band use, the Hermes Lite 2 has 384kHz bandwidth.

Max

I hope that didn't come across that Hermes Lite 2 is restricted to literally one band. Any HF band 0 to 32MHz, but only one at a time for TX use!

However, here's info about the multi-band skimming I mentioned. I've never tried it (or needed it). SDR Console one band at a time is perfect for 99% of my own needs:

https://m0taz.co.uk/2021/05/10-band-ft8 ... 4-skimmer/
https://www.lefars.org.uk/2021/01/spark ... per-m0nnb/

Just to be clear it's NOT the same as the multiband feature on SDR Console. Console (sadly) does not support this "receive slices" mode of operation on the HL2. That's partly because Simon has designed SDRC to work with a great many SDRs and cannot necessarily add features that cater to the vagaries of specific radios, especially the more esoteric features like this. But I mention it for your further interest.

73

Max

[bagmouse7]

There is a simple explanation here.

The video here:
https://www.sdr-radio.com/multi-band
Shows 6 bands at once, the lowest band shown is from 140kHz - 300kHz and the highest band show is from 4750MHz - 5050MHz.

This can be done with the SDRdx.
Start your SDRdx up with the maximum bandwidth available (10MHz).
Zoom out the waterfall display all the way out.
Make sure the main waterfall display is set to show the full spectrum from 0 - 10Mhz (you may need to grab the slider at the bottom of the waterfall and slide it all the way to the left).
Now start the mulitdisplay and select on of the displays that shows bands below 10Mgz.
The multidisplay can only show the bands that are currently being shown in the main waterfall display.
Since the SDRdx displays 10Mhz of bandwidth at once all the bands on the multi-display window have to be within 10Mhz of each other.
SDRs like the S3 (24Mhz) and the RX888 (32Mhz or more) are recommended because they can show very wide waterfalls so they are able to multi-display bands from a wider range of frequencies simultaneously.
Hope this clears up the confusion.