Tag Archives: SDRplay

SDRplay RSP-1 OEM Metal Case

Many thanks to SWLing Post contributor, Rafman, who writes:

The SDRplay RSP-1 OEM Metal case is ready for order and shipment Worldwide

Includes:

  • 1x Black aluminum metal enclosure with two labeled side panels, 1x Broadcast FM band-stop filter plus SMA Male to SMA Male barrel adapter,
  • 1x Black semi-hardshell carry case,
  • 1x Thermal pad to keep the RSP-1 cool and mechanically stable inside the enclosure and
  • 1x Accessory set including enclosure screws, GND lug bolt set and 3M anti-slip rubber feet.
    Can be used to upgrade the SDRplay RSP-1 ONLY to a metal enclosure. Helps block RF interference.

Note that owners of the very first RSP-1’s with F-Type connectors may require an additional F-Type pigtail adapter, or a MMCX to SMA pigtail to be able to use the BCFM filter internally. The BCFM filter can still be used externally.

Click here to view the RSP-1 metal case at Amazon.com (availability expected March 27).

Thank you, Rafman! I have the first generation RSP-1, so appreciate the note about using the filter internally via an adapter. That’s a nice enclosure.

SDRplay releases SDRuno version 1.13

SDRuno running the RSP2.

(Source: Jon Hudson, SDRplay)

SDRplay has just released SDRuno version 1.13 which adds the much requested ‘IF Out’ facility for Panadapter use. It also includes the following updates:

Bug Fixes

  • Fixed RSP2 IF AGC/gain slider display issues

Updates

  • Added IF Output mode for transceivers
  • Added 250 Hz to frequency step size list
  • Default page in the settings panels is now the left most page each time SDRuno is started
  • Added RSP2 IF GR/Gain value
  • Added Factory Reset in the Main Window OPT menu (1st Instance only)
  • Improved power function error handling
  • Added support for Sub Modes, Filter BW and Port Selction in the Memory Panel
  • Changed RDS window colour scheme to match other windows
  • Added new hotkeys ‘v’, ‘-‘ and ‘+’ which are for VFO, Out and In zoom buttons in the SP1 window
  • Hotkey ‘b’ now opens AND closes the memory panel
  • Changed the default sync Rig->VRX setting to true
  • API – RefClk o/p no longer stops when the master RSP2 stops streaming

To get this latest version, go to: http://www.sdrplay.com/downloads/

FM Notch Filter for SDRPlay RSP1

RF filters are used (as the name implies) to filter/remove the frequencies you are not interested in and/or let frequencies you want pass . They come in lots of types. For example a band-pass filter lets the signals in a frequency range to pass through it and rejects/attenuates other frequencies. The opposite of band-pass filter is a band-reject or band-stop filter (also called a notch filter) which rejects/attenuates signals in a specific range and lets other frequencies get through the filter. Lots of different filters are used in SDRs and traditional radios. For example AM low-pass filters (only let frequencies lower than 1.7MHZ or so pass) or band-pass filters for various ham radio bands.

One of the popular use cases for a notch filter is in the FM broadcast range (88-108 MHZ in most parts of the world)

When you live near a powerful transmitter, it can affect the operation of your receiver in other near frequencies (or overload your receiver’s front-end), but I didn’t want the notch filter for this reason. I’ve got a SDRPlay RSP1 (among many other SDRs) which due to its architecture, has some images of FM band in the UHF range (for example in 330-350 MHZ). In fact they’re the images of the product of LO harmonics and FM frequencies.

You can temporarily move/shift the frequency by changing the LO frequency which does not remove them, but moves them around.

Another method to remove these images is using a band-stop filter.

This is the filter I’m using (Thanks to my friend Amirhosein Hasanpur who designed and built it):

Here you can see the effect of using a FM notch filter on my SDRPlay RSP1:

FM, without filter:

FM, with filter:

UHF (images) without filter:

UHF (images) with filter:

Here’s a link to a Zip file containing the PCB (in Protel), schematics (pdf) and S Parameters (pdf):

https://www.dropbox.com/s/l98kylrofohgqxf/SWLing.zip?dl=0

Note: Like any other SDR test/review, the results depend on lots of different parameters (various gain values, LNA, antenna, software, etc). These pictures are captured with the same conditions just to show the effectiveness of this filter and your milage will definitely vary, but expect a similar outcome. If you live close to a powerful transmitter or use LNAs, you will receive some signals, even when using the filter.

Final note: this issue is solved in the newer version of SDRPlay (RSP2) : it has software-selectable notch filters for FM and MW broadcast frequencies.

Mehdi Asgari, the author of this post, is a regular contributor to the SWLing Post. Mehdi lives in Tehran and is an active member of the EP2C amateur radio club.

SDRplay RSP2 Pro now shipping from HRO

Many thanks to SWLing Post contributor, Ken Hansen (N2VIP), who notes:

Ham Radio Outlet has the SDRplay RSP2pro in-stock for $192.95.

As a reminder, the SDRplay RSP2pro is the version enclosed in a full-metal case for maximum RF shielding. Like the SDRplay RSP2 it has three software selectable antenna connections (long wire and two SMA), whereas the original SDRplay RSP1 has just the one SMA connector.

http://www.hamradio.com/detail.cfm?pid=H0-015447

Propagation-Triggered Spectrum Recording

Many thanks to Jon Hudon of SDRplay who shared the following on the SDRplay Facebook page:

One of the SDRplay user community, Jukka, has started an interesting discussion on what he has called ‘propagation-triggered recording’ – he outlines the concept, and what he is doing, on our forum – see http://www.sdrplay.com/community/viewtopic.php?f=9&t=1839

The idea is that you monitor signals to determine if conditions are particularly good and can thereby trigger an I/Q recording of a whole band during that particular propagation high point -Jukka welcomes more comments on this idea.

Many thanks, Jon. I would certainly be a fan of this as so many times I’ve missed fantastic band openings while travelling. It would be nothing short of brilliant to come home to automatic SDR spectrum recordings taken during prime propagation. At the moment, propagation is so dismal, rare openings are worth recording!

As Jon points out above, check out the SDRplay forum for more details.