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N9EWO Review:
Software Defined Receiver
SDRplay RSP1 - RSP1A
"WideBand SDR"
("RTL-SDR.Com" Metal Case Review on bottom of this page)
Our sincere gratitude to Sungchul Cho , as he made the SDRplay RSP1 review possible.
The RSP1A review was made possible in part from reader donations. ”Thank You”.

The UK made "SDRplay RSP1A" SDR.  Lightweight black plastic cabinet using a SMA antenna connector.
1 kHz to 2 GHZ coverage (no gaps). Full HF coverage with no silly converters too. Earlier
 RSP1 model was also tested. ALL "SDRplay" models are based on "MIRICS" UK TV Tuner IC's
 (MSi001/002-MSi2500), similar idea but improved performance over those low cost RTL dongles.
 The RSP1A improved features include a 0.5 TCXO
and additional filtering. One should not expect
 same performance when compared to the more expensive HF Elad FDM-S1
/ FDM-S2 SDR's, but we say excellent for the price.
(manufacture photo)

Approx. Test Sample of RSP1 Serial Number : #2501xx#14#92x
Approx. Test Sample of RSP1A Serial Number (Sample #1) : 180705849x
Approx. Test Sample of RSP1A Serial Number (Sample #2) : 1903030Axx
Country Of Manufacture (all) : United Kingdom

N9EWO's Review : SDRplay RSP1A "WideBand SDR" (software defined receiver)
(earlier model SDRplay RSP1 was tested previously, now discontinued)

*** What is a "SDRplay RSP1A" ??  /  No USB 3.0 on Host PC ***

The SDRplay RSP1A is a fairly low cost SDR (Software Defined Receiver) "computer connected" device that features full radio spectrum coverage without any silly converters getting in the way. One SMA antenna connector for all ranges.
RSP1A indeed touts a 14 bit architecture, but in reality uses the same ADC chip in the elder non A version. As one increases in frequency this gets reduced down to as low as 8 bits.

There is even decent front end band-pass filtering inside its semi-smooth plastic box and is improved with the later tested A version. Also added is a switchable MW/FM (and DAB for Europe) notch filters that work well. If one lives near powerful MW or FM broadcast station, this could be a major plus (when tuning outside the MW / FM bands) without any add on filters to have to fiddle with.

Power is supplied via the host computer USB port via a USB cable, so no additional external power supplies are required. Low current consumption is around 185ma (vs. around 150 ma for the non A version).

Operates with many operational platforms offered makes for a nifty Android SDR as well (not tested, requires Java with Android). In our testing here we will be limiting the scope to Windows 7 operating systems only (64 and 32 bit). Sorry, we did not test this device on any other Windows OS (Windows 8 or above) or platform.

"Important Note" using USB 3.0 (as experienced in testing) : We had no luck using the RSP1A with a USB 3.0 socket on the test PC. It installed the API-drivers when connected, but did not allow operation (could not find it after). Yes USB 3.0 are supposed to be backwards compatible. As soon as we switched to a 2.0 socket it worked fine. Appears most have not had problems here, so perhaps a PC driver issue in our case ? We were unable to find out why this was happening (the 3.0 port working properly with other connected devices) ?

*** USB Cable Chokes “To Be Or Not To Be ?” ***

Any new owner needs to supply the proper high quality "SHIELDED" USB cable (good idea to keep it under 3 meters in  length) and a connecting antenna cable. The SDRplay folk’s recommend that a USB cable be a shielded type (not all are) that has chokes on either end be used to help keep radio interference reduced.

In our testing we could tell no difference with more or less interference (using outdoor antennas with coax feed line) using a standard (non shielded) USB cable with and without the ferrite chokes . This was with a laptop computer or Desktop, cable length under 6 feet. Using with any indoor antenna, this could be a different story ?

But of course this will depend on YOUR situation and no 2 are going to be the same. As they say the shorter the USB cable the better. I would say better quality cable 6 feet (around 2 meters) or less length.

*** Genuine Plastic Case / Cool Operator ***

The RSP1A  is still housed in a plastic case , but on the inside now is a sprayed on metallic paint coating. It appears to help with household noise, but not by a major difference in our testing.

Aside from that it is in a most sturdy “plastic box” about the size of an over sized Klondike Ice Cream bar. It is held together with 4 screws, so no heat welded or glued together cases here.

We stuck 4 SMALL soft plastic "stick-on" feet on the corners of all test samples so to eliminate the very light cabinet from sliding around. Please Note : The plastic with the RSP1A was slightly more rough, which made it a bit more difficult for the adhesive with some plastic "stick-on" feet to stick properly. We found these clear 3/8 inch "Shepherd Hardware Products" number 9964 feet to hold properly (Menards and other stores in the USA). As it normally goes with these, please let it sit undisturbed for a good 24~48 hours after application for the adhesive to set.

At the time this report was being updated, an after market ALL METAL case is being offered by "RTL-SDR.Com (fits the original RSP1 or newer RSP1A). Available from ebay or Amazon (USA) for about $ 25. USD. We tested one of these and our findings can be found in a separate section at the bottom of this page.

There is a female SMA antenna connector (early versions used a female F fitting) and connection to the computer is via a B type USB socket. Certainly a much sturdier connector being used here say over a Mini or Micro USB.

Being in operation for hours, the case remained cool (only ever so slightly warm). The elder RSP1 model is not using a TCXO (uses "internal" crystal in the MSi2500 MIRICS chip), but overall stability appeared to be most adequate.

With the RSP1A a "0.5 ppm" TCXO was added which made only 4 Hz off frequency (at 20 Mhz) before any fiddling. But not that the test sample of the RSP1 was a slouch for stability (it is decent). There is tweak for the reference oscillator in both versions for off frequency adjustments in the EXTIO. Some SDR programs provide a way to adjust this as well (like with HDSDR and SDRuno).

*** Full DC To Daylight Coverage ***

RSP1A receiver coverage is from 1 kHz right up to 2 Ghz with no gaps (RSP1 started a bit higher at 10 kHz). Even the taboo 800 MHz frequency segments in the USA are covered (not that there is anything non digital to listen to there..there isn't).

*** Host Computer : Dual Core OK , but best with a FAST “Quad Core” Processor ***

Yes, one can use the SDRplay RSP1A (Microsoft Windows computer) with a more limited “Dual Core” processor around 3 GHz at say 4 GB of RAM (Memory) and only using a limited scope bandwidth (2 MHz sample rate, IF Bandwidth at 1.536 MHz or less). This is what was used for testing in this report in fact.

The slower the computer the worse the performance / dropouts and even lockups are possible. Any additional programs running along with it makes any limited computer recourses be even worse. Don’t even think of using an old "single core" computer at any speed, you will probably be disappointed (if it works at all).   

As it always goes with computer software/hardware, this will vary with the SDR program used. Connected to a speedy 3.0 GHz QUAD core computer and say have 8 GB of memory, it will be dropout / doggy free and the user will be a happy camper.

*** Driver / Tested Software (using "Windows 7" 64 and 32 Bit)***

Mirics API Drivers

The Mirics (API) / SDRplay drivers is the software that needs to be installed before the USB cable is installed for use with ANY software. No installation issues at any time with 4 different Windows 7 computers in testing. API-Driver version tested was 2.13.1. EXTIO version tested up to 1.2 (4.2 with the RSP1).

NOTE : SELECTED SDR Programs come packaged with the SDR Software / API driver and EXTIO install which makes it much easier to install. 

IMPORTANT : At the end of the HDSDR "Package" installation, be sure and allow the HDSDR program to be accessed so the EXTIO part of the installation will be properly installed (will ask / point you for the right EXTIO version / hardware, DO NOT let it reboot when you see the prompt...continue on). If this is not done, errors will appear as the EXTIO will not get recognized.This is also valid with the "EXTIO / Driver" standalone version (with no SDR software) that can be downloaded on the SDRplay website (at the time this text was added).


The 5 FREE software packages tested for this report were (in order of our ratings) :
1. -  SDRuno Version 1.22
2. -  HDSDR Version 2.76a / 2.80 beta11
3. -  SoDiRa Version 0.100 (Preview 30)
4. -  SDR# (SDR Sharp) Ver (1361) - (RSP1)
5. -  SDR Console (V2 tested only with RSP1)

1 . - SDRuno (Version 1.22 tested) *** Top Rated ***

SDRuno is the mother ship software first time we tested this was still in its early stages (version 1.04). 1.22 installed with no problems and a EXTIO is automatically done (no EXTIO is required at all for the 1.3 version and above).

We found version 1.22 to be excellent. It does take time to adjust to the "multi screens" and unusual layout, like user set menu's are all over the place (not just in one spot). But after awhile it's not a drawback. Two VFO's was good to see, however they do not store the mode/bandwidth (are the same between them). Memory channels do store mode, bandwidth and tuning step along with a alpha tag.  

Excellent GUI overall, including a decent "faux" florescent frequency display and nifty looking analog edgewise s-meter. It does have the most adjustments of any program tested in the lot (expect for the spectrum scope). One can easily select Spectrum Scope or Waterfall or both. Good direct keyboard entry was appreciated as well as the provided band preset buttons. Very handy muting feature, with volume adjustment on the GUI.

Supports FM Stereo and RDS (both work excellent), plus the S-meter accuracy is one of the best ever tested on a SDR device by the author (plus it requires no calibrating at all). Recorder is for IQ "spectrum" recording only. One will have to use a add on program such as Audacity for audio recording (no biggie).

So yes SDRuno makes to our top pick for general use.

Version 1.22 was also the top with DSD Plus in our testing (more later in this report).

2. - HDSDR (Version 2.76a /  2.80 beta11) *** Top Rated ***

(click on photo for screenshots)

Installed with no problems and easy to use. EXTIO plug in is required after installation and before use with HDSDR.

Spectrum scope colors (but not easy to do) and all of the important adjustments are there and EASY to use and understand. Does have a nice looking S-Meter, it over reads at default settings however there is a easy way to calibrate it. Direct keyboard entry is provided but a bit confusing to make work for newcomers just as with SDR Console (but not bad after adjustment to GUI).

One can adjust to even turn off the waterfall and or spectrum scope (or change the displayed sizes from default, but is not obvious). Text as taken from the old Winrad V1.32 manual  (which is still useful to get started with HDSDR as it's based on that) :

"The upper window is divided into two panes, the waterfall and the spectrum. It is possible to choose how to assign the available space between the two panes by using the right mouse button. Just place the mouse pointer on the frequency scale. The pointer will change shape, indicating that you can drag left and right the portion of the spectrum that is displayed (keeping the left button down) or you can drag up and down (keeping the right button down) the frequency scale which divides the spectrum from the waterfall. Much more complicated to explain than to do…". Just be sure when you adjust this that the receiver is in operation.

If you only desire the Spectrum Display using these adjustments and then desire the frequency indication ruler on the BOTTOM like I did (not on the top), then set in Options > Visualization >  Swap Spectrum / Waterfall  Position .
Another important spectrum display user note , by hitting C on the computer keyboard will CENTER the receive frequency (excellent feature).

Features include: Noise Reduction, IF and RF Noise Blanker, Manual and Automatic Notch Filter, AFC. Excellent ECSS that holds lock very well and operates on both sidebands or LSB or USB (selected in a 3 loop cycle by left clicking the mouse on the ECSS button). ECSS does add bit of bass kick to the audio. Built in recording interface that records the spectrum or audio (right click on the RED record button to configure). Even includes a scheduler as well. Sadly it does not offer FM Stereo but it does have memory storage ("FreqMgr" icon) and quick band presets. Even can download and import the latest EiBi data.

DRM with the DREAM software (and Virtual Audio Cable, same as with DSD+) worked quite well in our tests with fairly easy decode. HDSDR has a Digital mode that presets everything to make it easier. But this offsets the frequency for some strange reason so we had to move it a bit to make work (tested with Radio Kuwait on 15540 kHz).

Using it with DSD+ is mixed bag with 2.76a, but for some reason was improved using with 2.80 beta11. Depends greatly on settings as it does with any of them, but here is a bit more finicky (but overall works OK).

With the new 2.80 beta11 version : Adds "Band selection" and "frequency step selections" on main window (excellent as it also stores the mode and step with these presets). Auto-LO option and keep Tune when LO is changed are also 2 additional and welcomed features.

HDSDR uses the least computer resources to operate out of the lot (it's actually now a horse race with SDRuno version 1.22 in our later tests). If you have an older slower (dual core) computer that chokes with the others, this is the one you should try. Is really the ONLY one that will work with the elder Windows XP OS. Overall is a winner for overall use and performance. It’s simple, sounds good, fun and recommended for anyone starting out using a SDRplay RSP1 (or any SDR). Great program to get your SDR feet wet and learn the ropes and for general use after.

3. - SoDiRa (Versions .099 and 0.100 (Preview 24, 25 , 27, 29 and 30)

(click on photo for screenshots)

Not the most feature packed application (it's not) , but Bernd Reiser's "SoDiRa" does not only decode FM Stereo BUT C-QUAM "AM STEREO" as well. During skywave nighttime conditions (at the time this text was added), we received CFCO in Chatham Ontario (Canada) on 630 kHz in beautiful AM STEREO. This of course would also work in the SW part of the spectrum for that "pirate" that may show up using AM STEREO (which has indeed happened over the years). This program requires a EXTIO just as with HDSDR.

It indeed has built in DRM (no separate Dream program required). But takes a MUCH stronger signal over using HDSDR and Dream in our testing. In fact its more like near  useless in North America with DRM broadcast near "nada". Using the Dream software separately with SoDiRa (with the here VAC of course) also performed MUCH better over it's built in decoder !

Decent ergonomics and logical layout, but as with all SDR GUI's, there is a learning curve. Decoding has Simple and Universal decoding selections (please remember that default is selected for NO decoding). No easy volume adjustment on GUI which is a bit of a disappointment. As normal with any of them, FM "Wide" Broadcast reception takes more computer resources. But overall it's winner again including it's built in AM STEREO decoding (also has decent selectable sideband Sync Detector as well).  It worked excellent with the separate DSD+ decoder too (see more below on this subject).

NOTE : Version .099 (which is included with the 0.100 previews up to 28), was unstable in our tests. Preview 26 was not usable (it blew up right from launch, but was fixed quickly with Preview 27 and even better in 29). Older versions are not archived on the web site.  But overall this is a very easy to use SIMPLE program and we liked it. Hopefully improvements will continue. A most worthy program, excellent job Bernd !

4. - SDR#  (SDR Sharp) (RSP1 only)

This program was tested with the older original RSP1 version. An older version of SDR# (SDR Sharp) was required  to operate, version 1361 ( Also a older EXTIO version 3.7 MUST be used with 1361 which is not easily found anymore (do your own searches). It is common knowledge that more current versions of SDR# do not work well with SDRplay RSP1 (if you can make it work at all). 

Worked well enough and enough adjustments to satisfy most folks, easy to figure out. Not the easiest to deal with changing frequencies, but has a useful memory window and that is easy to enter and edit. We found the Spectrum scope not to be so user friendly or eye pretty (or usable for that matter), but is big and one can turn off the waterfall. Sadly the SDRplay RSP1 does not work with any of the SDR#’s extensive plug Ins.

Program has no S-Meter and only very limited color changes possible on the spectrum scope. Works adequately with DSD+ with the Virtual Audio Cable. Even with this working OK with the SDRplay RSP1 OK,  it was not left installed after testing. It does support FM Stereo where HDSDR does not.

5. - SDR Console (V2 - Tested with RSP1 only) *** Program Good , But Bottom Rated Because of Expiring Scheme ***

Was the easiest to use and most appealing GUI. Easy to install and to get up and running. No other software (EXTIO) was required for operation aside from the API and SDRPlay drivers.

SDR console V2 at the lower spectrum bandwidths were most usable provided nothing else was running in the background with a lesser computer. In fact it was the second runner up for using the least computer resources to operate. Supports FM stereo plus RDS.

Memory operation (V2) was straightforward and useful, however direct frequency entry was quirky / difficult and sometimes locked up the program. Important tip :  Be and enter the proper leading zero’s (a pain).  Features include: Noise Reduction, Noise Blanker, Manual and Automatic Notch Filter, Double Sideband AND LSB / USB "Synchronous Detection / ECSS" which holds lock well. Excellent AGC (Fast-Med-Slow) with adjustments. "Span" adjustments were first rate.

A huge downside and the reason it was BOTTOM rated, as this report was being complied , “SDR Console” uses an expiring license scheme. So whatever version you are using it turns into pumpkin sooner or later. Not a good scenario here in our view (in fact this is totally unacceptable to the author). We did not test the RSP1A with SDR Console (V2 or V3).

*** Generally Great Audio and AGC Performance ***

Audio quality was decent with all tested programs. We wish there was at least say a 5 band EQ adjustments in these programs to tweak audio frequency response a bit. However many sound card / drivers allow for limited bass / treble tweaking.

To our ears the AGC was tested as excellent with all programs. Sync detection helping the cause greatly with AM mode "HF fading" distortion. If any transmitted signal contains distortion, the RSP1A will let you know.

*** Dynamic Range / Sensitivity and General Performance ***

To make matters more fair we compared sensitivity with our original RSP1 sample using a standalone Yaesu VR-5000 wideband receiver. For my review on the discontinued Yaesu VR-5000 (click here).

Testing (ears method) here was done only with SDR Console V2 at default settings (which we found out are the best settings to use) :

-  LNA turned OFF
-  RF Gain at –50db
(other settings in the Mirics API also at Default)

Antenna’s Used (for both receivers) :
-  SW/HF Outdoor Antenna : 55 foot RF Systems MLB (long wire)
-  VHF/UHF Outdoor Antenna (above 30 MHz) : 19 inch ground plane at 25 feet height.

Dynamic Range : While tuning the ShortWave / HF bands “Dynamic range” (overloading) was never experienced during the testing period with the SDRplay RSP. It behaved itself very well even in the 49 Meter band at night. No FM Broadcast overloading either.

Receiver Noise : SDRplay RSP1 was the overall winner here. But in some areas the Yaesu actually won the battle.
Selectivity : Of course the SDRplay RSP1 blew away the Yaesu VR-5000 here , no real comparisons required.

***** Sensitivity Winners (RSP1 model as compared to the long discontinued Yaesu VR-5000) *****
(very weak signals and audio recovery, mode and bandwidth setting changed as required) :

MW / AM Broadcast : Yaesu VR-5000 (SDRplay RSP1 was OK on MW , but the VR-5000 was the clear winner even with it’s attenuator on)
SW 11 Mhz : SDRplay RSP1 (by a hair). Signals were about equal, but the lower noise floor made recovered audio from the SDRplay wins easy here, especially with the Sync Detector on. 
-  FM Broadcast 93 MHz :  Equal. Perhaps a very slight edge to the SDRplay RSP1. But it’s pretty much an even showing here.
162 MHz :  Yaesu VR-5000. Audio was heard better from the Yaesu here for some reason, but a near equal signal on SDRplay was present. Another close one.
-  450 MHz : Near Equal. S/N goes to the SDRplay here.

In general it’s a very sensitive device, just as much as the elder Yaesu VR-5000. Of course the overall performance edge has to go to the computer connected SDRplay RSP1. But the elder Yaesu VR-5000 held it’s own. The Sync Detector with SDR Console works fantastic. Double sideband ECSS or just LSB or USB selections. Holds lock with even signals that are near into the noise.

*** Spurious Signals Issues ***

Some users have reported STRONG local FM Broadcast signals bleeding (overloading) into other parts of the tuned spectrum with the original SDRplay RSP1. We did not experience any of this at our test location. Any image signals were also absent at the test location. Please note, we do NOT live in a large metro area with excessive broadcast signal levels. Of course the RSP1A has bandpass filters to help tame FM broadcast signals, where the original RSP1 did not..

*** "DSD Plus" Program (see our set up information on the bottom of this page)***

OK….we normally only cover Short Wave / HF part of the radio spectrum here with any reviews, but in this case we just had to try and make work the DSD+ program with the SDRplay RSP1A.

DSD+ is a popular Windows Computer software program used for decoding digital speech such as P25 with SDR receivers. With the tested version 1.101, includes an event log that shows call target and source ID history and an audio waveform screen, which can help determine if DSD+ is receiving audio correctly (a very useful feature as we found out). Has the ability to decode the following digital modes (and is automatic too). Please make note the DLL's are downloaded separate and when unzipped are placed into the same directly as the program files.

• NXDN4800
• NXDN9600
• DMR / MotoTRBO
• P25 Phase 1
• ProVoice

It can be used as stand alone program as well. In other words one can take a stand-alone scanner receiver, tap the discriminator audio output and feed that into the computer (line and or Mic input jacks). But in our case we desired to use the same computer that hosts the SDRplay RSP with the DSD+ program. To do that the use of a Virtual Audio Cable (VAC) is required. We used a FREE donation-ware version.   

After installation of the VAC and with certain adjustments and procedure (whew!!), it performed adequately espicaly with SDRuno and SoDiRa. This program decodes digital modes that are not covered on most standalone scanners as well. Trunking is not normally possible with only "one" SDR receiver. Success depended on the software used as well as careful adjustments (especially when using HDSDR which required higher levels).

That is the stinker with making DSD+ to work with the SDRplay RSP1A, frustrations and hours in the battle of setting it up. Provided below are my PERSONAL notes what I did to make it function. This of course it cannot cover everyone’s situation (computers, sound cards etc), so treat this only as a base. Some parts may be more my feelings and not facts.

Please keep in mind these tests were done using a Windows 7 “DUAL Core 3 Ghz” computer with 4 GB of memory. Your experiences may vary and could (should) work better with a more zippy and QUAD core processor computer? More memory does not hurt either (say 8GB). Again when using the SDRplay RSP1A (and especially with DSD+ in the mix) with a lesser computer one should not have ANY other applications running. Otherwise decode dropouts and other nastiness are possible with any of them.

IMPORTANT NOTES : Of course use FM mode (with no filtering) at around 15~20 kHz bandwidth for most digital modes. Setting of the VAC audio level is extremely important. If it's too loud or too soft, decoding will be choppy or even not at all. So watch your audio level (metering bar on the VAC in the Audio Properties).

So our the Preference list for the best program using DSD+ with the SDRplay RSP1A  :
(SDR# [SDR Sharp] was not included in these tests as it is no longer available for the A version) : Was not tested with SDR Console but that program was good with the non A version test sample with DSD+).

1. SDRUno. Plain and simply the BEST decode and near zero dropouts. (Remember the FM filtering needs to be turned off).
2. SoDiRa. Works good with DSD+ (pretty even with SDRuno).
3. HDSDR. Most usable. Only minor dropouts after a bit of level tweaking.

*** Final Word ***

The SDRplay RSP1A is clearly the winner in its price point for a REAL SDR device plus for DC to daylight frequency coverage. Gives for greatly increased performance when compared to those under $ 50. RTL-Dongles that we see sold all over the place at time this report was compiled. The improved front filtering with the A version is a nice improvement plus the added TCXO for a more accurate frequency display (before any tweaking). SDRuno was extremely desirable program after one gets used to it. It also works very well with DSD+ and Dream once set up PROPERLY.

Dave N9EWO
N9EWO, all rights reserved
Ver 9.1

WARNING : I will NOT be held responsible for any information that is listed here.

DSD+ Set Up With RSP1A / RSP1 using "SDRuno" Program (version 1.22)

(also a base for other programs including Dream for DRM)
Properly install the Virtual Audio Cable (VAC) and DSD+ before attempting.
(NOTE : These are MY suggestions / notes ONLY and your situation may be different).

Using Windows 7 (32 or 64 bit)

First Set up Volume Control / Mixer Options / Level (if DSD plus is not running, Mixer panel selections will be different) :

- Right Click the white speaker on the bottom bar
- Go to Volume Control Options
- Make sure that VAC is checked for "Sound Devices that show their volume0 control"
- Hit OK
- Now Left click the same white speaker on bottom bar
- Click on any icon on the bottom of the mixer panel marked "mixer"
- Be sure that VAC Audio OUTPUT slider is turned DOWN to minimum (down all the way)
- Speaker slider should be turned up
- Click dropdown on Devices to show VAC INPUT.
  Be sure the Input slider for the VAC INPUT and RX Control 0-0 (SDRuno) are both turned up fully.
- X out of that

- Once again RIGHT click the little white speaker
- Select Recording devices tab
- Switch VAC to Default device
- Click on VAC and the Properties tab and then Listen tab
- In Listen Tab be sure "Listen To This" Device is checked
- Playback through this device dropdown should be the computers "Soundcard / Speaker"
- Hit OK
- Select Playback Tab and be sure Speaker is the Default and that VAC is at ready status.
- Hit OK

SDR Uno Setup Second (in STOP mode)
Settings for SoDiRa and HDSDR will NOT be the same !

- In "RX Control"  panel, Chick on EXW on top bar.
- On this screen turn off DEEM (not lit up)
- X out of that
- On the "Main" panel select SETT on the top bar
- On the WME Input Device drop down select VAC OUTPUT
- X out of that
- On the "RX Control" panel again click on SETT
- On WME Output Device select VAC INPUT
- X out of that
- Select frequency, FM / NFM /  15K
- Select Start and then start the DSD+ Program

Dave N9EWO
N9EWO, all rights reserved
Ver 2.0

SDRplay RSP1A Llnks For Additional Information (all subject to change without notice)

- RSP1 and RSP1A eham Reviews

- RTL-SDR.Com Review

- NN4F Mini Review Of the RSP1A

- SDRplay RSP1A Setup With SDRuno v1.22 (You Tube Video)

- SDRuno Cookbook by NN4F and KD2KOG (a MUST read)

N9EWO Review:
"RTL-SDR.Com" Metal Case
 (for SDRplay RSP1 / RSP1A SDR Receivers)

The RTL-SDR.Com "Metal Case" for the SDRplay RSP1 or RSP1A SDR Receivers.
 Properly installed (and slightly modified) it can help with interference with local RF noise vs. it's suboptimal plastic case.
That is of course IF fed with HIGH QUALITY coax feedline and connectors ! (N9EWO Photos)

WARNING : I will NOT be held responsible for any information that is listed here.

N9EWO's Review : "RTL-SDR.Com" Metal Case for the SDRplay RSP1 and RSP1A (2 samples tested).

Country Of Manufacture  : China

The RTL-SDR.Com "Metal Case"

Lets face it, the SDRplay RSP1 and RSP1A SDR receivers are housed in a  "cheesy" lightweight low cost plastic shell of a case. The RSP1A has some very strange gray colored sprayed on coating on the inside that is supposed to help RF from getting in. However in our RSP1A's testing with a local FM broadcast powerhouse station, it received it just fine with 5 S-Units on the SDR Uno's S-meter. with no antenna connected at all. So that coating does much of nothing.

Another problem is with the plastic case is one does not get a very tight mounting of the SMA antenna connector (and gets loose in short order). This can lead to damage of it shielded jumper inside that connects to the main circuit board plug.

RTL-SDR.Com offers a custom after market "ALL Metal" case that allows for greatly improved shielding as well as providing a sturdy SMA mounting that will not loosen up. Well it's going to be MUCH improved anyway.

What Comes With It ?

No plastic is found in this package. 2 PAINTED Aluminum METAL Top and Bottom covers. Front and rear
Aluminum METAL covers that have proper silk screening markings (rear panel one is unpainted on the inside). 9 mounting screws (they give you 1 extra, at least that was the case with BOTH test samples) . A double threaded GROUND screw that mounts on the rear panel with mounting hardware is also included (unused in our tests as we cover why later).

Also in package was a nice zippered carrying case that also has space for a couple of small antenna's and a smaller short USB cable. Plus four very thin 3M feet so to keep the new case from sliding around (required). There have a rubbery feel to them, so makes the case stick well to a table if clean. As usual give a good 24-48 hours for the feet adhesive to set once applied.

Making The Switch / Bottom Heat Foam

This is pretty straightforward to move it over to the new case (common sense).

On the bottom of the new case there is a slab of heat sink foam to help with heat dissipation.  We found that it barley touches the bottom of the board (if at all). This is of little moment as it's operates fairly cool to begin with. It still could be helping here anyway as the little heat it is generating seems to be diverted to the BOTTOM of the case. We see one review on Amazon where reception was reported to get zonked with this heat sink foam in place. Our view here is there was some other factor involved (or it's just a rouge review) and was NOT the foam causing this. Perhaps here it was a improperly seated antenna connector on the board (or other antenna connector issue on this person's first mounting) ? Is just NO WAY this foam sitting on the "bottom" of the board could be affecting reception of the device is any way. Weird is right !

Carl Laufer of has these comments in regards to that Amazon review : "I agree there is no way that the thermal pad could change the reception characteristics of the RSP. The pad is essentially just a piece of rubber we included to help stop the RSP from sliding around inside. The RSP PCBs aren't exactly all manufactured to the same size, and so some are a little smaller than others. The rubber stops those smaller ones from feeling loose inside the enclosure. It also doubles as a thermal sink, but the RSPs run cool in the first place, so it's not really needed apart from in very hot climates."

One thing to remember is you ONLY wish to handle the PC Board by it's sides. Avoid touching ANY parts on the PC Board ! The input connector on it's board may pop off. Not to worry, this can be reattached once the antenna connector is mounted to the rear panel (just pops back into place, see photo). 

You may (probably will) experience it NOT being able to side into it's grooved slot on the bottom case as there (usually) is 2 PC Board manufacturing bumps on those 2 sides. A little trimming with a file will fix that in short order (you not need to go crazy here, take your time). But whatever you do you not force the board in if it does not side in fairly easy. Damage to it's multi layered pc board can happen if mistreated. There is ONLY one slot where PC Board slides in (NO there are NOT 2 sets of slots as commented elsewhere).

The board fit loose in the slot with both test samples. Not to fret as the front and rear of the board were very closely matched, so once the front and rear panels are installed we had a perfect tight fit (board did not move around period with both test samples).  

The Grounding Problem

Problem is none of the PC Board 4 mounting screws are used (connected) with this case. So how does the new metal case ground itself to the  receivers PC ground ? It's ONLY via the antenna pig tail and that is it. We ran a test with adding no additional grounding (other than cleaning the END paint off the top and bottom rear covers for the REAR cover which is unpainted) and it was a disappointment. The local FM broadcast power house was being received nearly as well as with the plastic case with no antenna connected.

To cure this issue we added inside a very FLAT copper spade lug mounted between the rear GND lug hole (right size screw and lock washer/nut , see photo below) and the other end "soldered" to the shell of the USB connector. The shell of the USB connector is of course grounded to the main ground of the  PC board. This also eliminates the need to run ANY messy wires inside the cabinet.

WARNING : One needs to be careful as not to use to much heat as not to damage the USB connector (tin the USB connector metal slightly before). See the photo below. Also be careful not to create any solder spittle or any other stray solder blobs. It would be a good idea to clean up flux residue after too on the soldered connection.

Tip : Be sure and install / solder the "lug" only after the bottom and front and rear sides are tightly mounted. However you will probably have to loosen those up a bit after in order to place the top cover on.

Needless to say once this was done, our powerhouse FM broadcast station was ZERO reception with no antenna connected. This fixed that issue 100% with both test samples.

Is It Worth it ?

The RTL-SDR RSP case is indeed worth the cost and bother as long as the grounding issues are taken care of. It also makes it feel less of the low cost toy.

Dave N9EWO
N9EWO, all rights reserved
Ver 1.9

For proper ground of the the SDRPlay's PC board ground and the new case ground
we added this lug between the GND mounting hole and soldered to the USB shell.
Also be sure and clean off the paint on the END of the top and bottom covers
 for the REAR panel (which is unpainted). (N9EWO Photos)

WARNING : I will NOT be held responsible for any information that is listed here.

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