Wednesday, July 19, 2017

ColibriNANO SDR: Test of the RF Noise Blanker

Intermittent broadband noise, possibly from high voltage lines, periodically pests the MW band here. In fact it covers most part of the SW band up to 8 MHz as well. Unwelcome as the noise is, it still gave me the opportunity to test the noise blankers issued with ExpertSDR2. They are also available in the dll for HDSDR.

Short version: The RF noise blanker works, and works well! In HDSDR it is possible to adjust the effect of the noise blanker, which is not possible in ExpertSDR2. This turned out to be quite important in order to find the best balance between noise level and audio quality.

The two jpgs below show the MW band with (above) and without the NB algorithm activated.
Admittedly there is a range of a 100 kHz or so with no noise, where the NB is not very efficient, but the overall impression is very good. An audio example from 999 kHz is quite convincing.


Sunday, July 09, 2017

Airspy R2/Spyconverter R2: After a Few Days of Testing

Interesting days with my second mini-sized SDR! I am preparing a comprehensive evaluation, from a MW DX-ers perspective, of the Airspy. Hard-core MW DX-ers have had a preference for Perseus and RFSpace SDRs (and also the Elad FDM-S2), so there are a couple of interesting questions here: We're unfamiliar with these kind of devices, and the manufacturers and prorammers may be a bit unfamiliar with how MW DX-ers use our radios.


Some observations:

  • Its 0.5 PPM TCXO gives excellent stability when using SDR#, but SDR Console V3 (preview version) and HDSDR have some strange intermittent offsets, up to 500 Hz. Simon Brown, the owner of SDR Console is aware of the problem and I'm sure it will be addressed.
  • SDR# has limited IQ recording functionality. I hope this can be resolved, by native software or by plugin. SDR Console V3 does this very well, except a bug which is being addressed.
  • For best gain vs. protection from overloading, it's necessary to pay attention to the gain controls. I remember this being an issue also with the 12-bit Afedri SDR-net.
  • Audio quality in SDR# is very good.
  • Sensitivity isn't measured, but compared to the KiwiSDR in an A-B test on threshold signal levels. The Airspy is apparently marginally less sensitive on a MW test I did. I couldn't hear any difference when I did the same test on SW. Mind you there are many factors that determine sensitivity, not least how the AGC is used and gain settings. True DX situations late summer/early autumn will give me more answers.
  • The Airspy has a fixed 10 MHz sampling rate. Smaller bandwidths are made by decimation of the sampling rate. The more decimation (smaller bandwidth), the better performance. I'm using 2500 kHz (of which 2000 or more kHz are alias-free) for my MW tests.
  • Apparently very good sensitivity on FM. Both SDR# and SDR Console V3 have RDS decoding.
I'm looking forward to doing more work with the R2 in the weeks to come, and I hope that I can make some contributions to software and plugin programmers. There's a bit of work to be done before I would recommend the R2 for hard-core MW DX-ers. The hardware part is good though.

Saturday, July 08, 2017

QSL: HLQH KBS-2 Daegu, 558

This KBS station is heard practically every day when conditions allow, but I hadn't sent a report until now. I received a KBS World QSL card, and a short note from the technical  department at KBS Pohang.

KBS-2 is the drama and entertainment channel of KBS.

Saturday, July 01, 2017

Airspy R2 + Spyverter R2

This interesting wide-band SDR arrived with personal delivery from the USA yesterday. Actually a friend took it with him so I could save VAT.

Just had time to see it play with SDR# and SDR Console V3.
SDR Console V3

SDR# without Spyverter, FM & RDS

SDR#

Saturday, June 24, 2017

ColibriNANO Test Run - And Some Thoughts

Read my impressions here. Could it be a winner? It hangs by a thread!

Wednesday, June 21, 2017

Another Mini SDR Awaiting Arrival

It will be interesting to see what the Airspy R2/Spyverter R2 combo will show off when it arrives in Kongsfjord on June 30. The Airspy has received lots of praise, like this one from Nils Schiffhauer, but will it deliver on MW?

Photo: Airspy.us

Thursday, June 15, 2017

ColibriNANO - A Few More Impressions

"Premature" is indeed making up opinions about a radio without even having plugged an antenna into it.  But it will have to wait another week. I've had the opportunity to play with software though, and make some notes.

The installation problem seems to be resolved, and only affected the first or so batch of receivers with serial numbers not programmed into the receiver's EEPROM. I have since connected the Nano to other PCs with no problems at all. The fate of the early adaptor, I guess.

I haven't found info on power consumption, but it does run off a USB 2.0 port, so it must be lower than 450-500 mA. This makes it a good candidate for field or remote operation using battery power. A tested and working setup is Intel NUC + SDR + hard drive powered by a 12V battery.

I do have to commend on the apparent build quality of the Nano. It's aluminium, tight, feels heavy (as heavy as 43 grams can feel) and looks "expensive". Because of the weight, it might be an idea to use a short USB extension cable to reduce strain to the PC's USB port.

The ExpertSDR2 software does have its shortcomings, said to be addressed later this year. HDSDR is the best (and indeed a very good) alternative right now, except there is a 60 dB signal reading error. There is support for SDR# too, but only for version 1005 which is rather old.

So we'll see after I've had the chance to listen to real signals, and measure its sensitivity. I do like the concept though. Pocket receiver redefined.
Photo: Expert Electronics

Tuesday, June 13, 2017

QSL: JOTK NHK-1 Matsue, Goutsu/Muikaichi relay stations, 1323

Another 100 watt catch from Japan came last October when the Goutsu and Muikaichi relay stations were heard with quite a good signal. In comparison, their 1296 main station was local-like at the time.

I received a friendly letter from the Senior Engineer yesterday.


Monday, June 12, 2017

ColibriNANO - It's Here. Sort of.

Yes, it's here. Only very, very first impressions so far. I haven't even connected it to an antenna (because I don't have one at my apartment).

It's small. It's hot. And I mean literally hot! So hot it's actually a tad unpleasant. I don't know if it's a bad sign or not.

Despite many attempts on two different PCs with two different type USB ports, I never got ExpertSDR (their native software) to run. The Nano was always disconnected. Drivers manually installed, still no cigar. Some inconsistencies in the manual did not help. I'm not excluding user error, but come on - this should be plug and play!

No problems with HDSDR though. It plays, records and plays back well. So good work on the ExtIO dll - at least so far. One problem though is that the gain is set 60 or so dB too high (I'll measure later on with my signal generator), but that error is easy to calibrate thanks to HDSDR's versatility.

SDR# is a different story again. It does open, but the window is never visible, only the miniature window visible when you hover the mouse pointer on the task bar.

So what to say. Unfinished? Will it fry? Or is it a keeper? Time will tell.

Update: It turned out that on the early sets, the serial numbers weren't programmed into the device's EEPROM. With that sorted out, ExpertSDR began to talk to the Nano. Now, there are other issues.

Sunday, June 11, 2017

Airspy HF+ (coming soon) - First Image

I checked into Airspy's site today, an noted that since last visit they've added an image. Probably not the real thing but an Autocad or similar image. The two screw-thread similar protrusions are likely the SMA connectors. If that is the case, we're talking s-m-a-l-l ...