Thursday, August 17, 2017

QSL: WEZS Laconia NH 1350

WEZS was heard in September last year just before they switched to night power. From a reminder yesterday came a long and friendly response from the General Manager.

Sunday, August 13, 2017

A Quick Look At The Elad FDM-S2

Seasoned FM DX-er Ole Forr lent me one of his FDM-S2s a few days ago, and I have shared some very brief impressions here. The short version: Good radio. Original software is not to my liking, but SDR Console V3 and HDSDR work well.

Saturday, August 12, 2017

Revised ColibriNANO Review - Doesn't Team Up With Teamviewer

I had to add a paragraph to my ColibriNANO review. The case is that when the Nano loads, in ExpertSDR or in HDSDR, Teamviewer CPU load goes all the way up 60-70 %, from its normal 5-15 %. Add the SDR program CPU load, and the processor is banging its head against the roof.

This is an important consideration if you plan to run the ColibriNANO with Teamviewer.

Friday, August 11, 2017

The MS-S7-Web Remote Antenna Switch

You can either have one radio for each antenna, or use an antenna switch. Antenna switches are found in any HAM store, but if you run remote, you need to be able to switch antennas remote as well.

Enter the MS-S7-Web Remote Antenna Switch. I first heard about it when it was introduced as an extension to the KiwiSDR. I had no plans to use it with my KiwiSDR, but the KONG crew has plans of erecting another beverage antenna in Kongsfjord, and I didn't really want to add another SDR + PC to the shack.

I bought the MS-S7 from Bulgaria in the beginning of June, but haven't had the opportunity to test it until now. If memory serves me right, I paid around EUR 170.

The package consists of an in-house antenna selector, which can be controlled via web, or manually. It is connected to an outdoor (which can of course be used indoor) antenna switching box with seven antenna connector in additon to one connector for the receiver. The antenna selector connects to your router or switch (or PC I presume, not tested), and it needs 12 VDC.
From the eBay ad

The antenna selector has green LEDs for each antenna. Also there's a blue power indicator LED. The green LEDs are quite dim and easy on the eyes. The blue LED is anything but! I feel tempted to replace this one, if not I do need to cover it somehow.

The device works via an Internet browser (Firefox and Chrome are recommended). It can be set up with a static IP (which is better than DHCP in this case), and the Device Settings will look similar to that below.

There are two tabs in the user interface, and the other is the contol panel, on which you're supposed to click on the "ON" labels to change antenna. You will hear two clicks, one to disconnect from one antenna, and one to connect to the other. Or so it's supposed to work.
Web based control panel

Web based config panel


But I often need to click an extra time to get the second relay to connect. This may make problems if you are running a script-based automated antenna switching schedule. If you do, it may be wise to program double-click instead of single-click. I've always managed to change antenna when I double-click.

So what about signal leakage from one antenna connector to the other? The short answer is: There isn't any. I was rather taken aback by this. I connected a signal generator to one port, and a longwire antenna to the other. I set the signal generator up to maximum (99 dBu which equals -6 dBm), and there wasn't a trace of a carrier on the frequency I had chosen to monitor on the longwire antenna port. So was the case with the other connectors - although I admit I didn't put a 50 ohm load on them.

I also checked for insertion loss. It must be close to zero, because I wasn't able to detect any difference.

So, apart from the gruelling blue lazer-like LED and the somewhat unpredictable antenna selector procedure, this is indeed a good product. I was a bit surprised to see that as of mid-August, this particular combination is not available on eBay.  Maybe it will return.

Saturday, July 29, 2017

Do You Want To DX In The Arctic?

You can! And you don't even need to pay an airline ticket!



Friday, July 28, 2017

Do You Want 10 MHz Spectrum Available?

Then, the ad says, "look no further". Pieter Ibelings at RFSpace connected his new Icom IC-R8600 receiver's IQ output to a PC, and fired up SpectraVue. Here's his tweet:



Now, with this presumably excellent new wideband receiver selling at USD 2600, you may have reason to look a bit further after all. You could for instance look for the Airspy R2 + Spyverter R2 which will offer you 9 MHz alias-free spectrum at less than 1/10 the cost. I'm not saying that the Airspy will do everything the Icom does just as well, but in normal situations my guess is that you won't notice much difference.

I do have to say though, as an Icom fan, it's a stunner.

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! It is possible to adjust the effect of the noise blanker. Easily available in HDSDR, a bit convoluted 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#