Kongsfjord - An NDB Hunter's Heaven?

I did some NDB DX some years ago, but I've done very little of it lately. I know that great NDB DX is possible though, since I've heard several 50-watt Papua New Guinea stations in the 1600-1700 kHz range.

One of my January Perseus files contained a recording down to 200 kHz, and well-known NDB DX-er Roelof Bakker (NED) offered to compile a log of what was heard on Jan 10 at 1430 UTC. The list left me stunned. I need to take up this part of the hobby...

Roelof made a very detailed report which you will find here. All from a few seconds, one late afternoon when conditions weren't really out of this world. One can but wonder what can be heard with a little more effort. Thanks very much for your detailed report, Roelof!

Sensitivity Bjarne

Sensitivity measurements – Bjarne's Receivers

I’ve owned a few receivers over the years. I’ve measured the MW sensitivity on most of them, and on one I borrowed.

Receiver	500 kHz	1000 kHz	1500 kHz
Telefunken E-1501[1]	-108 dBm	-112 dBm	-112 dBm
Racal RA6790/GM	-108 dBm	-109 dBm*	-109 dBm
EAC R-390A	-116 dBm	-116 dBm	-112 dBm**
JRC NRD-525	-112 dBm	-114 dBm	-115 dBm
Icom IC-R75[2]	-111 dBm	-111 dBm	-110 dBm
Icom IC-746Pro[3]	-112 dBm	-112 dBm	-111 dBm
Icom IC-703[4]	-110 dBm	-113 dBm	-113 dBm
Icom IC-7000	-102 dBm	-109 dBm	-111 dBm
Icom IC-R1500	-96 dBm	-96 dBm	-96 dBm
Etón E1	-112 dBm	-114 dBm	-115 dBm
SDR-IQ	-101 dBm	-101 dBm	-101 dBm
Perseus[5]	-105 dBm	-103 dBm	-104 dBm
QS1R/QS1R ext.preamp[6]	-93 dBm/-105 dBm	-94 dBm/-105 dBm	-95 dBm/-106 dBm

*Measured on 1100 kHz. On 1000 kHz there was a tone (spurious signal?) that prevented measurements.

** Surprisingly low. Measurements on 1400 and 1600 kHz showed -114 dBm sensitivity.

All measurements made with 400 Hz tone, 30% modulation on AM with AGC off and "wide" bandwidth (nominal 6 kHz except RA6790/GM; nominal around 4.5 kHz, and Etón E1, nominal around 7 kHz).

And the winner is… not very surprisingly, the EAC R-390A, but with the NRD-525 a very close second. At most locations, sensitivity is not always an issue. But at my location, sensitivity certainly is. The 525 is no more in my possession, but the R-390A will stay.

The SDRs lack a few dB to be up front, but they have other virtues. There will never be a perfect radio.

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[1] Attenuation pad removed below 1.6 MHz

[2] Fully Kiwa-modified

[3] Attenuation pad below 1.8 MHz removed, and preamp enabled

[4] Attenuation pad below 1.8 MHz removed

[5] Preamp on/off, dither off, preselector off. Other settings give less sensitivity. 500 kHz reading actually 800 kHz.

[6] A Wellbrook, 11 dB (nominal) preamp was put in the signal path to compensate for the QS1R not having an internal preamp (unlike the other receivers)

Another Kongsfjord Perseus File

This Perseus file is recorded on Jan 10, 2009 at 1430 UTC. This is rather late in the day, with  the eastern half of North America already sunlit, but some of the more dominant west coast MW stations can still be heard, together with several Pacific Canadian NDBs in the LW band. The half hour is full hour in India and Iran, and there should be a few stations from that region as well. Iran 702 and India 1566 were certainly very strong.

SpectraVue Beta Reads 1600 kHz Perseus Files!

With the exception of Winrad, SDR software has been proprietary to the hardware. SpectraVue for the RF Space SDRs, and Perseus for the - you guessed it - Perseus SDR. Finnish DX-er Tarmo Kontro alerted me about SpectraVue 3.0 beta 19 which is in fact able to read 1600 kHz Perseus files! The beta 16 could read 800 kHz Perseus files, but I was hoping Moetronix would develop Perseus support further. And indeed that happened! Above is an image of SV 3.0 beta 19 running a 1600 kHz Perseus file from October 2008 (incidentally just as I heard a KVXR ID on 1280). The software, although in beta, appeared to be very stable.

Now, this seemed to be good news also for other users. Netbook owners! The Perseus software is a fixed window 1024x648 (?) pixels, while most netbooks only run 1024x620, or even 1024x578 pixels. With 620 lines, running Perseus is sort of OK if you move the window a bit upwards and allow the task bar to be hidden. But SpectraVue is scaleable, leaving you in better control over the task bar and the desktop. I tested a 1600 kHz file on my MSI Wind running at turbo mode (1.98 GHz instead of the standard 1.6 GHz), and it was running very smooth, although with a high (90%) CPU load. As was pointed out by Anders Hultqvist though, a "chopped" Perseus file (using Chuck Hutton's excellent "WavChopper" utility) will not play at the utility's current state.

 SpectraVue 3.0 beta 19 is [Update: Was!] available from this site. Only the latest beta is downloadable, and there is no guarantee that following betas will support Perseus. Also, I am quoting the usual caveat: If you are not comfortable un-zipping and dealing with bugs and program crashes PLEASE do not download these Beta versions as they are continually changing and can be unstable or non-working.

Update: Well, Spectravue was "open" just for so long. The current beta on the link above is 20, which has a new limitation: "Limit Perseus File playback to SDR-xx owners". So there you go. No SDR-IQ or SDR-14, no Perseus playback. This posting has been changed accordingly.

New Kongsfjord Perseus File

Since the first Kongsfjord Perseus file was downloaded 188 times before I removed it, many seem to have found an interest in hearing how arctic dx is like. So I thought I'd keep you lads busy a bit more.

This file is from Feb 26 at 0600. Conditions towards North America were rather undefined with signals stretching from Ontario/Ohio to the west coast. A few Mexicans too. Again, most Europeans are Russian stations. Note 1485 - NRK Svalbard with regional programming originating from Tromsø before national news on the hour. 1485 is my indicator station as it is located in the signal path. Again, this file will only be available for a few days or perhaps a week.

The file is zipped from original 686 MB to 488 MB. Enjoy!

Kongsfjord DX Files

Update 16 April: The file has been removed. It is still available on this blog.

I have uploaded a 2-minute 1600 kHz Perseus file to  this location. It is 907 MB, so be sure you have a reasonably quick internet connection before you try to download. It will only be available for a limited time due to storage restraints.

The recording was made on November 1, 2008 at 1300 UTC. Most stations from the Americas are western US and Canada, from Montana/Idaho/Utah to the Pacific coast, Alaska and at least one Hawaiian. The European stations found are mostly Russian.

I was queried about the background noise. The general noise level is low, but I also have a "ticking" noise which is my local powerhouse, the Loran C. It is 250 kW, 14 km away as the crow flies, and in the same direction as North America. The frequency is 100 kHz. This is an extremely challenging adversary, if you excuse the expression. In order to avoid overload to broadband receivers like the Perseus (and many others), a 100 kHz notch filter is crucially important. Stefan Wikander made one for me many years ago, and I've copied that design (and a
modified design by Dallas Lankford) for all my antenna feedlines. Search elsewhere in this blog for details.

To avoid excessive Loran C noise bleed, maintaining the rest of the equipment at a 100%
quality level is equally important and takes a lot of time. For me, one poor connection is detrimental.

Setup: The beverage was fed with RG-316 coax to a self-made antenna connector made up of a cannibalised SE-6 switch box (an accessory to the Sherwood SE-3 sync detector). From the antenna selector to a Wellbrook 10 dB preamp w/ bypass, then to a 1:8 Wellbrook splitter/13 dB preamp w/ bypass. Bypass is important. During nights, often no preamps are engaged. During the lightest part of the day, often both preamps are engaged. I don't remember the preamp settings at the time of the recording, but at least one preamp was on to compensate for the loss
in the 1:8 splitter. Probably both.

Some of the Russian stations are quite strong, such as 657, 1134, 1449 and 1521. These are "local" stations, located on the Kola peninsula. Other Russian stations of potential interest are the VOA station on 810 (Kurkino) and one on 846 ID'ing as Radio Moscow Oblast. Location Electrostal?

QS1R Recording Function

RF Recording for the QS1R has been in the works for some time, and a few of us have (politely, I hope) queried the whereabouts of this critically important feature. While it is still  not ready, Phil Covington has written a dll for use with Winrad, which appears to be quite useful. Winrad's latest version as of March 15, v. 1.42 build 49, supports QS1R without problems. One can choose frequency spans from 50 to 1250 kHz, and RF recording is done by pressing the VCR-type recording button. The file saves by default to the winrad directory.

The picture is a bit misleading since it was screen-dumped from a remote connection. Winrad tends to be rather graphic-intensive, so updating via remote is difficult. Hence, the bandwidth window is "empty".

So, we can finally record RF from this excellent receiver! But I am hoping that the "real thing" isn't too far away.

Arctic Norway MW Bandscan

My Kongsfjord PC has been offline for the better part of a month due to a failing modem/router. I finally got a replacement, and finally the adverse weather we have had the past few weeks calmed for a few hours allowing me to drive to Kongsfjord and set it up.

While testing the remote control, I did a 30-second Perseus recording of the MW band at 1900 UTC. This is a time of the day when little interesting (from my point of view) is heard, but others might find interest in hearing signals from Eastern Europe and the Middle East (and even India). A few Western European stations also audible. I used the backlobe of my 310-degree North America beverage. Lots of Russian and Romanian stations, Iran mostly everywhere. KBRW-680 and KNOM-780 audible but not strong (they improved later on). NRK Svalbard 1485 very weak; this is usually a super dominant when conditions are right.

I suspect that the beverage is not in a very good state. The general signal level when I checked North America this morning was rather on the low side. It's been too dark, too windy and too snowy to even think about checking, not to say repairing it.

The Perseus file can be downloaded from Guy Atkins' blog under "Perseus SDR WAV Files". It's about 250 MB and covers 1600 kHz from 1859:46 to 1900:19 UTC.

Sorry about not having been very active on the DX scene lately. I have chosen to put my focus elsewhere for some time.

Arctic Lights Around Winter Solstice

Here on 71 North, it is dark almost 24h around Winter Solstice; only around noon do we see some twilight. But sometimes light itself is spectacular, such as today when iridescent clouds coloured the southern sky. These clouds are typical for the polar areas and are formed 20-30 km up where the temperature is down to -80 Celsius.With light like this, who cares if it's dark the rest of the day?

QS1R Selectivity, Audio Quality

Selecting the appropriate bandwidth is a two-step process. Clicking "FILT" or the bandwidth label (in the case of the picture: "4K") opens a new window from which you can select one of 16 preset bandwidths. Each can be tailor-made to your own liking. I was somewhat surprised to see that in AM mode, "4K" bandwidth is not 4 kHz, but 8! As long as you know, it's ok. Making a passband shift effect is easy enough; just adjust the slider on the bandwidth line. The bandwidth setting will reset to default if you press one of the bandwidth buttons on the bottom. Less elegant than the Perseus, but perfectly acceptable. I have no tools to measure the ultimate rejection of these bandwidths, so a comparison between the QS1R and the Perseus had to be made with ears only. I could not detect any difference between the two SDRs.

As we know, audio quality relies on a well designed AGC function. The QS1R GUI offers Long, Slow, Med, Fast AGC, or you can choose to turn it off. The settings can be adjusted the same way bandwidth can - at least in theory. The current GUI has the AGC options greyed out but the problem has been acknowledged by Cathy the GUI designer so I expect the option to be available soon. At present, even the "Long" AGC setting has a too short release time to cope with rapid fading. In such instances, "pumping" effects will be heard.

But audio quality and audio recovery is nonetheless superb. In situations with heavy interference, the weaker signal often appears more readable on the QS1R than on the Perseus. The difference is subtle, and the average listener may not detect it at all, but in some cases it could be the difference between hearing an ID or not. Audio recovery appears to be more "open" than the Perseus, making it easier to separate between several stations on the frequency.