Some time ago, I wrote about the Rubidium reference that I connected to SDR. The reference supplies a very stable and precise 10 MHz reference clock to the SDR, so that the sample rate does not drift. Drift in the sample rate causes drift in the received frequency, much like drift in the various oscillators in a conventional radio causes drift.

Just today, I replaced the Rubidium reference with a GPS disciplined reference.

Here’s what I got:

The reference itself is the box in the center. To the right is the power supply, to the left is the antenna.

A GPS disciplined reference or oscillator uses timing signals from the GPS satellites to control,or “discipline” the oscillator built into the reference using a tracking loop. The 10 MHz output is continuously adjusted to keep it at the correct frequency, usually by making very small adjustments and using long time constants (averaging periods), typically around 100 seconds or more.

The 10 MHz output from the reference connects to an input on the netSDR. Internally, that 10 MHz signal is used to produce an 80 MHz clock that is used to drive the A/D sampling.

Here is what the inside of the reference looks like:

Here’s a plot of WWV on 10 MHz:

I believe the frequency shifts you see are due to doppler effects in the ionosphere.

Now I can figure out exactly what frequency Captain Morgan is on.

Old Sol has been quiet lately. Far too quiet for the 10 and 11 meter band guys. As I’m typing this, the solar flux is back into double digits, at 95. The Sun Spot Number (SSN) is officially 24, but you need to squint real hard to actually see any sunspots:

Sunspot SunSpeck group 1452 has pretty much rotated out of view, taking the meager solar activity we’ve had with it.

The NOAA/NASA/Space Weather prediction boys promise that we’re still a year away from the peak of cycle 24, and activity will increase.

Go up. Yes, it will go up any time now, just you wait. Hey! Look over there! Global Warming!

Meanwhile, back in the real universe, the background x-ray flux is at B1 levels.

So what does all this mean for us DXers? The lower solar activity has several major effects. First, the highest frequencies that can be propagated are lower, in many cases much lower. During a solar cycle maximum with high activity, the higher bands are often open 24 hours a day. With the lower activity we’ve been having, this is not this case. Yes, 10 meters is still open at times, but not nearly as much, or with the good conditions that have been experienced in the past. So operators and listeners need to move down to lower frequencies.

The foF2 frequencies are correspondingly lower, which means that a given band (including 43 meters) will go long earlier in the evening. Operators may want to adjust their schedules accordingly, and consider transmitting a little earlier to reach a semi-local audience. OTOH, they’ll end up reaching more distant listeners earlier in the evening as well.

Second, D-layer absorption is lower, due to decreased x-ray flux from the Sun. This means that lower frequencies are not attenuated as much, which is a good thing, since in many cases that’s all that is propagating. The last few days, I’ve been hearing 48 mb (6 MHz) Europirates fade in as early as 2 hours before local sunset. And once the Sun does set, their signal levels increase to really strong levels. Likewise, US pirates such as Wolverine Radio have been reported across the US and into Europe with incredible signal levels.

Third, the lack of major solar flares and coronal streams affecting the Earth means that geomagnetic conditions have been very stable. No geomagnetic storms means stronger signals, and less fading.

The net result is that reception conditions for 43 meter band pirates has been extremely good lately. Lots of operators and listeners have been taking advantage of the excellent conditions, loggings are way up.

There is a coronal stream expected to start impacting the Earth around the 13th or 14th of April, so we’ll have to see what effect, if any, that has on conditions. Until then, enjoy the great propagation!

Software Defined Radios (SDR) have revolutionized the HF radio monitoring hobby. While most of the SDR manufacturers only offer Windows versions of their SDR application software, there are many third party solutions for other operating systems.

I use Macs, and there’s a great SDR app called SdrDx. It is based on the open source CuteSDR program (which fortunately uses the more permissive BSD license rather than the overly restrictive GPL license, allowing a much wider use of the code). SdrDx is free to download and use.

SdrDx works with all SDRs made by RF Space. I believe it may also work with some soundcard based SDRs, although I have never tried it that way.

As obvious by the screenshot (from a 24″ iMac) there’s a lot of controls. Besides the typical waterfall and spectrum displays, there’s also controls for memories and notch filters, as well as the ability to control the various AGC and noise blanker settings.

There’s a readme file that comes with the download, and recent versions of SdrDx have an optional tooltip display, so you can hover the cursor over a control to find out what it does.

The author of SdrDx is actively developing it, and has added quite a few features based on user suggestions. If you run Mac OS X, and are looking for an app to control your SDR, SdrDx may be the way to go. Download a copy and try it for yourself.

I’ve noticed LINK-11 (TADIL – Tactical Digital Information Link) transmissions in the 6940-6950 kHz region the last day or two. Operators may wish to avoid 6950 kHz, and perhaps even 6955 kHz, especially while these transmissions are occurring.

I have no idea where these transmitters are located, but if I had to guess based on propagation characteristics, I’d say maybe Canada or out in the Atlantic.

LINK-11 is operated by the US military. I’m pretty sure you don’t want to interfere with it.

While conditions may not have been spectacular, I was able to hear a lot of stations. All heard with a JRC NRD 545 receiver and my 635 ft sky loop antenna.

Here’s what I’ve heard so far, all loggings reported to the HFUnderground.com message board.

Stations Heard UTC March 30:
Trans Europe 15020 AM 1420 UTC
Mike Radio 21455 AM 1356 UTC
Fox Radio 6308 USB 0010 UTC

Stations Heard UTC March 31:
Mustang Radio 15000 AM 1115 UTC
Trans Europe Radio 15020 AM 1125 UTC
Rave on Radio 6925 USB 1215 UTC
Radio Underground 15050 USB 1242 UTC
Radio Spaceshuttle 15845 USB 1223 UTC
Radio Underground 15850 USB 1302 UTC
Radio Paranoid 15030 AM 1134 UTC
Baltic Sea Radio 18950 LSB 1346 UTC
Radio Scotland 15060 AM 1400 UTC
Radio Mustang 15020 AM 1415 UTC
Cupid Radio 21460 1435 UTC
Cupid Radio 15070 1523 UTC
Radio True North 21850 AM 1529 UTC
Undercover Radio 15050 AM 1538 UTC
Radio True North 15520 AM 1623 UTC

This is a great opportunity to hear a lot of Europirates!

Global Pirate HF-Weekend will be 31.3. – 1.4.2012. ( from hkdx2.blogspot.ca/ )

Be sure to visit either the #pirateradio IRC chat or Iann’s Chat while the event is taking place, to get current information on what stations are active.

1) RADIO SCOTLAND, Holland- 15.060 MHz – AM – 200 W
Saturdaymorning 08:00 – 10:00 h utc.
Saturday afternoon 14:00 (or 14:15) – 15:00 h utc.
Sundaymorning 09:00 – 11:00 h utc.
LIVE WEB-CAM: www.radioscotland.nl/Webcamrsi.html

Frequency 15.050 – 15.065 MHz, if 15.060 is occupied.

2) TRANS EUROPE RADIO, Holland – 15.000 – 15.100 MHz – AM – 65 W
Will be active during Saturday and Sunday morning and afternoon
on 19 mb.

3) BALTIC SEA RADIO, Scandinavia – 21.485 MHz – USB – 80/150 W W
On Saturday starting 08.00 and again 13.00 utc
On Sunday starting at 09.00 utc.

4) RADIO BORDERHUNTER, Holland – around /15 MHz/ 21.5 MHz – AM
More information later for dates and frq’s

x) OLD TIME RADIO, Scandinavia – 15.009 MHz – AM – 50 W
Short test was planned but cancelled for this weekend.

5) RADIO BLACK BIRD, Holland – 19 mb – AM
No frequency or time information yet.

6) WR INTERNATIONAL, England – 12.257 MHz – AM – 35 W
WR is on the air every Sunday from 08.00 – 11.00 utc.

7) BALKAN RADIO INTERNATIONAL – ??? MHz – AM -
New station from Balkan area. The station has new transmitter and
let’s hope it will be on air for this weekend.

8 ) RADIO SPACESHUTTLE, Scandinavia – 15.845 MHz – AM+SSB – 200 W
Saturday and Sunday some transmissions between 07:00-16:00utc on
15845 kHz (or nearby). AM and SSB (changing time to time)

9) FREE RADIO NOVA, Holland 15.070 MHz – AM
Sunday 1.4.2012 starting at 08.00 utc.

10) MIKE RADIO, Holland – around 21.500 MHz – AM
Not 100 %. 21.500 or 21.850 MHz.
Antenna tower still down for the winter.

XX) RADIO BLACK ARROW, Holland – 21.490 MHz – AM
Transmitter broken week ago – Possibly not on air

11) RADIO FOX 48, Scandinavia – about 15.092 MHz – USB – 300 W
Saturday 14.00 – 16.00 utc.

12) CUPID RADIO, Holland – 21.460 MHz (or 15.065 MHz) – AM
Saturday 31-3 euro afternoon broadcasting towards the U.S.A freq 21.460 mhz [when the band is down 15.065]
Sunday 1-4 starting at 08:00 utc till 10:00 utc freq freq 21.460 mhz [when the band is down 15.065]
Sunday 1-4 euro afternoon broadcasting towards the U.S.A freq 21.460 mhz [when the band is down 15.065]
Loads of sstv pictures will be send out during the broadcast.

13) MUSTANG RADIO, Holland – 15.000 – 15.100 MHz – AM – 50 W
Again new participant! More info later!!

14) RADIO LATINO, South Europe – 15.000 – 15.100 MHz -
26.100 – 26.200 MHz – AM – 40 W
Salsa mix-programme (30 min) on early morning on Saturday and Monday
at 06.30 – 07.00 and 07.30 – 08.00 utc! Progamme will continue longer if possible.
-26.100 – 26.200 MHz (in the morning, if propagation helps)
-15.000 – 15.100 MHz (in the evening, if morning propagation is bad)
More info and realtime-info on the web-page: radiolatino.bigbig.com/
E-mail: radiolatino@live.com

15) RADIO UNDERGROUND, England – 15.000-15.100 MHz -USB – 80 W
More exact frequency and times later, also 21 MHz is possible.

16) FREE RADIO VICTORIA, Holland – 21.880 MHz – AM- 50 Watts
On Sunday 1/4/12 from 08:00 ….. 10:00 UTC on the Dipole intend for Scandinavia and the Mediterranean Sea.
On Sunday 1/4/12 from 11:00 ….. 13:00 UTC on the Vertical ant. intend for overseas country,s .

17) RADIO TROPIQ, Central Europe – Many frequencies – AM 50 W / LSB – 80 W
Saturday
15.00 – 15.30 UT 15.050 MHz
16.00 – 16.30 UT 11.450 MHz
18.00 – 18.30 UT 9.950 MHz
Sunday
08.00 – 08.30 UT 18.205 MHz
09.00 – 09.30 UT 9.950 MHz

North America
18) Radio True North – 15.460 MHz (200 W) or 21.850 MHz (40 W)- AM
On air from 14.00 – 23.00 utc.
Also possibly on air on 6.925 or 6.950 MHz around at 02.00 utc

OUT OF HF-FREQUENCIES:
19) COOL AM RADIO, Holland – 10 Watts mobile – 6925 or 6940 kHz
This station is NOT HF-station because it uses 42 mb but I
took this in because it is special 10 W mobile!!

PIRATES – ATTENTION!
Info of free frequencies can be found here:
www1.m2.mediacat.ne.jp/binews/bia12.txt

BASIC SCHEDULE

1) European MORNING 08.00 – 12.00 UTC from Europe to Asia/Japan/Oceania.

2) European AFTERNOON 12.00 – 16.00 utc from Europe to North America and vice versa.

3) European NIGHT 22.00 – 24.00 UTC from North America to Asia/Oceania.

Firedrake is the unofficial name of a shortwave broadcast featuring loud oriental orchestral music. It exists solely to jam other signals, such as broadcasts by Sound of Hope, which broadcasts programming from Taiwan that is often critical of Chinese government policies and human rights abuse. The broadcasts only contain music; no form of on-air identification has ever been reported. Apparently, the source of the Firedrake shortwave transmissions is a China National Radio satellite feed.

While international regulations prohibit jamming, this has never stopped China (or the Soviet Union, Cuba, Iran, etc) from doing so. Rather than use a traditional jamming sound, apparently China believes that transmitting music 24 hours a day on dozens of frequencies doesn’t qualify as jamming. Or that no one will notice.

Here is a recording of Firedrake from March 29, 2012 on 14970 kHz.

Below is a relatively current list of known Firedrake transmissions:

Frequency     UTC Time
6280          2200-2400
7105          2200-2300
7280          1100-1300
7310          1300-1400
7310          2300-2400
7525          2300-2400
7565          2200-2400
7615          2200-2400
7970          0000-2400
9200          0000-2400
9450          1400-1600
9540          0900-1100
9635          2200-2300
10300         0000-2400
10965         0000-2400
10970         0000-2400
11500         0000-2400
11550         1200-1300
11760         0900-1100
11820         1330-1400
11980         2000-1700
12130         1500-1630
12160         1130-1200
12175         1300-1330
12175         1600-1700
12230         0000-2400
12300         0000-2400
12600         0000-2400
12670         0000-2400
12980         0000-2400
13060         0000-2400
13130         0000-2400
13270         0000-2400
13500         0000-2400
13850         0000-2400
13920         0000-2400
13970         0000-2400
14400         0000-2400
14700         0000-2400
14900         0000-2400
14970         0000-2400
15070         0000-2400
15500         0000-2400
15745         1230-1300
15750         1300-1330
15750         1400-1500
15800         0000-2400
15900         0000-2400
15970         0000-2400
16100         0000-2400
16700         0000-2400
16980         0000-2400
17100         0000-2400
17250         0000-2400
17450         0000-2400
17560         1400-1430
17920         0000-2400
18180         0000-2400

Here’s a waterfall I just made at 2155 UTC today, March 28, 2012, of WWCR Nashville TV on 6875 kHz, as captured by my netSDR running SdrDx software:

The sidebands extend all the way out to 6850 and 6900 kHz. That’s +/- 25 kHz wide. I inserted up to 30 dB of attenuation on the input signal, and the wide sidebands didn’t go away, so I don’t think this is an overloading issue.

Does the FCC have limits on the channel width SWBC stations can occupy? Is this really necessary?

Update:

Here’s a waterfall from 2327 UTC, showing both WWCR on 6875 and WYFR on 6915. Both are of similar signal strength, but only WWCR shows the very wide signal. Double click on the image to open it full size:

Over modulation?

FWIW, you can see that with both of these stations on, there isn’t a lot of space left for pirates on 43 meters. At 6925, you run into possible interference from WYFR on 6915. WWCR takes out at least 50 kHz, from 6850 to 6900. There’s several UTEs scattered around as well.

There’s been a rather dubious claim of pirate radio being destroyed. And the fun being taken out of it. Again. This concerned me very much, as I’ve been listening to pirate radio stations since 1978, and I’m pretty sure that it’s still fun. I turned on the radio, tuned to 6925 kHz, and sure enough, I didn’t hear any pirate radio, just static. Granted, it was one in the afternoon. If only I was living in New Zealand, then I’m sure I would have heard something.

Just to be sure, I decided to look at the last year or so to see how many pirate stations have been reported on the HFUnderground.com pirate loggings message board each month. Being as the HFU is the “original, most-viewed, reliable, blazingly fast, respected, loved, and imitated Pirate Radio site on the Net”.

Here’s what I came up with:

January       100
February       87
March          81
April         104
May            81
June           36
July           56
August         60
September      83
October       135
November      150
December      197
January       172
February      130
March          93 (as of March 23, so I'd estimate
we'll end up with about 125 for the whole month)

There’s an average of about five messages per logging thread. So multiply the above numbers by five if you want to know approximately how many people reported hearing a pirate transmission on the HFU during each month.

You can certainly see the drop in activity over the summer, presumably because the bands are noisy from thunderstorms, and people have better things to do than sit in front of the radio and listen to static.

And there’s a big peak around the end of the year holidays. No surprise there, as there’s lots of once a year stations that pop up that time of the year. All operated by the same six old white guys that operate 99 44/100% of the pirate stations that we hear anyway.

Looking at these statistics, I’m not sure how someone can claim that pirate radio has been destroyed. The number of reported loggings for January and February 2012 are about 60% higher than those months from the previous year. And it looks like March will be up by about the same amount. Graphing the number of loggings shows a clear increase over time. By using a linear trend fit, much like Al Gore does with temperature measurements, it is pretty clear that by 2020, there will be millions of pirate radio loggings on the HF Underground every month. The sheer number of eQSLs being sent out will probably cause the entire internet to go down:

Alternately, one could claim that the numbers are only higher because people have been flocking to the HFU. Hmm… no, I don’t think he’ll claim that.

A few weeks ago, I put up a new antenna, a delta loop for 43 meters. Since it was dedicated for a single band, the performance should be very good. My plan was to write a article here about how well it works, compared to my existing antenna, the 635 foot Sky Loop. That article never materialized, because… the delta loop doesn’t work any better than sky loop. What went wrong?

Shortwave listeners, it seems, are addicted to two types of new things: new radios, and new antennas.

We’re sure that the latest and greatest radio will substantially improve reception, reject QRM, and let us hear lots of stations we could never hear before. And Software Defined Radios promise to do all this and more (just ask Al Fansome). While a new radio often does offer conveniences and advantages over the old one, usually they turn out to be mostly minor improvements (unless you’re switching from say a portable to a desktop communications receiver, or finally giving up that old analog tube radio for a newfangled solid state rig with digital readout).

The same holds true, it seems, for antennas. Sure, if you’ve previously had an indoor antenna, and finally are able to put up your first outside antenna, the improvement will indeed be dramatic. You most likely will hear new stations that you never could pick up before, and the reception of existing stations will be substantially improved. You’ll also end up not hearing some things you previously did, like your plasma TV.

And switching from say a 50 foot random wire to a dipole or T2FD will also produce a noticeable improvement in reception. Not as much of an improvement as going to an outside antenna, but still significant.

But after that, it certainly does seem to be a case of diminishing returns.

When I switched from the T2FD to the Sky Loop, I did notice an improvement in reception, but it was not what one would call amazing. It was better, certainly, and worth the effort. But I went from a 132 ft T2FD to a 635 ft sky loop. Most of the improvement was on the lower frequencies and MW, as one would expect. Reception on the higher frequencies, say above 20 MHz was either the same or worse. Also probably as one might expect.

But, like the gambler looking for that last final big score, we SWLs have to try for the ultimate antenna. The one that will let us hear otherwise impossible DX. Like a pirate on 6925 kHz during the daytime transmitting from Montana. Possibly also being heard in New Zealand. To hell with the laws of physics!

So I ran numerous NEC models on various configurations of the delta loop, optimizing the dimensions and height for the best possible reception. Ignoring the fact that minor changes in things like ground conductivity cause huge changes in antenna performance. And that I have no idea what the ground conductivity is here, anyway. Plus, it probably changes when it rains. Also, the takeoff angle from the antenna varies quite a bit if you change the height of the antenna by a foot or two. Did I mention that my yard is heavily sloped?

But, I did the calculations, cut the wire, shot the fishing line up over the trees to pull up the rope, and installed the new delta loop. Then ran coax to the shack, connected it to the radio, and ran some tests that evening, to see how much better the performance was. It wasn’t. Signal levels were lower than with the sky loop, and more importantly, the signal to noise ratio was the same or worse. Plus, I had an antenna that basically worked for one band, whereas the sky loop is good from MW up.

So, I think I’m going to stick with the sky loop. No need to switch antennas, or use an antenna tuner. It just works. Although, if I take the delta loop and reconfigure it as a horizontal resonant one wavelength antenna… hmm… time to run some NEC simulations!