Tag Archives: Chris Smolinski

Guest Post: Listening To Pirate Radio Stations from South America

Many thanks to SWLing Post contributor, Chris Smolinski, who shares the following guest post. Note that this post has also been published on Chris’ excellent blog, Radiohobbyist.org:


 

Listening To Pirate Radio Stations from South America

by Chris Smolinski

Looking for a new DX challenge? In addition to shortwave pirate stations in the USA, and Europe (Europirates as we call them), there’s a relatively new group of pirate radio stations being heard in North America, those from South America.

It’s really only been the previous year that we’ve confirmed that there’s a significant number of pirate radio stations in South America that can be received here. Radio Pirana has been known for some time, and I believe thee were a few reports of it, and at least one other station that I cannot remember the name of, but that’s about it. For years there have been logs of very weak UNID stations heard on the 43 meter band (6800-7000 kHz), presumed to be pirates of some sort, and it is possible some of these were South American pirates.

Most of these stations use homemade transmitters, often of the “Lulu” design, with a IRF510 or similar MOSET RF final stage. That means they are generally in the 15 or 20 watt carrier range, although some are higher power. That also means that unless otherwise noted, all of these stations use AM mode, and in general the frequency is highly variable, easily varying 100 Hz or more from night to night, or even during transmissions.

One important caveat: Since most of these stations use relatively low power, and due to the long distances involved, signal levels are generally weak, although occasionally when conditions are excellent (especially if there’s grayline propagation), they can put in stronger signals. I am fortunate to live in a rural area with relatively low noise/RFI levels, and have several high end receivers and large antennas. My primary setup for catching these stations is a netSDR receiver and a 670 foot Sky Loop antenna. You’re going to want to use the best receiver and antenna you can for catching these stations, you’re not likely to have good (or any) results with a portable SW radio, RTL dongle, or small/indoor antenna. Also, I record the entire 43 meter band nightly on my netSDR, and then go through the recordings each morning. This lets me catch stations that may only appear for a brief period of time. That said, you can still hear them with a reasonable HF setup, although it may take persistence, checking each night, until conditions permit reception.

It’s well worth checking the Latin American Pirate logging forum on the HF Undergroundwebsite, to see what is presently being heard. The HF Underground is the best way to keep up to date with the hobbyist radio scene in general, with dedicated forums for North American PiratesEuropirates, and of course radio in general.

And for those of you into collecting QSLs – many of these stations are reliable QSLers!

In general, the easiest station to hear is Lupo Radio from Argentina. It is on the air most evenings on 6973 kHz in AM mode. At least at my location, it puts in the strongest and most reliable signal. Usually in the SIO 222 to 333 range, sometimes stronger. There are frequent IDs. I use Lupo Radio as a “beacon” to gauge how good conditions are to South America on 43 meters.

Another station that is often on the air is RCW – Radio Compañía Worldwide from Chile. They use 6925.13 kHz, and their carrier is more stable and usually on this offset frequency, which makes it easier to determine that it’s likely you’re hearing them vs a US pirate station.

New to the scene is Radio Marcopolo on 6991 kHz.

Also new to the scene is an as yet UNID pirate from South America on 6934.9 kHz. I have received them for several weeks now in the local evenings, usually starting around the 2300-0300 UTC window. They put in a respectable signal (relatively speaking), strong enough for Shazam to ID songs. They have frequent breaks in their transmission, with the carrier often going off and on many times during a broadcast. They also occasionally transmit audio test tones, and sometimes seem to relay audio from licensed stations in Argentina such as Radio El Mundo. This could be someone testing a new transmitter? A new mystery to solve!

Radio Dontri is somewhat unique in that they use USB mode, on 6955 kHz. They also send SSTV, which is sometimes easier to receive than music, and helps to verify that you’re actually hearing them, vs a US pirate on 6955. They tend to drift a lot, however, which can make decoding the SSTV transmissions challenging.

Outside the 43 meter band, there is Rádio Casa 8000 kHz. I have only received weak carriers from this station, although partly that may be because I do not frequently check for it, and it does not turn up on my overnight SDR recordings.

Radio Triunfal Evangélica is other station outside of the 43 meter band, they use the nominal frequency of 5825 kHz, often closer to 5824.9 kHz. Again I have only received a carrier from them. As the name implies, they are a religious station, affiliated with a church.

Now that we’ve talked about the pirate stations from South America, we should probably mention things you are likely to hear that are not pirates. Specifically, what we call Peskies (or Pesky as the singular), short for pescadores, the Spanish word for fishermen. Peskies generally use LSB mode, and can be heard on many frequencies in the 43 meter band, engaging in QSOs. Years ago, pirate listeners started to call these stations pescadores, since some of them were indeed fishermen, and could be heard discussing related matters. It might be better to think of most of them as freebanders/outbanders, much in the tradition of those transmitting on 11 meters. There’s a logging forum on the HFU dedicated to Peskies, if you’re interesting in learning more about them.

Occasionally they use AM mode. We’ve logged several on 6965 kHz (+/- of course), that at first were thought to be pirates. But they never transmitted music, and after some discussions with DXers in South America, it was determined that they were more properly considered peskies.


Many thanks, Chris, for sharing this excellent guest post with us! Until the Winter SWL Fest last week, I had no idea South American pirates were on the rise–what a great opportunity to catch interesting DX!

Readers, check out this and other posts on Chris’ website Radiohobbyist.org.

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Chris’ 2016 Pirate Radio Year in Review

Many thanks to Chris Smolinski who has, once again, crunched the numbers to give us a look at HF pirate radio activity in 2016.

[…]To gauge shortwave pirate radio activity in 2016, I analyzed the Shortwave Pirate loggings forum of the HF Underground (http://www.hfunderground.com). A computer script parsed the message thread titles, as well as the timestamps of the messages. This information was used to produce some statistics about the level of pirate radio activity. Of course, as Mark Twain has written: “There are three kinds of lies: lies, damned lies, and statistics.” Still, let’s see what we can learn.

There were 13,860 messages posted to 2,398 unique threads, compared to 13,944 messages posted to 2,183 unique threads in 2015. Activity levels are essentially flat, but still at historically high levels. Back in the 1990s, it was not uncommon for an entire month to go by with only a handful of pirate stations logged. If you want to know when the “golden age” of shortwave pirate radio was, I would say it is right now.[…]

Chris has posted his full analysis on RadioHobbyist.org.

As you can tell from Chris table at the top of this page, January is a very active month for HF pirates. If you’ve never chased pirate radio stations, check out our pirate radio primer. Pirate radio DXing is incredibly fun!

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Updates to the Morse Pad app

Many thanks to Chris Smolinski, who shares the following update:

I have a new version of Morse Pad for the iPad/iPhone/iPod Touch.

This update includes an improved decoder which better handles improper dot / dash / space timing by the sender (poor fist), automatic speed (WPM) algorithm, and adds AFC (Automatic Frequency Control), which auto tunes in the strongest signal present.

App Store Link: https://itunes.apple.com/us/app/morse-pad/id385629886?mt=8

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Chris tracks down sources of radio noise

spectrum-waterfall-sdr

Many thanks to SWLing Post contributor, Chris Smolinski, who shares this guest post from his blog, RadioHobbyist.org:


Yet Another !&*%$! Noise Source

by Chris Smolinski

The past few days, I have noticed higher than usual noise levels, generally on the lower frequencies, and particularly on the longwave band, including the 285-325 kHz DGPS band, where I run nightly SDR recordings, to later process the data and decode and detect DX DGPS stations using my Amalgamated DGPS app.

Thinking back to what new electronics devices have been added to the house, two came to mind, a new cable modem, and a new ethernet switch. The switch is up here in the shack, so it seemed to be a likely candidate. The switch is a D-Link DES-1008E 8-Port 10/100 Unmanaged Desktop Switch. It uses a mini USB port for power, using either the included AC adapter, or power from a USB port. When I installed it, I decided to not use the AC adapter, but rather a USB port on my UPS, figuring it was better to not add yet another potentially noisy switching power supply to the mix.

The test was easy, I just unplugged the power to the switch. Sure enough, the noise vanished. Great, the switch is a RFI generator. Or is it? As another test, I plugged it into a port on a USB hub. No noise. Hmm… so it seems that the noise is indeed from the USB port on the UPS. I did not notice any increase in the noise floor when I got the UPS a few months ago, but It’s something I should look into again, just to be sure. The UPS is a CyberPower CP1350PFCLCD.

Here’s a waterfall from the SDR, showing the DGPS band, 280-330 kHz. You can see where I changed the power to the switch from the UPS USB port to the USB hub, the bottom part of the waterfall is when the switch was still powered by the UPS (click to enlarge it):

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I still have a noise source just above 305 kHz to hunt down.

Update

I decided to see what I could do to improve things, and reduce the noise floor.

Here is the baseline, after no longer powering the switch from the UPS:
qormmpg

First, I relocated the AFE822 away from the computer and rats nest of assorted cables behind it, powered from an HTC USB charger:
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The squiggly noise around 305 kHz vanished!

I then switched to an Apple USB charger / power supply, as their products tend to be a bit better made:
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Another improvement, the overall noise floor is a bit less now.

But can we do better? I then switched to an older USB hub for power to the AFE822, that I thought might be better filtered:
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I then changed to a linear supply plugged directly into the AFE822. I don’t notice any obvious improvement? Maybe it even looks like a little more noise? Difficult to tell. You can see a DGPS station popped up on 304 kHz while I was switching things around, between the last two tests, it was likely Mequon, WI.

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Thank you for sharing this, Chris! I find a wideband spectrum/waterfall to be such a useful tool for tracking down sources of noise. Not only can you “see” the noise, but you can measure its bandwidth and identify what portions of the dial it affects.

Follow Chris at RadioHobbyist.org.

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New Beta version of SdrDx allows for AFEDRI AFE822 two input phasing

afe822x_bnc_pcb_640px

Many thanks to SWLing Post contributor, David Goren, who shares this tip from Chris Smolinski at Black Cat Systems:

If you have an AFE822 Dual Channel SDR, and a Mac, run, do not walk, to the SdrDx website, and download a copy of the beta version. It now lets you phase the two inputs, much like using an external phaser such as the MFJ-1026. Great for nulling out another station, or noise/QRM. I have some descriptions of how to do this, along with some recordings, and the relevant links, in this HFU post. I believe a Windows version will be out shortly.

Chris’ post on the HF Underground goes into more detail and includes audio samples:

A few months ago, I picked up an AFE822 dual channel SDR, one of the reasons was to experiment with using it as a phaser for MW DXing. It was a bit of a daunting task, having to essentially write an entire SDR app. I then realized I could instead write a “black box” app that sat between the SDR and the SDR app, which would take the pair of I/Q channels from the SDR, and adjust their relative amplitude and phase, and combine them into a single I/Q channel, and send that on to the SDR app. I played around a bit with that, and was quite impressed with the results. I passed on the general idea to the author of SdrDx, who has implemented it in a beta of the app, which is nice because now it is all self contained, rather than having to use my kludgy app in the middle Grin

There’s gain adjustments for each RF input, as well as a phase control, an invert switch to flip the phase 180 degrees, and switches to zero either of the RF inputs, useful when first roughly setting up the gains.

I am quite impressed with how well it is working. As an example, here is a recording of 1680 AM from earlier this morning. I toggled the invert on the phase control a few times, so you can hear reception flip between the two dominant stations on that frequency.

This is going to be really nice for MW DXing. SdrDx is for both Windows and the Mac. If you’ve been considering getting an SDR, this feature alone in SdrDx is reason enough to get an AFEDRI AFE822. If you do buy one, be sure to let Alex of AFEDRI know the reason is because of SdrDx, we need to support the authors of third party SDR apps we use, and let the hardware manufacturers know how important they are.

The URL for the SdrDx page is http://fyngyrz.com/?p=915

The download link for the beta (Mac only right now, once this is confirmed to be working well, I am sure he will update the Windows version) is http://fyngyrz.com/beta.zip

Some more tests, this time on some local Graveyard channels.

1230, getting rid of WRBS:

1240, getting rid of WJEJ:

How to use the phasing adjustment with SdrDx, an AFE822 SDR, and your Mac.

Download the Mac beta (Windows version coming soon) of SdrDx: http://fyngyrz.com/beta.zip
If you have not used SdrDx before or recently, first download the stable version, and run that: http://fyngyrz.com/SdrDx-AA7AS-Light.zip
SdrDx page: http://fyngyrz.com/?p=915

Familiarize yourself with SdrDx if you have not used it before. You need two antennas of course, one plugged into each of the AFE822 inputs.

To use phasing:

Click on the PHA button, turn on Dial Channel Phasing Mode. Click OK to close the window.

Click the Run button to get the SDR into Run mode. Tune in whatever MW frequency you want to use. Ideally one with two stations you can hear at the same time. Graveyard channels are great for this. Be sure to put the SDR center frequency offset from that. For example if you want to null 1300 AM, make the center frequency 1305 or something like that. Or the I/Q imbalance will cause problems.

Click the PHA button to open the phasing window again. You want to keep it open now.

Make sure the Invert checkbox is off, the Both Channels On radio button is on. Set the Phase slider to the middle, both Gains to zero, far left.

Adjust the first Gain slider to bring the signal level up to a reasonable level. S9. S9+10, whatever you want. Make a note of it.

Click Chan A Muted

Now adjust the second Gain slider to bring the signal level up to where it was before with the first RF input. The goal here is to make the signal levels about the same, so you can begin the process of nulling out one of the stations, with some chance of it working.

Click Both Channels On now, so you have both RF inputs active.

Adjust the Phase control, until you notice a dip in the signal strength. Try to get it centered in the dip as close as possible.

Then adjust one of the gain sliders, I usually use the one with the largest value to make things easier, to increase the dip in the signal strength.

Then go back to the Phase control, and try to increase the dip. You may now notice the dominant station starting to be nulled, by listening to it.

Then, like washing your hair, lather, rinse, repeat. You have to iterate back and forth many many times. Eventually, if your two antennas produce different enough signals for the two stations, you will be able to null it out. There are cases where you cannot null out one station, because the antennas produce the same signal for both of them. So nulling out one also nulls out the other. But this is rare.

You can click in the invert checkbox, and reception should switch to the other station. Listen to some of my recordings to hear this in action. You are changing the phase by 180 degrees when you do this.

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Most impressive, Chris!  Wow–I think this feature alone could make the AFEDRI AFE822 an invaluable tool for the mediumwave DXer. Those audio samples are amazing!

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