Anonymity For Pirate Operators and Listeners

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Today, the internet is used for virtually all forms of communications between pirate listeners and operators. Loggings are posted to message boards and mailing lists. Reception reports are sent to email addresses, with eQSLs coming back to the listener by email. And listeners (and some times operators) engage in real time chats via IRC and chat rooms.

The advantages over the older forms of communications in the dark ages (pre-internet) are numerous. The most important is undoubtedly the almost instant speed with which information can be received. Once the first listener logs a station (on a message board such as the HFU / HFUnderground or via IRC), other listeners can immediately learn of this transmission, and tune in, while the station is still on the iar. Back in the old days, the logging would be sent to a SW/DX club newsletter editor (I was one for the ACE back in the 90s) where it would sit until other loggings arrived. Then the loggings column would be edited and finally the newsletter published and mailed to club members. By the time others read the logging, it was weeks if not months old.

Likewise, operators can browse the message boards or chat rooms, and learn in real time how their signal is being heard. They can also find out if there is interference, and they need to move to another frequency, or go off the air. There have been many cases of a pirate operator learning that another operator was also on the air, and they could quickly change frequencies to avoid continued interference. Or wait and not go on the air until the first station was done with their broadcast.

Reception reports and QSL verifications are almost exclusively conducted via email today. The listener sends their report to the station’s email address, and gets an eQSL back by reply. Verifications are often received in a day or two, sometimes in a matter of hours or even minutes. In addition to the instant gratification factor, there’s a huge cost savings. No need for the often cash strapped operator to print up paper QSL cards, and for listeners to spent money on postage. And the pirate operator and listener don’t have to run the risk that the maildrop they use might share personal information with others, as has been rumored to have happened in the past.

eQSLs are not “fake” QSLs. They are verifications that you heard a transmission, and are just as real as a dead tree QSL. Anyone who claims otherwise most likely has impure motives for trying to convince you to send them your personal information.

Operators and listeners do need to be concerned about possible lack of privacy issues with internet based communications. These risks, and their solutions, include:

Email Anonymity

Many email systems include the originating IP address of the sender in the message headers. In other words, your IP address. With this IP address, your location can be determined, often to your city. Of the supposedly anonymous email services, yahoo and hotmail are known to include your IP address, making them not very anonymous. Gmail, on the other hand, does not include your IP address, making it the preferred email service. Most new operators are using gmail, but many older stations continue to use yahoo or hotmail accounts. This is extremely dangerous, and operators should consider switching to gmail. Likewise, listeners who wish to maintain an anonymous identify should also consider using gmail, if they aren’t already.

Message boards / Chat Rooms / Web Sites

Many pirate radio resources exist on the web. These include message boards, real time chat rooms, as well as general purpose websites. These sites all use web servers and clients, and share the same privacy risks.

When you connect to a web server, it records your IP address and what pages you viewed, as part of the server logs. The administrator of the website often uses this information to determine how popular various pages are on the site, as well as what parts of the world visitors are from. More sophisticated analytical tools can even “follow” a user as he navigates the website, to observe in what order he traverses the various pages. Generally this information is not used for nefarious purposes, but rather to help the website administrator improve the quality of the site, and increase the number of visitors.

Your IP address can be used in the same way as with email headers, to roughly determine your location. Of course, this is only relevant if the person examining the logs knows who you are. If you are just a visitor to the site, not logged in, then your IP address appears alongside the hundreds or thousands of other visitors, and there is no information that links it back to your identity. You’re just 192.168.0.1, or whatever your IP address happens to be.

If you’re logged into the site, then your IP address is of course linked to your user name. If you log in as a pirate operator with your station or DJ name, then the weblogs can be used to roughly determine your geographic location from the IP address. The solution is to use an anonymous web proxy. This is essentially another web server that you connect to first. Then you tell it the URL of the site you want to visit. All data between you and the final website is passed between the proxy, which hides your IP address. You just have to trust the web proxy that you use!

IRC (Internet Relay Chat)

Users connect to IRC servers with client software. Your IP address is available to IRC operators (usually not an issue since most of them have no idea what pirate radio even is) and sometimes to other users (which can be an issue). Many IRC servers mask the IP address, usually by changing the last octet. While this does hide your exact IP address, the remaining three octets are usually sufficient to roughly determine your location, as with email and the web. One solution is to use a pseudonym as your IRC nickname, not related to your actual name or station/DJ name. That way, you just appear as another pirate radio enthusiast, and no one knows who you really are. Another is to use a web based IRC client, and connect to it via a web proxy. Problem solved.

Safer web browsing

If you’d rather avoid being tracked on unfamiliar or “hostile” sites, try the Startpage search engine, which features the option of using Ixquick proxy to mask your location and machine type.  Many free web proxies will mask your location (IP), but few will mask your machine type.  Are you that one guy using Windows Vista on a PC with monitor resolution set to 800×600?  If so, you’re easy to spot. Ixquick proxy randomly rotates among a dozen or so types, making it more difficult for snoopy web/blog owners to identify visitors.

Note that some proxies will disable certain functions including Javascript.  It will also hinder the site’s web traffic logs and ad revenue.  If you trust and support a site, consider unproxying and giving the site owner the benefit of your visit.  It’s your choice, so be informed and choose wisely.  And if you get serious about web browsing security, check into the Tor project and other proxy options.

Personal Information in Documents and Images

If you create and send documents and images (such as PDF files or JPEG pictures) be aware that some applications include personal information in the document’s metadata. This could include the name of the registered user for the program.  There are various tools out there that can open documents and display any metadata that is present. If you’re concerned, get some of these programs and make sure that files you create and send don’t compromise your identity.  The free/shareware image editor Irfanview can be used to view metadata and, if desired, re-save images such as eQSLs with metadata stripped for security.

Enjoy Pirate Radio

Don’t let these issues dissuade you from using the internet as part of your pirate radio hobby. If you follow a few simple steps, you can feel secure about your privacy. And don’t let the Chatrooms and the Internet are Eeeeevil crowd scare you, they have ulterior motives for encouraging you to use their snailmail maildrops and other ancient forms of communications – namely to collect more details about you.

Building a Sky Loop Antenna

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Due to the continuing interest in the sky loop antenna, I’ve put together some notes and suggestions on the construction of these incredibly well performing antennas. One note – the sky loop is generally used as a receiving antenna. I don’t have any first hand experience using one for transmitting. Typically, the SWR is all over the place, so you’d likely need a tuner if you wanted to transmit with one. For receiving, no tuner is needed. The sky loop covers all of HF, and often down into MW as well, depending on the size.

First, the basics. A sky loop antenna is a large loop of wire mounted in the horizontal plane. How large? Typically, as large as you can make it. Bigger is generally better when it comes to sky loop antennas. Mine has a perimeter of 670 feet, and I am considering enlarging it. Often, this antenna is run around the property line of your yard, maximizing the length of the antenna as well as the cross sectional area. While the antenna is called a loop, this does not imply that it needs to be circular in shape. While a circle does maximize the area for a given length of wire, other shapes work well. Remember, you’re trying to maximize the amount of wire (perimeter of the loop shape) and area, so try to use as much of your yard as possible, although you don’t want to zip zag back and forth too much. You want to make the largest area polygon that you can. The likely constraint will be what trees or other supports you have available for getting the wire in the air. And of course, remember that safety is important – keep the wire far away from any overhead power lines.

Because the antenna is in the form of a loop (a continuous path of wire from one of the transmission line terminals to the other), it is inherently a low noise antenna. Comparing a sky loop to a dipole, you will find that the noise levels are generally much lower.

How to get the wire in the air? There’s lots of ways, what I find that works best is to put rope up into trees around the path I want the antenna wire to run. One end of the rope has an antenna insulator, the rope then goes up over the tree (or a branch or whatever you can manage) and the other end is secured to keep the insulator up in the air. I just put a large nail in the tree, pull the rope taut, and then wrap it around the nail several times to secure it. often I will put a second nail in the tree as well, a few feet below the first, and then coil the excess rope around the two nails, to keep it neat and tidy, and away from rope eating lawn mowers. Untying rope that’s been wrapped around mower blades is no fun. Been there, done that.

I use an EZ Hang to put rope up in trees.

The antenna wire itself then runs through the other end of the insulator. Since the wire is in a loop, this requires some planning, you need to put a bunch of insulators on the antenna wire, as many as you will need, and then use one for each of your antenna support ropes.

Here’s how I do it:

The EZ Hang shoots a fishing weight up and over the tree. There’s fishing line attached to the weight. Once the weight lands on the other side of the tree, I take off the weight, and attach the end of the rope to the fishing line. Then I use the reel on the EZ-Hang to pull the rope back through the tree, until it gets down to the ground at the EZ-Hang. Now I’ve got the rope going up and over the tree and back down. Then I can cut the rope off the spool, and attach an insulator (with the antenna wire already running through the other eye) to one end of the rope, and pull it and the antenna wire up into the air.

If your antenna is relatively small, you may get away with just four or so insulators, one at each corner of the loop. As the antenna gets larger, you end up with a lot of sagging due to the weight of the wire, and you need several intermediate support insulators on each side of the loop, to limit the sagging.

As far as the type of wire to use, there’s several possibilities. First, of course, is normal stranded copper antenna wire. I, however, got a great deal on a 1000 ft spool of #16 insulated wire. I went with that because the antenna wire would be going through trees and leaves, and wanted to minimize the chances of the wire being shorted out to ground. While probably not as important with a receiving antenna like this as with a transmitting antenna, I decided to play it safe. Also, the insulation happens to be green, and I think it does a good job of helping the wire to blend in the trees, making it difficult to see.

There’s a lot of debate as to how high the wire for a sky loop antenna needs to be. Computer modeling shows that the higher it is, the better it is at picking up low angle signals from DX stations. And in general with HF antennas, higher is better. On the other hand, if it is difficult for you to get the wire up very high, a sky loop with low height wire is still going to perform better than no sky loop at all. I started out with several sides of my sky loop being relatively low, 15 ft up or so, because that is what I could easily manage. Then, over time, I have raised those sections as I was able to. I do think the antenna performs better now that it is higher up, but I am not sure that the effects are dramatic. So my rule of thumb would be to get the wire up as high as practical, but I don’t believe there is any magical height you must achieve. Right now, the height varies between about 25 to 50 feet.

As I mentioned at the beginning of this article, the SWR (and feedpoint impedance) of a large sky loop antenna is all over the place. If you think about it, for many SW bands, the antenna is several wavelengths long. In my case, the antenna is about 670 (206 meters) feet in perimeter. So for the 43 meter pirate band (say 6.925 kHz), it is about 4.75 wavelengths long. At 15 MHz, it is over 10 wavelengths long. That said, I do not use an antenna tuner. While you could, I don’t think it is necessary for receiving applications. The antenna collects lots of signal, and I don’t believe you need to squeeze out the last S unit.

Since the impedance is usually quite high at any given frequency, I chose to feed the sky loop antenna with a 12:1 balun. I didn’t choose this based on any calculations, I just happened to have one available. I do keep meaning to try swapping other baluns, such as a 4:1 or even a 9:1, to see if there is any difference in the performance, but I have not gotten around to it. I do think some sort of balun is desired for the sky loop antenna, vs feeding it directly with just coax. You may be able to feed it with ladder line, but I have not tried that.

For the coax, I used RG6, which is commonly available and used for TV. I chose RG6 because it is very cheap, and personally I am sick of putting PL-259 connectors on coax. RG6 has F connectors, and I use an F to PL-259 adapter at the balun, as well as to connect to the radio inside the shack. There’s certainly no requirement to use RG6, you can use any good quality coax.

Performance does suffer once I get down to about the middle of the Medium Wave band. While I can pick up stations all the way down to 530 kHz, the signal strengths are much less than the upper end of the medium wave band. If you assume the antenna is a basic loop, the resonant frequency is about 1460 kHz, so this seems reasonable. I get excellent reception in the X band, 1600-1710 kHz. One of my reasons for wanting to increase the length of the loop is to hopefully get better performance lower down in the MW band. Although simple math shows that even if I doubled the length (which I am not sure I could do), the resonant frequency would still only be about 730 kHz.

Another possibility for worse performance on the lower part of the MW band is the choice of balun, as I addressed above. The impedance of a one wavelength loop antenna is about 120 ohms. With a 12:1 balun, that is reduced to about 10 ohms. And at the lower end of the MW band, the impedance is likely much lower.

If you’ve read my This is why you should disconnect your antenna during a storm article, you’ve seen what happens when you have a thunderstorm nearby. Your antenna is often quite good at collecting that energy, and sending it to your radio. There’s lots of good lightning protection devices out there that you may want to look into. Personally I also disconnect my antenna when there’s a storm, or even the possibility of a storm, especially if I am not going to be around. It takes a few seconds, and can protect your radio. It doesn’t take a direct lightning strike to damage a radio.

I hope this article will motivate several listeners who have the room to consider installing a sky loop antenna. You won’t be disappointed.

Baltimore’s BBQ That Isn’t BBQ – The Pit Beef Sandwich

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What some refer to as Baltimore’s version of BBQ isn’t BBQ at all. Of course, what would someone from the New York Times know about BBQ? I’m referring to the pit beef sandwich.

Pit beef is prepared by grilling a beef roast under high heat until it is medium rare, then sliced thin, and eaten as a sandwich with horseradish. Here’s how to make it:

First, the roast. I prefer sirloin tip, although some use top or bottom round. I don’t like the latter due to the thick wedge of fat then runs through it. I’ve heard of people using eye round, but grilled eye round is barely fit for human consumption, so I really can’t suggest that.

Next, the spice rub. I use two portions of salt to equal portions of ground red pepper, onion powder, garlic powder, paprika, oregano, and a little ground red pepper. There’s no exact science here.

Coat the entire roast with the rub.

Then put it in the fridge at least a day before you’re going to cook it.

Next, take the roast out of the fridge, and let it sit on the counter for an hour or so, to warm up a bit, so when you grill it, you’ll maximize the volume that stays at medium rare. Of course, the USDA food safety police say this is a dangerous food safety violation.

Meanwhile, get your grill going nice and hot, and put the roast on.

Grill with the lid off on high heat.

When your instant read thermometer says 123F, you’re done. That’s medium rare. The USDA says 145F is medium rare. They’re idiots.

Next, you want to tent your beef under aluminum foil, to let it rest, so you don’t lose the juices. Don’t skip this step.

While your beef is resting, you want to slice your onions. I use an electric meat slicer, since I’m going to use it to slice the beef anyway.

Slice your onions thin.

Slice your beef thin as well. Sure, you can use a knife if you’re good at it and not lazy. Me, I’m lazy. And I have a deli slicer, so I may as well use it.

Put some horseradish on your bun, the beef, and the onions. If you’ve got mayonnaise, throw it away now, before someone uses it.

Serve with chips. Ideally Grandma Utz chips, cooked in lard.

The radio connection? The Baltimore Hamboree and Computerfest held at the Maryland State Fairgrounds used to serve pit beef sandwiches. Now that there’s no outdoor tailgating, I’m not sure if they do anymore.

Vladimir Putin Destroys Pirate Radio

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For the last few weeks, there’s been a new source of QRM on the most popular shortwave pirate radio frequency in North America, 6925 kHz. Last night, it was particularly bad. Here’s a recording of what it sounds like, when tuned to 6923 khz USB.

Putin on the QRM

The offending signal is a Russian Military 12 Tone PSK AT-3004D modem, often referred to as the “Russian 12 Tone Modem” in utility DXer circles, and also the MS5.

There is a very good writeup about it at this site: http://www.signals.taunus.de/FFT/CIS12CH.HTML

Here is an SDR waterfall image of the modem:

You can see the stronger pilot carrier on the extreme right (highest frequency) as well as the 12 PSK channels.

The signal faded in at around 2300 UTC, was quite strong around 0030 to 0200 UTC, and faded out around 0400 UTC. The local fade in time is due to the Sun starting to set here, and the path being mostly dark, to support propagation on this frequency. The fade out time is due to sunrise at the transmitter site. This suggests a location somewhere in Europe.

If this modem continues to transmit around 6925 kHz, operators may wish to work around it, by avoiding 6925 kHz during the time the 2300-0400 UTC time the signal is present. Unfortunately this is also the most popular time for pirate transmissions. Due to the strong signal strength, and the wideband nature of the signal, it can to obliterate any weaker stations on the frequency.

Daytime Vs Nighttime Static Levels And The Impact On Reception

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Undercover Radio was on 6925 kHz USB several times on Sunday, May 20, 2012, conducting some transmitter tests in the afternoon, and with a show in the evening. I noticed how, even with a relatively weak signal strength in the afternoon, the overall reception was still good, due to the low daytime noise levels on the 43 meter band. Transmitter power was around 20-30 watts PEP.

Here is a graph showing the signal level of Undercover Radio on 6925 kHz, as well as background noise from an otherwise unoccupied adjacent frequency for 4 minutes, starting at 1700 UTC May 20, 2012:

Undercover Radio’s signal strength was about -92 dBm. Bear in mind that this was a voice only program with Dr. Benway talking, with frequent pauses in speech. Since this was an SSB transmission, the received signal level falls to the background noise level during pauses in speech.

The background static at 6930 kHz was -100 dBm

The net result is a signal to noise ratio of 8 dB, which is certainly adequate for fair to good reception.

Some recordings:
Undercover Radio 6925 kHz USB 1700 UTC
Background noise 6930 kHz USB 1700 UTC

Undercover Radio came back on at around 1900 UTC. Here is another comparison of Undercover’s signal vs background noise on 6932 kHz:

(Sorry, this time the noise is pink and the signal is blue. Just to keep you on your toes)

Eyeballing the graphs, it looks like the signal to noise ratio was about 15 dB, better than before. The quality of the received audio was indeed very good. Here is a recording

Next, Undercover Radio came on again at 0212 UTC.

The noise levels were around -85 dBm. Undercover Radio’s signal started at just around the noise level. At the time, he was running 20-30 watts PEP. Later, around 0245, Dr Benway realized he didn’t have the amp on, and then switched it on, going to 500-600 watts PEP.

One reason for the much higher nighttime noise levels is that not only is 43 meters open to DX from distant stations, but also to distant thunderstorms and other noise sources. Think of every thunderstorm in the world as a transmitter (which it really is). There’s thousands of active thunderstorms at any time, transmitting RF energy over the entire radio spectrum. This energy is received at your location from whatever parts of the world propagation is open to, on a given frequency. So while your signal can get out further at nighttime, it also has to compete with a lot more QRM sources.

During the daytime, the D layer of the ionosphere attenuates low angle radiation on 43 meters, preventing DX reception. You’re limited to just a few hundred miles. This applies both to the signals from radio stations that we want to hear, and distant noise sources.

Also notice how much Undercover Radio’s signal varied after the amp was switched on – by around 30 dB. That’s five S units! This tells us that signal reports, or even recordings, can be very hit or miss. One minute, an op can be at the noise level, a few minutes later, he can be many S units above it.

Two recordings. First, one from 0222 UTC when he was running 20-30 watts PEP, and the SNR was just a few dB. And second, one from 0300 UTC during a signal peak, when he was running 500-600 watts PEP, and the SNR was about 25 dB.

For comparison, here are some plots of WWCR, 6875 kHz, showing their signal level last night:

First, from 2230 to 0100 UTC (sorry for the X axis scaling, showing -100 for 2300 UTC. Blame Excel)

You can see that when their carrier went off the air, the noise level was around -80 dBm. And the signal varies by about 30 dB during the transmission, during nighttime. Earlier in the transmission, while it was still daytime, the signal was slightly weaker, but there was a lot less fading.

And second at 0300 UTC:

Perhaps the main point to take away from this is that while a pirate can be heard much further at nighttime than during the daytime on 43 meters, the lower noise levels and lack of significant fading during the daytime generally make for better quality reception, for those listeners within the several hundred mile NVIS range, and allows reception by listeners with more modest receiver/antenna setups. This is especially true when using lower power (grenade type) transmitters. Nighttime DX reception quality will be poorer, and limited to those with more substantial receiving stations. By selecting the time of day for operation, operators can to some degree select their audience and target area. A pair of transmissions, one in the daytime and one at night, would reach both local and DX listeners.

She had your dark suit in greasy wash water all year

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An unidentified station was first noted at around 0330 UTC May 17, 2012, on 6990 kHz, sending three phrases over and over:

“She had your dark suit in greasy wash water all year. Don’t ask me to carry an oily rag like that. They used an aggressive policeman to flag thoughtless motorists”

I made this recording on 6990 kHz USB at 0041 UTC on May 17, 2012:

As of 2315 UTC on May 17, 2012, the station has moved to 6950 kHz USB, with the same repeated phrases.

Andrew Yoder reports hearing this same station on November 5, 2011 on 21450.7 kHz.

Some quick searches of the internet came up with something called the TIMIT Sentence Prompts.

According to Wikipedia:

TIMIT was designed to further acoustic-phonetic knowledge and automatic speech recognition systems. It was commissioned by DARPA and worked on by many sites, including Texas Instruments (TI) and Massachusetts Institute of Technology (MIT), hence the corpus’ name.

TIMIT consists of phrases of 630 speakers of of different sexes and eight major dialects of American English. The database is designed to assist in the development and testing of Automatic Speech Recognition systems.

There is an online listing of the phrases. According to that list, phrases 1, 2, and 437 are being sent.

Presumably someone is testing a system to perform automatic speech recognition on HF transmissions, and is conducting some real world test.

There is a thread of loggings of this station over at the HFUnderground Message Board.

I can only hope they don’t accidentally start transcribing 6925 kHz while Toynbee Radio is on the air. That could cause their computer to blow up, a la Kirk’s ability to make computers self destruct by confounding them with illogic on Star Trek.

Some online references:
The DARPA TIMIT Speech Database for MastersThesis
The DARPA TIMIT Acoustic-Phonetic Continuous Speech Corpus

UPDATE:
Still going at 1128 UTC on 6950 USB.

Construction of a Helical Antenna for SATCOM Listening

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Previously I wrote about the various kinds of transmissions you can heard on the 250 MHz SATCOM satellites. While you can pick these up with a standard scanner antenna, reception is much better with a directional antenna.

This page documents my project to construct a helical antenna for SATCOM listening, 240-270 MHz.

The antenna is based off the design found on this page, which has the specific dimensions and other technical details.

Here are the supplies:
Four 4 ft long strips of steel, four 5 ft long pieces of 1/2″ PVC pipe, one 5 ft long piece of 1 1/4″ PVC pipe for the boom, and window screening for the ground plane.

Here’s a close up of the flange and fitting for the PVC boom:

Here are the four steel strips arranged in the radial pattern:

Next I drilled four additional holes in the flange, so it could be screwed to the eight radials:

#10 hardware was used to attach it:

Here it is with the PVC boom attached, to see the overall size:

And now with the 20 supports for the tubing installed:

The tubing is 1/4 inch diameter:

Here it is with the 5 turns of 1/4″ diameter tubing:

The screening has been added to the reflector. It is sandwiched between the strips for support:

The [mostly] assembled helical antenna. The matching section is made from tin-plate and is cut to be a quarter of a turn, about 60mm wide. It’s soldered or bolted to the ground plane at the connector end, and supported by an adjustment screw at the other end. I’ve honestly not noticed much if any difference in the received signal, by fiddling with it. See http://www.uhf-satcom.com/uhf/uhfantenna.html for more details on the matching section.

Final assembly will be done outside, so everything is not tightly fastened yet:

Here it is outside, mounted on a SG-9120 motor. The motor uses the DiSEqC protocol for control, which is sent over standard coax cable. It is a standard in the satellite TV industry.

The motor is controlled by a Moteck digibox, which sits inside the shack:

Another view:

The angle of the motor is adjusted based on the latitude of the receiving site, so that as the motor turns the satellite tracks across the geostationary orbit.

Signal Levels of Radio True North’s May 14th Transmission on 6950 kHz

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The graph below shows the received signal levels of Radio True North, a pirate radio station from Canada, which transmitted on 6950 kHz on Mary 14, 2012. The signal faded in at around 0200 UTC, and the transmitter was switched off at 0702 UTC – that can plainly be seen on the chart:

You can also see that after the transmitter switched off, the received signal levels were about -85 dBm, that is the background noise level. At peak, the signal was about -75 dBm, just a hair under S9. The signal to noise ratio is the difference between the signal and noise levels, or 10 dB.

Here is a short recording taken at around 0516 UTC, so you can hear what this signal sounds like. Remember, it is around S9, but the signal to noise ratio, which is what really matters, is only 10 dB. We had rain/thunder storms all along the east coast during this time.

Signal to noise ratios were discussed an earlier post, coincidently enough called Signal To Noise Ratios. There’s some simulated SNR recordings there. The 10 dB example sounds very close to the RTN recording above.

RTN was using his “usual power” (we’ll be vague and say a few hundred watts). Had he been using a lower power level, say 10 watts, the signal to noise ratio would have been about 0 dB, if not negative. He’s using a delta loop antenna, and is about 4,000 km (2,500 miles) away from my location.

Here’s a graph of RTN’s carrier frequency, as measured here:

You can observe both the power on drift, and short term cycling (about every 10 minutes) due to most likely to something thermal, perhaps a fan.

UHF Pirates – 250 MHz SATCOM Monitoring

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UHF SATCOM refers to satellite repeaters that operate between 240 MHz and 270 MHz. To receive SATCOM, you need a receiver that can tune the frequency range in narrow FM (most modern scanners can do this). You also need an outside antenna, and possibly a LNA preamp.

The satellites in question are operated by the US military. They are essentially repeaters in geostationary orbit. Because they are open (no access control) they are often used by third parties, most often by people in Brazil. It is very common to hear Portuguese transmissions. One listener, who spent several years living in Brazil, described it as

Portuguese slang spoken by people who never paid attention in school

Back in 2009, 39 Brazilian pirates were busted, but the activity continues.

Here’s a recording of SATCOM pirates, and another recording of SATCOM pirates

255.550 MHz is very heavily used by the Brazilian pirates. As I am typing this, I am also hearing pirates on 253.500, 253.750, and 262.190 MHz.

There is an excellent breakdown of all of the 250 MHz SATCOM Transponders By Satellite

While you can start with a basic outdoor scanner antenna, such as a discone antenna or other scanner antenna, many serious listeners eventually build a directional antenna, such as a helical. I will have construction information about one that I built in a future article.

Next, since the signal levels are often very weak, the use of a LNA preamp is highly recommended. I built one of the Down East Microwave Inc. GaAs pHEMT pre amp kits, and find that it really helps a lot.