When I travel to other countries, I try to take out a few minutes to scan the AM broadcast band. I have observed that over the past few years I am hearing less and less. Sometimes there is nothing to hear but static and local noise. Many counties are completely abandoning AM broadcasting in favor of FM and digital (DAB). The urban environmental interferance levels don’t help things either.
A recent bandscan in Athens provided a nice surprise. The standard AM broadcast band was full of strong signals, most playing music. I settled on a strong station on 828 kHz playing a program of American standards and light fare. There were a few short announcements in Greek but I was listening as I fell asleep, so didn’t catch anything I could remember.
A bit of research the next morning showed that 828 kHz, and most other stations heard on the AM band in Athens, are unlicensed hobby stations. The Greek government does not seem to care much and these stations are providing a service.
If your travels include Athens, don’t forget to bring along an AM radio. You won’t be disappointed.
VAT stands for “Value Added Tax”. It is a bit different from the sales tax that Americans are used to. It is a tax that it is added at every step along the supply chain where value is added. In the United Kingdom the VAT rate stands at 20% for most purchases. This makes prices on your London shopping spree seem higher than in New York.
The good news is, if you are not an EU resident (pre-Brexit), you can get a VAT refund on items to be taken from the country under certain circumstances. The VAT refund process in the UK is different from what I’ve seen in other EU countries.
In the Netherlands, for example, if you spend over a certain threshold at a shop and, if the shop owner is aware of the VAT refund paperwork, you’ll get a form that needs to be shown at a customs window at the airport. Sometimes you’ll also be asked to show the merchandise purchased to prove that it is leaving the EU. The customs officer will stamp the form and you mail it to the vendor for the refund. You can do this once when leaving the EU for all items purchased, even if purchased in other EU countries on the same trip.
One year at the Friedrichshafen Ham Radio show I purchased a nice handheld digital transceiver which cost about double in the USA at the time. In this case, the vendor’s bank charged a hefty wire fee for the transfer to my bank. The fee ate up much of the refund. The wire fee is avoided if the vendor participates in a program called Global Blue. In that case, Global Blue will refund the VAT directly to your credit card. This is the ideal situation and you get the full amount of your tax refunded to your credit card in the currency used for your purchase.
The UK, however, does things a bit differently. They have outsourced the VAT process at Heathrow to the money changing behemoth Travelex. Travelex makes its money by charging fees to move money between currencies. In this case, they are taking a percentage of the VAT and then charging you again for a currency exchange because they want to refund your VAT in US dollars rather than credit the full amount back to your credit card as Global Blue does. At least this is how it went down during our recent trip. Expect to get only about 11% back.
The transaction took place so quickly that I did not have time to think about it until afterward. Next time, I will insist that they refund the VAT in the currency of purchase to the credit card used for the purchase. We’ll see how that goes and if it results in a larger return.
Another unusual aspect of the Travelex VAT process is that it takes place outside of the security screened part of the airport. So, they don’t even really know that the merchandise or you are leaving the country that day. Strange indeed.
We recently returned from a nice visit to London. While temperatures were only in the mid 50s F, we’ll take that any day over the deep freeze that New Jersey has recently experienced.
f
I want to share two things that will make a visit to London more enjoyable. In this first of two posts, we’ll take a look at the Visitor Oyster Card. I don’t know why it is called an Oyster — it is a proximity card — but if you plan to use the various services provided by Transport for London (TfL) to get around, you’ll find it to be most convenient. It can pay your fare from Heathrow, in and around London on the Underground, and on buses and more. It features daily and weekly fare caps, so once you spend a certain amount, you don’t incur further charges during that time period. And, pay as you go fares are cheaper on the card than if you purchase individual tickets.
You can order your Visitor Oyster Card online or you can buy it at the Visit London shop at Heathrow. We put £40 on each card and at the end of a busy trip, we still had £10.10 left. And that proved to be fatal. The automated ticket machines will refund any balance up to £10 to your credit card and you can keep the card for future use. That extra 10 pence caused me to have to get personal assistance with the refund.
There is a £5- deposit (or activation fee) on the card which used to be refundable. It is no longer refundable. When I went to the window to cash out the 2 cards, I was given £20.20. But, to my surprise, the cards were cancelled and not returned. I had expected to either get the £5 deposit or the cards returned. Instead, I lost £10 on the deal. There used to be references on the TfL website which stated that the card can be emptied and retained for future use. I showed a PDF document from their website to the representative which clearly stated that the card would be returned.
Based upon my inquiry, it looks like those references were removed from the TfL website. Apparently, the policy was changed last year. The supervisor at the Heathrow Visit London office near Terminal 3 informed me that the change had something to do with GDPR. I am skeptical that TfL’s retention of the card I used for holiday travel somehow protects my privacy.
Lesson learned #1 — If you have a balance on your Oyster Visitor Card, keep it for a future trip. It never expires.
In Part 2, we’ll discuss VAT refunds and how not all refunds are created equal.
Note: This article was originally published in March 2017. I’ve revisited and updated it in preparation for a talk that I’ll be giving at the 2018 Winter SWL Fest. I’ve simplified the installation process. While doing so, I learned that Google now requires an API key for the application to have access to their maps. My github fork of the dump 1090 code has been updated to account for this development.
A key component of next generation air traffic control is Automatic Dependent Surveillance – Broadcast (ADS-B). The current FAA mandate is for all included aircraft to output ADB-B transmissions no later than January 1, 2020. But you don’t have to wait to receive and map ADS-B. There is a lot of air traffic to be seen.
dump1090 as viewed via a remote web browser.
Some folks are using complete downloadable images that are set up to feed flight tracking services such as FlightAware. If you’re interested in doing this, The SWLing Post featured an article that you’ll enjoy. I wanted to explore whether I could use some items already on hand to see a map of overhead aircraft on any computer on my home network.
I pulled out an older Raspberry Pi Model B and a 4 GB SD-Card and installed a copy of Raspbian Stretch Lite. The Model B has been retroactively called a Raspberry Pi 1 Model B. It is equipped with 512 MB of RAM, two USB ports and a 100mb Ethernet port.
I decided to use a spare older RTL-SDR stick based on the RTL2832U and R820T chips. This USB device comes with a small antenna that I hoped would be good enough to get me started. It is not in any way optimized for the 1090 MHz signals that are used by ADS-B and is roughly 19 parts per million (ppm) off frequency. It cost a bit over $10 at a hamfest a couple of years ago. The designs have improved since the early models were offered. Newer models include a TCXO (thermally compensated crystal oscillator) for stability and accuracy.
I needed software to take signals from the RTL-SDR stick and plot them on a map. That software is “dump1090”, originally written by Salvatore Sanfilippo. I added an install stanza to the Makefile, along with a systemd service file, for a smooth system install. I also needed to install the RTL-SDR USB drivers. The complete installation runs “headless”, meaning no monitor, keyboard or mouse need be connected. Remote management can be done via ssh.
There is a security change that comes along with Stretch. ssh is now disabled by default. After copying the initial Stretch image to the SD card and BEFORE removing it to place the Raspberry Pi, mount the boot partition and create an empty file named “ssh”. If you are not using ethernet, you could also pre-configure wifi settings.
First, bring the Raspbian Stretch installation up to date.
–quiet runs in the background
–net starts a webserver so that you can access via a web browser
–lat set to YOUR decimal latitude (negative for South)
–lon set to YOUR decimal latitude (negative for West)
–ppm if you know the ppm tolerance of your device (otherwise omit)
–gain -10 which sets gain automatically
A full parameter list can be reviewed by typing dump1090 --help.
With an antenna connected you can perform a quick device check by typing dump1090 --interactive. If all is well you’ll see a screen like this:
Hex Mode Sqwk Flight Alt Spd Hdg Lat Long Sig Msgs Ti/
-------------------------------------------------------------------------------
A39D11 S 6 1 4
A25D36 S 1775 7 4 3
AAA593 S 2575 205 075 7 2 7
A25238 S 4 1 12
A0480B S 19650 8 28 3
ACF4DD S 3825 7 2 14
A41F61 S FDX3018 2800 211 025 40.428 -74.332 23 83 0
A6FFFE S 1753 LXJ550 30475 371 226 8 63 0
C060B3 S 4625 6 14 1
ACF69B S 23250 6 25 1
A2D27C S 24000 13 42 2
A0BF90 S 9500 249 257 5 3 9
A7D30A S 40000 8 111 1
AE0192 S SPAR958 32675 22 93 0
ACC040 S 7825 8 146 2
ACA5DF S 26600 6 79 0
A80C7B S 4550 9 108 1
A7CC00 S 7825 35 123 0
ACF841 S 1507 14425 50 132 0
A8C802 S NKS149 23575 332 216 39.995 -74.262 12 160 0
A61949 S UAL1105 2725 14 60 0
AC2E20 S 1006 19925 22 130 0
AB766A S DAL1526 8525 216 038 40.444 -74.213 81 249 0
AA4440 S 5400 253 066 6 6 13
Control-C exits this screen.
Now start the dump1090.service.
sudo systemctl start dump1090.service
If all goes well, a netstat -an will show that there is a binding to port 8080.
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN
Now you can start up a web browser from any computer on your home network and see a map of planes overhead. If your router supports internal dynamic DNS you can name the RPi and access via something like http://skynet:8080. Alternatively, use the IP address, which can be obtained via ifconfig.
In this case, the URL would be http://192.168.1.123:8080.
Once the map appears, re-position it to your part of the world and enjoy learning about what is flying overhead. You can enhance your enjoyment by listening to your closest airport tower or air traffic control frequencies on a scanner. These transmissions use amplitude modulation (AM) and can be monitored an another RTL-SDR stick or a scanner, even a relatively old model.
My Aussie mate, Mark Fahey, has spent a number of years studying the Democratic People’s Republic of Korea. He passes on the following information about North Korean “spy numbers” stations:
“The Pyongyang numbers (designated V15) have either become less regular or changed their schedule since March. Its been a few months since I have personally received them – but I also haven’t been specifically tuning in for them lately so maybe I have simply missed noticing a timing change.
“If you want to find the North Korean numbers, they are read out in a block between songs within the regular programing of the Pyongyang Pangsong radio station. The choice of music immediately before the number block seems to indicate which recipient agent the transmission is directed to. For Agent 27 “We Will Go Together with a Song Of Joy” is played, whereas Agent 21’s song is “Spring of my Hometown.”
“The announcements typically take between 5 to 10 minutes to read dependent on the number of digits passed. The transmission schedule is variable; in early 2017 the broadcast alternated with a cycle of one week on Thursday night at 12:45AM Pyongyang Time (1615 UTC) and the following week on Saturday night at 11:45PM Pyongyang Time (1515 UTC).
“Pyongyang Pangsong can be heard on these shortwave band frequencies (it is also on MF & FM on the Korean peninsular):
If you’re interested in learning about what life is like “Behind the Curtain“, Mark has compiled a detailed multimedia publication based upon his actual observations inside North Korea. It is available at no cost via iTunes.
A key component of next generation air traffic control is Automatic Dependent Surveillance – Broadcast (ADS-B). The current FAA mandate is for all included aircraft to output ADB-B transmissions no later than January 1, 2020. But you don’t have to wait to receive and map ADS-B. There is a lot of air traffic to be seen.
dump1090 as viewed via a remote web browser.
Some folks are using complete downloadable images that are set up to feed flight tracking services such as FlightAware. If you’re interested in doing this, The SWLing Post recently featured an article that you’ll enjoy. I wanted to explore whether I could use some items already on hand to see a map of overhead aircraft on any computer on my home network.
I pulled out an older Raspberry Pi Model B and a 4 GB SD-Card and installed a copy of Raspbian Jessie Lite. The Model B has been retroactively called a Raspberry Pi 1 Model B. It is equipped with 512 MB of RAM, two USB ports and a 100mb Ethernet port.
I decided to use a spare older RTL-SDR stick based on the RTL2832U and R820T chips. This USB device comes with a small antenna that I hoped would be good enough to get me started. It is not in any way optimized for the 1090 MHz signals that are used by ADS-B and is roughly 19 parts per million (ppm) off frequency. It cost a bit over $10 at a hamfest a couple of years ago. The designs have improved since the early models were offered. Newer models include a TCXO (thermally compensated crystal oscillator) for stability and accuracy.
I needed software to take signals from the RTL-SDR stick and plot them on a map. That software is “dump1090”, originally written by Salvatore Sanfilippo. I added an install stanza to the Makefile, along with a systemd service file, for a smooth system install. I also needed to install the RTL-SDR USB drivers. The complete installation runs “headless”, meaning no monitor, keyboard or mouse need be connected. Remote management can be done via ssh.
First, bring the Raspbian Jessie installation up to date.
sudo apt-get update
sudo apt-get upgrade
Add some needed packages.
sudo apt-get install git cmake libusb-1.0-0-dev
Compile and install RTL-SDR drivers.
git clone git://git.osmocom.org/rtl-sdr.git
cd rtl-sdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON
make
sudo make install
cd ~
sudo cp ./rtl-sdr/rtl-sdr.rules /etc/udev/rules.d/
Prevent native DVB-T drivers from loading.
cd /etc/modprobe.d
sudo vi blacklist.conf
Add blacklist dvb_usb_rtl28xxu to the file and save. You may now reboot. After the system comes back online, plug in your RTL-SDR device and the driver should load. You may test by running rtl_test -t. If the device is properly seen by the driver you should see the following:
Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001
Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
[R82XX] PLL not locked!
Sampling at 2048000 S/s.
No E4000 tuner found, aborting.
Don’t be concerned by the “No E4000 tuner found” message. The E4000 is an older chipset that is no longer used by today’s RTL-SDR devices.
Compile and install the dump1090 code.
https://github.com/K2DLS/dump1090.git
cd dump1090
make
sudo make install
sudo systemctl daemon-reload
–quiet runs in the background
–net starts a webserver so that you can access via a web browser
–lat set to YOUR decimal latitude (negative for South)
–lon set to YOUR decimal latitude (negative for West)
–ppm if you know the ppm tolerance of your device (otherwise omit)
–gain -10 which sets gain automatically
A full parameter list can be reviewed by typing dump1090 --help.
With an antenna connected you can perform a quick device check by typing dump1090 --interactive. If all is well you’ll see a screen like this:
Hex Mode Sqwk Flight Alt Spd Hdg Lat Long Sig Msgs Ti/
-------------------------------------------------------------------------------
A39D11 S 6 1 4
A25D36 S 1775 7 4 3
AAA593 S 2575 205 075 7 2 7
A25238 S 4 1 12
A0480B S 19650 8 28 3
ACF4DD S 3825 7 2 14
A41F61 S FDX3018 2800 211 025 40.428 -74.332 23 83 0
A6FFFE S 1753 LXJ550 30475 371 226 8 63 0
C060B3 S 4625 6 14 1
ACF69B S 23250 6 25 1
A2D27C S 24000 13 42 2
A0BF90 S 9500 249 257 5 3 9
A7D30A S 40000 8 111 1
AE0192 S SPAR958 32675 22 93 0
ACC040 S 7825 8 146 2
ACA5DF S 26600 6 79 0
A80C7B S 4550 9 108 1
A7CC00 S 7825 35 123 0
ACF841 S 1507 14425 50 132 0
A8C802 S NKS149 23575 332 216 39.995 -74.262 12 160 0
A61949 S UAL1105 2725 14 60 0
AC2E20 S 1006 19925 22 130 0
AB766A S DAL1526 8525 216 038 40.444 -74.213 81 249 0
AA4440 S 5400 253 066 6 6 13
Control-C exits this screen.
Now start the dump1090.service.
sudo systemctl start dump1090.service
If all goes well, a netstat -an will show that there is a binding to port 8080.
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN
Now you can start up a web browser from any computer on your home network and see a map of planes overhead. If your router supports internal dynamic DNS you can name the RPi and access via something like http://skynet:8080. Alternatively, use the IP address, which can be obtained via ifconfig.
In this case, the URL would be http://192.168.1.123:8080.
Once the map appears, re-position it to your part of the world and enjoy learning about what is flying overhead. You can enhance your enjoyment by listening to your closest airport tower or air traffic control frequencies on a scanner. These transmissions use amplitude modulation (AM) and can be monitored an another RTL-SDR stick or a scanner, even a relatively old model.
Yesterday, a cacophony of irritating noises permeated my brain on board an otherwise pleasant United flight from Orlando to Newark.
Some airlines think they have improved service by providing free entertainment streaming on personal mobile devices. And of course, in-flight wifi is becoming ever more commonplace. Actually, what the airlines have done is saved a bundle of money on maintaining those personal seat back screens. They’ve also created a major new source of in-flight irritation.
The problem is not the airlines per se, but the inconsiderate and ill-mannered behavior of un-civil society members on board.
Let me make things clear. If your child is playing a game on their mobile device, turn off the sound. I don’t want to hear the bloops and beeps.
If you are watching a video, turn off the sound or use headphones. I am not interested in your video, no matter what it is.
If you are texting inflight I don’t want to hear a chime, buzz, or bell each time you receive a message. Turn them off.
If you are listening to music, use headphones and keep the volume at a level so that I don’t have to listen to your music. I don’t want to hear it no matter how good you think it is.
Cabin crews — please add a blurb to your in-flight announcements regarding courteous use of personal entertainment devices. Require use of headphones with any sound generating device. If you hear or see someone violating this request (which ought to be a rule) instruct the violator about expected behavior. Don’t ignore it to the point where I need to call you over to deal with it.
I reserved an automotbile rental for the June stay in Friedrichshafen with Dollar. The rental was actually fulfilled by Hertz. I expected to pay about €92 for a weekend rental, including taxes.
The vehicle dropoff was on a Sunday morning at the sleepy Bodensee Flughafen and was unattended. I dropped off the keys as instructed. The vehicle was left in perfect condition.
When the charge came through about a week later, it was for over US $400. I was mystified and miffed. I had not (yet) been contacted by Hertz about any issues.
I contacted Dollar via their customer service web form, referencing my initial reservation number. No one from Dollar bothered to return my contact request about the billing discrepancy. When I returned home, about a week after the car was dropped off, I contacted Chase to dispute the excess charge.
Hertz in Germany billed me €290 for this!Then, after a few more days, a letter arrived from Germany. The letter claimed €290 in damage to their vehicle. Nonsense. I probably did not drive it more than 15 km during the whole stay and there were no incidents. So, I reported the claim to Chase’s car rental insurance program.
I finally, after some weeks, received a photo of the damage. Just nonsense. As you can see, it is a minor scuff that a US car rental company would never be concerned about.
Be careful. If you rent a car in Germany, do a complete walk around and either take their insurance or have your own. Kudos to Chase and their United Explorer Card for having my back and paying the claim on this one with no trouble at all.
In June I attended the Ham Radio 2016 show in Friedricshafen, Germany. I had the opportunity to purchase a nice, compact digital transceiver. The Hytera PD365 cost surprisingly less than it would in the USA. And, as a bonus, I could get the 19% Value Added Tax (VAT) refunded once I brought it home.
Sort of…
There are shops around the world that are setup to make the tax refund easy and will rebate it directly to your credit card. Not so with Difona Communications GmbH, but they were able to provide a tax refund form at the show. I had to get it stamped by customs upon leaving the European Union and then mail it back to the vendor in Germany. They paid the refund via international wire transfer.
Here is where the fun began. I received about $14 less than expected and set about trying to find out where the difference went. It was not easy. There is no transparency in such transactions. I had to call my bank more than a handful of times before I could get to someone knowledgeable enough to assist.
Early calls revealed that the funds came in as US dollars via the Automated Clearing House (ACH). The ACH received the funds from Fed Global. What is Fed Global? The Federal Reserve Bank. The Fed suffers from a complete lack of transparency and will not speak to the consumer at all. Kudos to those in Congress who want to audit the Fed. I’m with you.
Fees were deducted from the amount that the vendor paid to me. The vendor — Difona — indicated that this is what should be done at the time of the transfer. Difona did not disclose this to me when I sent them an inquiry asking for documentation on the transaction. Had this been disclosed, it would have saved me and others a lot of time spent on calls and emails to research the discrepancy.
Caveat emptor!
Hytera PD365 compact DMR radioStill, I purchased a good piece of merchandise at less than 2/3 of the USA cost. I learned that in the case of a VAT refund, it is better to deal with Global Blue particpating merchants. Otherwise, expect to pay an undocumented and substantial fee for a wire transfer and expect no documentation or transparency.
