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Yesterday, my calendar was pretty full. Not an uncommon thing these days. I needed a break from all of the running around town, so I set aside the better part of an hour to play radio.
I packed up my Panasonic RF-B65 and the latest copy of the WRTH. (I didn’t plan to actually reference the WRTH’s schedules for this outing, but I do enjoy reading through the station listings while I tune around.)
I found a local park en route to my next appointment and set up my kit on a picnic table only moments after light rain had moved through the area.
I didn’t know what propagation would be like, and frankly I didn’t care. Sometimes, it’s just nice to tune through the bands and see what’s there.
I call this a “radio therapy” session because, for a small portion of the day, the ritual takes my mind off of everything else around me. I get some of the same benefit from mountain biking and reading a good book (although, not at the same time).
Everything was going according to plan: the weather was pleasant, I had the whole park to myself, and Hazel (my canine companion) noted each and every squirrel within a 50 meter radius of our picnic table.
My bliss was cut short by two things.
First of all, the batteries in my Panasonic were running low. I had forgotten to charge them. (Doh!) Oh well. That didn’t really matter because secondly, a landscaping company brought their crew by to mow the grass…starting at my side of the park!
That’s okay–I still managed to get a good twenty minutes of radio therapy and Hazel counted at least 47 squirrels to harass on a future visit.
Hazel thinking, “Seriously? Another pack?”
I’ve also been evaluating a soon-to-be-released pack manufactured in Montana by Red Oxx. Turns out, it’s the perfect size to protect my RF-B65 and still have room for a copy of the WRTH, a wire antenna and–had I thought about it in advance–four spare AA batteries. Since I’m also a certified pack geek, expect to see a review of this mystery bag soon!
Anyone else planning a little radio therapy soon? Please comment!
Thanks for sharing this, Balázs. The video actually makes a good point: it takes so little to make an effective FM antenna to receive local stations. I’ve been with repair technicians when working on radios They’ll often use their precision screwdriver as an antenna to test the receiver before reassembly.
I also carry a couple cheap instrumentation patch cord with alligator clips on both ends to act as a short antenna or antenna extension when needed. Honestly, It’s amazing how often I reach for them!
If you’re in the market for a used K3S you might want to pay extra diligence to what you’re actually buying.
An eBay seller “xtreme830” is selling Esthetic upgrade kits that can be added to a K3 to make it look like a K3S. As always, buyer beware.
K3S serial numbers begin with #10,000.
Thank you for the warning, John! That’s a little crazy, in fact. I would be most concerned about people buying esthetically altered K3 transceivers at hamfests where one often forgets to check serial numbers. Buyer beware!
Many thanks to SWLing Post contributor, G. Koopal, who shares the following analog and DRM broadcast schedule for “Direkt aus Tamsui“ (“Direct from Tamsui”).
Aktion “Direkt aus Tamsui“ 2019
Testsendungen am16. August (Freitag)
ANALOG
Frequenz 11990 kHz (325): 17:00-17:05 UTC
Frequenz 9540 kHz(315): 18:00-18:05 UTC
DRM
Frequenz 11990 kHz: 17:15-17:20 UTC
Frequenz 9540 kHz: 18:15-18:20 UTC
Offizielle Sendetermine:
11990 kHz 1700-1800 UTC 9540 kHz 1800-1900 UTC
30. August (Freitag) / analog
31. August (Samstag) / analog
01. September (Sonntag) / DRM
06. September (Freitag) / analog
07. September (Samstag) / analog
08. September (Sonntag) / analog
13. September (Freitag) / analog (Mondfest)
14. September (Samstag) / analog
15. September (Sonntag) / DRM
20. September (Freitag) / analog
21. September (Samstag) / analog
22. September (Sonntag) / analog
I had a number of important plans and goals yesterday which I conveniently set aside to build kits instead. Have you ever had one of those days?
Building kits is a little like therapy for me. I find it relaxing, fun, and it gives me an opportunity to tune out everything else in the world while that soldering iron is hot.
I’ve been on a search for two types of fused Anderson Powerpole distribution panels: a portable one for the field with at least 4 ports, and a large one for the shack with 12-16 ports and at least two USB 5VDC ports.
Sadly, there is no large one on the market that I would like right now. I checked every vendor at Hamvention and the Huntsville Hamfest this year and while there are large panels available, none of them have USB ports. That and the price for a 12-16 position DC distribution panel can easily exceed $120.
As for the small panels for field use, many of them are a bit too bulky and pricey. The inexpensive ones lack individually fused ports.
My buddy Dave (K4SV) knew I was on the hunt, so at Hamvention he directed me to the Ham Radio Workbench podcast table. There, I found the ideal portable solution in kit form. And the price? A whopping $25.
Take my money!
Yesterday, I built the kit in near record time. It went together so fast, I forgot to take progress photos.
What I love about this DC distribution kit is it actually has more features than other products on the market:
There’s a green LED to indicate power has been applied to the panel and a red LED to indicate any faults
Each position is individually fused with standard blade fuses
Each position also has a red LED to indicate if the fuse has blown
I also love the size and configuration.
The kit does not come with an enclosure or base of any sort, so I had planned to simply attach it to a dielectric plate to prevent the bottom of the board from shorting on a conductive surface.
This enclosure protects the entire panel on all sides so I’ll be able to throw it in my backpack and not worry about the connectors snagging on other items. The price is a reasonable $12 shipped. Done!
This little DC panel pairs well with the 4.5 aH Bioenno Lithium Iron Phosphate battery I purchased on sale at the Huntsville Hamfest. Together, they’ll power the portable SDR system I’m putting together. More on that in a future post! Stay tuned!
UPDATE: I understand Ham Radio Workbench may eventually print the circuit boards for this project. In the meantime, another affordable option I’ve used is this pre-built panel from Electro Sales on eBay: https://ebay.us/UyJPkh
Alexanderson Alternator station SAQ says it received 438 listener reports — ‘an incredible amount’ — for its June 30 Alexanderson Day transmissions from Sweden including 8 ‘super’ DX reports, five from the USA and three from Canada.
The historic electro-mechanical transmitter, which dates back to the 1920s, is fired up periodically throughout the year on 17.2 kHz.
“We are very thankful for all your enthusiastic and positive feedback, with images, recordings, videos, and even Morse ink writer strips,” SAQ said.
The station is a World Heritage Site in Grimeton, Sweden and SAQ’s June 30 message commemorated the 100th anniversary of the first east-to-west transatlantic voice transmission from the Marconi station in Ireland to Cape Breton Island, Nova Scotia.
SAQ has posted an interactive map showing the locations of all received listener reports from recent transmissions and video of the Alexanderson Day transmission event has been posted to its YouTube channel.
Many thanks to SWLing Post contributor, Mike Ladd (KD2KOG), who shares the following guest post. Note that the following tutorial is also available as a PDF (click here to download).
Basics to decoding Inmarsat L-Band signals using the RSP SDR
by Mike Ladd
Note: CHECK WITH YOUR LOCAL LAWS BEFORE DECODIING ANY SIGNALS FROM THE INMARSAT SYSTEM
(some text taken and edited from the RTL-SDR Blog website)
This document is not a definitive guide to Satcom, L-Band transmission or the Inmarsat system. This is a collection of information that I have found scatter throughout the internet and re-compiled into a document, this document. My aim is to help you get started and hopefully guide you in the right direction. Expect typographical mistakes, inaccuracies, or omissions
Inmarsat is a communications service provider with several geostationary satellites in orbit. Inmarsat provides services such as satellite phone communications, broadband internet, and short text and data messaging services. Geostationary means that the Inmarsat satellites are in a fixed position in the sky and do not move.
The Inmarsat 3-F(x) satellites have transponders transmitting data in L-Band (1.5 GHz) that can be decoded.
The modes we will cover in this document are Aeronautical (Classic Aero or ACARS) and Inmarsat-C (STD-C) using an RSP1a, RSP2/2pro or RSPduo connected to the SDR-Kits modified L-Band patch antenna. The Inmarsat system is not limited to only these types of networks. We are limited to the decoders available. https://en.wikipedia.org/wiki/Inmarsat
Two of the most popular decoding applications are JAERO used for ACARS and Tekmanoid STD-C Decoder used for decoding STD-C NCS transmissions on the Inmarsat 3-F(x) satellites
Virtual Audio Cable: A virtual audio cable allows you to pipe audio from application (SDRuno) into another application (a decoder like JAERO) digitally. I will assume SDRuno is already installed with your device attached and functioning properly.
You can now download a virtual audio cable package.If you already have a virtual audio cable package installed, you can skip to the next section. If you don’t have a virtual audio cable application installed, you only need to choose one and only install one of the two, either one works fine
Close any running apps, install the virtual audio cable and reboot your computer. When your computer boots back to your desktop, your computer will now have a virtual audio cable pair installed on the system.
You can verify by going to your Control Panel and double clicking the Sound icon. VB-Cable and Virtual Audio Cable will only install a single virtual audio cable pair, one is for the input (Recording) and one is for the output (Playback). A single pair is all that is needed (as shown below).
JAERO
(some text taken and edited from the JAERO website)
JAERO is a program that decodes ACARS (Aircraft Communications Addressing and Reporting System) messages sent by satellites (in this case Inmarsat) to Airplanes (SatCom ACARS). This is commonly used when airplanes are well beyond VHF range.
JAERO also allows for decoding and demodulation of voice calls, due to local laws and privacy, I will not show or discuss how to do this. You can find more information about that JAERO feature online.
JAERO can be downloaded from the link provided on the first page of this document. After downloading the installer, simply double click the setup file and install it on your primary drive.
Tekmanoid STD-C Decoder
(some text taken and edited from the USA-Satcoms website)
Inmarsat STD-C is a data or message-based system used mostly by maritime operators. An Inmarsat C terminal transmits and receives on L-Band to various geosynchronous satellites that service each major ocean region.
The Tekmanoid STD-C decoder will decode STD-C Inmarsat EGC (enhanced group call) and LES (land earth station) messages. Some of these messages contain private information. Reception of these messages may not be legal in your country; therefore, your local laws should be checked.
The Enhanced Group Call (EGC) service is a message broadcast service with global coverage (except the poles) within the Inmarsat-C communications system. Two of the services provided are:
FleetNET and SafetyNET
FleetNET is used to send commercial messages to individuals or groups of subscribers (for example, individual companies communicating with their own Mobile Earth Stations (MES). SafetyNET is used for broadcasting Maritime Safety Information (MSI) such as Navigational warnings, meteorological warnings, meteorological forecasts and other safety related information (including Distress Alert Relays) from official sources.
The LES station acts as an interface (or gateway) between the Inmarsat space segment and the national/international telecommunications networks.
The Tekmanoid STD-C decoder requires Java JRE in order to run. The link for the Java runtime environment is on page 2 of this document. For information contact the developer direct [email protected]
There are alternatives to using the Tekmanoid STD-C decoder, but in my opinion the other decoders available do not perform as well on low end systems or even work without needing “helper” applications to be installed. Tekmanoid STD-C decoder is very easy to use and works great on my low-end system using minimal system resources.
Putting all the pieces together
ACARS and STD-C messages will transmit via the Inmarsat satellite deployed within your coverage area/region, you will need to choose the Inmarsat satellite that is closest to your coverage area.
Note that only different frequencies are used between ACARS transmissions and STD-C transmissions. You will only need to receive from one of the available 3-F(x) Inmarsat satellites.
L-Band ACARS transmissions are in the 1.545 GHz range but STD-C messages are on fixed frequencies (shown on page 8)
Since STD-C transmissions are broadcasted on fixed frequencies, we want to monitor the TDM NCSC channel, again these are fixed for the following Ocean Regions. Choose the region closest to your location (page 9).
Inmarsat satellite: Inmarsat-4 F1 (IOR) Direction: 25° East Frequency: 1.537.10 GHz
Inmarsat satellite: Inmarsat-4 F1 (POR) Direction: 143.5° East Frequency: 1.541.45 GHz
I will assume you have located the Inmarsat satellite that covers your region. I suggest using a compass on your mobile phone to pinpoint the general direction. The direction is in ° (degrees). I am referencing true north, not magnetitic north (traditional analog compass). https://en.wikipedia.org/wiki/Magnetic_declination
You can also download an app for your smartphone called Satellite AR (Android and IOS). After you locate the correct direction of the Inmarsat satellite, you will want to place the L-Band patch on a flat metal surface. I have read that the receive pattern of this patch antenna is z (about 85-90°, straight up). Point the top of the antenna facing the Inmarsat satellite. Using the roof of my car worked just fine, just remember to point the front of the antenna at the satellite.
Launch SDRuno and click the PLAY button, remember that if the RSP(x) is in ZERO IF mode, give frequency separation between the VFO (top frequency) and LO (bottom frequency). In LOW IF mode this is not needed. I suggest running a sample rate of 2 MHz, larger bandwidths are not needed.
The SDR-Kits patch antenna requires that the RSP(x) Bias-T be enabled. The Bias-T option is enabled within the MAIN panel of SDRuno. See the SDRuno manual located here. https://www.sdrplay.com/docs/SDRplay_SDRuno_User_Manual.pdf view page 17.
Select the Virtual audio cable as the output in SDRuno, this is selected via the RX Control panel. SETT. button and clicking on the OUT tab.
Have SDRuno’s Volume slider (RX Control) at about 35-40%
Upper sideband is recommended but I found the best mode to use for L-Band ACARS or L-Band STD-C decoding is DIGITAL with a filter width of 3k.
Be sure to set a proper step size (right click the RX Control frequency readout). The step size is not important for STD-C transmissions because these signals are only on one frequency for the satellite in your region but L-Band ACARS signals will be on many frequencies. Setting the proper step size will avoid issues when you point and click on signals you want to decode using the JAERO decoder.
You will want to center the signal with a little breathing room within the AUX SP filter passband. The filter slopes are very sharp. Keep the signal centered and away from the extreme edges (red markers).
Select your virtual audio cable within the decoder’s audio input preferences.
The Tekmanoid STD-C decoder sound properties are located under Settings in the toolbar menu.
JAERO’s sound settings is located under the Tools menu and Settings.
For STD-C decoding use the frequency from page 8 of this document, remember we only want to monitor the TDM NCSC channel in the Tekmanoid STD-C decoder.
For JAERO decoding, I suggest you start in the 1.545 GHz portion and observe the constellation in the JAERO decoder.
The signal to noise ratio (SNR) needed for successful decoding in these decoders will need to be greater than 7dB. When working with a weak satellite signasls, try decimating the signal using SDRuno’s decimation feature. (MAIN panel, DEC).
I hope this document helps you get started decoding Inmarsat L-Band transmissions from the I3-F(x) satellites. I am sure I missed some key features, remember this is only a primer/basics to decoding these types of transmissions.
Warmest of 73,
Mike-KD2KOG
Many thanks for sharing your tutorial here on the SWLing Post, Mike! This looks like a fascinating activity that really requires little investment if one already owns an RSP or similar SDR. I’m certainly going to give L-Band a go! Thank you again!
