A number of SWLing Post readers have asked about the metal case upgrade for the SDRplay RSP1A. It has been out-of-stock for several months. I just learned via Mike Ladd on Facebook, that the case is back in stock and shipping via eBay. He also noted that it will soon be available via Amazon.com. The price is $24.95 shipped via eBay.
My good friend David Cripe (NMOS) has recently informed me about a new product he’s offering to the radio community via his eBay store: Kev-Flex Stealth Kevlar Antenna Wire. Kev-Flex looks like a superb option for field antennas of all stripes especially since it has an incredibly high tensile strength. It’s available in 75′ bundles, but Dave can also cut custom lengths. NM0S is also a trusted retailer in the ham radio world, so you can purchase with confidence.
Here’s the product description and link:
Kev-Flex is a unique antenna wire manufactured exclusively for NM0S Electronics. The lightweight center core of the wire is made from Kevlar fiber, giving the wire its incredible strength. The Kevlar core is wrapped with six tinned strands of 30 AWG copper. The effective surface of the wire creates an effective skin area capable of handling well over 100W.
The cable is protected from the elements by a coating of UV-resistant black polyethylene. With a total diameter of only 1/16″ (incl. insulation) and a weight of just 16 feet per ounce, the tensile strength 125 lbs allows lengthy unsupported horizontal runs. Kev-Flex is ideal for extremely long LW-antennas and Beverages and is great for balloon or kite-supported antennas. Its low weight and high break-load makes it most suitable for SOTA activations and other field operations.
The outer insulation makes the wire kink-resistant, and its slippery finish makes it ideal for stealth antennas that must be passed through trees or other obstacles without snagging.
This antenna wire is sold in 75 foot long bundles, which is enough for a 40M dipole or EFHW. Two 75 foot bundles would make a great 80M dipole. Custom lengths are available on request.
– Kevlar fiber core wrapped with six 30 AWG copper strands
– Weather-proof black polyethylene (PE) insulation, 1/16″ O.D.
– Weight: 16 feet per ounce
– Breaking-load: 125 lbs
– Velocity factor 0.97
Thanks to a hat tip from the Southgate ARC, I discovered that the excellent MagPi magazine has featured a number of ham radio projects in this month.
I’ve outlined below a list of the projects with page numbers–note that many are simply summaries that link to full project notes in previous editions:
- Page 52: Pictures from space via ham radio
- Page 71: ADS-B flight tracker (we also have a short tutorial here)
- Page 72: WSPR transmitter
- Page 73: Remote SDR scanner
- Page 74: Digital voice hotspot
- Page 75: Satellite tracking
- Page 75: APRS IGate
I highly recommend downloading each issue of MagPi–it’s a brilliant, informative magazine and is chock-full of projects and ideas for Pi fans of any age.
I’m a big fan of the Raspberry Pi and use it for a number of applications. This issue has encouraged me to give WSPR a go and perhaps even build a DV hotspot in the near future.
Raspberry Pi kits are quite affordable–Amazon has a massive selection from bare-bones units to full packages which include everything you need to get started. I’m a fan of both Canakits and Vilros.
I also purchase Pi systems, accessories, and hats from AdaFruit.
Post Readers: Are you a fan of the Raspberry Pi or other mini computers? Please comment and share your projects/ideas!
Many thanks to SWLing Post contributor, Don Moore–author of Following Ghosts in Northern Peru–for the following guest post:
A Guide To Vagabond DXing
By Don Moore
Ever since I served as a Peace Corps volunteer in Honduras in the early 1980s, Latin America has been my primary focus for both DXing and traveling. So when I retired in 2017, my main goal was to begin taking long annual trips . . . and I do mean long. From October 2017 to May 2018, I traveled through Peru, Ecuador, and Colombia visiting about fifty different towns and cities. This year, I’m on a five-month trip through southern South America. In Latin America you can get just about anywhere cheaply and easily by bus, so that’s how I get around. It’s also a great way to meet people and to see the countryside. But luggage can become a burden, so I limit myself to a single mid-sized wheeled suitcase and a large knapsack. And that means that my mobile DX shack has to be very carefully planned.
Your plans may not include multi-month odysseys like mine, but I think my experiences will help you prepare to DX on your next trip, wherever it might be. Of course, what makes a good mobile DX shack depends on what your DX interests are. I consider myself a station collector, in that I want to make loggings of lots of new and different stations and to build up an understanding of radio broadcasting in different regions. So on my travels I concentrate on the medium wave broadcast band and longwave beacons, with maybe little bit of shortwave utility DX. (There’s not much on shortwave broadcast that I can’t also hear at home.)
Take the DX Home With You
For years my standard DX travel gear was a Sony ICF-2010, a cassette recorder, and an old Radio West ferrite loop antenna. But listening time was always limited since it was a vacation. There were other activities on the agenda and I was generally too tired to get up early for DXing. I always went home with some interesting loggings and audio recordings, but once I left for home the DXing was done.
SDRs have changed all that and now my first rule of travel DX now is take the DX home. The best souvenir of a trip is the hundreds of hours of DXing that I take home with me. In a 2016 trip to central Colombia, I made about 300 MB of recordings of the medium wave band. While listening to them later I logged over 400 stations from twenty countries (and I still have about half the files to go through). I never would have even gotten close to that many stations listening on my Sony like an ‘old-fashioned’ DXer, hi!
Lately, I’ve been accumulating SDR files much faster than I could possibly go through them, so it’s a fair question to ask what the point is. When will I ever listen to them all? Like most DXers, I’m not fortunate enough to live in a perfect DX location. When conditions are mediocre, I’d rather spend my DXing time going through some more interesting SDR files. And, I know I’ll have lots of good DX waiting for me years from now when I’m no longer able to travel the way that I do now. For me, SDR recordings make much better souvenirs that some cheap tourist trinkets that will gather dust on a shelf. It doesn’t matter whether your travels take you to a nearby park or to a distant continent. SDRs can preserve the DXing experience for years to come.
My Mobile DX Shack
The centerpiece of any DX shack is the receiver. On my 2017-18 trip, I had an Afredri SDR-Net with an SDRPlay RSP1 as a backup, but this year I replaced the Afedri with an Elad FDM-2. Together, my two SDRs are smaller than all but the smallest portable receivers. Of course I also need a laptop, but I’m going to take one anyway. An important consideration in selecting a travel SDR is to get something that is powered off the laptop’s USB connection so that it is easy to DX totally off battery power if line noise becomes an issue.
The other vital component of DXing is the antenna. A good on-the-road antenna for SDR DXing has to be small, easy to erect, broadband, and versatile. That sounds like a lot to ask, but the perfect DX travel antennas do exist.
For compactness and ease of use, nothing can surpass the PA0RDT mini-whip. How good is it? That’s what I used to log over 400 medium wave stations in Colombia in 2016. I just attached the unit to my coax and threw it about three meters up into a short tree. The antenna works best when mounted away from nearby structures, but sometimes I’ve gotten decent results placing the PA0RDT on balconies and windowsills of tall buildings. It’s mostly a matter of luck as to how bad the local noise levels in the building are and how much the building itself may block signals. Using a short support, such as a broom or a hiking pole, it may be possible to mount the unit a meter or so away from the building.
The biggest drawback of the PA0RDT for serious MW and LW DXing is that it is non-directional. For a directional antenna, a Wellbrook loop is great if you’re traveling by car, but that one-meter diameter aluminum loop doesn’t fit in my suitcase. Fortunately, a few years ago Guy Atkins and Brett Saylor told me about an alternative: buy a Wellbrook ALA-100LN unit and attach it to a large homemade wire loop. Now my travel kit includes two nine-meter lengths and one eighteen-meter length of #18 stranded copper wire. The wires can be spliced together for loops of 9, 18, 27, or 36 meters circumference, according to what fits in a location. Erection of a wire loop is easy enough with a suitable tree branch. I just throw the wire over the branch and then form it into delta (with the bottom running just above the ground) using two tent stakes and some short cord to hold the corners. The ALA-100LN unit goes in the bottom center.
The loop doesn’t have to be in a delta; that’s just often the easiest to erect. I’ve successfully used squares, rectangles, trapezoids, oblong diamonds, and right angle triangles. Any balanced shape with the ALA-100LN in the bottom center should be bi-directional in a figure-eight pattern. Non-balanced shapes will work equally well but with unpredictable directionality. Just keep the wire in a single plane and place the ALA-100LN unit someplace along the bottom.
Both the PA0RDT and the Wellbrook require a 12V power supply. The North American version of the Wellbrook comes with an excellent noise-free 110V power supply, but that’s of no use in 220V countries and also I want to be able to DX totally off battery power when necessary. Fortunately both antennas use the same size power connector, so I carry three eight-cell AA battery packs for remote power.
My mobile DX shack is rounded out with everything that is needed to connect the parts together. I have at least four of every adapter and patchcord, since I know they won’t be easy to replace on the road. For lead-ins, I have 12-foot and 50-foot lengths of lightweight coax with BNC connectors. I also have a few F-to-BNC adapters so I could buy some standard TV coax if needed. A 4 TB hard drive provides plenty of space the SDR recordings I plan to make. (Before leaving, I fill it with videos that I can delete after I watch them or when I need space.) For DX references, I download various station lists online so that I have them available even if I don’t have an Internet connection. It’s also important to keep those lists with the SDR files from the trip so that if I’m listening to the files years from now I’ll have references which were current at the time.
A common concern for traveling DXers is getting through airport security. When I went to Colombia in 2016, I wrapped my DX gear in clothing for protection and then stuffed everything into my backpack. Security didn’t like what they saw and I had to empty the bag so that every single item could be examined and swabbed for explosive residue. The TSA lady was very nice about it, but I wanted to minimize the chance of that happening again.
At an office supply store I found a plastic storage box that fits inside the main pocket of my backpack. My SDRs, antenna components, and hard drive get wrapped in bubble wrap and all placed together in the box along with small cables, adapters, etc. Larger items – the wire, coax, and stakes for the loop – get packed in my checked bag.
At the airport, I slide the box out of my backpack, place it into a cloth shopping bag, and then send it through the X-Ray machine on its own so that the agent can get a close look at the contents. So far in about a dozen security checks in the USA, Peru, and Mexico, the box of gear hasn’t caused so much as a pause on the conveyor belt. And, if the box would get pulled for a closer look, at least I won’t have to empty the entire backpack again.
Where to DX
A mobile DX shack isn’t worth anything without a suitable place to DX from. Hotels may work if you have a balcony where you can put a small antenna, but more likely than not there’ll be problems with RF noise. The best hotels are ones that are a collection of cottages or bungalows or that otherwise have an open yard-like space for an antenna. My favorite place to find possible DXing sites is on AirBnB. It’s often easy to find AirBnBs that are on the edge of town or even in the countryside with lots of space. Of course, since I don’t have a car, I need to make sure I can get there using public transportation.
The key to selecting a DX location is to examine all the photos very carefully. Is there open space for the antennas? Are there trees or other potential supports? Is there a gazebo, terrace, or other space that could be used for DXing? Google satellite view and Google street view can be very helpful in scouting out a location (And it’s surprising how much of South America is now on Google Street View.) And, I always look for possible noise sources. One place I almost rented in Colombia turned out to have high voltage power lines running next door when I found it on Street View.
I always tell the hotel staff or AirBnB host what I’m doing so that they understand why the gringo has wires running around. And I make sure not to put my antennas or coax anywhere that might interfere with the employees or other guests. Most of the time I’m able to erect the antenna near my room and run the lead-in into my room through a window. Then I can leave my laptop running all night to make scheduled SDR recordings. That’s the Holy Grail of DXing – catching the overnight DX while you sleep. But if my room turns out to have too much RF noise (as has been the case a few times), then I head out to the gazebo or terrace to DX using battery power. That does mean I have to stay up late or get up early since I can’t leave the laptop outside on its own. But, some of the best DX that I’ve had has come from running off full battery power in gazebos.
Antenna security is another consideration. At one place I stayed I wasn’t comfortable leaving my expensive antenna components unattended outside all night. And then there was what happened on my first trip to Colombia in 2010. I knew that a place I would be staying at for two nights had an open field right behind it, so on that trip I took 500 feet of thin insulated wire for a mini beverage-on-the-ground. DXing was great the first night but terrible the second. When I went out the next morning to wind up the wire I learned why. The worker who had been weed-wacking the hotel gardens the previous day had also done the field, and in doing so he had cut my wire in three places. He had, however, very nicely tied the wires back together.
Share the DX
Finally, if you take an SDR on a trip and get some good DX, make a selection of your files available for download. Other DXers will enjoy hearing what the band sounds like somewhere else. Several dozen of my files from Peru, Ecuador, and Colombia are available for download in a shared Google Drive folder. If you see something you want, be sure to download it now. The winter DX season is just starting here in deep South America and in the coming weeks I’ll be replacing some of those older files with ones made in Argentina and maybe in Uruguay and southern Brazil. I’ve found a lot of places to stay that look to be perfect for a vagabond DXer.
- My Shared Google Drive Folder where you can find some samples of my on-the-road SDR recordings
- The Wellbrook ALA 100LN unit
- The PA0RDT miniwhip – see the email address at the bottom of the article for ordering information. I highly recommend getting the original PA0RDT. There are several cheaper versions for sale, but DXers have reported quaility control problems with those.
- The storage box that I found at an office supply store.
- My 2016 Colombia DX Log
- My Homepage
For fun, here are some of the better places I DXed from in Peru, Ecuador, and Colombia. The key thing to look for is an open place for the antennas:
- Mauro Hilton in Manizales, Colombia (No connection to that other Hilton)
- AirBnB in Loja, Ecuador
- AirBnb in Huanchaco, Peru
- Mitu Wasi Hospedaje in Tarapoto, Peru
- Posada de Sauce in Sauce, Peru
- Bungalows El Rancho, San Ramon, Peru
- The Rosa Ermila Hotel in Cascas, Peru. The DXing wasn’t very good, but I had the rooftop terrace all to myself.
Don, thank you so much for sharing your travel DXing expertise. This article is absolutely brilliant and so informative for anyone who wishes to make SDR field recordings. I love how carefully you’ve curated and distilled your portable setup and have given priority to having antennas for all occasions. I also think carrying spare parts and, especially, a spare SDR makes a lot of sense.
Post Readers: As we mentioned in a previous post, Don is an author and has recently published “Following Ghosts in Northern Peru: In the Footsteps of 19th Century Travelers on the old Moyobamba Route” which is available in Kindle and print formats via Amazon.
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Many thanks to SWLing Post contributor, Rawad Hamwi, who shares the following guest post:
My Story With Radios
by Rawad Hamwi
My passion for the world of radios started 15 years ago when I “accidentally” got my hand on a vintage Sanyo U4SS radio/cassette player.
At that time, FM didn’t mean that much to me, and to make the long story short, it was anything but interesting! So let’s move on and discover that SW band.
I was totally shocked with the findings! Music of different genres, languages I heard for the first time ever, bizarre sounds, Morse broadcasts, etc.. However, the most chilling and exotic thing which caught my attention was that weird “presumably” number station, broadcasting an endless and never-ending loop of “Alpha, Bravo, Charlie”! I could never ever forget that! That SW “thing” was quite interesting, isn’t it?
Back in 2004, the shortwave band was HEAVILY crowded with so many stations from all over the globe, and the idea of being able to listen to all of that stuff without moving away from your couch was something interesting!
Over that period, I owned some portable shortwave receivers/antennas, starting with the Grundig G3, Tecsun PL-660, and last but not least, the trust-worthy Sony ICF-SW7600GR with Sony AN-LP1 active antenna and the Terk Advantage AM antenna, that’s just to name but a few.
And now, drum roll, please!! May I proudly present the legendary Zenith Solid State Trans-Oceanic Radio Receiver. That armored tank is far from anything portable in today’s terms! But still, its reputation can’t be questioned.
Last Christmas (Dec – 2018), my uncle gave me his Sony ICF-7600D which was in a perfect cosmetic/working condition. It was sitting in his drawer for almost 20 years without being used! Operating that “piece of history” is satisfying!
A year before, my grandparents gave me their “Made in Japan” Sony ICF-SW11. You may notice that screen protector over its display, it did a good job in disguising some fine scratches. This radio had been used occasionally, though it’s a solid performer.
Whoa, lots of radios to choose from! A decision was made by giving the Grundig G3, Tecsun PL-660, and the Sony ICF-7600GR/AN-LP1+Terk Advantage a short break and keeping them in my hometown (Lebanon). Both the 7600D and SW11 will join me in Saudi Arabia for at least 6 months until I return back.
Here comes the turning point! Last month, there was a great deal on eBay. A decent Sony ICF-2010 with an above-average condition. I didn’t think twice before buying it, I wanted that radio a long time back and at last, at last, it’s here..sitting on my desk!
To add some nostalgia to the scene, a brand-new vintage “Made in Japan” Seiko World Time Rate Exchanger was listed on eBay, and you can predict what happened next! It was a beautiful add-on.
It joined my vintage Casio DQ-580 alarm clock that was set to display UTC time
Unfortunately, Sony ICF-2010s had some issues with their front-end FET if they were hit by a strong static charge. The solution was by building a DIY protection circuit, based on a schematic available online.
The random wire antenna I use is connected to a 9:1 impedance transformer for the purpose of impedance matching, and to add more protection, a lightning arrester joined the setup. Furthermore, some folks said that winding the 50-ohm coaxial feed cable to a toroid could improve the reception, so..why don’t I give it a try?!
Finally, the BNC male plug coming out of my protection black box is coupled with a female BNC to male 3.5 mm mono adapter which goes towards radio’s external AM antenna socket.
Now, why don’t I utilize the FM band too? I have two in-car FM transmitters. The first one is connected to a satellite receiver to transmits its audio feed via a RCA to 3.5 mm stereo cable, and the second one is attached to a Chromecast Audio device.
-1-Turn on the transmitter
-2- Go to TuneIn
-3- Look after “Conyers Old Time Radio”
-4- Pipe that audio stream throughout Chromecast
-5- Set your radio’s sleep timer to 30 minutes and…I wish you a very good night!!
Google’s Play Store contains much more radio-related apps than Apple’s App Store. Below are my main drivers for decoding digital transmissions.
When it comes to rechargeables, my choice for AA size is Eneloop and Energizer for D size
The Internet contains enormous easy-accessible resources but having a hard copy isn’t a bad idea I guess!
That’s all folks, thanks for reading and if you think there are some rooms for improvements, sharing your ideas will be much appreciated.
Thank you for sharing this, Rawad! You’ve amassed a fantastic collection of portable radio gear and all of it seems to be in excellent shape! I think it’s brilliant that you took the time to build antenna protection for your Sony portables–so many people don’t think of this and end up using an antenna that’s too long and static zaps their FET.
Again, many thanks for sharing your story with us.
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