Category Archives: How To

Black Cat Systems’ 22 Meter Band Part 15 CW Beacon Kit

Many thanks to SWLing Post contributor, Robert Gulley (AK3Q), who notes that Black Cat Systems has developed a simple 22 meter beacon kit. The price is $20 shipped! A few details:

The kit includes the PCB and components, including a custom programmed microcontroller that will continuously transmit the ID / callsign of your choice, up to 8 characters, at about 13 wpm.

Small size – just 2 7/8 by 1 1/2 inches. Easy to build, just a few components, all through hole, no surface mount.

When ordering you note your callsign/ID to send and it will be pre-programmed.

Black Cat Systems has all kit details including full instructions on their website.

If you like the idea of building a beacon, you must also check out the beacon Dave (AA7EE) built recently–a true work of art!

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Everyday Carry: My EDC packs and radio kit

SWLing Post contributor, Matt, writes:

Thomas: I know you’re a self-proclaimed pack geek and so am I! You published a photo of your EDC pouch in a post last year. Just a teaser really! What is that pouch and I assume you have a larger carry bag as well? Can you provide more details? I’m ever revising and honing my own EDC pack. Any details would be appreciated.

Thanks for your question Matt!  Besides radio, you’re bringing up on one of my favorite topics: packs! You may regret having asked me!

Yesterday evening, I snapped a few photos of my EDC (Everyday Carry) bag and the pouch you’re referring to. Your inquiry is prompting me to consider publishing a more detailed look at my EDC gear–especially since radio is such an important part of it.

I do carry a larger EDC bag at all times. Typically, this is the Tom Bihn Pilot:

For years, I carried a Timbuk2 messenger bag, but it didn’t have the type of organization I prefer in an EDC bag. My EDC bag must be rugged, water resistant and accommodate my 13″ MacBook Air while still having enough depth to comfortably fit the rest of my gear.

I’ve been using the Tom Bihn Pilot for almost a year and have been very pleased. The Pilot is an investment to be sure, but (like Red Oxx) Tom Bihn construction quality is superb and comes with a lifetime warranty.

It’s amazing how much gear will comfortably fit inside without making the bag bulge. The Pilot also has a dedicated water bottle pocket in the middle of the front panel. While I do carry water, it primarily houses my never-leave-home-without-it Zojirushi Stainless Steel Mug (affiliate link) which is filled with piping hot dark roasted coffee!

I also use the water bottle pocket to hold full-sized handled VHF/UHF radios. It accommodates either my Kenwood TH-F6, Yaesu FT2D, or Anytone AT-D868UV perfectly. Indeed, all of the front pockets will accommodate an HT since the zippers terminate at the top of the bag. Long antennas can easily poke out while the zipper still seals 99% of the opening.

The Pilot has one main compartment that houses my 13″ MacBook Air laptop.

The Pilot laptop compartment is spacious and has two built-in pockets opposite the laptop sleeve: one of these pockets (the one on the right in the photo above) holds my EDC pouch, the other holds first aid supplies, an Olight SR1 flashlight and Nitecore LA10 latern (affiliate link). My laptop is in a TSA-friendly Tom Bihn Cache.

While the Tom Bihn Pilot is the bag I use most days, also use a Red Oxx Micro Manager and–when I need 25 liters of capacity–the Tom Bihn Synapse 25.

I pack most of my EDC gear in pouches, so moving from one bag to another takes me all of one minute.

My EDC pouch is the Maxpedition Fatty Pocket Organizer (affiliate link). I love this pouch because it’s incredibly durable, affordable and opens like a clam shell to lay flat.

Everything has its place. Not only does it hold my Yaesu VX-3R handheld, but also a multi-function knife, a Leatherman Style PS tool, clippers, earphones, multi-bit screwdriver, USB stick, notepad, spare VX-3R battery, a mini first aid kit, titanium spork, and much more! Someday I’ll pull the whole thing apart and note each item.

Why do I choose the Yaesu VX-3R? First of all, it’s compact. This HT is so small it’ll tuck away anywhere. Not only is it dual band, but it’ll also receive the AM broadcast band (even has a little ferrite bar inside), the shortwave bands, and the FM broadcast band.

The mini rubber duck antenna will work in a pinch, but I also carry a flexible Diamond SRH77CA in the floor of the Tom Bihn Pilot’s main compartment.

When I attach the Diamond antenna, it significantly increases the VX-3R’s capabilities.

While the VX-3R does cover the HF bands, don’t expect amazing performance. Selectivity is poor, but sensitivity is adequate. For a shortwave antenna, I carry a short length of coax: one end is terminated with an SMA connector, the other has the center conductor exposed.

I also carry a short alligator clip cable which I clip to the exposed center conductor and then to a length of wire. The end result is a very cheap, flexible and effective portable HF antenna!

Someday, I’ll take everything out of my EDC pack, inventory the contents and publish a post about it. Somehow, that’ll please my inner pack geek! I’m overdue a review of the Tom Bihn PIlot and Synapse 25.

Post readers: Do you have an EDC pack built around a radio? Please comment and include links to your favorite gear!

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Hand Made Vacuum Tubes by Claude Paillard

This is an amazing video – hand-made vacuum tubes! About 17 minutes long – well worth the watching if you have any interest at all in old equipment!

https://vimeo.com/47812871

You can find the video here

Enjoy!

Robert Gulley, AK3Q, is the author of this post and a regular contributor to the SWLing Post. Robert also blogs at All Things Radio.

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Turning the Raspberry Pi 3 B+ into a stand-alone SDR

(Source: RTL-SDR.com)

Nexmon SDR: Using the WiFi chip on a Raspberry Pi 3B+ as a TX capable SDR

Back in March of this year we posted about Nexmon SDR which is code that you can use to turn a Broadcom BCM4339 802.11ac WiFi chip into a TX capable SDR that is capable of transmitting any arbitrary signal from IQ data within the 2.4 GHz and 5 GHz WiFi bands. In commercial devices the BCM4339 was most commonly found in the Nexus 5 smartphone.

Recently Nexmon have tweeted that their code now supports the BCM43455c0 which is the WiFi chip used in the recently released Raspberry Pi 3B+. They write that the previous Raspberry Pi 3B (non-plus) cannot be used with Nexmon as it only has 802.11n, but since the 3B+ has 802.11ac Nexmon is compatible.

Combined with RPiTX which is a Raspberry Pi tool for transmitting arbitrary RF signals using a GPIO pin between 5 kHz to 1500 MHz, the Raspberry Pi 3B+ may end up becoming a versatile low cost TX SDR just on it’s own.[…]

Click here to read the full article at RTL-SDR.com.

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Video: Homebrew AM Loop Antenna Project by Thomas Cholakov (N1SPY)

Many thanks to SWLing Post contributor, Thomas Cholakov (N1SPY), who shares his latest video explaining the operation of a simple homebrew AM loop antenna:

Click here to view on YouTube.

Brilliant video, Thomas! I love the fact you included a demonstration with your SDRplay RSP1A as well. Via the spectrum display, it’s easy to see the the loop’s bandwidth and also the gain it provides when tuned to a station.

I love your AM loop antenna as well–such a simple design and ideal for demonstrating the mechanics of a passive loop antenna since all of the components are visible. I’m willing to bet you built this antenna for less than $10. Smart design as it’s both portable and effective! Keep up the excellent work, Thomas! We look forward to all of your future videos.

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RSGB presentation on RF Interference

Digital-Frequency-DialMany thanks to SWLing Post contributor, Gary (W4EEY), who writes:

I want to recommend an excellent presentation on RF Interference from
the Radio Society of Great Britain (RSGB) Convention in 2015. The
presenter is Ian White, GM3SEK, who has a Blog website here:

https://gm3sek.com/

You can find the presentation video on YouTube here:

Click here to view on YouTube.

The presentation runs for about one hour and contains some valuable
information to help you fight noise and interference in your shack.

Thanks for the tip, Gary!

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The new Raspberry Pi 3 B+ and a number of RPi projects

Last month, on “Pi Day” (March 14, 2018) an upgraded Raspberry Pi 3 B was announced on the Raspberry Pi website. The new $35 B+ sports a few performance enhancements over the original–most notably:

  • A 1.4GHz 64-bit quad-core ARM Cortex-A53 CPU
  • Dual-band 802.11ac wireless LAN and Bluetooth 4.2
  • Faster Ethernet (Gigabit Ethernet over USB 2.0)
  • Power-over-Ethernet support (with separate PoE HAT)
  • Improved PXE network and USB mass-storage booting
  • Improved thermal management

Here’s a short promo video posted with the announcement:

Click here view on YouTube.

I immediately navigated to my favorite Raspberry Pi source–AdaFruit–and requested a notification when the new units were available to purchase. A few weeks later, I got the notification and placed an order within minutes (you see, when the Pi 3 B was first released, I hesitated a day and had to wait a few weeks for the second shipment!).

I received my RPi 3 B+ a few days ago:

I immediately attempted to put this unit into service but learned that it requires the latest firmware which was only released a week or so ago. If you have have an RPi 3 B+, here’s where to fetch the latest firmware:

NOOBS:
https://www.raspberrypi.org/downloads/noobs/
or if you want Raspbian:
https://www.raspberrypi.org/downloads/raspbian/
and install on SD per instructions here:
https://www.raspberrypi.org/documentati … /README.md

After receiving this latest Pi, I quickly realized I’ve bought a number of Raspberry Pi models over the years and currently have them in service for a variety ofc projects.  Here’s a list of all of my current Pi-powered applications:

That’s a total of seven RPi projects that are in service at time of posting!

As I mentioned earlier, I try to buy most of my Pi equipment from the amazing AdaFruit retailer–I like supporting what they do even if I pay a small premium.

But AdaFruit seems to rarely have stock in some of my favorite Pi bundle packages. If I’m buying a Raspberry Pi for a new application, I look for a package with at least a case, a 2.5 amp power supply, a 32 or 64GB MicroSD card, and two heat sinks (though I’m not certain the B+ needs a heatsink). I tend to grab this one or this one from Amazon (affiliate links).

Post readers: Have you ever used a Raspberry Pi? If so, in what sort of applications? How many do you own?  Please comment!

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