Category Archives: How To

Troy updates the Tecsun PL-880 hidden features reference sheet

Many thanks to SWLing Post contributor, Troy Riedel, who has recently added the hidden bandwidth adjustment feature to Cap Tux’s excellent PL-880 reference sheet.

Here are links to download the updated sheet:

I will also add this to the Complete list of Tecsun PL-880 hidden features page: a place where you can comment if you note any previously unpublished PL-880 hidden features.

Thanks again, Troy!

Video: Ivan’s Airborne TV DX catches

Many thanks to SWLing Post contributor, Ivan Cholakov (NO2CW), who writes:

A while back I shared a short story about FM reception from commercial jetliners. I do that regularly on my flights but I also gave “Airborne TV DX” a try.

My equipment is as follows:

  1. Windows laptop
  2. Hauppauge USB dongle receiver WinTV-HVR-955Q
  3. 3-inch stick antenna

The receiver comes with its own WinTV software for tuning, scanning, watching and recording TV programs. It is one of the few USB dongle size receivers for North America’s ATSC digital TV standard. A have posted a video of my reception recordings from a roundtrip flight Miami to St Louis.

The video is located here:

Click here to view on YouTube.

My notes regarding this activity:

Reception from commercial airplanes is possible as far as 400 miles with the simple unobtrusive “stick” antenna.

Channel scanning is pretty slow and it is possible that by the time you detect a signal, save it, and tune to it you are 50 miles away from the point where you detected it.

Many times signals are detected but no video can be shown due to weak signal. Users in Europe may have a different experience as the availability of DVB-T USB dongles and software is much wider.

TV DX can make a coast to coast flight a much more interesting experience!

No doubt, Ivan! Thanks so much for sharing.

Ivan is quiet adept at logging and recording FM and TV DX while in the air and at sea. Click here to view his previous posts.

A New Approach to FSL Antenna Construction

Introduction

I’m very fortunate to live across town from my good radio hobby pal Gary DeBock. He has been responsible for the rapid growth in Ultralight radio DXing and the construction of Ferrite Sleeve Loop (FSL) antennas. Living near each other as we do, I’ve benefited a lot from his expertise and creativity in the hobby. We’ve enjoyed visiting about Ultralight radios and antennas many times over a leisurely lunch. If you’re unfamiliar with Gary’s efforts, just do a YouTube search on his name and see just a few of the many FSL antenna variations he’s built!

Gary uses PVC tubing, “Fun Noodle” foam cylinders, sections of curved foam, and rubber plumbing adapters almost exclusively as the core supporting structures for his FSLs, from small 3-inch models to 17-inch monsters. Gary certainly has perfected his own techniques with these raw materials; he’s an expert in combining them. He even makes PVC table structures to support his FSLs during Oregon coastal DXpeditions, as seen in some of his YouTube videos.

These materials work well, but over time even FSLs as small as 7 to 8 inches in diameter begin to sag and lose their perfectly circular shape. This seems to be caused by the shifting of individual segments of foam which are wrapped around a “Fun Noodle” core and center PVC tubing.

What possibilities are there for other materials in FSL antenna construction? It would be a fun challenge to build a small to medium sized FSL antenna that would have these qualities:

  • Maintain a circular cross-section without sagging
  • An appearance less like a threatening explosive and more like a commercial product
  • Use alternate construction methods for those not skilled with cutting & gluing PVC tubing

I began to keep my eyes open for likely candidates as I visited hardware stores, department stores, and office supply outlets. Eventually some ideas began to gel.

Raw Materials

Here is a visual and descriptive list of what I used in this alternate design of Ferrite Sleeve Loop antenna. I won’t go into great detail about dimensions, quantities, and measurements, as other DIYers should be able to easily follow the general idea presented here. This article is mainly to get you thinking about other ways to construct a ferrite sleeve loop antenna.

The Core of the Matter

This 18-inch long, semi-rigid foam roller is six inches in diameter. It’s a workout and exercise aid which I found in the sports department of my local Walmart store. The cost was approximately $13. This one-piece foam is a perfect foundation for holding and protecting the fragile ferrite rods and keeping them in a circular arrangement; since the roller is in one piece there is nothing to shift around, or sag. When placed on this core, the final diameter of the FSL antenna is approximately seven inches.

So, what to put the antenna in? Something needs to suspend and protect the antenna as a substitute for the PVC frame previously used. This Sterilite tote box is the perfect size to hold the antenna. As shown in the photo, the dimensions are approximately 14-1/4″ X 9-5/8″ X 12-1/4″; the model number is 1896.

Early on, I decided that the flimsy “locking tabs” on the cover would not suffice for holding the relatively heavy antenna when carrying the tote by the handle. I drilled holes and attached a dozen small Nylon nuts and bolts to secure the cover. (Nylon avoids distorting the medium wave reception pattern of signals, as metal hardware could.)

An ample quantity of 200mm ferrite rods are needed, plus a air variable capacitor (preferably with a 8:1 reduction drive shaft), and Litz wire. 1162 strands/46 ga. Litz provides the most sensitivity but the coil will cover a greater width on the rods.

Gary likes to use waterproof medical tape, sticky side out, to hold the rods in place, but I like to use Gorilla brand tape, as it is extremely sticky and holds the rods better. My choice for the rod-to-coil spacing  material is two turns of 1/8″ thick bubble wrap.

This is the foam core, ferrite rods, bubble spacer, and coil assembly prior to fitting in the Sterilite tote container. Before assembly to this point you’ll need to cut the foam roller to length using a serrated knife or electric carving knife. Two sturdy cable ties help hold all of the rods in place. A better alternative might be strips of 1/2″ wide Velcro straps purchased from a fabric shop or home improvement store.

Another key item to this construction method is the use of plastic drywall anchor screws. These are meant to be pushed and screwed into gypsum wallboard for sturdy attachment of bolts or picture hangers on walls. When screwed through drilled holes in the side of the Sterilite tote, they secure and suspend the foam roller/ferrite sleeve loop assembly. The density of the foam roller is sufficient to give a good grip to the drywall anchors. Eight to ten anchors per side are enough to hold the assembly in place. See the photo at the beginning of this article for a good view of this mounting method.

Every good FSL antenna design needs an official sounding manufacturer! With tongue firmly in cheek I’ve appropriated the name shown on this self-produced label. Clearly, a Ferrite Sleeve Loop antenna from Naughtabaum Ferrite Specialties Ltd. stands a better chance than most of passing through TSA checkpoints, right?

I hope this article has given you some new ideas for FSL antenna designs. There’s certainly room for improvement, including making the antenna’s ferrite rods look less intimidating…less like a bundle of dynamite! Perhaps the entire assembly can be wrapped with something that shields the rods from view, or you could use an opaque tote container rather than a clear model.

Be on the lookout for useful materials to repurpose. Trips to your local home improvement stores, office supply, and other outlets will give you further ideas on how to design your own Ferrite Sleeve Loop antenna.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

A Replacement Whip Antenna for Sony ICF-SW7600G

The Sony ICF-SW7600G (Photo: Universal Radio)

This is a guest-post by Eric, WD8RIF.

I’ve had my Sony ICF-SW7600G for almost twenty years. Early on, my very young son broke the receiver’s telescoping whip antenna and it was a simple and inexpensive matter to order a replacement whip assembly from Universal Radio, the Sony dealer from whom I had purchased the radio.

Recently, the receiver’s antenna failed at the pivot-point. First, the factory-supplied countersunk screw’s Phillips-head stripped out through repeated attempts to tighten the pivot over the years until finally I  had to replace the screw. The best replacement screw I could find was a 2mm x 6 Allen-head screw from an R/C hobby shop that appeared to work fine until I managed to strip the antenna’s threads through over-tightening this screw. (Perhaps the Allen wrench simply provided too much torque for such a small screw.)

Clearly, it was time to actually buy a replacement antenna. This turned out to be easier said than done. Universal Radio is no longer a Sony distributor and has no access to parts for Sony products. A visit to the Sony website disclosed that service-parts are handled by two other companies, neither of which could provide the antenna—a surprising thing to discover since I think the antenna used in the ICF-SW7600G is the same part which is used in the current-model ICF-SW7600GR. A search on Amazon disclosed a seller offering the part for over $52, far more than I wanted to pay. Perhaps belatedly, I thought to check eBay where I found several listings, some offering the genuine Sony part shipped directly from Japan. I was intrigued, however, in the listing by stone_deng (link) who offered a non-OEM replacement antenna, shipped from Virginia, for $16.80 with free shipping. The description claimed the antenna was a perfect-fit replacement. Figuring the price would make this a good gamble, and because I wouldn’t have to wait weeks for delivery from Japan, I placed an order for one on a Monday evening and the postman delivered the antenna to my mailbox the following Friday. (I noticed as I was composing this post that stone_deng has raised the price for this antenna to $19.90 with free shipping.)

In comparing the replacement antenna with my original Sony part, the only difference I could see is that the metal tip of the replacement antenna is of a different style. Dimension-wise, the two antennas appeared to be identical.

Installation of the new antenna was simple. A single screw secures the antenna to the radio.

Remove this screw and pull the antenna straight out of the receiver.

It should be possible to slip the new antenna into the hole, twisting it to properly line up the mounting-flange, and run the screw back into place. In my case, the new antenna insisted on snagging on something inside the radio and I ended up removing the rear-panel entirely to install the new antenna rather than try to force the antenna into place. Fortunately, the rear panel is easily removed.

Remove the battery-cover and the four AA cells. Remove the five black Phillips-head screws that are marked on the rear panel with arrows. The rear panel will then lift straight up. Insert the new antenna into its hole, lining up the mounting flange with the screw-hole, and insert and tighten the screw. Carefully place the rear panel into place, lining up the four screw holes, and insert and tighten the five screws. Re-insert the AA cells and replace the battery cover.

I’m hopeful that this non-OEM antenna will prove to be rugged but time will tell. If this antenna proves to be inferior than the original in some way, I will post a follow-up to this post.

Obligatory disclaimer: I don’t know stone_deng, and I don’t have any financial interest in his company or products.

Eric McFadden (WD8RIF) is the author of this post and a regular contributor to the SWLing Post. Click here to visit Eric’s website which features QRP operation. Eric is based in Athens, Ohio.

Build a Raspberry Pi-powered SDR

Many thanks to SWLing Post contributor, Jeremy Clark (VE3PKC), who writes:

I have developed an SDR receiver that may be of interest to your readers. It can be used directly with the Raspberry Pi2B/3B. It comes in several versions DIP/SMD.

Check out this MP4 movie:

I have two eBooks which are basically design manuals for the DIP and SMD version of my SDR receiver. Each eBook has an Internet linked parts list, so that the reader can get their own parts to keep costs down. The DIP eBook is $7.90 CAD and the SMD book is $14.90 CAD.

Click here to view Jeremy’s website.

Thank you, Jeremy–this looks like a fascinating construction project!

Readers: just to be clear, Jeremy is selling eBooks detailing construction–not kits. He did mention if you’re interested in obtaining the PCB, he can sell this as well.