Category Archives: Antennas

RCI Sackville Antenna Farm Map and Legend

I’ve been going through some old paperwork recently and discovered this map of the antenna farm at Radio Canada International’s former Sackville, NB, transmitting site (click to enlarge):

I was given this printout by one of the staff members at Sackville when I visited there in the summer of 2012–only a few months before they closed, permanently.

I thought perhaps some others here in the SWLing Post community might enjoy checking out this map.

I do miss hearing RCI on the air. Hard to believe it’s almost been a decade.

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Giuseppe’s Homebrew “TFerrite 2” Mediumwave & Shortwave Antenna

Many thanks to SWLing Post contributor, Giuseppe Morlè (IZ0GZW), who shares the following:

Dear Thomas my friend,

I built another Tferrite, (TFERRITE 2), for medium waves–this time also with the shortwave option.

A single variable capacitor, 800 pf, and a primary winding on the 2 ferrites of about 46 turns, a secondary winding of 3 turns to pick up the signal and send it to the receiver.

On the PVC tube I wound 4 more coils, for the shortwaves, connecting the ends to the same variable together with the other ends.

I interposed a switch on one end to eliminate or insert shortwaves.

I am sending you these 3 links from my YT channel where you can see the tests I have done in these days with no propagation.

The yield in mediumwave is excellent, like the other one, yet also good for the shortwaves–to be so small it compares very well.

Let me know what you and the whole SWLing community think!

Thanks to you and a greeting from Italy, Formia on the Tyrrhenian Sea.
73. Giuseppe.

Videos

View on YouTube.

View on YouTube.

View on YouTube.

This is brilliant, Giuseppe! Thank you so much for sharing your homebrew antenna projects. It seems they work so well from your beautiful urban location in Italy!

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Wire antennas vs. mag loop antennas

In the past few weeks, I’ve gotten a lot of questions from readers who are trying to decide if they should install a magnetic loop antenna or a simple wire antenna at their home. Obviously, most of the questions come from shortwave radio listeners, but some have come from ham radio operators as well.

I realize that there’s a common theme to my answers and I thought it might be useful to share it here on the SWLing Post for future reference. I started to write a slightly more comprehensive article about this, but I quickly realized I want to keep my advice as short and clear as possible. I’ll be painting in broad brush strokes, but here you go:

If you live in an environment with a lot of radio interference…

Magnetic loop antennas are your friend.

By design, mag loop antennas are some of the best antennas for mitigating the radio frequency interference (RFI) that plagues so many of our homes and neighborhoods. When oriented vertically, mag loop antennas can also be rotated to null out unwanted signals on lower frequencies.

Mag loops come in a wide variety of configurations:

  • The most popular among SWLs are wideband amplified loop antennas manufactured by companies like Wellbrook, Chameleon Antenna, MFJ, DX Engineering, Cross Country Wireless, Bonito, and a number of manufacturers in China. Unlike passive loop antennas, wideband amplified antennas require no manual tuning. These loops do require a power source, typically fed through a Bias-T or batteries.
  • Passive loop antennas are popular among ham radio operators because they’re easy to build and, unlike amplified loop antennas, one can transmit into them if designed correctly. They’re less popular among radio listeners only because they typically have a very narrow bandwidth and need to be re-tuned (via a variable capacitor) each time you move frequency even a few kilohertz. The NCPL (Noise-Cancelling Passive Loop) which is also known as the Moebius or YouLoop is a bit of an exception and doesn’t require tuning, but does require a receiver with a very high dynamic range.

Loop antennas can also be very stealthy. In fact, Loop on Ground (LoG) antennas are essentially invisible and could be deployed (under the cover of darkness, of course!) in the most restrictive of neighborhoods. Note that since LoGs are horizontal, they are essentially omni-directional. [13dka corrects this in the comments: “This is somewhat ambiguous and not entirely correct: LoGs are horizontally oriented but (somewhat surprisingly) vertically polarized, and even more surprisingly they have the trademark property of verticals”]

We’ve also featured other stealthy loop designs like this porch loop.

As with any antenna, mag loops prefer to be outdoors but can be effectively used indoors if that’s the only option.

If you live in an environment free of radio interference…

Outdoor wire antennas are very hard to beat.

I am a case in point, in fact: I live in a rural, remote location without any meaningful RFI. All of my external antennas are homebrew wire antennas and they serve me incredibly well.

If you’ve been a reader for long, you may note that I don’t personally review amplified magnetic loop antennas often–these are typically published by some of our amazing contributors. This is because I like to do “apples to apples” comparisons and usually don’t have a second compact magnetic loop antenna for comparison here at SWLing Post HQ.

Almost without exception, my cheap homebrew wire antennas outperform wideband amplified mag loop antennas…sometimes, by orders of magnitude.

Many years ago, I tested a Pixel Loop amplified mag loop antenna (now under a different name and sold by DX Engineering) specifically for use on the mediumwave band to null unwanted stations. It was a very capable amplified mag loop antenna, but other than its MW nulling abilities, all of my homebrew wire antennas outperformed it on the HF bands. Reception was, at times, dramatically better on my wire antennas.

Of course, for a wire antenna to perform properly, it needs to be deployed properly. There are excellent resources out there that describe ideal heights and configurations for any given wire antenna design.

Keep in mind that wire antennas can be incredibly stealthy as well. It’s very difficult to see a wire antenna among or in front of a patch of trees, for example. At a previous home, I deployed a horizontal delta loop antenna on my property that–if you knew where to look–was easy to spot from the road. In all of the years we lived there not one neighbor took note, though, because the antenna wire had sky blue jacketing and I deployed it while no one was looking.

Summary

Experiment!

This isn’t an either/or choice for most of us. There’s no harm in building a simple wire antenna and trying it at home first. If the local noise floor is high, then consider adding a magnetic loop antenna to your arsenal as well.

You might find that the wire antenna has an advantage on frequencies where you have less radio interference, and the mag loop serves you well in those portions of the band with thicker RFI and QRM.

Find the best antenna system that works for you at home, but always remember that hitting the field with your radio has advantages as well!

What did I miss?

I omitted numerous antenna designs that aren’t straight-forward loop or simple wires. Check out some designs by our contributors Grayhat, , TomL, and many others here on the SWLing Post. As always, please feel free to comment!

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Mike compares four active mag loop antennas

Many thanks to Jon Hudson who shared the following on the SDRplay Facebook page:

In this new video, Mike Harwood compares 4 different active mag loop antenna at various frequencies up to 52MHz using two SDRplay RSPduos which allowed simultaneous spectrum snapshots of the 4 loops in action with real signals.

These are loops from Bonito, Cross Country Wireless, LZ1AQ and Wellbrook.

This is the second of Mike’s antenna comparison videos. He welcomes comments which will help shape the content for future antenna experiments:

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Paul’s thoughts about Mediumwave DXing in Alaska

Many thanks to SWLing Post contributor, Paul Walker, who has kindly allowed me to published some notes he recently shared among MW DXers about DXing in McGrath, Alaska, USA:
During a Zoom hang out with a bunch of Pacific NW DXers, one of the things that come up was why my DXing in Alaska is beyond amazing, and we’ve come to a few conclusions.

The extended darkness. Sunrise in the middle of winter here is 3+ hours later than the west coast, so once their Skywave burns off, I’m left with darkness over the pole and to my west.

There’re no operating AM stations within just under 200 miles from me which is a big help. I have heard distant signals on the same channel as “semi locals” such as 780 and 1080.
And I’m pretty sure there’s something to the fact I’m close to the North Pole. Still far, but closer than most.

Interesting to note though: pre sunset DX isn’t a thing there. What I’ve unscientifically discovered is it seems to be that the entire Pacific has to be dark for DX  to be worthwhile for me in the evening … despite my evening DX being Canada and the lower 48 US States.
What most everyone else hears at night, such as the transpacific signals from Japan, China, Australia etc…, I hear in the morning. Hearing anything from Asia or the Pacific at night is EXTREMELY rare.

[Since I’m DXing outdoors in extremely cold conditions] I’m getting extra batteries, extra audio cables (to go between the recorder and the radio), another radio, and another recorder. Oh and some hot hands hand warmers. Also have some extra gloves and hats ordered too.. getting prepped for winter DXing well ahead of time!

The hand warmers are as much for my gloves as they are for my digital recorder… AA batteries don’t last long during continuous use in extreme cold.

i also have a portable battery and extra cable so I can use it for my phone. Those lithium ion batteries hate cold even more than aa alkaline batteries–they will shut off in the cold. In fact, you have to not only warm it up but charge it. The cold causes it to think tis dead…. and even warming it up won’t work.

Here’s a video link to my FSL antenna designed and built by Gary DeBock:

DXIng is one of the reasons I moved back up here to Alaska and it’s entirely fascinating. I learn something new every “DX season”.

Lower 48 theory and ideas just don’t hold a bunch of weight up here … I’ve had ideas and suggestions from some really smart people that just didn’t work out.

Until you’ve DXed in Alaska, it’s hard to explain and understand.

Thank you for sharing your notes, Paul! Having never done DX in those latitudes, I can only imagine how different conditions might be–especially in those long, dark winters!

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Grayhat’s NCPL (Noise-Cancelling Passive Loop) antenna “tweak”

My NCPL antenna

Many thanks to SWLing Post contributor, Grayhat, who shares the following modification he made to a Noise-Cancelling Passive Loop antenna last year. He’s kindly allowed me to share his notes here, but apologized that at the time, he didn’t take photos of the project along the way and recycled many of the components into yet another antenna experiment.

Grayhat writes:

Here’s a simple tweak to the NCPL, made easy for anyone. Let’s start with the commercial NooElec 9:1 balun version 1 (not 2) … made in USA.

Look at the schematic of the balun:

Cut the R1 (0 Ohm resistor – jumper) so that the center tap of the transformer won’t be connected to ground, then solder a short piece of wire to the tap.

The first pic (top) shows the balun seen from top side, the arrow indicates the small hole going to the transformer tap.

This pic shows the bottom of the board with the trace to cut and the spot for soldering the tap wire (needs cleaning with a bit of sandpaper to remove the cover paint). The solder is as easy as 1-2-3 once the trace is cut and the spot cleaned just insert a wire from the top of the board and solder it to the bottom and there you go!

Build the NCPL using “fat” coax (RG8 will do) with the top cross connection.

NCPL modification schematic

Side note: the top “cross connection” is the weak point, so it would be a good idea putting a short piece of (say) PVC pipe over that point, the piece will also help suspending the loop or sticking its top to the support pole, as for the feedpoint, a small electrical junction box will fit and protect the tiny balun from bad weather

Now the difference: connect the two center conductors of the NCPL to the balun input and the braid to the wire going to the center tap (as above).

Such a configuration will give some advantages over the “standard” NCPL one. The loop will now be galvanically isolated from the feedline/receiver so it will have much less “static noise.” Due to the tap, the typical 8 pattern of the loop will be preserved, this means that the loop will now have much deeper nulls.

By the way, the balun could just be wound w/o buying it. I suggested the nooelec since that way anyone with little soldering ability will be able to put it together. Oh and by the way it’s then possible adding a small preamp at the balun output if one really wants, any preamp accepting a coax input will work. 🙂

Again, if you can/want, give it a try !

Many thanks for sharing this, Grayhat! We always welcome your inexpensive, innovative urban antenna projects!

Post readers: If you have question, feel free to comment and I’m sure Grayhat can help. 

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Recommendations for an HF/VHF/UHF station in an apartment or flat

Photo by jay blacks on UnsplashMany thanks to SWLing Post contributor, Jamie, who writes:

Hi,

I would like to ask a few questions about what would be a good set up for my situation.

I am in a 2 storey property, which is not owned by me (renting via community/public housing), located in a large city in Australia. I currently have an SDRPlay RSP2, along with standalone AM/FM tuners – Sony XDR-F1HD and Onkyo T4970. The computer and all radios are upstairs at the back in a room that is not attached.

Given renting would limit what I can do, what would be best for me to get. For MW and SW frequencies, I am trying to decide between the MLA30+ or the AOR LA400. For above 30MHz (6m, 2m, broadcast FM etc) I am deciding between the AOR SA7000 or a Discone.

I have been told that putting antennas in the roof space is not recommended. Would they work fine in the room near a window? I should mention, I do have a 50ft end fed longwire with 9:1 balun, that has been in storage and never used.

I am also looking at upgrading my receiver. Trying to choose between the WinRadio WR-G305e or the Icom IC-R8600 (would also get the RS-R8600 CD software for computer controlling the receiver). How do the specs compare between these two?

Thanks for your time, and hope that wasn’t too many questions.

Regards,

Jamie

Thank you for your inquiry, Jamie, and I hope you don’t mind, but I’m sharing this message as a post as we have readers who are in the same type of living situation and listening environment. In addition, I believe owners of the gear you’ve mentioned might be able to offer some helpful advice!

I can tell you that you’re correct: in general, antennas want to be near windows or, better yet, outdoors. Even placing an antenna on a balcony can make a big difference in terms of lowering the noise floor. This is less an issue with VHF/UHF, but those antennas also benefit from being outside since there’ll be less attenuation from obstructions.

For HF, I would personally suggest you check out the MLA-30 loop first since it’s such a modest investment and is fairly flexible in terms of how you can configure it. I’m sure our regular contributor, Grayhat, will have some helpful advice as he’s a bit of an expert with urban HF antennas.

Also, the IC-R8600 is a brilliant wideband receiver. Depending on what you wish to have for frequency coverage, I would also suggest you check out the Icom IC-705 transceiver (noting that its RX coverage is not as comprehensive as that of the IC-R-8600).

Post readers: Please feel free to comment with some suggestions for Jamie, especially if you have experience with urban radio listening.

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