The Great Antenna Shoot Out of 2014

The Big SAL has been up and running for over a month now, and all is well. The wind hasn’t taken it down, and I’ve peaked and tweaked it to get as much performance out of it as I can. But was it worth it? Can it hear things that the other antennas can’t? With that question in mind, I have put together a few comparisons of the SAL and my other two antennas on different frequencies and under different conditions. The results are dramatic to say the least.

First, a brief description of our contenders:

It doesn't get any simpler than this.
It doesn’t get any simpler than this.

The Longwire. This antenna is about as basic as it gets. It’s a sloping longwire going from a ground rod up into a nearby walnut tree. It’s about 65′ long, slopes at about a 30 degree angle, and is about 30′ at it’s highest point. There’s no balun, just a direct solder into a SO-239 connector. It shouldn’t work as well as it should, but all in all its a pretty nice antenna. The antenna runs from North to South.

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The Pixel Technologies Pro-1B

The Pixel Technologies Pro-1B. This would’ve been a godsend when I lived in Baltimore, and spent most of my time fighting the leaky transformers and transmission lines that ran down my back alley. Since it receives off of the ends, it spends most of its time oriented North and South, but it can be rotated.

You can read more about the loop, and see some of the shaky cell phone demo videos in a previous blog post.

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The SAL on construction day.

The Shared Apex Loop array (SAL 20). The latest tool in my listening arsenal, and the one I’m sure my readers are about sick of hearing about. Hey, what’s not to love though? This is easily the most directional of the three antennas I have, allowing me to choose incoming signals from any of eight points on the compass. With the additional computer interface, I can also steer this antenna with a couple clicks of a mouse, making it about ideal for remote listening.

Each of these three antennas is connected to a four port Alpha Delta antenna switch, which feeds into another four port Alpha Delta switch that allows me to select one of four different radios. Only the Perseus was used in this case.

With all this in mind, let’s see if the SAL can earn its keep so to speak, or if I would’ve been better off spending my hard earned money on a dummy load and a keg of beer.

Comparison 1: Radio Vanuatu, October 29, 2014. Approx. 1230 UTC.

This video is pretty much a slam dunk for the SAL-20. It takes a signal that neither the magnetic loop or the longwire could really hear and makes it intelligible.

While I could tell something was there with the other antennas, the SAL was the only one to recover any listenable audio.

Comparison 2: VL8A, November 5, 2014. Approximately 1230 UTC

Radio Australia (VL8A out of Alice Springs) on 4835 isn’t a very difficult catch, it is very difficult to get an intelligible audio before WWCR’s sign off at 1300. Their transmission on 4840 usually overwhelms the Aussies. note the really narrow passband on the Perseus.

Comparison 3: 1030 kHz, mediumwave. November 6th, 2014. Approximately 0300 UTC.

This is another case of seeing how each antenna handles co-channel interference. In this case, it’s the 50,000 watt WHO radio on 1040, located about 40 miles to the Southeast of my location.

Comparison 4: WPSO, October 7, 2014. Approximately 0230 UTC

Not much of a comparison really, but interesting nonetheless. All three antennas had a loud copy on ESPN Radio out of Indianapolis on 1500, but I could hear something else underneath it on some of the deeper fades. When I pointed the SAL to the Southeast, I heard Greek music. After some digging around, it turned out to be 250 watt WPSO out of Port Richey, FL. The music matched up with their web stream, so no doubt about this one. No video, but I do have some audio:

[soundcloud url=”https://api.soundcloud.com/tracks/171128979″ params=”auto_play=false&hide_related=false&show_comments=true&show_user=true&show_reposts=false&visual=true” width=”100%” height=”450″ iframe=”true” /]

Some Final Observations

Obviously the SAL-20 is a beast, and I’m happy to have one at my disposal. Its performance and relatively compact size make it a no brainer for guys like me who do not have the real estate for a Beverage wire. No, it is not a cheap antenna, but what in this hobby is? Getting the last 10% of performance out of any hobby will cost you, and this is definitely an antenna that gets you into that last 10%. Is it better than a Beverage? No, probably not, but that would be a really interesting comparison.

There’s an old adage in the ham community that says more receive antennas are better than less, and I would agree with that. Each of these antennas has a role to play at my listening post, and each can excel under different conditions. One example of this was Dr. Benway’s recent Undercover Radio transmission on 1720. While I don’t have any audio or video of this, I found the magnetic loop to be the best performer of the three. It gave me just a little more signal strength than the SAL in a situation where I really needed it, and the longwire didn’t hear much of anything.

So yes, the SAL definitely earns its keep and then some. I’m glad I have my other antennas to fall back on, but the SAL will definitely be doing most of the heavy lifting from here on out.

I highly recommend this antenna.

Life with the SAL-20

I haven’t had a lot of time to do a proper write up about the Shared Apex Loop array just yet, but I will have some more information on how it performs here in the near future. In the mean time, here is a demo video I made this last weekend of the loop antenna on 6070.

It should be noted that, on my long wire antenna, both stations were about equal in strength.

How Do I Decode a Weather Facsimile (WEFAX) Off of my Shortwave?

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While I suppose it could be a case of weak Google-fu, my searches for info on how to decode weather facsimiles off of the shortwave turns up a whole bunch of not much. There’s some very helpful frequency guides and a few decoders, but not much else on how to put it all together. With that in mind, here is my effort to make this seemingly daunting process a little easier to wrap your head around.

First off, keep in mind that this process only SEEMS daunting. In reality, this is a nearly 90 year old technology. People were doing this back in the early days of radio with tube powered equipment and lord only knows what for a printer. With your modern receivers and computer technology, you’ve already got a huge head start over what the earlier experimenters had to work with. After this tutorial, you’ll find wefax decoding to be a piece of cake.

Heeere’s What You Need!

The Perseus in mid decode.
The Perseus in mid decode.

A radio. Yes its an obvious requirement, but you will need a radio capable of receiving upper sideband (USB). Since these signals are transmitted on frequencies not allocated to international broadcasting, it would be best if the receiver is capable of listening in on the entire HF band, and not just shortwave broadcasters. A software defined radio will be a BIG help, but its not necessary. Stand alone radio users will need to come up with a way to feed the signal into your computer, but we’ll talk about that later.

A computer. Mac, PC, Linux, Windows… doesn’t matter. There’s decoders out there for pretty much anything you’re running if you look hard enough.

Decoding software. There’s a lot of weather fax decoders out there, but I’d recommend fldigi to start with. It’s available for Apple and PC, and it does an excellent job. If you can’t run fldigi, give Sorcerer a try. It’s a little less intuitive, but it can decode just about everything on HF that isn’t encrypted, and works well. Just to keep things simple though, this tutorial will only focus on fldigi.

Audio cable. If you’re using a stand alone radio like a Sangean, Tecsun, Sony, or Drake, you will need to get an audio cable to feed the signal from your radio to your computer’s sound card.

You won’t need a separate cable if you have an SDR, but you may need an extra piece of software called Virtual Audio Cable. Configuration of VAC is a little beyond the scope of this tutorial, but there are a lot of other VAC resources out there if you have problems.

Guide to Weather Fax Frequencies. You’re REALLY going to want to download this now. This is a comprehensive guide to all known weather fax transmitters around the world, and is very helpful when it comes to finding weather fax frequencies.

Putting It All Together

The first thing you’ll need to do is connect the radio to the computer. The actual connection can be as simple as running a cable from the headphone jack of the radio to the microphone input of the computer, but keep in mind you might need a stereo to mono adapter to make it all work. Your mileage may vary.

Next, if you haven’t already installed your decoder software, go ahead and do that now. Once it’s installed, and assuming that you’re using fldigi, go to the Op Mode section at the top, go down to wefax, and select WEFAX IOC-576. The only difference between the two (that I know of) is that the other standard gives you smaller maps, so stick with IOC-576 for now.

Fldigi software and the three panes: top, middle, and bottom.
Fldigi software and the three panes: top, middle, and bottom.

Fldigi software is broke up into three separate ‘window panes’. The top pane is the view of what you’re receiving at this moment, sort of a sneak preview of what is being decoded. The pane below that is a viewing window where you can see previous faxes you’ve already decoded. The bottom one is a view of the signal as it arrives, and is where you can make fine adjustments to the tuning. We’ll talk more about this in a bit.

Now that the radio is connected, turn it on and see if there’s any trace of a signal on your decoding software. If the bottom pane of fldigi goes from black to yellow and blue, you’re in luck! Your computer is hearing your radio, and you’ve succeeded in getting the signal from one into the other. Go ahead and switch the radio into upper sideband if you haven’t already, and lets try decoding some faxes!

Now, take a look at the guide to wefax frequencies and find a station relatively close to you. Here in North America, I’d recommend New Orleans, Port Reyes, or Boston. All should work though, just choose your frequency based upon the time of day. For our example, we’ll use Port Reyes on 12786.

Its important to keep in mind that a lot of radios have what is called an ‘offset’ in sideband modes. Without getting into the nitty gritty details of radio waves and sidebands work (although that might make a good future blog entry), just remember to aim low. For example, if we are trying to tune into a fax station on 12786, you will want to enter in something like 12784 into your radio and start tuning around. Also remember that you might have caught the station between faxes, which means you might be waiting a while for another transmission. You can either try another transmitter site when that happens, or check out the schedule for the next transmission and wait it out.

Once you do hear a transmission though, which should sound something like this, you should see something like two yellow and red streaks running down the bottom pane of fldigi, and a red box sort of thing. That red box is your fine tuning, and can be moved around with your mouse. Go ahead and line up those two red lines onto the centers of the red and yellow streaks, and wait for the magic to happen. If you can’t move the box around with your mouse, look down in the lower right hand corner of the program for a button labelled AFC. If there’s a green light in that box, click on it to turn it off. You should now be able to move the red box to wherever you need.

An example of what a properly tuned wefax transmission should look like in the tuning pane of fldigi. Note the red box and how its sides are alligned with the red/yellow stripes.
An example of what a properly tuned wefax transmission should look like in the tuning pane of fldigi. Note the red box and how its sides are alligned with the red/yellow stripes.

After a while, you should start to see your results appear in the preview screen. The first one might be off centered, but don’t worry about it. It will synch up on the next transmission. While your first fax is coming down, this would be a good time to tell the program where you’d like them saved. To do this, go to the Configure drop down box and select modems. Navigate to the ‘Wefax’ tab, and select the directory where you’d like your faxes saved. I have a folder on my desktop called, originally enough, Wefax Decodes where all of my faxes get saved.

So you’ve got everything worked out. There’s signal from the radio to the computer, you’ve tuned into a transmission, and you’re waiting with wide eyed anticipation as your first fax materializes in front of you. There’s just one problem… Why is it crooked??

Time to correct the slant
Time to correct the slant

Don’t worry, this can be corrected. Just below the first pane in fldigi you will find a box labelled Slant with an arrow to either side. Use these arrows to straighten out your fax while it is decoding. The solid black line on the side of the fax is a big help with this. Once your lines are straight, you probably won’t have to do this again. In my case, the slant is set to .008 and I haven’t had to adjust it since it was first calibrated.

So there you have it, a semi-brief primer on how to decode weather faxes. Hopefully you’ll find them as enjoyable and addictive as I do.

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Hurricane Gonzalo heads towards Bermuda.

The Saga of the Shared Apex Loop Array (SAL-20)

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The finished product.

Back at the Dayton Hamvention in 2013, Array Solutions debuted a new compact receive antenna system called the Shared Apex Loop array, or SAL. Building upon the foundation laid by the EWE, K9AY, and the flag and pennant antennas, the SAL featured true time delay phasing, and no need for a control wire from the shack to the antenna or grounding. Best of all, if the plots and modeling were any indication, this antenna might actually live up to the promise of Beverage like performance in a small lot.

This last weekend, after being flooded out the last time I tried to put it up in July, I took advantage of what may be our last good weather of the year and got a SAL 20 up and running in my yard. It wasn’t easy, but its up and receiving signals.

My make-shift soldering station.
My make-shift soldering station.

Since the wires that came with my antenna had a close encounter with the lawnmower, I needed to cut new ones to make into the four loops. According to Array Solutions, they recommend 62′, but a little longer is fine as long as all the wires are the same length. With this in mine, I cut four lengths of wire each 64′ in length, using up the rest of my 12ga wire minus an 11″ remnant.

After that, I went ahead and fed them through the mas before feeding the couplers, an insulator, and a shrink wrap tube over the wire before tinning them. There’s a reason soldering is not listed on my resume as a skill, but I did ok, and sealed the joints with the shrink wrap after I was done.

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The mast is up, held in place with two ‘shepherd’s hooks’. Note the wires taped to the mast to keep them from getting tangled (again).

Now it was time to get this beast up in the air, and here’s where I met my first obstacle. I managed to tangle my wires up pretty good while I moved the antenna over to where I’d be putting it up, and I ended up having to cut them and start over. This time though, I didn’t solder them before setting the mast up. Instead, I taped them to the mast at the base so that they wouldn’t get tangled again, and soldered each one individually.

Now that I finally had it up in the air, I went and put the stakes into the ground and tied each loop down at the corner, forming four triangles at right angles to each other. Since my dog bone insulators didn’t show up until this morning, I improvised and used inch long sections of PVC pipe. They’re cheap, they were available, and the antenna won’t care.

A close up of the magnetic coupler.
A close up of the magnetic coupler.

Once everything was in line and tied down, I measured out the distance for the couplers from the center mast. According to Array solutions, Each coupler should be about 86″ from the center of the mast with the positive lead facing outward. Using a measuring tape from the base of the mast, I lined up each coupler so that the center was at the 86″ mark. This will need a little fine tuning before its a finished product, but it’s a good starting point.

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DX Engineering’s crimping tool for the win!

Now that everything was positioned properly, I wired all of the couplers up to the central ‘junction box’, and attached the delay cable. After making quick work of a coax run to the shack (thanks to DXEngineering and their awesome F type connectors and crimping tool), it was almost time to see if this antenna was worth the effort.

Of course, as with most of my projects, I came up a cable short. The control box for the antenna uses an RCA out jack, while everything I own is either an N or SO-239. Time to break out the soldering iron again, and one sacrificed RCA cable and a PL-259 pig tail later, I had a crude but effective RCA to PL-259 cable.

The 'finished' control box that needs to be cleaned up a little.
The ‘finished’ control box that needs to be cleaned up a little.

Now by this time it was already dark, and the instructions do not recommend trying to optimize reception after sunset. I still wanted to see what this antenna could do though, so fired up the Perseus and I went about putting the new antenna through its paces. Some of my initial tests were kind of disappointing, like my inability to null out the nearby KASI on 1430 (the same station I tested the Pixel Loop out on last year). On other frequencies though, I could hear a different station with each direction I chose, which is pretty cool.

Later on in the evening, I saw a post about Magic Lantern International, a Euro pirate, relaying a show on 6205 kHz. While my copy on them wasn’t very strong, they were strong enough for me to identify the music being played and catch a ‘Laser Hot Hits’ (the station they were relaying) ID. Just out of curiosity, I fired up the Elad through my secondary long wire to see how it compared. The Elad and the long wire didn’t catch a trace of them. The SAL-20, pointed to the Northeast, had a listenable copy, while the 75′ long wire couldn’t even catch a whiff.

While this antenna is still a work in progress, this beast shows an awful lot of progress. I not only heard VL8A and VL8K this morning, I also heard a very loud and listenable signal from North Korea as well. Even better than that though, I saw some faint traces of carriers from Asian mediumwave transmitters. That’s not much to go on, but it’s more than I’ve seen from any foreign mediumwave signal before.

All in all, this is shaping up to be a fantastic DXing season.