29 October 2009

definition and usage of sio codes

"Logs, or it didn't happen"

When I log shortwave broadcast receptions, I include an SIO code in my notes (such as "SIO 353"). The SIO (strength, interference, overall) code, a simplified form of the SINPO (strength, interference, atmospheric noise, propagation conditions, overall) code, is a standard way to rate shortwave reception. Each value of the code uses a scale of 1 (worst) to 5 (best), and the highest possible SIO code is 555. SIO codes are commonly included in reception reports sent by a listener to a broadcaster.

A SINPO code includes two more components but requires the listener to break strength and interference into two categories each. Shortwave listening novices (a group in which I still belong) may not know how to do this. For the sake of simplicity, I'm starting with the SIO code.

Reception reports along with SIO or SINPO codes help broadcasters understand the success of their transmissions. Transmitter sites are sometimes operated by a different organization than the broad caster, and listeners are often hundreds or thousands of miles away from broadcasters, thanks to the wonders of ionospheric propagation. So, reception reports from the broadcast target region can be very valuable to broadcasters.

Here are the three components of SIO, along with how to determine the value for a given reception:

• Strength

This rating indicates the effectiveness of the transmission for your particular location. Factors such as transmitter location, transmitter antenna direction, transmitter strength, ionospheric condition, and atmospheric attenuation can affect the strength of a broadcast. This category can be scored by evaluating the loudness of the broadcast above the noise floor, and whether any signal fading is present.

Some stations offer propagation maps that show where particular broadcasts are expected to reach. If that information is available, it can help to set your expectations about how well you might receive a transmission.

I've heard that atmospheric attenuation is better counted against the interference score, although the cause of a weak signal is not always easy to determine. North American shortwave listeners can check the latest NOAA solar data at n3kl.org. Or you can listen to the geophysical alerts on WWV or WWVH.

• Interference

This rating tells the broadcaster if there are any problems with transmitting on a particular frequency with the intention of reaching specific locations. Rather than rate the amount of locally-generated interference you receive (which the broadcaster can't control), rate the interference on the frequency itself. Same-channel or adjacent channel interference are the reasons to subtract points for this category.

If you want to factor out local interference when determining this score, try tuning to another broadcast of comparable strength within the same meter band, ideally as close to the primary frequency as possible. This can help you determine the baseline noise level. The ideal situation would be to perform your listening in a location that is largely free from radio frequency interference.

• Overall

This is your opportunity to describe the overall quality of the broadcast in spite of the signal strength or interference. This score is likely going to be in the range between the strength and interference scores, but does not need to be a simple average of the two scores. In my experience, interference is less of a factor than the signal strength, especially when the signal is fading in and out.

Some broadcasters such as Sound of Hope and Radio Marti are victims of intentional, targeted jamming. In those cases, interference plays a major role in the overall quality of the broadcast, especially if the jamming signal is louder than the desired broadcast.

If you haven't logged SIO codes before for your shortwave receptions, I'm hoping that this article gives you enough information to start doing so. I also recommend being generous in sending your reception reports to broadcasters. You may receive something in return (QSL cards, stickers, newsletters, schedules, or other gifts), stations may respond in order to provide better transmissions, and it can help ensure continued broadcasting to your area.

22 October 2009

tecsun pl-310 first look

I received a Tecsun PL-310 at last. Silver was my color of choice. My second attempt at purchasing this radio succeeded, just a few days before they started appearing on eBay. I just got it out of the box, so here are some initial thoughts on this new Tecsun product.

The radio has a nice appearance, but feels flimsy in my hands. With some of my radios, I wouldn't be concerned while holding both the left and right ends and twisting it slightly to test its durability. With this radio, I don't think that's a good idea. Some Chinese radio manufacturers have certain products or certain production runs that they deem export quality, and I'm not sure whether my radio qualifies. It is an early production run to be sure, so I'm hoping Tecsun will deliver a more refined product later on. This product offers the full range of FM (64-108/87-108 MHz) and MW (520-1710/522-1620 kHz) frequencies that anyone would want, plus LW (153-513 kHz), so from a technical standpoint, this product can satisfy all portable radio markets.

In contrast to the fabric protective bag that Tecsun includes with many pocket radios, this radio comes with a zippered clamshell, perhaps made of nylon. The inside has a little pocket, and my folded shortwave cheat sheet fits nicely. It's a thin enclosure, so it's mainly useful for avoiding scratches during transit.

This is the first radio I've purchased that comes with a USB cable. It makes this DSP-based product for analog broadcasting almost seem like a modern electronics product! The mini USB port on the radio is labeled "DC-IN 5v", so it's intended for NiMH battery recharging. I don't yet know of other uses for the USB port.

All of the Chinese-language documentation was included, which I can't use, but I enjoy having to look at anyway.

Oh, I suppose you want me to put in some fresh batteries and turn this thing on?

General

• The radio made two quick beeps upon insertion of the batteries. The beeping can be disabled by pressing the bell button (corresponding to the 0 key) when the radio is off.
• Both the volume dial and the tuning knob are notched continuous encoders. The tuning knob has a bit more resistance than the one on the PL-350, but its feel is similar to that radio. It's not like the strong resistance on the PL-200 tuning knob (which annoys me). I didn't expect the notched volume dial though.
• The only way to change the tuning knob from small to large steps is to turn quicker, according to my experience so far. I don't really like this. I want to be able to turn the knob and know exactly how much the frequency is going to change.
• When volume is adjusted, the volume level (00-30) is shown at the top right of the screen momentarily. With a strong local FM station, I didn't hear anything but static for volume levels 00-04. Level 30 was ridiculously loud and the speaker was distorting. For a mid-sized room, a volume level of 10 works well for me.
• The LCD screen shows dbµ and db numbers, updated about once a second. Pressing the "display" button quickly will toggle this section of the screen among the db meter, the alarm clock time, and the temperature. I haven't figured out how to change the temperature readout to fahrenheit yet. Pressing the "time" button will momentarily show the current time (according to the radio) in this same top-right region.
• The code system used on previous Tecsun radios such as the PL-200 is not needed here to set the FM frequency range, the MW step size, or the 12/24 hour clock preference. While the radio is off, just press the buttons "FM SET", "12/24", or "9/10 kHz" (corresponding to buttons 1-3 respectively) until the desired setting is shown on the screen.
• Similar to just pressing the labeled buttons to perform a function while the radio is off, the battery button (corresponding to button M at the bottom left of the numeric keypad) toggles between NiMH battery mode (allowing recharging) and alkaline battery mode (disallowing charging).
• When using 9 kHz steps for MW, temperature will be displayed in celsius (for example, 23ºC. When using 10 kHz steps, temperature will be displayed in fahrenheit (for example, 73ºF).
• Pressing a numeric key while listening to a weak signal or a blank frequency produces audible momentary static, or occasionally, a rapid pitch shift that sounds like a zap special effect.
• Toggling the screen backlight with the light/snooze button momentarily boosts the volume. I don't like that.

FM

• Selecting an FM station is easy! Just punch in the frequency digits: "9" "6" "5" gets you to 96.5 MHz; "1" "0" "2" "9" goes to 102.9 MHz. Unfortunately, I'm seeing quite noticeable lag after pressing each digit, and sometimes, a keypress doesn't register.
• When an FM stereo signal is received, two speaker icons are shown on both sides of the "FM" indicator. FM stereo can be enabled or disabled with a dedicated button on the right side of the interface. Stereo output is only useful when using the headphone jack.

SW

• When tuning to a shortwave frequency, the meter band of the frequency is momentarily displayed at the top right of the screen, such as "120 mb". This doesn't happen when switching to a frequency outside the range of the bands.
• I heard a faint WWVH signal and a strong WWV signal on 5000 kHz.
• Shortwave reception can also take advantage of the AM bandwidth settings.

MW

• For AM, bandwidths of 6, 4, 3, 2, or 1 kHz are offered, and toggled with the "AM BW" button as you might expect. For my ears, 4 kHz sounds best for my local flamethrower, KCBS 740 kHz.
• If there's a local/dx setting somewhere in this radio, I haven't found it yet. Bummer, because I'd really like that for mediumwave.
• I was able to hear KRLA identify while listening to 870 kHz, so this pocket radio has DX potential. That's a 3 kW station at night, about 400 miles away in Glendale, California.
• I received a clear signal from KOMO on 1000 kHz, a 50kW station about 800 miles away in Seattle, Washington. I had to lower the bandwidth to 2 kHz to get rid of the annoying adjacent channel chirps coming from local station KIQI 1010 kHz.

LW

• It was not intuitive to tune to longwave frequencies, so here's how I did it: with the radio off, I held down the MW/LW button for a few seconds, and the display showed "LW On". Then, with the radio on, pressing the MW/LW button toggled between mediumwave and longwave as one would expect out of the box. I'm not sure why longwave is disabled by default.
• While tuned to 404 kHz, I heard the MOG airport beacon which is about 300 miles away from me. The radio was very buzzy while tuning through longwave, and the airport beacon was very faint. That's all I've been able to do with longwave at my location.

Conclusion

This is quite a promising pocket radio. I like that this radio can receive weak, distant mediumwave stations with ease and clarity. I like the more immediate interface provided by simple digit-pressing for frequency selection. The construction quality could be improved, and buttons could be more responsive than they are. I don't yet have any information such as battery life or reception capabilities compared against other radios in the same class. Since I don't plan to do a full review of this radio, I may post occasional updates in the future and I'll do my best to answer specific questions from readers. So, feel free to ask questions or share your own experiences with this new product.

20 October 2009

wire antennas in cramped space

Now that I have some of the best portable shortwave receivers available, I either need to upgrade my radios or my antennas in order to get more out of the broadcasts that are generously sent in my direction. I'll start by upgrading my antennas.

My small apartment makes this difficult. Indoor antennas are my only hope, and I can't run a straight wire for longer than about 20 feet diagonally along my ceiling. I finally established permanent mounts for two wire antennas that I use, which helped somewhat with nighttime reception. However, I just realized I had an asset that has remained untapped for my four years of shortwave listening: I have a box that contains approximately 800 feet of unshielded Category 5 cable. I don't need lots of ethernet cables, so I can cut a length of Cat 5, and get eight individual wires at that length which can be shortened as required.

For my first project, I want to make a five-band antenna specially designed for the NCDXF/IARU beacons. This provides me with five specific frequencies to target, and the high frequencies of the beacons require less material. I'm going to make half-wavelength elements, so the elements will be between about 18 and 35 feet long. Also, the longest element for 14100 kHz should be decent for CHU on 14670 kHz and WWV/WWVH on 15000 kHz.

But what about that 20-foot straight line limit that I mentioned? With a sharp 45-degree turn or several gentler turns, I can extend the antenna for 30 feet. I could toss the antenna up on the roof and either hope nobody notices or remove it when it's not in use. I could call my landlord and request some holes be drilled through my walls.

Or, I could ask the experts. I posted some questions about this problem on the dxing.info forums.

15 October 2009

ham reception on 14175 khz

A few days ago, I spent an hour listening to some ham radio operators on 14175 kHz (SSB). This was on 02 August 2009, 1830-1930 UTC. For most of the hour, I could only hear one person speaking. As I can only listen to other people transmitting, it makes me feel like I'm eavesdropping. I've recently learned that this practice is known as reading the mail. I was using my Eton E5 receiver along with a Degen DE31 loop antenna.

During the hour, I learned that the primary speaker was in the Seattle, Washington area. Much of the conversation centered on getting home windows replaced, discussing radio technology, planning a party, buying trucks, buying jewelry, and getting a check from an insurance company to replace part of a roof. Here are some quotes from what I heard:

"We don't tell people to bring anything because there's plenty of food."
"No four-letter words in this house."
"The only one that gets wet is me out there, doing the salmon, but that goes pretty fast."
"We made the rounds at pawn shops looking for stuff. i guess they do big business in this kind of environment."
"I should've never bought the darn thing. It's just a piece of junk."
"I reduced the mic gain a little bit."
"This winter, maybe I'll get that 922 in here."
"Barb keeps trying to talk me into getting a new truck. I don't know when the 2010 Toyotas come out."
"Tundra is the big one."
"I've got a Ranger now... it's probably good for the rest of my life. And we got the fanciest cab we could get. They make that Tacoma with three and four doors, which I don't want. I want the one that has the little fold-up seats in the back. They don't give you much choice on color."
"I bought my Ranger through Costco."
"...Island County ... Bellingham..."
"When I go to a dealer for a car, I bypass their salesmen and go upstairs to the fleet dealer."
"We'll put the truck in the driveway with a For Sale sign on it."
"When we went down to Seaside, we got 24 miles to the gallon in that little car."
"How many miles do you have on your truck now, W7LFA?"
"The inside of the truck is just like new, but it's got 109,000 miles on it."
"How noisy was your 922? Does it have a fan in it?"
"I suppose they went out and had a big lunch at the Olive Garden after we left."
"Good signal up here in Seattle."

Callsigns heard: W7LFA, W7EPA, W7ZP.

09 October 2009

shortwave listening cheat sheet updated

When I got started as a shortwave listener in 2005, much of my listening was done outside for better reception and less interference. Hanging a wire antenna from my old apartment bedroom didn't help much; radio waves only had a narrow path to reach me. Being outside away from my computer left me separated from the shortwave information I needed to effectively tune in. So I produced my shortwave listening cheat sheet, a single letter-size page with information such as broadcasting frequencies, North America broadcast schedules, and reception tips. I folded the sheet into a 1/8 size so I could easily put it in my pocket. I'm happy with this low-tech solution.

When I moved a few years ago, I got an apartment that's more favorable for indoor shortwave reception, so I didn't keep the cheat sheet updated. However, I've just updated it for 2009. Unfortunately, I don't have approval from all of the information sources to distribute the information, so I'm providing this image to show what's included and how it has been formatted.

I find it useful to get broadcast schedules from primetimeshortwave.com and eibi.de.vu, and condense the information by choosing specific broadcasters within specific times. Most of my shortwave listening is between 0000-0700 UTC, so the schedules included on my cheat sheet focus on that time range.

For the number station schedules on my cheat sheet, some of them are expected to broadcast on certain days of the week. In instances where a broadcast is expected on more than two days of the week, I write the days in this condensed form: (_m_w_fs) represents monday, wednesday, friday, and saturday. This format also lets me use a single character for both tuesday and thursday, because the position rather than a unique letter is the identifier.

Cramming all of this information onto one side of a sheet of paper is achieved with these tricks:

• Top, bottom, left, and right page margins are 0.15 inch. I printed one copy with 0.10 inch margins, but the printing was cropped at the edges.
• The font is 8-point Monaco.
• Horizontal character spacing is reduced by 1%. The text is still legible with even lower settings, but I can fit all of the desired information already with the current format.
• Line spacing is reduced to 0.8, allowing for many extra lines on the page. Additionally, lines without any text are reduced to a line height of 0.4.
• Some information that would only take up a couple lines across the whole page has been crammed into the right column next to other unrelated data. Unfortunately, the broadcast band and ham band sections don't efficiently use their space.
• Radio Australia has a complex schedule. I don't listen to it very often, and I can't always receive it. To save space, I consolidated that section of the schedule by simply listing every frequency they use during 0000-0800 UTC. Schedules on the cheat sheet for other broadcasters are more precise.
• This may make morse code purists unhappy, but I use a forward slash instead of a hyphen to represent the dashes in my morse code section. This allows me to easily count how many dashes are in a character when I've reduced the character spacing down so much that hyphens would otherwise run together.

I've also produced an audio version of this data, using Mac OS X text-to-speech. All of the data is stored in 16 separate mp3 files, with a total duration of 39 minutes. The text has to be massaged to sound nice, so I have to maintain the information in a second document. For example, I'd rather hear a frequency spoken as "seventy-eight fifty" than "seven thousand eight hundred and fifty." Here's how I reformatted the data about North American time stations: "time stations. frequencies in kilohertz. WWV, colorado. 25 hundred, 5000, 10000, 15000, 20000. WWVH, hawaii. 25 hundred, 5000, 10000, 15000. C H U, ontario. 33 30, 78 50, 14 6 7 0."

As an example, here's an mp3 of the time station data.

Do you do something similar to keep shortwave listening information more handy? What sorts of information do you use the most?

03 October 2009

my failing eton e100 works again

I don't have a very good explanation of how this happened, but I brought an Eton E100 back from the dead. This particular E100 (based on the Tecsun PL-200) has had a rough life. I bought it used, and kept it in my bathroom. So, it endured humid conditions due to the shower and a weak ventilation fan. And it went through a few gravity incidents.

At one point, it would act very confused when powered on. The LCD would show corrupt or blinking characters, and no sound was produced. I couldn't tell what band it was on, and the numeric keypad, up/down buttons, and tuner knob weren't responding. I removed batteries for lengths of time, tried different sets of batteries, tried the reset switch on the bottom, and nothing was working. So I took the batteries out and stuffed it into a dresser drawer to be forgotten.

I saw the radio again a few days back, and wondering about radio electronics, I opened up the case to look inside. Everything looked normal, except for a large capacitor that showed evidence of leaking. When I reassembled it, I put in two batteries just for fun. When the radio powered on, it started...behaving normally! Honestly, I didn't make any internal modifications more extensive than gently removing a small amount of debris. I'm not taking any credit here; this E100/PL200 has crazy super self-healing powers. Honest.