The IBOC Mess In North America

Reader's note:

The IBiquity Digital Corporation was sold to Dedicated To Sound, Inc. in 2015. Information in this article is offered for historical purposes. Contractual agreements with DTS are undoubtedly very similar.

NOW FOR A RANT

"Bacon frying in a pan", that's what the co-channel interference sounds like when you are 10-20 KHz from one of Ibiquity Digital Corporation's AM HD Radio-equipped stations. At nighttime in the northeast part of the US, a veritable RF storm of digital hash appears across the entire AM broadcast band precluding reception of many distant stations. What a mess.


IN-BAND, ON-CHANNEL?

Huh? I'm not sure why they call it "In-Band, On-Channel" - it most certainly is NOT "On-Channel". The 15 KHz digital sidebands either side of the main carrier bleed fully beyond the adjacent AM channel center and into that adjacent station's far sideband. No filter, on any receiver, regardless of bandwidth, can reject it. In order to provide room for these expanded sidebands superimposing digital information on top of analog audio, stations also have had to narrow their audio response to an absolute 5 KHz maximum, further reducing standard analog audio quality. Adherence to strict technical standards is now an absolute imperative, both in the transmitter, modulation technique, and antenna or you have an even worse interference problem. And we all know radio stations often fail in this area of strict adherence. This, currently, is what the FCC calls "Hybrid" digital operation, the precursor to going fully digital at some future date.


ENTER MONEY AND BIG BUSINESS

Now on to money and big-business, which seems to fuel today's society more than ever. Have you ever seen the licensing agreement that radio stations must capitulate to in order to broadcast under Ibiquity Digital Corporation's patents?

Here's the meat of it, and what the radio station must agree to if they wish to broadcast IBOC HD Radio:

1. The agreement is perpetual. You are handcuffed to Ibiquity, your provider and benefactor, forever.

2. Pay a one time fee of $25,000 to Ibiquity for rights to broadcast the Main Audio Channel. A station now pays a private, for-profit company for the right to broadcast its main signal.

3. Revenue sharing (part of your profit goes to Ibiquity). Pay 3% of incremental net revenue derived from any supplemental audio services made possible with HD Radio technology (a minimum of $1,000 per year per audio channel).

4. More revenue sharing (more of your profit goes to Ibiquity). Pay 3% of incremental net revenue derived from transmission of Auxilliary Data (Secondary and Tertiary digital data not associated with the Main Channel Primary Data).

5. Pay me again. Software upgrades to the existing HD Radio system must be licensed by paying an extra annual fee or the prevailing rate at the time of increase.


ENTER THE GOVERNMENT

And sad to say, the US Government (in name of the FCC) acts as a money-funneling agent for Ibiquity in their authorization of Ibiquity as the sole supplier of HD Radio technology. Call it monopoly if you wish. Yeah, yeah, I know - so Ibiquity has the patents on this technology. So what. Money, money, money, and more money. What ever happened to the public interest?

THE BIG DELAY

One more thing. Did you know that HD Radio is delayed by several seconds because of the technical encoding requirements? The figure most often seen is 8 seconds. No more taking the radio to the ballgame and listening to the commentator instead of the stadium announcer. No more listening to your favorite radio announcer describing the game while you watch it on TV.

SOME INTERESTING INFORMATION

As of this writing, some 289 stations are licensed through the FCC to broadcast in HD on the AM band in the US.

Here's a useful page which attempts to document all AM IBOC stations, and stays fairly current:

http://topazdesigns.com/iboc/station-list.html

CONCLUSION

Let's hope from a radio enthusiast and DXer's standpoint that IBOC eventually fails when radio stations give up on the technology. Some have started to do that.

Sangean DT-400W Mini Review

The Sangean DT-400W is a dream receiver. Let me explain what I mean by this. If I had had one of these little radios when I was a teenage kid in the early 1960s I would have been in heaven. Digital tuning. It receives AM and FM frequencies, though no shortwave. It receives the Weather band. Good sensitivity. Fair but acceptable selectivity. Shirt pocket sized, and ten times better than the Japanese transistor radios of the day. And today, almost the perfect ultralight. I ordered mine from PROVANTAGE.COM for $49.58 plus shipping.

The DT-400W is the size of a pack of cigarettes, only thinner. It is in a vertical format, as were the transistor radios of many years ago. Audio is crisp, and very enjoyable. It has no external antenna, save the loopstick at the bottom of the radio for the MW band.

Two AA batteries are required. Battery life is fair, though nowhere near the Kaito WRX911. I use a pair of 2500 mAH NIMH rechargeables.

Tuning is accomplished with up and down arrow buttons. 19 memory positions are present for saving your favorite channels. A drawback I find is that you cannot tune out of a memory channel as the memory function is part of the carousel band switching method: AM-FM-MEMORY. You must switch back to the AM or FM band before you can tune again.

Sensitivity is good, and better than most ultralights. I find the selectivity only fair, but about the same as most small ultralights. In a dense RF environment, you may have some channel bleed on adjacent frequencies. The new DSP ultralights promise better selectivity, but so far have not shown better sensitivity. I find its nulling capabilities on the MW band also excellent.

Lack of an FM or Weather band antenna has been overcome by having the radio's circuitry couple to the headphone lead-in when headphones are connected. A short wire is also supplied with a headphone type plug on one end to act as an antenna if you are using the speaker.

The DT-400W comes with a nice belt clip which you can attach to the back. Volume control is a traditional wheel at the top. A switch is also at the top which will give DBB bass boost to the radio. A lock switch is at the right side which will prevent the radio from changing settings or tuning should you bump it.

Power button is at the top as well, and a quick press turns the radio on and sets a 90 minute timer. The radio will turn off after 90 minutes in case you fall asleep. Holding the power button down for an extra second will void this "feature". The dial has a nice, warm yellow backlight which comes on for a few seconds if the controls are touched.

The DT-400W couples to a passive loop fairly well, though not as well as some ultralights. Coupling needs to be quite close. Remember the loopstick is at the bottom of the radio.

Though not a cheap buy at a $50-dollar bill, the DT-400W lives up to my expectations very nicely. When I want a small portable unit to take with me, I usually grab it versus the other radios I have. Very nice, indeed.

Kaito WRX911 Mini Review

I've had the Kaito WRX911 ultralight for a couple of months now since ordering it from JR.com. What a fantastic receiver for the price - $16.99 plus shipping! I bought the black one. It is slightly larger than a pack of cigarettes and about as thick.

The WRX911 is an analog set with slide rule tuning dial. Mediumwave AM, FM, and shortwave bands are included. The dial is tight, I can find almost no slack in it - very good for such a small, inexpensive radio. The tuning knob is sized large enough to get a good grip on, a little larger than the tuning wheel of the Sony SRF-59. Tuning is still touchy, though not as touchy as the SRF-59. Shortwave tuning range is 4.6 - 22 MHz. It is a very quiet receiver, being analog.

The radio uses two AA sized batteries. With headphones, battery usage is almost nil. A fellow owner claims upwards of 400 hours battery life. Batteries do not come with the unit. Included with the radio are a pair of earbuds and a cloth carrying case with drawstring.



The WRX911 uses a ferrite loopstick antenna for the MW band. Contrary to the wildly-enthusiastic reports of superb nulling ability, mine was only so-so out of the box and I questioned why. I noticed some interaction with the telescoping whip on the MW band, so I opened the case and had a look. Naturally, the whip has a short jumper which connects it to the circuit board. Tracing the circuit path, it seems to also connect somehow to one end of the loopstick wiring. The MW sensitivity is increased a little with this connection to the whip, but this severely compromises the nulling ability. Mostly I bought the WRX911 for MW reception anyway, so using a soldering iron, I unsoldered this connection (see photo) and taped off the wire, and rechecked. The nulling ability improved dramatically and is now as good as noted by others. And I no longer receive Radio Poland (on shortwave) at the high end of the MW band! Note that unsoldering this wire gives you no reception possibility on shortwave or FM.

Sensitivity with the antenna mod is still fair, though a little down from before. The radio's sensitivity is less than the Sangean DT-400W but easily brought up to acceptable with a small loop or external tuned ferrite rod like a Q-Stick. I have a homemade 4-inch tunable ferrite bar which does a nice job in coupling to the WRX911. Coupling to a passive loop is good. Currently I use both 12 inch and 42 inch loops here. Reception on the 42 inch is phenomenal.

Selectivity on the WRX911 is fairly good, a world of difference better than the Sony SRF-M37V, and perhaps on a rough par with the Sangean DT-400W.

The radio has a separate on/off switch from the volume control. I find it easy to forget and leave it on. I think it would be better had they incorporated it into the volume control.

For $16.99, how can you go wrong with this radio? Cheap fun. Get one before they are gone.

The 12-Inch Passive Loop

Now on to some projects I've been working on here this summer.

Haven't built a passive loop in many years, probably since way back in the 1970s, so thought I'd get back into it. The first is a 12-inch loop (12 inches per side). Now where do I find 100+ feet of wire? Who wants to buy wire? Not me.

I had a 20 foot length of 6-conductor, solid, twisted-pair telephone wire in a box in the cellar. The cover can be stripped with a razor blade or Xacto-Knife if you work carefully. In 15 minutes I had it complete. Take each pair of wires, tighten them up in an electric drill motor chuck, tie the other end to a door knob, and unwind them. Now you have 120 feet of nice, 24 gauge insulated wire of different colors.

I then spliced and soldered the lengths together. The wooden form consists of two 1/2 x 4 x 17 inch hardwood pieces formed into a cross by notching and gluing. The 4-inch width makes it sit up nicely all by itself. I then cut a small, 4 x 4 inch piece of thin wood veneer and nailed it to the center of the cross for support and a mount for the variable capacitor.


I didn't bother filing spacing notches for the wires, choosing to wind the coil in a close-wound fashion. Small wire nails in appropriate places make nice anchors for the wire. 26 turns of wire were wound around the form. My variable capacitor is a 250 pf unit, so a few extra turns were called for. Normally you wouldn't need 26 turns for a 365 pf unit. This loop tunes from about 510 KHz to 1500 KHz or so. A small jumper wire, about 4 inches in length with alligator clips on either end, is used to clip off a couple of turns of the loop to get the tuning range up to 1710 KHz.

Sensitivity of the loop is good, better than a 4-inch tuned ferrite rod placed next to your ULR. Nulling is sharp. Best thing about this loop is that it is extremely portable and can be set on a small garden table next to your chair. New York City, about 265 miles from here, is not generally receivable under daytime circumstances. Using this loop, stations like WFAN-660, WABC-770, and WCBS-880, all 50KW, are adequately above the noise level and are comfortably received using headphones.