Many AM stations that are DA-2 or even DA should consider downgrading to a lower power level and getting rid of their DA system.  Directional antenna systems on AM stations are maintenance nightmares.  Unfortunately, in the 50’s, 60’s and 70’s, it was often thought that adding power, extra towers to an AM station would give them great swaths of extra coverage.  Sometimes it worked out, sometimes it did not.  Often what happened was some area was added, but in areas that where nulls toward protected stations, signal strengths went down.  What the station ended up with was more towers, more maintenance, monitor points, a sample system, and more expense.

Taking an AM station in the other direction might actually make more sense.  Go back to one tower non-directional 1 KW or whatever power can be used in the daytime.  Time was when the FCC would only allow certain power levels; .5, 1, 5, 10 and 50 KW.  Those were what a new station had to work with.  No longer is that the case, any power level can be used so long as it meets interference contours and the city of license contour coverage requirements.

Presunrise authority is normally 500 watts and is available at 6 am, post sunset authority varies but often a PSA extends the on air time to 9 pm in the winter time.  For a local radio station, which is what all but the class A AM stations are destined to become, this will be adequate.   For a loosing station, it may be that, or turn in the license and sell the land to a developer.

Diplexing on another AM stations tower closer to town is also a good way to get out of maintaining an expensive antenna array with diminishing income.

Something to think about.

Giving them the synchronizing track on site is not very hard, however, I was surprised to hear that not every radio station does that.  In fact, one of our, ah, ehm, Clear Channel competitors from The big Metropolitan Center Nearby could not be bothered to do it for the 4th of July fireworks this summer and last summer too.

The synchronizing track is on the left channel of a CD that Garden State Fireworks created, it is 1200 baud FSK data, 8,N,1, so it is pretty robust.

I thought I would post on how I do it and why. First of all, for the how part, there are two options:

1. Play the music CD at the remote site and relay broadcast quality music back to the studio without any time delay.  Hard to do even with an ISDN line.
2. Play the music CD at the studio and relay telephone quality audio for the firing track to the remote site from the studio.  Have the remote site play the air signal over the local PA system.

Option number 2 is technically far easier than option number 1, although it takes a fair bit of coordination.  Also, the sound reinforcement guy didn’t like the air signal idea because the quality of the audio.   That is a little nit picky, especially given the fact that much of the music at the fireworks show will be drowned out by the fireworks explosions.    In the end, he saw it my way.

Here is a list of equipment needed:

1. Telco auto answer coupler, such as the Indy Audio
2. Telco Hybrid, such as the Telos
3. If the announcer is at the fireworks site, a POTS CODEC such as a Comrex Matrix or blue box
4. Wireless microphone
5. Telephone set and cord with RJ-11 connector
6. Miscellaneous mic cables, power cords, etc
7. At the remote site, two pots lines from the local phone company, long distance  service as required.

Here is the block diagram:

Note, this assumes no delay in the telco network, which under ordinary circumstances using wired, not cellular network, there should not be any.  The touchiest part of the whole thing is getting the stage coordinated with the studio during the transition to the remote broadcast.  Once that is done, everything else just falls into place.

The firing computer is located on shore next to our broadcast booth.  They send the signal out to the barge on a wireless LAN link.

That is the how part.  Here is the why (soundtrack is a little low):

That is from three years ago, but you get idea.

Even though I don’t work for these people anymore, I asked if they needed help with the broadcast this year.  ”Nope, we got it, thanks.”  I will be paying close attention.

I find it works very well with the android phone and the iPhone.   I put one Google ad at the top of each story to defray costs, once again.

Let me know if you have problems, we aim to please.

On a slightly related note, I am also experimenting with a customizable android app that will convert radio station web streams into mobile content.  If a radio station is already doing song titles using RDS, that output can be adapted and applied to the android app.  I could then market it to individual radio stations, in my spare time.

First, I attempted to down load a few apps, but they either crashed or didn’t do what I wanted or weren’t in the right language, or something.

Clear Channel has something called iHeartRadio, which is a clearing house for mobile users that want to listen to Clear Channel radio streams on their iPhones.  I don’t know, once you have heard one Kiss-FM station, you’ve heard them all as far as I am concerned.  Most other Clear Channel programming is boring and uninspired.

What I finally ended up doing was going to Moodio and reading up on a few things.  Here is a good step by step way to use Moodio to listen to radio station web streams on any mobile device.

1. Be aware that not all data plans are the same.  ATT, Sprint, and others now cap data transfer and charge extra if a subscriber goes over.  Know your plan.
2. On a regular computer, go to Moodio (http://www.yourmuze.fm/)
3. Set up a user account
4. Select from there list, the stations you want to listen to.  They have many US stations as well as many from Europe.  If the station you are looking for is not there, you can request that it be added.
5. Select the default data rate.  Since I have unlimited data, I chose the highest rate for the best sounding audio.  Others may want lower data rates so as not to exceed data caps.
6. Point your mobile device web browser to www.m.yourmuze.fm
7. Log into your account
8. The stations on your listen list will be displayed.

That is a lot of steps to take.  Somebody has to be very into radio or a radio station to do something like that.  A forward thinking radio station or group will be writing or paying somebody to write mobile streaming apps for their stream(s).  A forward thinking radio station or group would then feature links to these apps prominently on their web pages.  Very prominently if they are in a PPM market.  Ahem, very prominently if they are in a PPM market.

That is what a forward thinking radio station would be doing…

One of my aims in writing this thing is to provoke thought.  The fact that the editor of Radio World is asking his readers about the direction the publication is heading is a sign that, at least in one case, I have been successful.

My other aims are:

• pass along useful information
• tell my story
• write stuff (I am compelled to write things)

Regarding Radio World itself, I still read the digital version of the magazine found on the Radio World website.  The importance of impartial reporting of radio broadcasting’s technical issues cannot be overstated.  These days there are many pressures being applied to Radio in general from things like the FCC, Big Group Radio, MMTC, Ibiquity, NPR, the recording industry and others.  Some of these groups do not have the radio industries best interests in mind, but rather are looking to improve their take.  Indeed, some of the schemes proposed are technically flawed or down right destructive.  Biased reporting degrades the integrity of any publication and diminishes it’s value and when it comes to the most read technical trade magazine, that is alarming.

I applaud Radio World for it’s recent publication of articles that bring to light HD-Radio’s technical issues.  That is a welcome development and such things should continue.   Technical writers need to be technically minded people, not someone that retypes press releases.  When it comes to new technology, hard question need to be asked and answered, that is a reporter’s job after all.

The phone is great, I enjoy the functions, the GPS navigation tool, gmail, news, and all the other apps.  It fills many roles while I am out gallivanting around earning a living.

I have tried Pandora in the past on my computer.  I found it to be okay, not great.  I guess my main issue was it seemed a little boring just listening to music.  It was good music, and when I interacted with the programming, voting a song up or down, the music selections got better.  But it was distracting to interact while I was trying work on the computer and in the end, I turned the volume down an it became background noise.

In the car, I figured, things would be different.  I could listen to Pandora the same way I listened to my car radio.  Lots of music would be great and not distracting at all.

Except…  I found it to be… boring.  The music was great but the whole thing lacks personality.  I suppose we are blessed around here with several radio stations that play new music.  With Pandora there was almost no new music, even if I created a new music radio station.  Further, it seemed like something was missing:  human interaction.  I enjoy hearing the deeeejay talking about some band factoid or some such.  Just listening to music endlessly left me wanting something more.  Perhaps that is just me.

Whilst on the road to various places, I like to listen to WEQX in Manchester, VT; WDST, Woodstock, NY; WKZE, Salisbury, CT; WXPK, White Plains, NY.  All of those stations have personality and play great music.  They also stream audio, which means I can listen to them on my phone.

So Pandora gets a meh, the phone gets a thumbs up.

The FCC is still in the comment/response process (FCC Docket 04-296) which can get long and drawn out.  I would not expect to see any NPRM until late fall 2010 with any changes taking effect in early 2011 or so.

Basically, CAP looks like this:

An EAS to CAP converter monitors a CAP source (think e-mail server) and when a CAP message is received, it converters it to EAS protocol and sends it to a input source of a  EAS encoder/decoder.  The EAS encoder/decoder then passes that information through and broadcasts it.   Of course, the EAS encoder/decoder can still be programmed to pass through specific types of messages for specific area and ignore all others.

Thus far, several manufactures have designed CAP converters for use with existing EAS units:

• TFT, Inc model 2008 CAP to EAS converter
• SAGE Alerting Systems ENDEC
• Gorman Redlich CAP to EAS decoder system
• Digital Alert Systems DASDEC-II
• Trilithic systems EAS plus

Implementation would look something like this:

For a TFT-2008 system.  Others such as SAGE and Trilithic are integrated into the EAS encoder/decoder units.  Basically, the CAP part of the EAS system needs an ethernet port with access to an IP gateway to receive messages from the CAP server located off site.  That is the weak link in the system, as far as I am concerned.

It is not like some of our so call trading partners have been trying to tinker with the inner tubes or anything.  It is also not like that same trading partner makes most of the cheap ethernet switches and routers found in many radio stations, hardware that can be easily configured remotely.  Configured to redirect certain IP addresses to new, exciting, and exotic locations such as Iran or Pakistan.

Perhaps I am paranoid, or not.  It falls back to my time in the military when somebody said “It’s good to be a little paranoid if everyone is out to get you.”

It is a thick book and covers AM, FM and TV broadcasting technology as it was understood in 1975.  There are several chapters about “current” things that no longer apply, there are also many very useful items, such as studio construction, AM and FM broadcast antennas, tower maintenance and so on.

I will keep this on my shelf because it is an interesting primer on AM broadcast antennas with all attendant formulas and charts.  It is quite interesting and fun if one is looking for the theoretical efficiency of a 185 degree radiator at 1 mile.  I remember WPTR (now WDCD) in Albany had a three tower with 206 degree radiators, 50 KW carrier power on 1540 KHz.  It seemed to be quite effective, when I was chief engineer there, we used to get reception reports from South Africa.

Perhaps one day, I’ll put some of that information to good use with an AM station of my own.

We are off for a quick couple days to stick my feet in the lake and perhaps catch a few small mouth bass.  Unfortunately, the internets do not reach our humble cottage, so you’ll have to entertain yourselves for a few.

When I come back, we’ll get back into some of the interesting radio engineering policy issues, including the FCC’s snub of the SBE.

The licensee of each broadcast station is required to satisfy all reasonable complaints of blanketing interference within the 1 V/m contour.

And for FM stations, it is part 73.318:

Areas adjacent to the transmitting antenna that receive a signal with a strength of 115 dBu (562 mV/m) or greater will be assumed to be blanketed.

Any interference to any device with that signal contour is blanketing interference.  73.318 further states that:

permittees or licensees who either (1) commence program tests, or (2) replace their antennas, or (3) request facilities modifications and are issued a new construction permit must satisfy all complaints of blanketing interference which are received by the station during a one year period.

I have always taken a more pragmatic approach to interference complaints.  Rather than pass the buck and tell the home owner or business owner that it is not our (the radio station’s) problem, I’d go and try to help them out.  Generally speaking, the interference problems are close to the transmitter site, so on the next trip to that site, I would bring RFI filters and my 25 years of RF experience and solve the problem.  I would like to think this help the station’s and the company’s imagine in the community.

Most of the problems are pretty easily solved, although once in a while, I have come on some head scratchers.  An AM station playing on the outlets in a guys garage, the mic cords on a church PA system, and an off switch on a blender, off all things.  The Bare Naked Ladies had a line in the song Light up my Yard: “we can dance to the radio station that plays in our teeth.”

What I have found is start with the simple stuff first, check the ground on the electrical service entrance panel.  One might be surprised to find it disconnected, corroded or missing completely.  More than one occasion, I have fixed all of the RFI problems with a simple turn of the screw holding the ground wire to the grounding electrode.  In my experience, this is the most common single failure point.  A disconnected ground will cause the entire neutral wiring system to act like a giant AM antenna, with all sorts of bad outcomes.

RFI suppression ferrite

Most often, telephone answering machines, cordless phones and other devices powered by wall warts are suspect.  Those devices do not have a path to ground.  A few turns of all the wires coming and going from said device around a ferrite core such as a snap on TDK RFI EMI filter available from Mouser will take care of it.  Mouser has several different versions available.

Occasionally, one needs to put on a detective hat and do some foot work.  Mast mount TV antenna preamps can cause untold heartache and problems.  One such incident involved the second harmonic of an FM station falling exactly on channel 11’s audio frequency.  This was affecting several houses in a one block area.  I finally found the problem at one of the complaintent’s house when I pulled the TV out and found the preamp power supply.  Unplugging it made all the problems go away (I hate Radio Shack).

Usually process of elimination will discover the problem and thereby reveal a solution.  The aforementioned church incident was discovered after I began unplugging microphone cords from the back of the Mackie mixer in the choir loft.  It turns out several mic lines were plugged into the back of the mixer, unused and unterminated, creating a large long receiving antenna on the cable shield, which happened to be aligned perfectly to pick up RF from an AM station.