Fanfare FP-TRO Receiver / Translator for HD-RadioTM

[PocketRadio]

"Fanfare FP-TRO Receiver / Translator for HD-RadioTM + analog"

"Introduced at NAB '06, The FP-TRO quite literally replaces the necessity for demodulation and remodulation at a translator. Instead, the "TRO" converts the modulated carrier internally from one frequency in theFM broadcast band to any other frequency within the band. Not only that, initial field tests have shown the TRO is capable of translating cleanly, to the next adjacent ,without any visible(scope) or aural interference. To complete the installation, a linearized PA system is required. As such, a TRO-equipped translator does not demodulate the signal and therefore does not impinge on any intellectual property for which licensing may be required."

http://www.fanfare.com/

"Introducing the Fanfare FP-TRO receiver / translator"

http://www.fanfare.com/fp-tro-sht.html

Now, look at these comments:

"Correct me if I'm wrong, but don't most translators demod the signal off of air and then remodulate it with a (typically) lower power transmitter on a different frequency? (Just confirming that I know how the typical translator works. Like I say below, I'm an RF wannabe thirsting for knowledge.) So if you don't demod and then remod the signal, you don't need an additional liscense (read royalty) fee? Interesting... Should be easy to mix the signal from reception frequency to translator frequency. Mix down to IF, filter, then back up to the target freq staying out of the baseband realm. I suppose baseband wouldn't matter either, as long as the signal envelope stays intact.I wonder if you'd have to worry about phase issues. Does anyone make a box that does that?"

http://tinyurl.com/3ywgx8

Now, wouldn't that be ironic !

 

[Chuck]

Most translators take the composite output from a tuner and run it into a composite input of a transmitter. That transmitter in turn rebroadcasts the station on a different frequency. The tuner’s composite output is essentially a mono signal without de-emphasis. It originates in the tuner before the stereo decoder. Back in prehistoric days, lots of mono tuners had a "MPX" jack for an external stereo (or quadraphonic) decoder. This is essentially the same thing.

The composite input on the transmitter is intended to accept the output from an external stereo generator/processor. By going from composite out to composite in, you are skipping the stereo decoding process in the receiver as well as the stereo generating process at the transmitter. Theoretically this gives improved signal to noise, and allows hidden signals like RDS or SCA channels to pass without having to be regenerated.

It is also possible to demodulate the received signal into left and right audio channels, and feed the repeating transmitter with those signals. This can cause some nonlinear processing effects, since the signal is being converted several times.

I know of at least one situation where a translator's output appears to the listener to be quieter running left and right audio than it is, using the same equipment with a composite feed. I've never really figured out why. Perhaps the filters in the audio section of the receiver (or maybe the stereo generator) do a good job of rolling off noise above 15 KHz while the composite output is flat. In any case, it sounds better in this particular installation. The problem with just running audio in and out is it does not pass through any RDS info or any SCA channels. But sometimes you do whatever you have to do to make it work.

I know that Fanfare has offered their HD compatible translator receiver for some time now. I’ve only heard of one installation of such a translator. It is in Houston on a university campus. I’m told that its HD coverage was “adequate” to cover the campus with HD. It was installed because the originating station (whose studios are on campus) could not be reliably received on campus in HD. It seems that the transmitter is too far away from campus for the HD signal to penetrate through the concrete, brick and steel buildings on campus. Hmmm… This information was related in an open SBE session at last summer’s Texas Association of Broadcasters convention and told by an engineer from one of the large HD transmitter manufacturers.

It would be interesting to find out how HD actually works on translators. Maybe it would be worth calling Marv at Fanfare. He is usually more than willing to share information. (He makes a great tuner also.) Since he is making a receiver for the purpose, he might be ale to shed some light on the subject. Crown is making an all-in-one-box HD translator too. I think they use a Fanfare receiver as well.

If it is possible to get 10 miles or so out of an HD translator, then I’d be interested. Unfortunately, I think you are pushing the laws of physics to expect much more than 3-4 miles, or even less if the translator is not full power. Quite a few translators operate quite successfully with as little as 10-20 watts ERP in analog.

 

[Play Freebird]

I've built several FM translators over the past 20 years, using both "direct conversion" at the IF stage (as done in the Tepco and TTC equipment), as well as some that feed demodulated audio from the output of a tuner into a stereo generator and exciter. In theory, direct conversion causes less degradation -- but unless the input signal is really strong and clean, problems can arise from the retransmission of wideband noise, so I prefer to demodulate and then generate a clean, low-pass filtered stereo signal.

Fanfare is promoting their "direct conversion" HD box as a "loophole" to get around iBiquity's intellectual property issues. If iBiquity's lawyers refuse to waiver the licensing fees for translators, they are simply shooting themselves in the foot. Unless demodulation takes place, the digital component of the HD signal cannot be regenerated, so if it's degraded by noise or adjacent channel interference (quite likely in fringe coverage areas where translators are typically located) this garbage will be retransmitted, causing high bit error rates, poor HD performance, and listener dissatisfaction.

Standard practice in other types of digital repeaters is to regenerate a clean bit stream, not to amplify the digital signal along with the noise and then transmit both down the line.

Station owners are being hit hard enough with licensing fees for their primary facilities. The least iBiquity can do is give them a break on translators.

 

[Mike Walker]

It'll be interesting to see how this shakes out (talk about a generic post that could be generated by a "bot" and attached to any thread)

 

[Chuck]

Standard practice in other types of digital repeaters is to regenerate a clean bit stream, not to amplify the digital signal along with the noise and then transmit both down the line.

Station owners are being hit hard enough with licensing fees for their primary facilities. The least iBiquity can do is give them a break on translators.

That makes a lot of sense. Even digital signals eventually reach a point of diminishing returns where the noise makes it very difficult to discern the "ones" from the "zeros."

It is important to remember that translators are not usually dealing with a robust signal to begin with. If the signal was good at the location, they would be very little need for the translator.

 

[Chuck]

It'll be interesting to see how this shakes out (talk about a generic post that could be generated by a "bot" and attached to any thread)

I'm glad that you are not in the "Spam-Bot" business.