Picking up an AM radio station over 400mhz?

[aps_ak]

So, earlier today I was running the signal stalker on my 106, and came upon what sounded like a sports broadcast. Sure enough, it was our local AM ESPN radio station. This sounded like a direct stream, and not someone just holding their radio up against the speaker. The AM was 550, and it came over 455.35000 frequency. Could this be someone patching the AM radio through, given that it's a football sunday, or is it possible to monitor radio stations with a scanner?

 

[K5TXC]

These channels are used for remote broadcast by radio and TV. There are other frequencies in the low 150 Mhz and 160-161 Mhz, plus 25 to 26 Mhz.

This is a link to the federal website: Electronic Code of Federal Regulations:

Title 47: Telecommunication
PART 74—EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES

(4) UHF segments: 450.03125, 450.0375, 450.04375, 450.050, 450.05625, 450.0625, 450.06875, 450.075, 450.08125, 450.0875, 450.09375, 450.100, 450.10625, 450.1125, 450.11875, 450.125, 450.13125, 450.1375, 450.14375, 450.150, 450.15625, 450.1625, 450.16875, 450.175, 450.18125, 450.1875, 450.19375, 450.200, 450.20625, 450.2125, 450.21875, 450.225, 450.23125, 450.2375, 450.24375, 450.250, 450.25625, 450.2625, 450.26875, 450.275, 450.28125, 450.2875, 450.29375, 450.300, 450.30625, 450.3125, 450.31875, 450.325, 450.33125, 450.3375, 450.34375, 450.350, 450.35625, 450.3625, 450.36875, 450.375, 450.38125, 450.3875, 450.39375, 450.400, 450.40625, 450.4125, 450.41875, 450.425, 450.43125, 450.4375, 450.44375, 450.450, 450.45625, 450.4625, 450.46875, 450.475, 450.48125, 450.4875, 450.49375, 450.500, 450.50625, 450.5125, 450.51875, 450.525, 450.53125, 450.5375, 450.54375, 450.550, 450.55625, 450.5625, 450.56875, 450.575, 450.58125, 450.5875, 450.59375, 450.600, 450.60625, 450.6125, 450.61875, 455.03125, 455.0375, 455.04375, 455.050, 455.05625, 455.0625, 455.06875, 455.075, 455.08125, 455.0875, 455.09375, 455.100, 455.10625, 455.1125, 455.11875, 455.125, 455.13125, 455.1375, 455.14375, 455.150, 455.15625, 455.1625, 455.16875, 455.175, 455.18125, 455.1875, 455.19375, 455.200, 455.20625, 455.2125, 455.21875, 455.225, 455.23125, 455.2375, 455.24375, 455.250, 455.25625, 455.2625, 455.26875, 455.275, 455.28125, 455.2875, 455.29375, 455.300, 455.30625, 455.3125, 455.31875, 455.325, 455.33125, 455.3375, 455.34375, 455.350, 455.35625, 455.3625, 455.36875, 455.375, 455.38125, 455.3875, 455.39375, 455.400, 455.40625, 455.4125, 455.41875, 455.425, 455.43125, 455.4375, 455.44375, 455.450, 455.45625, 455.4625, 455.46875, 455.475, 455.48125, 455.4875, 455.49375, 455.500, 455.50625, 455.5125, 455.51875, 455.525, 455.53125, 455.5375, 455.54375, 455.550, 455.55625, 455.5625, 455.56875, 455.575, 455.58125, 455.5875, 455.59375, 455.600, 455.60625, 455.6125, 455.61875.

 

[K9WG]

You are probably listening to the signal the field reporter uses to monitor the studio. The reporter will have a UHF receiver so they can tell what is going on and get information about commercial breaks etc.

 

[n7lxi]

Those frequencies are called RPU (Remote Pick Up) channels. Most of the equipment used for broadcast quality audio on VHF and UHF is made by Marti Electronics. The equipment is referred to, at just about every radio station in the country, simply as "the Marti".Remote Pickup Transmitters - SRPT 30

When radio stations send cue audio over a UHF or VHF backhaul channel, it's referred to as IFB, or Interruptable Feedback. Interruptible feedback - Wikipedia, the free encyclopedia That is, the program audio, or a mix-minus feed (program audio without the talent's microphone mixed in) is sent back to the remote talent. It's interruptable by an intercom circuit from the producer or control operator. This allows the talent to know when the commercial break is over, who the next phone caller is, or any other info that the producer needs to convey.

 

[K9WG]

n7lxi - thanks for the information. I use to listen to WIBC during the Indy-500 on their UHF channels. Could hear some real interesting things during commercial breaks.....

 

[n5ims]

As this thread (http://forums.radioreference.com/shortwave-broadcast/224885-wbap-fm-station-receive-france.html) indicates, the remote broadcast signals can sometimes go pretty far. WBAP is a DFW AM station that has IFB signals on UHF and 25/26 MHz band.

One thing that makes the IFB signals used more the last few years is the delay that is used to sync up the audio so the station's "HD" and standard transmissions. The "HD" signal, by design, is between 6 and 8 seconds later (due to the extra processing). With a truely "live" signal, they used to be able to simply listen to the air signal, but with the delay this isn't practical since there would be "dead air" after each commercial break.

 

[n7lxi]

As this thread (http://forums.radioreference.com/shortwave-broadcast/224885-wbap-fm-station-receive-france.html) indicates, the remote broadcast signals can sometimes go pretty far. WBAP is a DFW AM station that has IFB signals on UHF and 25/26 MHz band.

One thing that makes the IFB signals used more the last few years is the delay that is used to sync up the audio so the station's "HD" and standard transmissions. The "HD" signal, by design, is between 6 and 8 seconds later (due to the extra processing). With a truely "live" signal, they used to be able to simply listen to the air signal, but with the delay this isn't practical since there would be "dead air" after each commercial break.

Right. One station I worked at used the IFB to send "predelay" to the hosts, so they could still do a live talk program and still have the ability to 'dump" callers that let a bad word slip. For remote set ups, I always liked using the radio channels better than using ISDN or other wired comms. It was easier, more flexible and a lot cheaper.

 

[n5ims]

Right. One station I worked at used the IFB to send "predelay" to the hosts, so they could still do a live talk program and still have the ability to 'dump" callers that let a bad word slip. For remote set ups, I always liked using the radio channels better than using ISDN or other wired comms. It was easier, more flexible and a lot cheaper.

Same idea, but different type of delay. That's a standard delay used as you indicate to dump foul language. The delay I was referencing is used to make the "HD" channel audio and standard analog audio be in sync. The way IBOC works is if there's enough signal for the HD version of the program it uses that and if not it uses the analog version. Without this delay the receiver would either skip or repeat about 6 seconds worth of the program as the user's receiver switches between the two (as can happen often while driving in an urban area). This is described here --> The IBOC handbook: understanding HD ... - David P. Maxson - Google Books