Can anyone explain whats on 450.7 MHz ?

Except for the hum, the sound quality is superior.
Also, its way ahead of the other frequency mentioned often.

Did you check the FCC database to see if it is licensed???

Actually, its pretty obvious whats on 450.7 MHz since I have been listening there for quite a while.
My question really is, Why? Whats the purpose?
No I didn't go to the fcc database. I suspect that would not explain it much. Other than perhaps Who is behind it, unless its a pirate.

Perhaps KC23594 Lic. to Citicasters ?

http://dettifoss.fcc.gov/acweb/viewer/viewframeset.jsp?__executableid=208&id=150 835&connectionhandle=q7whmBpUho%2btg5MUYUgZxq1%2brbtKHLkAq7RmnwSbegyRYEMWxKx8m0p EgUAaXCZHB8MSDImIexxWt7foY7wBuIMEv18lQxjMCQCTjGYfVbM%3d&closex=null&outputname=% 2fgenmen%5fa%2fdb%5f19%2fd%5fadmin%5fl%5flm.roi&saveoutput=false&outputType=ROI& serverurl=http%3a%2f%2fdettifoss%3a8088&volume=dettifoss8

I hear it fine in Hillsboro on my Icom 8500 (about S-8) using a small UHF antenna. Sounds good in "wide FM" (150 Khz) mode... I hear the hum and distortion in "FM" (12 Khz) & "narrow FM" (5.5Khz) mode.

Since it is "pre IBOC delay" it might be a STL.

Could the purpose of this signal be to send cues to talent at live remotes? It would be interesting to take a listen when they are doing a live remote or an on-the-scene news report. This signal is in a band that is often used for broadcast auxiliary purposes. Unfortunately, I don't have a receiver that covers this frequency.

If I'm not mistaken. There is a database on the SBE 124 web site. That list some of the users. Using that frequency in the Portland area. That should help narrow down a bit.

Speaking of the SBE 124 web site. I've noticed over the past few weeks. This web page does not came up. Could it be down, or just off the air in Engineering jargon.

"This web page does not came up."
Does not came up?????

It comes up everytime I try it, which is often. I just tried it and it works fine.

The "hum" could be the 27 Hz repeater control tone. 450.700 can be used for wideband audio for temporary STLs, remote broadcasts, etc...

I first notice this mystery 450.7 broadcast about 2 months ago. I had not been looking on that band for along time before that, so it may have been there quite a long time.
I believe its 24/7 since I noticed it. Every time I listen, random days/times, its there. Thats a long time for a remote broadcast.
The "hum" is continuous, sounds to me like harmonics of 60hz. My uhf speaker does not do bass.

It's unclear from the posts what is being broadcast on the freq., but the SBE database (not updated, but for this freq. it's probably pretty accurate) yields the following:





450.7000 KWJJ PORTLAND Portland KC-24272 MIKE EVERHART, CE (503)-228-4393
Use: RPU How Used: Shared
Receive Antenna Omni Transmitter Antenna Yagi
Emission 50F3 Ground Level 1015.0 Center of Radiation 607.0
Transmitter Location : Mobile
Receiver Location : KGON Tower, Healy Heights, Portland, OR


450.7000 KEWS PORTLAND Portland, OR KC-23594 BYRON SWANSON, DE (503)-295-9233 (503)-227-5873
Use: RPU How Used:
Remarks: MARTI
Xmit Latt/Long : / Rec. Latt/Long : 45-31-21 / 122-44-46 Azimuth (T): Mobile
Antenna Polarity of this system is V
Emission 50F3 Ground Level 0.0 Center of Radiation 0.0
Transmitter Location : Mobile
Receiver Location : KGW TV Transmitter Site


450.7000 KWSA-AM K.FALLS Klamath Falls Mike McKenna (213)-498-7449
Use: RPU RPT How Used:


450.7000 KUGN (AM) EUG Eugene, OR KB-55633 Ken Broeffle, DE (541)-485-5846
Use: RPU How Used: Primary
Xmit Latt/Long : 44-02-55 / 123-10-04 Rec. Latt/Long : 44-02-55 / 123-10-04 Azimuth (T): Omni
Antenna Polarity of this system is V
Emission 50F3 Ground Level 400.0 Center of Radiation 0.0
Transmitter Location : 422 Commerce St., Eugene, OR
Receiver Location : Same





02/15/03 Page: 42
Oregon/ SW Washington Broadcast Auxiliary Frequency Coordination
Attention: Everett E. Helm at (503)-977-7752
OPB, 7140 SW Macadam Ave.
Portland,, OR 97219-3099
http://www.broadcast.net/~sbe124/
E-Mail: Everett@Helm.net or Everett_Helm@opb.org

FREQUENCY LICENSEE REC. CITY CALL SIGN CONTACT Phone Fax Number
-------------------------------------------------------------------------------- ---------------------------------------------------

450.7000 KATU PORTLAND Wireless Mic ALAN BATDORF (503)-231-4256 (503)-231-4624
Use: Wireless Mic How Used:


450.7500 KRSK-FM Portland, OR KPK-860 GARY HILLIARD (503)-226-9191
Use: Remote Pick Up How Used: RPU, SHARED WITH KGON
Remarks: TX mobile/ RX Healy Heights
Xmit Latt/Long : / Rec. Latt/Long : / Azimuth (T): Omni
Antenna Polarity of this system is V
Transmitter Location : Mobile
Receiver Location : Mobile, Portland Metro Area

I am not hearing KWJJ,KEWS,KWSA,KUGN,KATU nor KRSK on 450.7

So what are you hearing on that frequency then...

I think I just heard an 1190 KEX ID.
....
Yup,1190 KEX ID again.

I noted that the info was not updated. CLEARLY, the entry for KEWS would now read KPOJ, which is the same barn as KEX.

450.700 is a shared freq for broadcasters RPU. It is also available for broadcast wireless microphones.

Move on folks.

So, "KPOJ" is transmitting Rush Limbaugh, Dr. Laura, and all the other 1190 KEX programming on a Mobile transmitter for at least the last 2 months? [Do the KPOJ hosts approve of that?] What is the purpose?

Just curious about the transmission, please dont take it off, because I want the option of hearing "1190" without the 10 second delay, severe filtering, distortion, HD noises, etc.

What if KWJJ, KGON or KATU wants to use the frequency?

"What if KWJJ, KGON or KATU wants to use the frequency?"

I'm sure if that was the case, they (KEX) wouldn't be using it full time.
Also, where do you live geographically? It is possible that the transmission you are hearing is not propagating all over the place.
If you're really curious, call them up and ask them about it.

If Jr_tech gets it good in Hillsboro, and I am on the east side, [I dont know where thatonedude is.], then I suspect the "mobile transmitter" is in the west hills somewhere.

I don't think they would take my call!

It may be that KEX is using a repeater in the west hills to broadcast their on air signal for use as a mix minus IFB, so don't assume it's a mobile that is the source.

Call the area frequency coordinator for everything under 500 MHz,
Mike Steiner (KATU) 503-231-4218 If you can't get through to him call Everett Helm, the everything over 500 MHz guy at OPB.

The fact that two separate teceivers in two separate locations are picking it up pretty much eliminates any wild card anomalies.
(That is to say I've seen malfunctioning receivers have IF problems
that could yield such a result).

I'm in SE,near Gresham..
(Sorry,need to be better about stating my location.)

Can you explain "mix minus IFB" ?
I dont understand.

IFB Interruptible Fold Back In ENG and RENG (electronic news gathering, radio electronic news gathering) the reporter in the field has his little earplug. What is fed to that earplug is the air signal without his contribution (mix minus). This way the reporter can hear the toss to him and any subsequent tape rolls that are not originating from the remote location. All the reporter needs is a pocket UHF receiver or pager or a wire from the remote truck where such a receiver can be located with a better antenna. It is also interruptible by the producer's intercom for cues and necessary updates. During non use hours, usually this kind of system (usually UHF, but used to be VHF 160ishMHz) is turned off so the freq can be used by the assignment editor to track his reporters, but since cell phones came into being, the importance of these auxiliary frequencies has been diminished and in the instant case, they apparently are just letting it transmit the air signal when not in actual use.

The hum sounds alot like what you get if you put your finger in the center conductor of a RCA phono plug connected to the input of an audio amplifier.
[60 Hz + harmonics]

This tells me the 450.7 transmitter was probably connected to the audio source in a "quick and dirty" manner, rather than using an impedance matching balanced to unbalanced (or vice-versa) transformer, or something isn't shielded properly.

I have not heard any behind the scene producer's directions or instructions on 450.7, nor any "mix minus" but maybe I have not listened at the right times for that. I just basicly hear 10 seconds early and with better quality audio (ingore the hum) what then appears on 1190.

Re: Quality ... That's because it's FM and has more bandwidth on the channel to occupy than AM.

RE: Quality.....
No, thats because 1190 chooses to severly chop off all of the audio above about 5Khz, resulting in a dull muffled sound. [Most other AM stations that do not do that, and thus have much better bright and clear sound quality on a good AM radio.] The 450.7 signal does not have the treble filtered out of the audio. Also, 1190 adds HD noise and distortion during the day. In addition, 450.7 sounds "uncompressed", unlike 1190.

Thanks for the information on the IFB! I hadn't thought of the "little earpiece" receivers, but that would certainly be a good use for this.

The processing for the 450.7 MHz signal is going to be different than for the main, IBOC-delayed air feed. Isn't the 5kHz filtering at stations broadcasting IBOC inside the IBOC exciter, anyway?

"Thanks for the information on the IFB! I hadn't thought of the "little earpiece" receivers, but that would certainly be a good use for this. "

You're welcome. 450 auxiliary frequencies have been licensed for a long time for IFB use as well as general 2-way usage,

"The processing for the 450.7 MHz signal is going to be different than for the main, IBOC-delayed air feed. Isn't the 5kHz filtering at stations broadcasting IBOC inside the IBOC exciter, anyway?"

I'm not involved anymore, but I would imagine that is correct, since that has been where the high end normally gets whacked.
I have read that it is steeper than before IBOC, which is why it sounds muffled. I tried to explain previously that on the 450 carrier, the full boat audio is being FM'd with probably 10k of bandwidth available, and usually that audio is not processed except for a brute force limiter/clipper that can be part of the 450 transmitter, so being synchronous it will be low noise and high fidelity depending on the quality of the source audio. Trust me, they aren't making any effort to make the 450 feed good, rather the decreased quality of the AM is the result of IBOC. This is a much discussed topic on some of the other radio engineering forums I frequent.

Bottom line .... AM is inherently noisy and bandwidth limited with respect to conventional analog transmission ... period.
It's just that when they layed out the AM broadcast band, things were a lot different. The AM band in the U.S.'s strength is distance, not fidelity. In other parts of the world, they use FM on the lower frequencies that we use for AM, so they get both the distance and the fidelity.

audio low pass filtering is done in the audio processing, not the exciter.

AM is not necessarily "bandwidth limited", unless you got a memo from the VP of engineering suggesting there is corporate policy to whack off everything over 5Khz.
1190 and a couple others locally do 5 khz whacking (day and night), other AM stations locally do approx 10Khz audio. There is significant difference at the receiving end with some radios.
AM audio could easily go beyond +/- 10khz, but there is some rule.
We have discussed this topic around and around over the last few years, Andy, you may have miss out on those discussions.

According to a little research, implementing IBOC requires
limiting the analog bandwidth to 5kHz. It's not the VP engineering's decision, it's a result of going digital.

Several new analog transmitter spec sheets including Harris DX10 AM reveal freq response to only 10kHz. So IBOC rules aside, the xmtr just won't pass anything more. This is achieved
through filtering at the exciter stage.
There is always bandlimiting filtering in a transmitter, hence exciter. It can't pass type acceptance (or whatever type acceptance is called now) without it.

The AM chain has been bandwidth limited both at the xmtr end
(first in the 80's by the FCC/NRSC) and second by the radio receiver manufacturers(in their attempt to minimize ACI).
(see below from ibiquity white paper)

http://www.nrscstandards.org

http://www.ibiquity.com

The US AM channels are presently allocated
with a 10 kHz spacing and 20 kHz bandwidths.
This results in overlapping bandwidths between
first adjacent channels. Over the years many of
the manufacturers of AM automotive receivers
have reduced receiver bandwidths to minimize
the effects of first adjacent channel interference.
Optimal AM performance would be best
achieved if AM channels did not overlap. As a
first step in minimizing this overlap the National
Radio Systems Committee (NRSC) petitioned
the FCC to reduce the AM bandwidth from 30
kHz to the present 20 kHz standard. The NRSC
standard achieved its goal of reducing second
adjacent channel interference, however, it did not
decrease first adjacent channel interference.
Tests conducted in 2001 show that most
automotive receivers in the marketplace have
reduced the bandwidths since the adoption of the
NRSC standard to approximately 3.5 kHz

AM IBOC will limit the analog transmission
bandwidth to 5 kHz, which allows receiver
manufacturers to increase the receivers analog
bandwidth to 5 kHz and eliminate the first
adjacent channel overlap. This will improve the
fidelity of the analog portion of IBOC
transmission and maximize the available
spectrum for IBOC. However, this newly defined
bandwidth is best implemented with audio
processing that has been optimized for a 5 kHz
audio passband.

You missed the VP memos (Clear Channel, and another one) that included ALL of their AM stations (day and night), not just the ones that that have the IBOC installed. Before that VP memo, KEX and also 620 was 10khz (approx) audio, and sounded real good. After the memo took effect (and before HD transmissions), they sounded like opposite-of-good.
The alledged reason was to optimize the reception of the 3.5kHz receivers, and cut interference, but we know that the hidden reason was to dumb down the fidelity of sound on good quality receivers in order to be able to later claim that HD is like way better than analog AM. [note: CC is part owner of ibiquity]
Ibiquity is not an unbiased source of information on this topic.

Getting back to 450.7, could the purpose be "iboc delay workaround" for traffic reporters, on-the-scene news reporters and sportscasts so they know when to talk?

In the satellite work I did in the 90's, whenever real time IFB and air monitoring was possible, it was implemented ... usually over phone lines when out of range of the 450 system.

So it's entirely possible.

BTW, if there is any movement to exploring alternative's to Ibiquity's system I can't find any evidence of it on the net.

Bottom line for me: Short of an occasional Blazer game, I haven't listened to AM radio since I left my position as Chief Engineer/All night DJ of KVAN 1480 in 1978, so whether IBOC works or not nor its impact on analog service means very little to me. There's no music there and talk radio does not interest me.
Come to think of it. FM has all kinds of music but nothing that interests me, either. I listen to my CD changer in the car or my iPod ... 6000 cuts I know I like. Radio died in 1996. I think I said that before (once or twice).

Did you know it's illegal to even tune in these 450 frequencies under the same Federal code that makes it illegal to listen in on cell phones?

http://floridalawfirm.com/privacy.html

We're all going to prison!

Billboise: Sorry... That's not true. There isn't anything illegal with listening to STLs or remote pickups...

BTW, want to hear the KUIK STL? If you're between the Hillsboro airport and the transmitter over by Movies on TV, set your scanner to 950.50 mHz. Also, our remote pickup frequency is 161.70 mHz (at a maximum ERP of 390 watts, WOW), but I think the Marti transmitter is actually only about 50 watts though...

Curious....
I was listening to 450.7 (Drudge Report) tonite and at approx 10PM, 450.7 went totally off the air (no audio, no RF carrier).
Quickly, I went to another radio and tried 1190.
There was 1190 RF Carrier, but not any audio.
About 1 or 2 minutes later, 450.7 came back on with audio and that was followed about 10 seconds later by return of audio at 1190.
Can anybody explain?

Not enough info to really know. The audio feeding the transmitter could have been the audio on 450.7 if they are using it as an STL, but it could have been the failure of another STL, possibly a fiber optic link STL which feeds audio both to the transmitter and the base station/repeater operating at 450 located at the transmitter site, or it could have been the failure of a fiber STL up to west hills where it feeds a microwave link to the KEX transmitter site to carry audio there, and it may feed the 450 service in the west hills where it is used as some kind of IFB as we previously talked about. It may have come back first because some soft switch might have hung when whatever failed went down. Then again, I'm just guessing.