Third, undocumented KFI IFB frequency?

[madscanner]

At my location in the eastern San Gabriel Valley, I am able to clearly receive KFI's IFB audio using a rooftop discone on 166.250 MHz (WPSG400) and 450.725 MHz (KPK405).

But I am also hearing the same audio on 165.335 MHz at a very weak level. Its audio is the same ~30 second undelayed audio the other two frequencies exhibit versus the 640 kHz broadcast. And yet nothing comes back for this frequency when searching the FCC ULS database. Is anyone able to receive the same signal? How strong is it where you live? I don't think it's an intermodulation product in my receiver, although anything is possible.

 

[AM909]

I show that area of VHF is government/NTIA allocated, with 12.5 kHz spacing, so 165.335 shouldn't be a valid freq.

I hear it here on 165.3375 with a service monitor and a radio, a mile or two from the KFI 640 kHz transmitter, at about -100 dBm. The RR databases says it's a Coast Guard freq. Maybe the CG is repeating it for some reason?

 

[KevinC]

At my location in the eastern San Gabriel Valley, I am able to clearly receive KFI's IFB audio using a rooftop discone on 166.250 MHz (WPSG400) and 450.725 MHz (KPK405).

But I am also hearing the same audio on 165.335 MHz at a very weak level. Its audio is the same ~30 second undelayed audio the other two frequencies exhibit versus the 640 kHz broadcast. And yet nothing comes back for this frequency when searching the FCC ULS database. Is anyone able to receive the same signal? How strong is it where you live? I don't think it's an intermodulation product in my receiver, although anything is possible.

Is 166.250 extremely strong? Your 165.335 may be 165.340, which is twice the second IF (455 KHz) lower that most scanners use.

 

[AM909]

I'm pretty sure the signal is there, on 165.3375. [i.e. that it's not an image]

 

[prcguy]

I'm hearing 165.335 very weak about -103dBm on an R8600. The 166.250 is -88dBm on the same radio, same antenna.

 

[mikegilbert]

Could be an old Marti wideband FM STL or RPU transmitter.

 

[AM909]

With a poor antenna, a couple miles from the 640 TX, with a different service monitor, I see 166.2500 at about -75 dBm and 165.3375 at about -85 dBm. Audio on both seems identical to the 450.725 audio, at least for the last few minutes.

There's a morse ID fairly frequently (like every 5 minutes), but it's pretty low dev. If someone hears it strong enough and wants to record it, we could probably filter out the human chat enough to read it. (I can't stand to listen to it long enough) Chances are, though, it might just say what I logged on 166.25 a couple years ago, which was "DE KTLA" for some reason.

 

[madscanner]

Thanks for the responses, everyone. It appears my receiver was set to 5 kHz spacing when scanning that range. 165.3375 is probably correct.

That said, 166.25 is not full quieting for me, but it is close to it. And since 166.25 - 165.3375 / 2 = 456.25 kHz, a 455 kHz-spaced difference frequency intermodulation product of 166.25 certainly looks plausible at this point.

However, with these other reports of hearing it too in spite of 166.25 being weak for others, I'm wondering if that spacing is merely a coincidence after all.

Does anyone have a directional antenna they could compare the peak strengths of 166.25 and 165.3375 with? If they peak when pointed in different directions...

@AM909 - Could you have unwittingly logged "DE KTLA" from 161.685 instead? That's KTLA's IFB. (Back in the good old days, I used to hear Marta Waller on the set, chewing out and lecturing her co-anchors on the proper ways of addressing her.)

 

[AM909]

Thanks for the responses, everyone. It appears my receiver was set to 5 kHz spacing when scanning that range. 165.3375 is probably correct.

That said, 166.25 is not full quieting for me, but it is close to it. And since 166.25 - 165.3375 / 2 = 456.25 kHz, a 455 kHz-spaced difference frequency intermodulation product of 166.25 certainly looks plausible at this point.

The 455 kHz IF image was the first thing I considered, but it would require a single-conversion receiver, which seemed unlikely. I effectively ruled that out by hearing it with three different receiver designs. It would also be 2.5 kHz off-channel from the 165.34 image freq – it's about 150 +/- 50 Hz high of 165.3375.

It's probably 25 kHz nominal bandwidth (highs start getting cut off if I set BW to 12.5 kHz).

@AM909 - Could you have unwittingly logged "DE KTLA" from 161.685 instead? That's KTLA's IFB. (Back in the good old days, I used to hear Marta Waller on the set, chewing out and lecturing her co-anchors on the proper ways of addressing her.)

It's entirely possible that I was suffering a lack of wit. However, I remember thinking it was unusual at the time. I listened for a while and it appears to have multiple IDs that are each on about a 10-minute cycle.

 

[madscanner]

The 455 kHz IF image was the first thing I considered, but it would require a single-conversion receiver, which seemed unlikely.

That was my hunch as well, since the receiver I'm using is a triple conversion model -- a Pro-2006 retired from most things except ham. But it's also pushing 35, and with my memory of the analog circuitry mechanics of single, double, and triple conversion similarly aging, I wasn't feeling confident enough to state flat out it couldn't be my radio developing some age-related senility.

I effectively ruled that out by hearing it with three different receiver designs. It would also be 2.5 kHz off-channel from the 165.34 image freq – it's about 150 +/- 50 Hz high of 165.3375.

Thanks. In that event, considering the frequency's allocation to federal users, the signal is quite a mystery. I can't imagine any reason they would want KFI's undelayed IFB audio in their spectrum. Besides, their radios would be versatile enough to program in 166.25 in RX-only mode if they really needed to hear it.

Could this be an extreme case of the "rusty bolt effect" happening at the transmitter site on account of a non-linear re-radiator right next to 166.25's transmitting antenna?

Still hoping someone with a directional Yagi can chime in.

It's entirely possible that I was suffering a lack of wit. However, I remember thinking it was unusual at the time. I listened for a while and it appears to have multiple IDs that are each on about a 10-minute cycle.

I spent some time digging. The WPSG400 license indicates that 166.25 lives at 250 Mesa Lila Road in Glendale. Google Earth shows that to be the address of the mouth of a very long dirt road leading away from a residential neighborhood into the Verdugo mountains. It eventually swings around and connects up to a radio site east of Verdugo Peak itself, whose written site description in this Glendale city document matches what I see visually in Google Earth. One of the Panoramio images at that location is labeled "Tribune Ktla TV Tlesoft Corporation" (also here).

Just a guess: KTLA has something up there, 166.25 is co-located with it, and you partially decoded "WPSG400 DE KTLA"?

 

[nd5y]

Are there any NOAA weather transmitters in the same area?
See if you can hear them in the 161.48-161.65 range.

PRO-2006s can have images about 0.91 MHz lower than the actual frequency.

 

[prcguy]

Are there any NOAA weather transmitters in the same area?
See if you can hear them in the 161.48-161.65 range.

PRO-2006s can have images about 0.91 MHz lower than the actual frequency.

Its not an image, its real. I'm picking it up on several radios here including a Harris XG-100M.

 

[sovrcat]

Confirmed in Pasadena CA December 2025 on 450.725MHz. Very clear signal for music broadcast, no noise on my bowelfeng when they are broadcasting. Poor sound quality (from their mic?) while talking, amplitude of their mic is off, topics about UFO conferences / politics, weird people shilling their alternative medicine or dating services. Every few minutes plays morse code sequence. Creepy!

 

[ENGINEERCARL1]

Confirmed in Pasadena CA December 2025 on 450.725MHz. Very clear signal for music broadcast, no noise on my bowelfeng when they are broadcasting. Poor sound quality (from their mic?) while talking, amplitude of their mic is off, topics about UFO conferences / politics, weird people shilling their alternative medicine or dating services. Every few minutes plays morse code sequence. Creepy!

Somebody turned the old UHF Quantar back on at Mt. Wilson I guess. I used to hate having to reset that thing every third day because the audio would flatten out and get useless...

EC

 

[madscanner]

Somebody turned the old UHF Quantar back on at Mt. Wilson I guess. I used to hate having to reset that thing every third day because the audio would flatten out and get useless...

Were you on KFI's engineering staff, or are you talking about having to reset a different Quantar at some other station?

Back when KFI started truncating their analog broadcast audio at 5 kHz to squeeze in IBOC, that 450.725 broadcast auxiliary transmitter became my preferred listening method. It was one of the widest "narrow FM" signals I had ever heard through my Pro-2006, which easily passed audio up to 8 or 9 kHz. At my location through a second story discone, the signal was also full quieting. All it lacked was bass, but that wasn't catastrophic for talk.

Anyway, if it was actually you keeping 450.725 on the air for KFI, then consider this my decades-late thanks.

 

[ENGINEERCARL1]

Were you on KFI's engineering staff?

Yes. From 2000 to 2006 myself, A. O. “Tony” Dinkel, and the Chief Engineer John Paoli took care of the AM properties KFI, KLAC and KXTA. Toward the latter part of that after all the properties were co-located in Burbank, 1150 was added.

Back when they started truncating their analog broadcast audio at 5 kHz to squeeze in IBOC, that 450.725 broadcast auxiliary transmitter became my preferred listening method.

You, and more than a handful of LAPD officers that had it programmed into a spare zone on their Rovers…

It was one of the widest "narrow FM" signals I had ever heard through my Pro-2006, was much more dynamically-relaxed sounding (pre-Optimod I suppose),

It was processed a bit, and went up on a T1 with the rest of the programming for KOST (the Quantar was in the same building as the KOST FM Tx).

and at my location through a second story discone, the signal was full quieting. All it lacked was bass, but for talk programming, that wasn't catastrophic.

Anyway, if that was you, then despite this being a couple decades too late, thanks for constantly resetting that thing.

It was literally a telemetry switch on the KOST Moseley remote control. Since I was the morning guy that had to deal with Bill Handel, I’d have an UHF HT so I could hear pre-delay and still go around and do work. So if the audio was flat, I’d have to reset it or I wouldn’t know what was going on.

But you’re welcome. That was a wild 5+ years, and accelerated my career.

EC

 

[madscanner]

Yes. From 2000 to 2006 myself, A. O. “Tony” Dinkel, and the Chief Engineer John Paoli took care of the AM properties KFI, KLAC and KXTA. Toward the latter part of that after all the properties were co-located in Burbank, 1150 was added.

Very cool, and kudos. John's name rang a bell, and then I remembered he's the CE whose memorial is hanging on the wall of the transmitter building. (I saw the Marv Collins tour video on Youtube long ago, and the various pages Scott Fybush dedicated to the property over time.) It must have been a great place to work as an engineer. Even past the era of big budgets being spent on AM, KFI was always a very well-engineered sounding signal.

As for 450.725, I never knew what that was, so your mentioning it was a Quantar surprises me. I thought Marti made most of the 450 MHz RPU transmitters in the wild. Do you remember the model or anything? I'd get a kick out of looking at its technical specifications, as I'm pretty sure it came close to topping out my Pro-2006's full audio bandwidth in NFM mode, which was (surprisingly) around 8 to 9 kHz according to the spectral view in Adobe Audition.

I only ever heard one NFM signal through that 2006 that was crispier than KFI's Quantar. It was a simplex dispatcher's base station transmitter for a senior citizen shuttle bus service called "TLC" in Azusa. It was licensed to use an antiquated 39 MHz frequency, so I always guessed that they had vintage 1960s equipment opened up to 10 kHz or something.

You, and more than a handful of LAPD officers that had it programmed into a spare zone on their Rovers…

I always wondered how popular those things were with unintended listeners. Some of the stuff you would hear on them definitely wasn't what the people speaking would've wanted getting out. I recall when KTLA's 160 MHz band IFB constantly leaked their production control switcher's audio output. You could hear everything pre-master control, including people talking on the set before the 10 o'clock news began, and sometimes during breaks. One night, I got to hear Marta Waller give Emmet Miller a vicious verbal thrashing on the proper way of addressing her.

It was processed a bit, and went up on a T1 with the rest of the programming for KOST (the Quantar was in the same building as the KOST FM Tx).

Well, versus the intense 5 or 6 band multiband processors customarily used for AM density build-up, whatever protection limiting and monoband compression 450.725 had on it was comparatively relaxing to my ears. In fact, these days, it's the only way I can listen to KFI without hearing the Voltair PPM watermarking enhancement. So it's still providing a public service in my book!

 

[ENGINEERCARL1]

Very cool, and kudos. John's name rang a bell, and then I remembered he's the CE whose memorial is hanging on the wall of the transmitter building. (I saw the Marv Collins tour video on Youtube long ago, and the various pages Scott Fybush dedicated to the property over time.) It must have been a great place to work as an engineer. Even past the era of big budgets being spent on AM, KFI was always a very well-engineered sounding signal.

John was the most amazing guy to work for. Very low key, and had the patience to help me when I’d get too deep in the weeds with a project, like the custom delay control I built for KLAC and the Lakers control rooms. I was devastated when he died suddenly, and when I’m in SFO I stop my and pay my respects where he is interred.

As for 450.725, I never knew what that was, so your mentioning it was a Quantar surprises me. I thought Marti made most of the 450 MHz RPU transmitters in the wild. Do you remember the model or anything? I'd get a kick out of looking at its technical specifications, as I'm pretty sure it came close to topping out my Pro-2006's full audio bandwidth in NFM mode, which was (surprisingly) around 8 to 9 kHz according to the spectral view in Adobe Audition.

It’s not hard to wideband a Quantar. Tony loved UHF two-way (he had 446.12 in OC), so I’m not surprised he souped it up.

I only ever heard one NFM signal through that 2006 that was crispier than KFI's Quantar. It was a simplex dispatcher's base station transmitter for a senior citizen shuttle bus service called "TLC" in Azusa. It was licensed to use an antiquated 39 MHz frequency, so I always guessed that they had vintage 1960s equipment opened up to 10 kHz or something.


I always wondered how popular those things were with unintended listeners. Some of the stuff you would hear on them definitely wasn't what the people speaking would've wanted getting out. I recall when KTLA's 160 MHz band IFB constantly leaked their production control switcher's audio output. You could hear everything pre-master control, including people talking on the set before the 10 o'clock news began, and sometimes during breaks. One night, I got to hear Marta Waller give Emmet Miller a vicious verbal thrashing on the proper way of addressing her.

I had a copy of a tape one time that a scanner listener had sent to our PD of a rather spicy conversation between a weekend board op and the traffic girl. The traffic girl was relating a rather successful hookup she’d had the night previous…

Well, versus the intense 5 or 6 band multiband processors customarily used for AM density build-up, whatever protection limiting and monoband compression 450.725 had on it was comparatively relaxing to my ears. In fact, these days, it's the only way I can listen to KFI without hearing the Voltair PPM watermarking enhancement. So it's still providing a public service in my book!

If I remember back that far, he probably just hung either an Aphex Compellor or a DBX 212 on it, more for level gain and minor soft limiting than anything else. Other than that, it was just another output on the pre-delay DA (that just happened to have an IFB interrupt on it).

 

[madscanner]

John was the most amazing guy to work for. Very low key, and had the patience to help me when I’d get too deep in the weeds with a project, like the custom delay control I built for KLAC and the Lakers control rooms. I was devastated when he died suddenly, and when I’m in SFO I stop my and pay my respects where he is interred.

I miss the days when most radio was still locally or at least regionally owned, and people like that were everywhere. Alas.

It’s not hard to wideband a Quantar. Tony loved UHF two-way (he had 446.12 in OC), so I’m not surprised he souped it up.

Custom modifications certainly explain why it sounded so crispy. All the other L.A. users of the 450 and 455 bands sound telephonic by comparison. Every so often, I encounter a ham repeater whose input and output are passing more than the usual dreary 300 to 3000 Hz. Sometimes, one operator with a modern-ish radio limited to 3 kHz, and another with something very vintage, will chime in simultaneously, and the difference is like day and night (example). I've often wondered why this modern mediocrity got accepted by the amateur and business/government two-way worlds alike, and then stuck around for as long as analog lasted. Having only done it for SSB spectrum efficiency on the crowded HF bands would've made sense. But above HF, why was everyone content (and on the analog ham bands today, why are they still content) to sound so bad when they didn't (and still don't) need to?

I had a copy of a tape one time that a scanner listener had sent to our PD of a rather spicy conversation between a weekend board op and the traffic girl. The traffic girl was relating a rather successful hookup she’d had the night previous…

lol, wow. I hope that PD had a sense of humor and just showed the traffic girl how to use the intercom locally, rather than doing anything disciplinarian (or worse) to her career.

 

[ENGINEERCARL1]

I miss the days when most radio was still locally or at least regionally owned, and people like that were everywhere. Alas.

I ran into Lowry Mays (then, the uber-boss of Clear Channel) at the inauguration party for the new studios in Burbank. He asked me what I did (in that characteristic Texas drawl of his) and when I responded that I was part of engineering for KFI he replies, "Oh! Take care of that ole' girl for me..."

Custom modifications certainly explain why it sounded so crispy. All the other L.A. users of the 450 and 455 bands sound telephonic by comparison. Every so often, I encounter a ham repeater whose input and output are passing more than the usual dreary 300 to 3000 Hz. Sometimes, one operator with a modern-ish radio limited to 3 kHz, and another with something very vintage, will chime in simultaneously, and the difference is like day and night (example). I've often wondered why this modern mediocrity got accepted by the amateur and business/government two-way worlds alike, and then stuck around for as long as analog lasted. Having only done it for SSB spectrum efficiency on the crowded HF bands would've made sense. But above HF, why was everyone content (and on the analog ham bands today, why are they still content) to sound so bad when they didn't (and still don't) need to?

If KFI is still using MA1 (the combination analog/HD modulation scheme for AM radio) I'd start to wonder why. Before the tower fell down we were having a hard time trying to pass the entire 10 kHz through the tuning house. With the new tower I'm sure it's engineered to pass without excessive spectrum regrowth...but nobody really wants it anymore. There are too many other avenues for the content (streaming & KOST HD2 to name just 2).

lol, wow. I hope that PD had a sense of humor and just showed the traffic girl how to use the intercom locally, rather than doing anything disciplinarian (or worse) to her career.

At that time the only local traffic origination in-house was Mark Denis mid-days, and Mike Nolan drive-times. Anybody else you heard came from Shadow Traffic in mid-town LA. So a local option for an intercom wasn't really an option, and the AMX-36 console used in KFI Airmix only had a finite number of talkback busses.

Carl