Verifying RRDB Data for Ventura County

[kj6psg]

I've been going through the RadioReference database for Ventura County for some time to make corrections and additions, mostly to the FCC licenses. A lot of the data is over 10 years old, but some things haven't changed aside from narrowbanding. Here's my results so far, starting with County Sheriff:

• Sheriff 2 (155.535) and 4 (159.210) are under WQFZ352, not WPMA238. WPMA238 doesn't cover these pairs. Sheriff has a mix of licenses that combine to form their simulcast.
• Sheriff 3 (156.150) is under WZX690, not WPMA238.
• All licenses for Sheriff 6 / PD Band 5 (156.015) are under KHQ28 or KK2948; I'm inclined to believe it's KHQ28. KNNN385, which is listed for the license in existing RRDB data, is Ventura County CCD Campus Police's license. Ventura PD and Oxnard PD also need updates to reflect this.
• I don't know if either of the Sheriff Detective frequencies are in use, since both are now inputs to Fire channels that didn't exist when these were added to the RRDB.
• I don't monitor airband so I have no way to tell if this is correct, but VCSD Helo has a license (KBC2) for 122.950, not 129.950.
• The license for the Juvenile Justice Complex on 851.700 is WPSR226, not WSPR266.

County Fire is covered almost entirely under KMB552, and only a handful of their frequencies use other licenses.

• County Fire Command 14 is under KMB552.
• County Fire Command 17 is probably KMJ940.
• The old Oxnard Fire repeater is still on the air, using the 154.145 / 156.210 pair, CTCSS 141.3, under WPME903. I haven't heard it in use, but it's not in my scan lists. I don't have a current name for it, but you might!

The configuration of the County Services repeaters is fairly interesting and quite janky. There's several different repeaters, seems to be about 3 per pair, that are each configured with a variety of tone pairs. Some output tones are shared across the repeaters, and the input tones are usually split to prevent all repeaters on the pair from keying up and interfering with each other (they never share an input tone on the same frequency). The repeaters are all quite different; they have different hang times, one drops PL on transmit, and one is still wideband with CWID for an expired license. They aren't used too often but you'll hear Animal Control. I have no idea who is using what tone, or if they're even still using LMR.

• The 153.785/158.775 pair is under KXQ695 and I've logged tones 67.0, 107.2, 123.0, 127.3, 141.3, 162.2, and 186.2.
• There might be a 153.800/158.850 pair as WPLP441 but I've never heard it.
• The 153.815/158.745 pair is under KMM468 and I've logged tones 107.2, 123.0, 127.3, 141.3, and 162.2.
• The 153.845/158.940 pair is under KMM468 and I've logged tones 107.2, 123.0, 127.3, 141.3, and 162.2.
• There's a FB2 license, WQRA484, on Hall and Laguna for 153.920 MHz, but I've never heard anything on that frequency.
• Any of the County Services channels listed with an input other than this in RM mode (like Animal Control 1) should be updated with the correct pair.
• County Animal Control 2 is under KXQ695, not KHQ28.
• County Parks Department's output is listed as 154.385, while it should be 153.815.
• County Public Works is listed under KME545 while it should be under KMM468.

Data for the cities is mostly correct:

• Simi Valley LG Interop is on a +3 MHz split, standard for T-Band, with an input of 485.2125, not 487.2125.
• Ventura Police is in an interesting situation, since they haven't actually licensed Band 2 for the hilltops it's on (Grant Park comms site, Willis Peak, Hall Mountain). The closest license is KCP553, which covers FB2 operation at the station. WPNZ729, which covers Band 1 and Band 3, was never updated for 154.175 MHz from 155.625 MHz.
• The input for Oxnard Public Works, 153.965, is 159.285 per its license.
• I had a note somewhere that the input for Oxnard PD Band 3 was incorrect, but I need to go monitor for the correct value if so. It wasn't far off.

The WPVJ709 license covers the LARTCS pairs taken out of the old radiotelephone service. There is supposed to be a LA-RICS site on South Mountain in the distant future under WPNP718, so perhaps there is/was LARTCS on South as well? It's not something I pay much attention to.

Narrowbanding is complete on all frequencies, and the modes for the frequencies subject to narrowbanding (above 150 MHz, below 470 MHz) should all be updated from FM to NFM if not done so already so scanners use the correct audio levels and/or receiver bandwidth. The only exceptions are the disused county services repeater(s) and maybe a user of 155.145 MHz.

I haven't submitted this to the database yet since I haven't actually finished going through everything (such as the Education frequencies, which I understand some are in the process of transitioning into VHF DMR), and I want to make sure there's no errors or overlooked details before submitting.

 

[es93546]

I've been going through the RadioReference database for Ventura County for some time to make corrections and additions, mostly to the FCC licenses. A lot of the data is over 10 years old, but some things haven't changed aside from narrowbanding. Here's my results so far, starting with County Sheriff:

• Sheriff 2 (155.535) and 4 (159.210) are under WQFZ352, not WPMA238. WPMA238 doesn't cover these pairs. Sheriff has a mix of licenses that combine to form their simulcast.
• Sheriff 3 (156.150) is under WZX690, not WPMA238.
• All licenses for Sheriff 6 / PD Band 5 (156.015) are under KHQ28 or KK2948; I'm inclined to believe it's KHQ28. KNNN385, which is listed for the license in existing RRDB data, is Ventura County CCD Campus Police's license. Ventura PD and Oxnard PD also need updates to reflect this.
• I don't know if either of the Sheriff Detective frequencies are in use, since both are now inputs to Fire channels that didn't exist when these were added to the RRDB.
• I don't monitor airband so I have no way to tell if this is correct, but VCSD Helo has a license (KBC2) for 122.950, not 129.950.
• The license for the Juvenile Justice Complex on 851.700 is WPSR226, not WSPR266.

County Fire is covered almost entirely under KMB552, and only a handful of their frequencies use other licenses.

• County Fire Command 14 is under KMB552.
• County Fire Command 17 is probably KMJ940.
• The old Oxnard Fire repeater is still on the air, using the 154.145 / 156.210 pair, CTCSS 141.3, under WPME903. I haven't heard it in use, but it's not in my scan lists. I don't have a current name for it, but you might!

The configuration of the County Services repeaters is fairly interesting and quite janky. There's several different repeaters, seems to be about 3 per pair, that are each configured with a variety of tone pairs. Some output tones are shared across the repeaters, and the input tones are usually split to prevent all repeaters on the pair from keying up and interfering with each other (they never share an input tone on the same frequency). The repeaters are all quite different; they have different hang times, one drops PL on transmit, and one is still wideband with CWID for an expired license. They aren't used too often but you'll hear Animal Control. I have no idea who is using what tone, or if they're even still using LMR.

• The 153.785/158.775 pair is under KXQ695 and I've logged tones 67.0, 107.2, 123.0, 127.3, 141.3, 162.2, and 186.2.
• There might be a 153.800/158.850 pair as WPLP441 but I've never heard it.
• The 153.815/158.745 pair is under KMM468 and I've logged tones 107.2, 123.0, 127.3, 141.3, and 162.2.
• The 153.845/158.940 pair is under KMM468 and I've logged tones 107.2, 123.0, 127.3, 141.3, and 162.2.
• There's a FB2 license, WQRA484, on Hall and Laguna for 153.920 MHz, but I've never heard anything on that frequency.
• Any of the County Services channels listed with an input other than this in RM mode (like Animal Control 1) should be updated with the correct pair.
• County Animal Control 2 is under KXQ695, not KHQ28.
• County Parks Department's output is listed as 154.385, while it should be 153.815.
• County Public Works is listed under KME545 while it should be under KMM468.

Data for the cities is mostly correct:

• Simi Valley LG Interop is on a +3 MHz split, standard for T-Band, with an input of 485.2125, not 487.2125.
• Ventura Police is in an interesting situation, since they haven't actually licensed Band 2 for the hilltops it's on (Grant Park comms site, Willis Peak, Hall Mountain). The closest license is KCP553, which covers FB2 operation at the station. WPNZ729, which covers Band 1 and Band 3, was never updated for 154.175 MHz from 155.625 MHz.
• The input for Oxnard Public Works, 153.965, is 159.285 per its license.
• I had a note somewhere that the input for Oxnard PD Band 3 was incorrect, but I need to go monitor for the correct value if so. It wasn't far off.

The WPVJ709 license covers the LARTCS pairs taken out of the old radiotelephone service. There is supposed to be a LA-RICS site on South Mountain in the distant future under WPNP718, so perhaps there is/was LARTCS on South as well? It's not something I pay much attention to.

Narrowbanding is complete on all frequencies, and the modes for the frequencies subject to narrowbanding (above 150 MHz, below 470 MHz) should all be updated from FM to NFM if not done so already so scanners use the correct audio levels and/or receiver bandwidth. The only exceptions are the disused county services repeater(s) and maybe a user of 155.145 MHz.

I haven't submitted this to the database yet since I haven't actually finished going through everything (such as the Education frequencies, which I understand some are in the process of transitioning into VHF DMR), and I want to make sure there's no errors or overlooked details before submitting.

Good comment! If I were you I would make database submissions with what you have before gathering data for the entire county. You have useful information that people can use right now. If you have an error, then correct it with a submission as soon as you find it. Given the detail of your comment, I'm thinking an error is unlikely.

Lots of people don't see the importance of having the correct FCC license listed. I use those all the time when I want specifics about repeater locations. I know I can click my way to the FCC website for just that license and never have to open the FCC website in another tab to do so. I've also found some frequencies a department has licensed, but isn't in the database. I put those in my scanner and every once in a while hear the frequency being used simplex for work or tactical channel. Someone in town once asked me what the town road department was using at work sites where traffic is routed onto a single lane because the other lane is closed for the work. I knew of one licensed, but apparently never used frequency, that was not in my scanner. I put it in my scanners and found they were using it for such things. There is the potential to make even more significant discoveries.

I've experienced loading things into my scanners and the FM and FMN not being correct. Most notably when I've loaded a FM channel, not knowing it was a FMN channel, and not programming it for audio boosting. I think I've got a dead carrier sometimes and if I'm not logging my receptions and I'm in another room, not looking at the scanner, it gets pretty confusing.

Keep up the outstanding work. We need more members like you. My wife and I don't visit Ventura County at all anymore. We lost the 2 friends we had there. I've reached the age of 70 and this is happening more often. "Getting old is not for sissies."

 

[kj6psg]

From some discussion in PM:

• I had the callsign for Oxnard Fire 154.145 wrong; it's WPME903.
• 122.950 and 129.950 are very different things; 129.950 is under KPV3 and 122.950 is UNICOM. I haven't touched airband in a decade so these are things I can't verify myself.
• 158.850 is not a Fire channel; it's (supposedly) the input to the 153.920 repeater. Someone I know who visited a site (or sites) it's licensed for said that there was no equipment on that channel at that location(s). It's possible that the channel(s) have been repurposed or eliminated altogether.

I've experienced loading things into my scanners and the FM and FMN not being correct. Most notably when I've loaded a FM channel, not knowing it was a FMN channel, and not programming it for audio boosting. I think I've got a dead carrier sometimes and if I'm not logging my receptions and I'm in another room, not looking at the scanner, it gets pretty confusing.

Setting a narrowband channel as wideband causes low audio levels and worse SNR (noise power is a function of bandwidth). On some receivers and/or channels, CTCSS decode may fail as the CTCSS tone deviation is also halved; I've experienced this on VCSO channels with a Motorola XTS5000. A dead carrier shouldn't happen unless there's AM demodulation on FM or vice-versa. As 15 kHz, and now 7.5 kHz, adjacent-channel packing happens more often nowadays, using the correct bandwidth wherever possible is more important now than it was in 2005.

 

[LAflyer]

As a reminder, do not submit just based on FCC license info. Not only can the info be stale, we well know users don't always comply or configure their systems per their licenses.

Instead, kindly submit based on confirmed data.

Lastly, about narrow banding date having passed, I can confirm first hand there are multiple governmental users in LA County for example that are not compliant, so one should not assume everything is NFM today.

 

[kj6psg]

As a reminder, do not submit just based on FCC license info. Not only can the info be stale, we well know users don't always comply or configure their systems per their licenses.

Instead, kindly submit based on confirmed data.

Lastly, about narrow banding date having passed, I can confirm first hand there are multiple governmental users in LA County for example that are not compliant, so one should not assume everything is NFM today.

The results are from real data, and the FCC license callsign updates are to allow real data to match license data as best as possible. I check narrowbanding status usually against CTCSS deviation, but sometimes against peak voice deviation. CTCSS deviation is a better sign of narrowbanding status since narrowband users on the input will produce a roughly narrowband signal on the output, even if the repeater is still operating wideband. I've seen plenty of mismatches between FCC data and real installations.

 

[KK6ZTE]

The results are from real data, and the FCC license callsign updates are to allow real data to match license data as best as possible. I check narrowbanding status usually against CTCSS deviation, but sometimes against peak voice deviation. CTCSS deviation is a better sign of narrowbanding status since narrowband users on the input will produce a roughly narrowband signal on the output, even if the repeater is still operating wideband. I've seen plenty of mismatches between FCC data and real installations.

I think he's more warning against guys who spam the DB with updates they find on their endless google searches and aren't even on the same side of the country.

 

[kj6psg]

That's fair. I'll be verifying narrowbanding status on all channels I can hear before finally submitting.

 

[kj6psg]

I'll be verifying narrowbanding status on all channels I can hear before finally submitting.

I took some measurements of CTCSS deviation and compared them to decode thresholds for wide/narrowband limits. Everything I checked is in the 'likely narrowband' category. Narrowband should be about 300-500 Hz deviation (12-18%), and wideband should be 500-950 Hz deviation (10% - 19%). It's not a foolproof method of verifying channel bandwidth as misconfiguration can produce out-of-spec values, but it's a quick way of sorting things into 'probably wideband' or 'probably narrowband' as the low end of narrowband CTCSS deviation isn't enough to trigger a wideband CTCSS decoder; my radios need about 6.5% of full deviation for CTCSS to decode. Since they're able to communicate and hear each other, they're probably using the channel bandwidth matching their CTCSS deviation. Quantars seem to like to encode CTCSS at 17-18% unless manually configured to do otherwise, and a lot of the VHF public safety transmitters around us are Quantars.

I took the measurements with SDR and a flat FM demodulator. I take my recordings the same way, so I was able to recover deviation values from past audio; much easier than waiting for a system to be active. Conversion from audio levels to Hz deviation was done by finding the difference in audio level when tuning +5 and -5 kHz away from an unmodulated carrier to determine how many units in audio level correspond to a 10 kHz swing, then verifying that a 1247 Hz tone at 1st Bessel null gives a +/- 3 kHz deviation reading. I take a recording of the transmitter being tested, apply a notch-pass filter to the CTCSS tone frequency, measure the audio levels in the resulting tone, and use my previous calibration to figure out the tone's original FM deviation. I'd be surprised if there were more than a 25 Hz error in my readings.

The County simulcast system runs narrower CTCSS deviation than standard, about 250 Hz / 10%, for both sheriff and fire. If you're finding inconsistent CTCSS decode on their channels when using older equipment, that's why. My BR330T does just fine though.

The one transmitter for County Services on 153.785 with the abnormally low PL deviation doesn't appear to encode its own PL, but rather just retransmit the received PL. If the narrowband conversion was done by simply turning the transmitter's deviation down by half without adjusting the still-wideband receiver, and the units on the input transmit a standard narrowband signal with about 450 Hz CTCSS deviation, then I could see why it's only putting out almost exactly half of what it's should. Pretty gross if you ask me. The telltale sign that CTCSS isn't being regenerated is that the CTCSS deviation varies based on who's talking, and different types of reverse burst should be detectable as well.