HDFX-FLEX-4k channel not tunable issue - jtespi

Reception, channel detection, network issues, CableCARD setup, etc.
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jtespi
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HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jtespi »

I have the same issue of 1 channel/station not being tunable despite a high signal strength and quality.
All subchannels are affected. When I connected my portable TV to the same antenna as the HDHR tuner box, the TV was able to pick up the station without issue.

I posted this issue in a separate thread because I thought it was related to VLC. VLC just shows 1 still frame while it tries to open the stream.

nickk
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Re: HDFX-FLEX-4k channel not tunable issue

Post by nickk »

jtespi wrote: Mon Aug 30, 2021 8:26 pm I have the same issue of 1 channel/station not being tunable despite a high signal strength and quality.
All subchannels are affected. When I connected my portable TV to the same antenna as the HDHR tuner box, the TV was able to pick up the station without issue.

I posted this issue in a separate thread because I thought it was related to VLC. VLC just shows 1 still frame while it tries to open the stream.
If you are getting a frame of video in VLC then the issue you are seeing is not related this the issue in this thread which is specific to a broadcast issue with channel CFTO-21.

[moderator - thread split]

jtespi
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Re: HDFX-FLEX-4k channel not tunable issue

Post by jtespi »

nickk wrote: Mon Aug 30, 2021 10:55 pm If you are getting a frame of video in VLC then the issue you are seeing is not related this the issue in this thread which is specific to a broadcast issue with channel CFTO-21.
Sorry I wasn't clearer, this is happening to me on a different channel K19LZ-D in Las Cruces, New Mexico, US.
Is there any way to determine what exactly is the issue? I don't think the broadcaster would be able to fix the issue if I am not specific, since regular TV sets don't seem to be affected.

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by nickk »

Can you please turn on "send diagnostic information" from the HDHomeRun device webpage (system menu), then try playing the problem channel. Let it sit for a minute even if the video has stalled at one frame, then post back with the Device ID of your HDHomeRun.

Nick

jtespi
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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jtespi »

Okay, I toggled send diagnostic info off then on again since it was previously turned on. Device ID 10A0D0A6.

On this unit, I'm also having the issue of every successive tuner becoming weaker than the one before it. For example, tuner0 has the highest signal quality % (second bar) and tuner3 has the lowest.
This really only shows up on channels with signal strength below 90% (first bar).
For channels with marginal signal strength, the difference can be enough so that it is unwatchable on tuner3 but fine on tuner0.

However, hopefully this unviewable channel (K19LZ-D) issue can be fixed first - because I don't see a work around for it and it's the ABC/CW affiliate.

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by nickk »

521MHz is reporting 51-52% signal quality which isn't enough for reliable reception.

Reception of K19LZ-D is ok so something else must be going on there. Can you please do a 30s capture:
http://10A0D0A6.local:5004/auto/ch503000000?duration=30

Nick

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jtespi »

Hi Nick, it looks like whatever issue the channel had cleared up a few days ago. I've been able to view it in VLC without issue.
I wonder what the problem was?

Anyways, I still made a 30 sec recording of the channel: https://drive.google.com/file/d/14z1Hja ... sp=sharing

The recording worked fine and it looks like I can finally see the EPG data in VLC from that short recorded snippet. Whenever I launch VLC from the config_gui [using UDP:/127.0.0.1:5000], I can't see any EPG data.

Now my only issue is pesky K22NM; any idea why the signal quality is so low despite the signal strength being above 80%?
According to FCC data, K19LZ should be broadcasting at the same tower site as K22NM but with lower ERP and yet I have no issue receiving K19LZ. I could try contacting the main station behind K22NM (KOB), but when I emailed KOB back in July they said that the tower was operating as usual after some type of maintenance.

I've tried 2 preamps and antennas to try to get K22NM reliably but it seems the best solution is my current one with no preamplifier. Could the full power station KRWG on the next channel (6 MHz away on 527 MHz) be causing the low signal quality? That station is so powerful where I live that just sticking a wire into the coax connector of any TV will let it pick up KRWG.

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jasonl »

K22NM-D is broadcasting at 350 W and KRWG is broadcasting on the adjacent channel at 200,000 W, so that's a difference of 27.57 dB just in power, and that without accounting for differences in location. That could potentially cause signal issues. There's also a channel 22 translator of KOAT in Deming that has some signal spill over into Las Cruces, generally affecting areas east of the line formed by I-25 and I-10, and getting stronger the further east you get towards the mountains, and that would really be a problem in those area. The correct answer here is for KOB to boost the power on K22NM-D to overpower them, but that would require them to reach an agreement KOAT to ignore the interference they cause to each other, and probably also get approval from Mexico, because that's required for stations near the border. I don't think Mexico would care because someone had the good sense to give the US the channels from 27 down and Mexico the channels from 28 up, but you never know.

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jtespi »

jasonl wrote: Tue Sep 07, 2021 6:42 pm K22NM-D is broadcasting at 350 W and KRWG is broadcasting on the adjacent channel at 200,000 W, so that's a difference of 27.57 dB just in power, and that without accounting for differences in location. That could potentially cause signal issues. There's also a channel 22 translator of KOAT in Deming that has some signal spill over into Las Cruces, generally affecting areas east of the line formed by I-25 and I-10, and getting stronger the further east you get towards the mountains, and that would really be a problem in those area. The correct answer here is for KOB to boost the power on K22NM-D to overpower them, but that would require them to reach an agreement KOAT to ignore the interference they cause to each other, and probably also get approval from Mexico, because that's required for stations near the border. I don't think Mexico would care because someone had the good sense to give the US the channels from 27 down and Mexico the channels from 28 up, but you never know.
I just checked the Longley-Rice coverage map of the KOAT repeater K51DS-D and my location in NE Las Cruces is completely blocked from getting a signal of it by the Sleeping Lady Hills which are by the Las Cruces Airport.

A similar map from RabbitEars for K19LZ-D that should be located at the same tower as K22NM-D shows that ch. 19 should be a bit weaker in my area than ch. 22.

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jasonl »

If you plug your address in to the signal search map on RE, what do your field strength and signal margin come up as for those 2 stations? The L-R map on there is a good estimate for your chances of actually receiving a broadcast, but it's using that as a minimum threshold, and not displaying signals that might be enough to interfere but would never be decodable. To make a really simple analogy, your jerk neighbor can drive you crazy having his music too loud at a volume level well below the point where you can actually tell what song he's listening to. Also, it's probably not helping that the two stations are what, 15° apart in compass heading?

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jtespi »

jasonl wrote: Thu Sep 09, 2021 6:04 pm If you plug your address in to the signal search map on RE, what do your field strength and signal margin come up as for those 2 stations? Also, it's probably not helping that the two stations are what, 15° apart in compass heading?
Hi Jason,
The KOB repeater K22NM-D actually comes up as having a slightly stronger signal than KVIA's repeater K19LZ-D. However in my application, the signal is much noisier I assume (since signal strength is in the 80% range while signal quality is barely above 50% most of the time).
  • KRWG (23): 183° true, field strength 108.49 dBµV/m, signal power -21.14 dBm, signal margin 68.83
    K22NM-D: 239° true, field strength 72.58 dBµV/m, signal power -56.95 dBm, signal margin 33.02
    K19LZ-D: 239° true, field strength 69.90 dBµV/m, signal power -59.33 dBm, signal margin 30.65
KRWG and the 2 low-power stations from the Las Cruces airport are 56° apart. KRWG is 10.8 km/6.7 miles from me compared to 24.1 km/15.0 miles for the 2 others.
My antenna is pointed directly at 240° and I'm using the Antennas Direct DB4e 4-element bowtie antenna. Luckily there is a detailed datasheet with a gain vs. azimuth plot. Interestingly, I'm able to receive KFOX - which is 76° E of where my antenna is pointed and the antenna should have a -5 dB gain at that azimuth (285° on the plot).

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jasonl »

Does K51DS-D (or its actual callsign, K22ME-D, for some reason the FCC's LMS site doesn't update callsigns properly and therefore neither does RE) come up on the report, probably down in the gray area at the bottom?

jtespi
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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jtespi »

Yes, it appears further down the list in grey. It is listed lower than two full-power stations from El Paso that I know I can't receive (KVIA and KTSM).

For the KOAT repeater in Deming, RabbitEars says the following:
- Transmitter distance 88.5 km/55 mi; 256° true; Field strength 36.00 dBμV/m; Signal power -93.53 dBm; Signal margin -3.56 dB.

I'm pretty sure I'm not getting any meaningful interference from this station, the terrain blocks the signal from even getting to me.

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jasonl »

The terrain blocks most of the signal from reaching you, but some of it will hit the edge and diffract (bend) around it. There might not be enough signal left to actually decode it, but there can still be enough there to cause problems. The model indicates that K22NM-D's signal should be strong enough to overpower that and come in anyway, but it's still just a prediction rather than measured results.

One thing you should try is rotating your antenna to point further south to try to use that 17° difference in direction to try to get the Deming station further into a hole without harming K22NM-D as much. You'll probably need to sit there with a laptop with HDHomeRun Config GUI running to monitor the strength and quality on 22 to see if you can find a more optimal spot. It's going to be a challenge with the DB4e since it lacks directionality at lower frequencies, but you might be able to find a sweet spot with some experimentation.

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Re: HDFX-FLEX-4k channel not tunable issue - jtespi

Post by jtespi »

The L-R coverage map on RabbitEars shows the Deming station does not even reach my specific location. There is no color, it is blank. The last color is red, which the legend says is 41-50 dBu signal. So nearly all the signal is blocked.

Unfortunately, if I rotate the antenna basically at all (more than 5°), I will completely lose K22NM-D. I'm going to try to elevate the antenna and secure it better with a tripod mount. Currently, the antenna vibrates a bit whenever the wind blows since it is attached to the side of the chimney. Hopefully the tripod mount on the top of the chimney will limit vibrations and also give it more height. [the chimney is capped & not in active use]

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