WDIV/NBC Detroit Signal Quality

[KeithAbbott]

@jasonl; looking for some help with signal quality issues for WDIV/NBC Detroit, especially since the Winter Olympics start in a few weeks:

• Televes 149483 DAT BOSS MIX UHF-VHF attic antenna (positioned at 118 degrees true north)
• Televes 531981 SmartKom Antenna Amplifier and Combiner (all signal amplification happens in this device, antenna amplifier has been disabled)
• HDFX-4K-DEV device IDs: 10AAB199, 10ABADC7 (firmware version 20250815: Send diagnostic information flag has been enabled for the past week+)

There are occasions where the signal for WDIV is practically perfect; for instance, January 1st thru January 4th. Then, starting January 5th, the signal became rough and has been rough ever since (see attached graph). The broadcast tower is 103 degrees true north from my house, approximately 9.4 miles away. No mountains or hills. Tropo does not currently look to be a concern.

Looking at the graph, there are four different times when the symbol quality dropped to zero, with signal quality fluctuating above and below 30dB. This has caused pixelization and picture stuttering when viewing.

Can you look at the diagnostic information and see if it provides any insight on how to increase my signal quality? If it looks like the signal strength from the tower is too low coming into the antenna, I can switch to my Televes 149784 DAT BOSS LR UHF antenna.

Graph: https://drive.google.com/file/d/1UgMjHR ... sp=sharing

[jasonl]

Signal strength seems OK, right at 0dBmV. Can you set the signal source to Cable and run a channel scan, then set it back to Antenna and run another scan?

[KeithAbbott]

Done.

[billmich]

this station has been operating from aux tower/aux power......

https://www.mibuzzboard.com/phpBB3/view ... hp?t=66809

[KeithAbbott]

billmich, thank you for providing this information, I appreciate it.

Although to be honest, my first thought was "are you freaking kidding me!".

I would not have any issue with this, if television stations posted on their website when they are not operating from their primary transmitter. That way, when I have troubles, I could just go to their website and see that they are not transmitting at full power. But I know of no way to find that information out, except thru word-of-mouth like now.

The last time this happened (last October), it took two weeks to get a response from WDIV to my emails. Ultimately, I had to cc all of the WDIV email addresses that I could find on their website to get a response. I hate having to do that, but come on, two weeks? This is the response that I received:

Code: Select all

We apologize for the delay in response on this problem you have been experiencing. 

Since October 5th, the transmission line work effecting your reception has been completed. We are back at full power on our Main Antenna. 

At this point, I would recommend to fully rescan the channel settings on your TV(s).

For faster response in the future, please use our WDIV Help Center https://help.clickondetroit.com/home/

No mention of any follow-up work necessary in a couple of months. Maybe this outage was unplanned...

There is a growing part of me that regrets even heading down the OTA path. I feel like I am always battling signal quality issues. Multipath, tropo, transmitter issues, etc. etc.

[KeithAbbott]

this station has been operating from aux tower/aux power......

https://www.mibuzzboard.com/phpBB3/view ... hp?t=66809

Reading this post more carefully, I think it was referring to the work that was completed in early October, not recent work.

[jasonl]

OK, as expected, no weird signals getting through, the amp is working as designed and only passing the TV signals.

First thing to check, is the HDHomeRun is at least 3' away from other electronics, especially anything that deals with RF? Wireless routers often spew emissions on some random frequency in the 550-600MHz area, and if the HDHomeRun is close enough, it can clobber a single channel and leave others untouched.

Beyond that, have you tested without the amp in the loop, and with the antenna pointed at 103° instead of 118°? I assume it's at 118° for WADL, but 15° is a pretty significant deviation as directional as that antenna is.

[KeithAbbott]

First thing to check, is the HDHomeRun is at least 3' away from other electronics, especially anything that deals with RF? Wireless routers often spew emissions on some random frequency in the 550-600MHz area, and if the HDHomeRun is close enough, it can clobber a single channel and leave others untouched.

My HDHomeRuns are rackmounted with other devices (in order from top to bottom):

• Wired Router
• Rackmount Switch
• Rackmount Patch Panel
• Ooma Telo (uses DECT 6.0 to communicate with cordless handsets)
• Headless Mac Mini running Windows 11
• QNAP NAS
• (2) HDHomeRun OTA Tuners
• Headless Rackmount SageTV Server
• (2) APC Uninterruptible Power Supplies

All of the devices utilize wired network connections. I had not disabled WiFi in the Mac Mini, but it is now. The only device that should still be emitting RF is the Ooma Telo, which utilizes DECT 6.0.

This rack is up 24/7, if there was interference from other devices I would think I would never get good signal quality.

Beyond that, have you tested without the amp in the loop, and with the antenna pointed at 103° instead of 118°? I assume it's at 118° for WADL, but 15° is a pretty significant deviation as directional as that antenna is.

I have not tested without the amp in the loop, at least not since I added the amp. It's located in an unheated attic above my garage, not pleasant to get to during our winter months. I'll see what I can do in the next few weeks. I have my other UHF antenna (Televes 149784 DAT BOSS LR UHF) aimed at 103 degrees, but was still getting signal quality issues when WDIV was set up to use that antenna. I'll try to point the Televes Mix antenna to 103 degrees, and see if that helps.

On a side note, as much as I love the SmartKom unit, I wish it would display the signal strength and quality for the channel before amplification. That would probably help a lot in troubleshooting signal quality issues.

[KeithAbbott]

Beyond that, have you tested without the amp in the loop, and with the antenna pointed at 103° instead of 118°? I assume it's at 118° for WADL, but 15° is a pretty significant deviation as directional as that antenna is.

Testing without the amp in the loop will take a little more effort, but I was able to repoint the antenna and do a little testing (with the amp). Here's the antenna positions that I tried:

• 107°: 1/17 12:34-13:02
• 103°: 1/17 13:28-13:57
• 118°: 1/17 14:06-14:35 (back to where it started)
• 124°: 1/17 14:45-15:44

Interestingly, the closer I positioned it to 103°, the worse the signal quality got. So I returned the antenna to 118°, and then just for grins, I tried the antenna at 124°. Oddly enough, at least by my amateur eyes, I think the signal quality was the best at 124°. So I'm wondering if I'm dealing with a bad case of multipath. Can you take a second look at the diagnostic information and see if anything jumps out at you?

[jasonl]

124° was significantly better than the others, only 1104 packets with uncorrected errors in the entire hour, where 103° and 107° were getting like 10000 per minute at points. Multipath sure sounds like a potential explanation. Anything on the direct path or maybe to the north a bit that would be a potential issue, like a tall building or a road with a lot of semi trucks on it? Nothing screws up reception quite like 75' of metal driving past.

[KeithAbbott]

So I'll be doing more experimenting with antenna positioning in the 120°-140° range.

As far as the uncorrected errors, I would think zero uncorrected errors would be the ultimate goal, but is probably unrealistic for anyone. What would be a realistic target in your experience? I'm just trying to determine how far off 1104 packets with uncorrected errors is from where I should strive to be.

[jasonl]

Personally, I can go 0 errors on the major UHF channels here under normal weather conditions. High winds, rain, and lightning tend to disrupt that.