Bit Rate Errors - causes and fixes?

[primestar31]

Don't need to watch a video. I've done countless experiments myself in various locations, using multiple antennas connected directly to tuners, with and without preamps. My evidence speaks for itself.

The signal-to-noise ratio (S/N) at the tuners demodulator is what matters most. Signal-to-noise ratio is related to what is referred to as ‘noise margin’.

Often a large contributor to S/N is the tuner noise figure. Typical tuners have noise figures that range from ~6 to 8 dB.

So, even with a very short transmission line, adding a preamp can improve overall S/N ratio.

This improvement comes about via the gain of the preamp, along with its lower noise figure. The preamp raises the signal (actually signal plus preamp & other noise) to high enough level that the tuner noise becomes a smaller fractional contributor to total noise.

A larger antenna is better than a smaller antenna and preamp combo, HOWEVER, since a GOOD preamp can lower the overall system noise level, it can help stabilize weaker signals.

 

[comfortably_numb]

A larger antenna is better than a smaller antenna and preamp combo, HOWEVER, since a GOOD preamp can lower the overall system noise level, it can help stabilize weaker signals.

Agree. If I could mount a larger, higher antenna, I could probably overcome the signal loss and eliminate the need for the preamp. But since I can't, and I'm limited to an attic install, I don't have a choice.

 

[Bahnzo]

Agree. If I could mount a larger, higher antenna, I could probably overcome the signal loss and eliminate the need for the preamp. But since I can't, and I'm limited to an attic install, I don't have a choice.

You have your antenna in the attic? So of course a preamp works, because you have a long cable run. That's what a preamp is for. But just saying "You have towers 50 miles away, buy a preamp" is wrong. Every expert agrees there.

 

[FTA4PA]

I have Stellar Labs deep fringe outdoor mounted VHF-Hi and UHF antennas and I still need the preamp or it is a no go for stable reception.

 

[comfortably_numb]

You missed what I said before about experimenting with other antennas with short cable runs and no splitters; see primestar31 post #21

I'm not saying the preamp is right for every application. You asked about possible fixes for your bitrate errors. I think it couldn't hurt to try the preamp. Worst that happens is you return it 🤷🏻‍♂️

 

[FTA4PA]

You missed what I said before about experimenting with other antennas with short cable runs and no splitters; see primestar31 post #21

I'm not saying the preamp is right for every application. You asked about possible fixes for your bitrate errors. I think it couldn't hurt to try the preamp. Worst that happens is you return it 🤷🏻‍♂️

Exactly!

 

[Bahnzo]

If you're 50 miles from the towers, you probably want to integrate a preamp.

You missed what I said before about experimenting with other antennas with short cable runs and no splitters; see primestar31 post #21

I'm not saying the preamp is right for every application. You asked about possible fixes for your bitrate errors. I think it couldn't hurt to try the preamp. Worst that happens is you return it 🤷🏻‍♂️

Except it didn't. You told me simply because I was 50 miles from the towers, I probably needed a preamp.

Again, I'm glad it works for you. You obviously have loss in your line. Again, go read the link I gave from the manufacturer themselves where they say the amp is only for loss in lines. When I told you that, you disagreed, even with that. I don't know what more to say when you don't want to believe the experts you said you needed to hear from first.

<shrug emoji>

 

[primestar31]

You missed what I said before about experimenting with other antennas with short cable runs and no splitters; see primestar31 post #21

I'm not saying the preamp is right for every application. You asked about possible fixes for your bitrate errors. I think it couldn't hurt to try the preamp. Worst that happens is you return it 🤷🏻‍♂️

For just a preamp, this is the best one out there that I've tested over the years. So anybody that wants to try JUST a preamp with their present passive antenna, would do well to try this one:

Televes 560383 Single Input Antenna Preamp, 5G Cell Filter, Coaxial F-

Televes 560383 Single Input Antenna Preamp Orders placed by 3pm Central Time will ship the same day (M-F)! OVERVIEW: This new one input T-Force mast-mounted preamplifier is an entirely new design optimized for the new repack TV frequencies. This particular unit features one input covering the...

www.nesselectronics.com

 

[comfortably_numb]

For just a preamp, this is the best one out there that I've tested over the years. So anybody that wants to try JUST a preamp with their present passive antenna, would do well to try this one:

Televes 560383 Single Input Antenna Preamp, 5G Cell Filter, Coaxial F-

Televes 560383 Single Input Antenna Preamp Orders placed by 3pm Central Time will ship the same day (M-F)! OVERVIEW: This new one input T-Force mast-mounted preamplifier is an entirely new design optimized for the new repack TV frequencies. This particular unit features one input covering the...

www.nesselectronics.com

Good info. If my CM7777HD ever craps out, I'll try this one

 

[Trip]

So when I was significantly younger than I am now, living with my parents in the fringes (more than 50 miles from any TV station), I used to have an outdoor antenna in my bedroom that I could reposition and reorient without screwing up the viewing of everyone else in the house. The coax run was definitely not long on that one.

It was significantly less effective without a pre amp. The amp definitely made a difference, and I received stations and watched shows that would have been impossible without it.

I'm not entirely sure why the OP is so allergic to the idea of even testing one out. It should be pretty easy to buy one, open carefully, test, and if it doesn't help, pack it back up and send it back.

If there's anything I've learned in 20+ years of tinkering, it's that TV reception is as much an art as it is a science. A lot of my successful reception setups have depended a lot more on trial and error than one would think.

- Trip

 

[MartyDe]

OP you think about listen to what Trip says. I'm a retired broadcast engineer, FM and UHF TV. One thing I truly believe is RF is going to due whatever it wants to. Books, designs, careful planning,....it doesn't care. Some times fooling around is the only way, and boy do you learn a lot.

 

[MartyDe]

As you can see from the first sentence in my post above, RF also can scramble your brain. I'll try again.
OP please think about what Trip had to say.

 

[rabbit73]

...I occasionally get dropouts on a couple channels, and according to my Roku signal screen, it's being caused by bit-rate errors. I'm wondering what causes these.....

Hello, Bahnzo. Looking at Wikipedia is helpful:
Bit error rate - Wikipedia
EXTRACT
Bit error rate
In digital transmission, the number of bit errors is the number of received bits of a data stream over a communication channel that have been altered due to noise, interference, distortion or bit synchronization errors.

The bit error rate (BER) is the number of bit errors per unit time. The bit error ratio (also BER) is the number of bit errors divided by the total number of transferred bits during a studied time interval. Bit error ratio is a unitless performance measure, often expressed as a percentage.

Factors affecting the BER
In a communication system, the receiver side BER may be affected by transmission channel noise, interference, distortion, bit synchronization problems, attenuation, wireless multipath fading, etc.

The BER may be improved by choosing a strong signal strength (unless this causes cross-talk and more bit errors), by choosing a slow and robust modulation scheme or line coding scheme, and by applying channel coding schemes such as redundant forward error correction codes.
END OF EXTRACT

The FEC (Forward Correction Correction Code) that is transmitted with the signal can correct a limited number of errors. When that limit is exceeded, the signal can no longer be received, and drops out at the "Digital Cliff."

The ATSC defines the recommended sensitivity of an ATSC 1.0 tuner in terms of BER:

ATSC Recommended Practice:
Document A/74:2010, 7 April 2010

RECEIVER PERFORMANCE GUIDELINES

5.1 Sensitivity

A DTV receiver should achieve a bit error rate in the transport stream of no worse than 3x10E-6 (i.e., the FCC Advisory Committee on Advanced Television Service, ACATS, Threshold of Visibility, TOV) for input RF signal levels directly to the tuner from –83 dBm to –5 dBm for both the VHF and UHF bands.

and what, if anything, I can do to help improve it.

You haven't given us a rabbitears.info signal report for your location, so it is difficult for me to give you good advice for that.

I can, however, tell you how I have been working on my problem.

I have a very high noise level from electrical interference to my indoor antenna that makes it difficult to receive VHF-High channels 7 and 11.

The tools that I have been using are an RTL-SDR V3 SDR ($30) with RTL-SDR Scanner software and a SiliconDust HDHR4-2US tuner. The SDR shows me the shape of the signal and the HDHR GUI gives me the signal quality. I find it awkward to use BER in scientific notation and much prefer to use other metrics of signal quality including SNR and MER.

Those measurement tools allow me to try different antennas, different antenna locations, and a preamp to find the best combination.