ATSC3 vs 8vsb Signal Quality

[fugett1]

Setting up my Flex 4k, I've noticed a curiosity on signal quality. There's a tower that is a must have about 20 miles away, the ATSC3 the signal is 90% and quality is pegged at 100%, which is obviously great, but one of those "must haves" is DRM encrypted. There's a ATSC 1.0 transmitter of the same channel on the same tower but I get marginal generally unusable signal, even though the transmit power is higher. Can anyone help me understand why this is? I do have a Channelmaster amp with the 4Max antenna, with a LTE filter before the amp.

Tower is 100' AGL, 18.2 miles distant -

Channel 22 - 800 kW - 103.1 WSAZ 90% strength, 100% Quality, Solid Symbol
Channel 15 - 1000 kW - 3.1 WSAZ 78% strength, 0-62% Quality, intermittent Symbol

Thanks in advance!

[kyl416]

A signal quality that's bouncing around is usually a sign of multipath interference. You might have to adjust your antenna to find a sweet spot to aim for instead of directly at the tower.

[jasonl]

Presumably you don't have line of sight to have signal strength numbers that low with that antenna and that amplifier at that distance. ATSC 3.0 is going to handle that better because the low-level transmission format is just better at it. You may also see differences in how the signal diffracts at different frequencies, even though both are coming from the same antenna. You may be able to find a better spot for the antenna.

[xmguy]

I have the same problem with the CBS channel in my Nashville area (WTVF RF 36, 1.0). I'm nearly 70 miles away, It's 1mW. I can't get it well. I CAN get the 3.0 variant, same power, same distance. The 3.0 channel changed it's code rate recently. That can make the signal better too.

[howardc1243]

A signal quality that's bouncing around is usually a sign of multipath interference. You might have to adjust your antenna to find a sweet spot to aim for instead of directly at the tower.

about 15 degrees left or right of the tower will do depending on the direction of the signal flow.