Tuner sensitivity (efficiency/quality?) rating.

First, of all, the FCC's criteria for power, spacing, tower location, tower height, etc is far more intricate than it might appear. As someone who has had to deal with interference issues at a number of locations from some often surprising sources, I can safely say they do a pretty good job given the lay of the land, both literally and figuratively. Case in point was an FM I was part of. We researched everything, got the license and signed on only to discover the beat frequency of two other stations was a harmonic of our own, attenuating our signal over a chunk of the city we were looking to serve. It took some time to re-engineer everything to move to a new frequency and they were more than helpful in dealing with an unforeseen situation.

The trouble with tuner performance is a similar issue. Sure, you can get some pretty good results in a lab and publish the specs, but each installation is going to be faced with its own, often unforeseen challenges. The biggest challenge is probably the user. I would hazard a guess the average (read: non-AVSer) television viewer got much more than a passing mention of electromagnetics in a high school science class. They buy whatever antenna is on the rack at Walmart, string it up and then wonder why it doesn't work. Take Tampa. A lot of those UHF-leaning antennas with little more than a dipole for VHF get returned. Tampa's a VHF-heavy market. Try explaining multipath to that average set buyer and watch their eyes glaze over.

Digital's a whole 'nuther beast. It's all or nothing. In the analog days, a little ghosting or a weak signal was no big deal. With digital, it's all-or-nothing. Add in the changes to the RF landscape - WiFi, cell phones and cell towers, smart homes - heck, everything has an interference-generating microprocessor in it, these days. Put all of this together and it's easy to see the installation challenges.

From a manufacturer's prospective, yeah, they could build better tuners, but why would they? It's a feature most buyers will never use and there's a cost-per-set to include tuners. Manufacturers want to keep that cost as low as possible. To them, increasing the price for a display to appeal to a segment that's obviously in a money-saving mode doesn't make a lot of sense. Cents, either, for that matter.

In your case, there's probably an easy-to-spot issue. If you'd like to see the Antenna Help thread at the top of the section and follow those instructions, I'll bet we can figure it out. Do remember to post in your local thread. If you want to include that info here, I'll just move all of this there.

EDIT: Scrolling back through the SF thread, it appears you're trying to use a CM 4228 in a VHF situation. That's not going to work. Sure, it's going to get some VHF.. a paper clip will, too. For a strong signal to get through a splitter to a garden-variety tuner, you're going to need the right antenna.. one with the proper length elements with enough off-axis attenuation to deal with Frisco's notoriously-bad reflections.

avs2099 said:

Wrong thread, Don?

The point of the thread was to discuss issues around tuner performance not antenna gain. It is obvious what is easier.

To anybody paying attention the improvements in tuner quality are quite noticeable but impossible to quantify.

Going back to my initial example with same channel and 3 different tuners:

the almost perfect performer is LG CX, second place with slight constant distortion is HDHR CONNECT 4k and last place is TiVo Roamio which is unwatchable. All tuners are given the same signal on RF 5. I know this is far from scientific but what other tools are there to measure tuner's performance?

Click to expand...

I know I've read about some Tivo's' (I think it was the Bolt) having issues with the automatic gain control and fact that they have multiple tuners can affect reception since the signal is split internally. Also, did you try a different splitter? Some do not split the signal equally but is usually labeled as such.

I've found when using amplifiers that some will overload a tuner very easily. For example, my Sony TV which is around ten years old does not overload but a Magnavox DVR will with some signals so I have an attenuator on that to reduce the signal. Regarding the old converter boxes, the Zenith 901 does not overload while the DigitalStream 9950 would with the same antenna amplifier until the signal was reduced. So as you say, there are differences and have been since the first digital tuners.

EDIT: one other thing. Since your signal of RF 5 is VHF, did you try switching the cables as VHF signals can be received with just those in a strong signal environment and depending on how you're receiving the signal, that may cause a problem on the Tivo.