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Discussion Starter · #1 ·
How is the tuner in the AM21N? Does it handle multipath and other problems well? And I HIGHLY doubt it, but has anybody tried connecting more than 1 to an HR2x/HR34 via a USB hub? If so, did it allow you to record 4 OTA channels at once?
 

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The AM21N gets pretty good reviews as a decent ATSC tuner. But realize that it contains a built-in splitter to feed two ATSC tuners, so you can't expect results quite as good as a direct connection to your TV's single ATSC tune.

No, there's no way to double up AM21's on one DVR, not even the HR34.
 

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It performs very comparably to my regular AM21. The AM21N's signals strength showed a little more stability for me compared with the AM21 but both have performed fine.

FWIW, I get every station from 33 miles LOS to the transmitters. I pick up the signals with an attic mounted antenna.
 

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My AM21N is very comparable to my tv's tuner, with signal strength numbers pretty much the same for all OTA stations up to 70 miles away (with outside antenna).

One thing to be aware of, though, is that the AM21N will not likely be able to tune all available OTA stations, due to tuning limitations discussed in other threads.
 

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Discussion Starter · #6 ·
Mainly wondering how it's going to compare the the Tivo Premiere's OTA tuner. I've had some problems with it (Course, can't be SURE it's the tuner itself).
And I didn't really think you'd be able to use more than 1 AM21N, but figured it was worth a try. Never know.
 

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Can anyone confirm:

First I was told a number of times that the AM21 and AM21N are basically the same.

Now I'm hearing from some that the AM21 has a single tuner and the AM21N has dual / two tuners.

HELP ?
 

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jeremymc7 said:
Can anyone confirm:

First I was told a number of times that the AM21 and AM21N are basically the same.

Now I'm hearing from some that the AM21 has a single tuner and the AM21N has dual / two tuners.

HELP ?
Some people are wrong because both versions of the AM21 have dual tuners. The only way it would have one tuner is if it was attached to a single tuner receiver(H series) or an HR configured to use only one tuner...
 

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moghedien said:
Some people are wrong because both versions of the AM21 have dual tuners. The only way it would have one tuner is if it was attached to a single tuner receiver(H series) or an HR configured to use only one tuner...
Close...of course if it was hooked up to a non-DVR, since you can only watch 1 live station at a time, it acts as a single tuner, there are no dual tuner HD receivers from D*. On all compatible dvr's, it is always 2 tuners, even if you only have one active sat tuner.
 

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litzdog911 said:
The AM21N...contains a built-in splitter to feed two ATSC tuners, so you can't expect results quite as good as a direct connection to your TV's single ATSC tune...
Power dividing the signal to two tuners should not in any way compromise reception, especially since it is an active device and there is probably unity gain to both tuners unlike what you would see with a passive hybrid splitter.

But even if it were a passive loss, that would be inconsequential unless it dropped the s/n ratio below 15 dB, which would only happen if you were right on the ragged edge signal-wise, and that would already mean you were seeing intermittent pixellation that would thwart decent reception (you'd just see it a bit more often). Digital signals are not carrier-level dependent as are analog signals, so boosting the RF level or power-dividing the RF level with splitters is not really as challenging to reception for digital as it is with analog. What is typically challenging for digital is the multipath ratio, and splitting the signal does not materially change that.

The s/n ratio generally does not become a problem until you are so far away that multipath becomes an even bigger problem, in most cases, meaning you can afford to split a workable signal without penalty most of the time. We are conditioned to think that level is more important than it is because it used to be of primary importance; the s/n ratio was 46 dB or better for analog, and any loss of carrier level compromised PQ, which of course is also not an issue with digital.
 

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I have been told that later generation chips in receivers can make a big difference when it comes to ability to have a viable signal and multipath.

I've asked before if anyone knows which generation chip DirecTV is using.
So far, can't find the answer.

Previously, I've mentioned my displeasure with the AM21. I've experimented.
Using the same antenna with the AM21 and the tuner in my Sharp HDTV, the Sharp's reception is way better than the AM21's.

A few months ago, I bought a Hauppauge WinTV/aero-m receiver connected to my computer. This one has a 7th Generation chip. Using the same antenna, it puts not only the AM21, but the Sharp to shame. Many more stations.

It's too bad that when DirecTV came out with the AM21N that its circuitry wasn't updated to allow better reception.
 

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GP245 said:
I have been told that later generation chips in receivers can make a big difference when it comes to ability to have a viable signal and multipath.

I've asked before if anyone knows which generation chip DirecTV is using.
So far, can't find the answer.

Previously, I've mentioned my displeasure with the AM21. I've experimented.
Using the same antenna with the AM21 and the tuner in my Sharp HDTV, the Sharp's reception is way better than the AM21's.

A few months ago, I bought a Hauppauge WinTV/aero-m receiver connected to my computer. This one has a 7th Generation chip. Using the same antenna, it puts not only the AM21, but the Sharp to shame. Many more stations.

It's too bad that when DirecTV came out with the AM21N that its circuitry wasn't updated to allow better reception.
Which "gen" is kind of a murky subject; after about the 4th gen different companies started putting out different levels of technology with arbitrary "gen" numbers. This means don't pay that much attention, because one man's gen 7 could be older and less refined than another man's gen 6.

There are 2 things that I know for sure other than that:

1) the later it is manufactured the better it will likely be. A notable exception was the venerable HR10-250, which had a finicky tuner that many older tuners were much better than at the time. As it turned out, the problem with the HR10 could be worked around with attenuation, as it had not much headroom at all.

2) the improvements from moment to moment are revolutionary, not simply evolutionary. In 1999 when digital broadcasting came to my town I spent a week with a $200 12-ft yagi, the best antenna I could buy, vainly trying to get reception in an urban setting, by trying different placements atop a building that covers most of a city block. This was using a professional HD tuner that cost $35,000 (I am a broadcast Engineer). I could barely get a picture at all, regardless of what I did. By 2006 we could pick up the same signals in the same location downstairs in a windowless room, on a paper clip stuck into a $199 Vizio.​

Most of this is due to improvements in active EQ, which means newer, better tuners can reject multipath signals that are much closer time-wise than older tuners can, and this has been improving very significantly with each generation. There was a time (around 2005-6) when you absolutely had to have line of sight. Now, you don't, even if that implies a high multipath ratio.

And I have heard that the newer AM21 has a much better AGC circuit, and that is tuned for fringe reception, so in most cases it should be a significant improvement over the older AM21.
 

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Discussion Starter · #15 ·

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kevinturcotte said:
How well does the AM21N deal with multipath? *THINK* that's part of my problem. Could be the Tivo Premiere's OTA tuner as well. I've attached my data from tvfool.com I have a Channel Master 4228HD (http://www.solidsignal.com/pview.asp?mc=03&p=4228-HD&d=Channel-Master-4228HD-8bay-HDTVUHF-TV-Antenna-(4228HD)&c=TV%20Antennas&sku= pointed at 8 and 44 and getting signals in the mid 60's. 38 does also have signal, but it's like low-mid 30's. Hoping the AM21N will improve on this!
Kevin, I am going to assume you mean "halfway between" 8 and 44, since the 4228 is highly directional in typically a single direction. And 36 degrees is still quite a spread.

I highly recommend the 4228; I think it is the best antenna money can buy, but it may not be ideal for your location, since you seem to have stations coming from just about every azimuth. You may actually be better off with an omni. Its a trade-off; directionality or multipath rejection. Another solution might be a "joiner" with filtering, which can combine two antennae. Combining antennae of course reduces multipath rejection, again at the sake of being able to pick up signals in multiple directions, but in the right circumstance with the right filtering it can be effective.

What I usually suggest for someone with stations all over is to simply forget about those you don't really need. If you get ABC from two directions, choose one. Narrow things down to the stations you really can't live without, and then try to see if there is a way to pick them up. An antenna with less directionality might be in order if an omni just causes too much interference to get in. If you get locals over sat, you can eliminate all of those and still get them that way, then you can concentrate on just the stations you can't get over sat.

Remember that the antenna typically will have a back lobe (180 degrees out) that is pretty effective. For instance, if you are midway between two stations, point the antenna at the farther weaker one, and pick up the stronger nearer one off the backside. This is of course no good if the stations are 90 degrees apart. But you can use that to help in other potentially weird angles.

Another technique to try is to point the antenna at the station that is hardest to get, and see if the others come in (the 4228 probably has too much directionality for this, however). Then you might be able to cheat the antenna one direction or the other so that you can pick up the others without losing reception on the weakest one.

There is only so much you can do in your situation, and really, the best way for someone in that situation to improve reception is with a better tuner rather than with a more-directional antenna (you may have to go less-directional). I think it might be worth trying the new AM21, as it has improvements for sure over the original, but may still not be state of art. But odds are if they messed with the electronics to get better AGC (which they apparently did) they might have also messed with the tuner stages or put newer ones in. Better AGC will not really help with multipath much, but all situations are a combination of level and multipath issues, so having better AGC could still help.

Rotators are sort of 1950, and don't make a lot of sense with DVRs, but you could also erect two separate antenna systems pointing different directions and dedicate one to one DVR and the other to another. That would give you the best of both worlds, good azimuth coverage and good directionality. Point your 4228 at a group of the furthest, hard-to-get stations, and pick up the nearer, more spread out stations with a separate antenna system that is less directional than the 4228.
 

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Discussion Starter · #17 ·
Yeah, a rotator wouldn't really work. Either the DVR would want to record 2 channels in opposite directions, or I'd forget to move it lol
Question though. HD locals here are good. With a well aimed antenna, getting signals at least in the 80's, what's going to go out first in a storm-the dish, or the antenna?

TomCat said:
Kevin, I am going to assume you mean "halfway between" 8 and 44, since the 4228 is highly directional in typically a single direction. And 36 degrees is still quite a spread.

I highly recommend the 4228; I think it is the best antenna money can buy, but it may not be ideal for your location, since you seem to have stations coming from just about every azimuth. You may actually be better off with an omni. Its a trade-off; directionality or multipath rejection. Another solution might be a "joiner" with filtering, which can combine two antennae. Combining antennae of course reduces multipath rejection, again at the sake of being able to pick up signals in multiple directions, but in the right circumstance with the right filtering it can be effective.

What I usually suggest for someone with stations all over is to simply forget about those you don't really need. If you get ABC from two directions, choose one. Narrow things down to the stations you really can't live without, and then try to see if there is a way to pick them up. An antenna with less directionality might be in order if an omni just causes too much interference to get in. If you get locals over sat, you can eliminate all of those and still get them that way, then you can concentrate on just the stations you can't get over sat.

Remember that the antenna typically will have a back lobe (180 degrees out) that is pretty effective. For instance, if you are midway between two stations, point the antenna at the farther weaker one, and pick up the stronger nearer one off the backside. This is of course no good if the stations are 90 degrees apart. But you can use that to help in other potentially weird angles.

Another technique to try is to point the antenna at the station that is hardest to get, and see if the others come in (the 4228 probably has too much directionality for this, however). Then you might be able to cheat the antenna one direction or the other so that you can pick up the others without losing reception on the weakest one.

There is only so much you can do in your situation, and really, the best way for someone in that situation to improve reception is with a better tuner rather than with a more-directional antenna (you may have to go less-directional). I think it might be worth trying the new AM21, as it has improvements for sure over the original, but may still not be state of art. But odds are if they messed with the electronics to get better AGC (which they apparently did) they might have also messed with the tuner stages or put newer ones in. Better AGC will not really help with multipath much, but all situations are a combination of level and multipath issues, so having better AGC could still help.

Rotators are sort of 1950, and don't make a lot of sense with DVRs, but you could also erect two separate antenna systems pointing different directions and dedicate one to one DVR and the other to another. That would give you the best of both worlds, good azimuth coverage and good directionality. Point your 4228 at a group of the furthest, hard-to-get stations, and pick up the nearer, more spread out stations with a separate antenna system that is less directional than the 4228.
 

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Your OTA signal should be much less vulnerable to weather than the dish. I've never lost OTA in many, many years of use (due to weather). Sat loss is several times per year here in the midwest, where we have strong thunderstorms and some heavy wet snows.
 
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