jdemaris

FOX TV

If you are not near any other sources of RF energy (FM transmitters, Cell phone towers etc) then I am not saying that amps will NEVER help reception problems. Amps have their place, and yours is a perfect example of a situation where they are actually useful, but they are the absolute last thing I would try after all other aspects have been exhausted. I would only recommend them in situations like yours where the problem is obviously low signal levels due to the distance away from the transmitters.

There is currently research ongoing into this very topic by industry experts. I am providing some useful links below to reception articles written in TV Technology magazine by Charlie Rhoades, who is an industry renowned expert on DTV reception and his opinions on amplified antennas are in the first link provided, along with a list of all of his reception articles written by him in the the last few years in the second link.

http://www.tvtechnology.com/article/88282

http://www.tvtechnology.com/section/digital-tv

Maybe some insight from experts into reception issues in general, and amplifiers specifically will help viewers along these lines. The first link addresses amplifiers specifically, but the research is not complete as of now. One last note is that their site is sometimes slow to load.

__________________
Some people think the Bush administration is responsible for the DTV transition !!

IDRick

Thanks for posting the links!

Interesting comment in the first one: "If there’s an active indoor antenna, temporarily replace it with a good passive indoor antenna. If that doesn’t solve the problem, add a really linear low noise amplifier such as the Channel Master 7777. "

I agree that many issues have been resolved by switching to passive indoor antenna. However, following that up with recommending a CM 7777 for indoor use is way over the top.... Pre-amp and tuner overload are *very* likely...

jdemaris

You did state that you "do not recommend amplifiers at all . . . " and also that issues like mine are not "common" in your market. I'm not trying to pick a word-fight here but . . . to not recommend at all is just as silly as me recommending everybody use an amp.

I admit I don't know what your "market" is. If you have something to do with Fox TV (going by your username), I can say that I get several Fox channels at all my rural properties. There are people who read these forums trying to make decisions on equipment, and such a negative statement can cause as much confusion as a blanket pro-amp statement.

The USA has around 300,000,000 people in it. At least 60,000,000 are in rural areas, and another 140,000,000 live in suburban or quasi-rural areas. That's a lot of people who may not get TV at all, or very well, without some sort of signal amplification. I'll add that I've met many people who tried to get digital TV reception and gave up - without even trying an amp due to some misinformation they read somewhere - or even worse - advice received at the local Radio Shack store. I've heard and read, often, about how amps cannot make a small antenna behave as if it's bigger - yet many times a preamp can do just that. Also read about the digital cliff at 65 miles which is also untrue. Also about digital, or UHF digital only working with line-of-sight transmissions - again, not true. For somebody who's been working with this stuff over the years, they can sift through such conflicting statements. But, somebody with no experience trying to read up first, and then do things right? That can be tough.

I still maintain that preamps and lineamps can be very useful and not just to an esoteric few. My in-laws live in the City of Alpena, Michigan and lost their only two TV channels after the digital change. A $27 preamp and a $45 antenna fixed their problem. The only other option (and I tested) was to install a 40 foot tower and antenna 450 feet from their house on a hill. Then the antenna gets those two channels with no preamp when tested on-site - but with a 450 foot run, a line-amp would be needed, even with RG-11 coax.
Seems the $72 invested was much more cost-effective than the tower and long line-run.

Don_M

I like most of what you've said here, but this...
...cannot go without challenge. What you offer as proof is anecdotal evidence that only applies to the rural areas with which you're familiar. For suburban and urban viewers -- areas which include nearly 70 percent of the nation's population, BTW -- your axiom is a recipe for reception-robbing amp or tuner overload. It may also mislead rural readers into thinking that they can skimp on the antenna and get the same results.

The only way an amp can possibly make "a small antenna behave as if it's bigger" is by counteracting cable and splitter losses. Please review the discussion here, under the heading "Signal Amplifiers, Preamplifiers," for details. Money quote:
If amps were capable of doing as you suggest, lots of us could have saved a great deal of money by connecting bent paper clips to them instead of antennas!

jdemaris

No on several counts. I offered nothing as "proof." I offered my experiences, based on just that. "Experiences" that I've had installing many antennas for 40 years in many suburban and rural areas. An individual event is certainly anecdotal. Many anecdotal events is more of a pattern. I'll further add that many times I've fixed problems that defied book-logic by using anecdotal-based suggestions.


Sorry but not true. A good LNA can take a signal at the antenna that is present but too weak for the TV tuner to acknowledge, and make it so a picture appears on the screen. A line amp can make up for line-loss and keep signal strength strong enough so the TV tuner takes it. Main difference is that the noise caused by the first amp matters much more (LNA at the antenna). The line-amp noise matters little since it only has a small effect on final signal-to-noise ratio. Go to an area where some signals are known to be weak. Then, install the highest gain antenna you can find. Then tune into a fringe channel that the antenna can just barely get with no help from a preamp. Chances are, in that exact spot, an antenna with much lower gain and a much smaller size will pull in that same channel with a good preamp as long as it's able to get some signal. Is it always that simple? Of course not. A preamp cannot make a signal out of nothing. It can, however, take a weak signal and make it strong enough to work on your TV. Just as a high-gain antenna can make the difference over a low-gain antenna. To reduce this to the paper-clip argument is silly. Using a small antenna will often result in being too far below the threshold of getting any signal at all. Then the amp does nothing but make noise. Note that I never said anything like a small antenna is as GOOD as a large antenna, nor did I say a small antenna and amp will ALWAYS get what the larger antenna gets. I did say that sometimes a small antenna certainly can behave like a much bigger antenna - and that is very easy to verify. Sounds to me like you've never camped or road-travelled with a small portable antenna and amp. I test potential antenna sites with a 24" antenna and amp on a 20' pole, and can list many experiences I've had - taking that 24" amplified antenna and then installing a Winegard HD8200, or a DB8, or twin 91XGs etc. I assume my results would be regarded as impossible, going by your comments. Today, I can go up the hill behind my house and hook up that 24" antenna and get 6-7 stations. I can hook a Winegard HD8200 in the exact same spot and height - with no amp - and get nothing. If I then hook a good amp to that Winegard I get over a dozen TV channels. So, what does that all mean? In means - in this anecdotal circumstance - the small two foot antenna with amp is outperforming the fourteen foot antenna without an amp, and the converse is true when the big antenna gets an amp. I suspect you've never tried these sorts of comparisons.

Note again - you commited the formal-logic flaw of "reducing to the rediculous." I suggested that small antennas with amps can sometimes behave like much bigger antennas with no preamps. I said nothing about anything paperclip sized, nor did I say small antennas are logical replacements for large high-gain antennas. Not all is discrete reasoning here - there are shades inbetween "all" or "nothing."

cwmiddleton

I started my DTV experience with a Wineguard HD-1080 antenna on a 20 ft pole. I could only get 4 channels at maybe 20% to 40% signal strength. I added a Wineguard AP-8275 pre-amp and now I get 12 channels, 3 range from 60% to 70% and the other channels at 80% to 90%. I have about 100ft of coax. I'm 32.1 miles from the transmitters.

JER

I used to live in down town Salt Lake City. There, the transmitters are on a 9500 ft ridge about 18 miles SW of town. The elevation at my house was about 4200 ft with line of sight to the towers.

At the time, I was using a typical chimney mounted Radio Shack combo antenna. I had a Radio Shack distribution amp in the attic to drive several jacks in the home. The system worked great! My analog reception was beautiful and absolutely problem free.

Then came the day when I brought home my first DTV receiver. I was excited to see what digital was all about and I immediately pluged the receiver into the living room jack with a short coax jumper cable. I quick did a channel scan and waited patiently expecting to see amazing digital pictures on the screen. I waited and waited, and when the scan was finally done do you know what I saw? ABSOLUTELY NOTHING! No channels were found whatsoever!

I thought I did something wrong so I went back and read the manual! I checked the cabling and scanned again. Still nothing. I rotated the antenna and still nothing. I was beginning to think that the receiver was DOA, but I found that hard to believe. Even harder to believe was that I wasn't getting anything even though my analog reception from the same jack was perfect. I replaced the jumper cable and still got nothing after several more scans. In a fit of desperation I pulled a small indoor antenna I had stuffed deep in the closed and hooked it up. Just like that I had a couple of digital channels. While I didn't get all of them at least I knew it wasn't the receiver and so I kept on investigating.

Eventually, after playing some games with traps and attenuators and getting filthy dirty climbing into the attic crawl space to adjust the distribution amp I was finally able to determine that I was getting signal overload and that the main rooftop antenna would work just fine if I dialed the gain of the amp all the way back or removed it entirely. While this didn't help the analog reception it was essential for digital.

At the time I was astonished to see that an antenna, amp and cable setup that worked superbly for analog, was simply not "out of the box" ready for digital. Had I not been an engineer and trained to look and diagnose such problems I'm pretty sure that I would have been taking that receiver back to the store or I would have punted and called the cable guy.

So while amps can and do help in rural and deep fringe areas, they can also be disastrous in urban and suburban areas. With the proliferation of strong signal sources into even remote areas, my basic recommendation remains "try without an amp first and then add one only if you find its necessary".

My hunch is that FoxTV's viewers in the mountains of Roanoke, VA are probably in a more similar situation to what I saw in Salt Lake than to what others have seen in rural areas in Michigan and elsewhere. In areas with big mountains and lots of "height gain" its probably comes down to a signal quality more than a signal strength issue. in those situations amps are more likely to do harm than good, so his recommendation of no amplifiers is probably the right call for his market.

In the final analysis there will be situations where amps help and some where they hurt. The trick I think is to get people thinking about what problem they are trying to solve rather than just blindly buying and installing one.

FOX TV

Remember that he was talking about his particular location, and not speaking generically or in general. This author is well renowned as one of the top RF and reception experts in the nation, and possibly the world. To me, what he says is gospel, and his reception testing including the use of amplified antennas is ongoing.

His intent was to show that a low gain indoor antenna with an amplifier can in some cases be an advantage, but again, this is location specific, and would not apply in every case. He was also looking at gain and linearity of that specific amp, and in his situation, he saw a definite improvement. You also need to note that he has access to all types of test equipment, and this area of broadcasting has been his life's work, he is definitely one to be listened to. When Charlie speaks about RF and DTV reception, I listen and learn.

__________________
Some people think the Bush administration is responsible for the DTV transition !!

jdemaris

I'd like to hear specifics about exactly what made your "analog" system not "digital ready." That is something I have yet to encounter. I have however, found many VHF only antennas that would not pick up a UHF signal, and many TV stations changed from VHF to UHF. Also, the converse. Also removed several amps that were too limited in the frequency range, and were only meant for VHF bands. None of the aforementioned has anything to do with analog or digital. Just the frequency, signal strengths, etc.

That I agree with. I always test an antenna first - on site, no amp. And then, work from there. By testing on site, long wire runs don't become part of the equation. If an antenna, hooked up on site only gets two channels with no amp, and gets twenty channels with an amp - that is kind of a no-brainer to me. That is, unless you don't want the extra channels. On the other hand, if hooking in an amp gains nothing, I don't use it. I'll that many people only test at the TV site, and not at the antenna. That leads to a lot of guess work and/or calulating since you don't really know, for sure, what kind of reception difference there is - between on site and at the TV.


I agree with that also. But, there is a huge difference between someone saying he "never recommends and amp" to recommending to "use as needed."

If I bought a diesel powered car and the engine blew, would it then make sense to warn others to never buy a diesel car?