AVS › AVS Forum › Gaming & Content Streaming › HD Radio › Indoor Amplified Antenna That Works!
New Posts  All Forums:Forum Nav:

Indoor Amplified Antenna That Works!

post #1 of 26
3/19/07 at 6:41am
Thread Starter 
I have found something rarer than hens' teeth, a liberal republican, or an open-minded evengelical. An indoor amplified antenna that actually works for HD!

It's the Philips MANT510. I got mine at Wal Mart. 50db claimed gain, and it actually pulls in MORE stations with higher gain...the noise level staying low enough that it doesn't wipe out HD! Far from it, I get MORE stations that I did with my Magnum Dynalab SR100 "Silver Ribbon". Now I get WFHE Hickory NC on 90.3 in HD, which means I can get Car Talk, A Prarie Home Companion, Morning Edition, All Things Considered, and a bunch of other public raido programs in NOISE FREE STEREO for the first time! Definitely a keeper for 30 bucks!
Reply
Reply

AVS Top Picks

post #2 of 26
3/19/07 at 7:40am
How does the antenna compare with a folded dipole?

Brian
Reply
Reply
post #3 of 26
3/19/07 at 8:31am
Thread Starter 
Better than a simple dipole. My SR100 was already pulling in more stations than a dipole. This pulls in a few more than the SR100.
Reply
Reply
post #4 of 26
3/19/07 at 10:37am
Thread Starter 
I hate to say this, but upon further comparison this afternoon, I found the Philips to receive EXACTLY the same number of HD signals as my SR100. Must have been some atmospheric oddities this morning. Still, it's not worse than the SR100. It seems to be EXACTLY as good, and is easier to obtain (available at Wal Mart, Circuit City, and others). It's exactly the same price, too. So you could pick one up while out running errands, rather than mail-ordering from a tweaky audiophile store (Audio Advisor had a VERY leisurely attitude about shipping my SR100! It took TWO WEEKE from the time I ordered. And they had it in stock!)
Reply
Reply
post #5 of 26
3/19/07 at 12:44pm
Michael
The Philips is electrically amplified and the Magnum is not. Should that be a consideration as to which one I should buy?
Richard
Reply
Reply
post #6 of 26
3/19/07 at 12:55pm
Quote:
Originally Posted by Mike Walker View Post

Better than a simple dipole.

Do you mean a folded dipole? I'm referring the indoor antenna made with twin lead that has two parallel wires for the antenna and feedline. It used to come with all tuners.

Unless an indoor antenna is longer than a half wavelength or uses a phased array of some sort, it is very unlikely to perform better than a folded dipole. The only realistic way it could is to use an amplifier with a lower noise figure than that in your tuner. This is possible but unlikely.

Most indoor antennas are short, vertically polarized conductors with limited bandwidth, an indefinite ground-return path (that may include the feedline), and a noisy amplifier.

Vertical polarization may work better than horizontal if the antenna is less than 15 feet off the ground. See http://users.tns.net/~bb/height.htm for more.

Brian
Reply
Reply
post #7 of 26
3/19/07 at 1:25pm
The MANT510 are amplified rabbit ears. I checked all over the web but couldn't find any specs. Is the noise figure stated on the box or in the instructions?

Rabbit ears can be arranged to receive circular polarization. This can be used to reject interference, particularly multipath interference. For more, see

http://users.tns.net/~bb/rabbit.htm

Brian
Reply
Reply
post #8 of 26
3/19/07 at 2:46pm
Quote:
Originally Posted by doxytuner View Post

Michael
The Philips is electrically amplified and the Magnum is not. Should that be a consideration as to which one I should buy?
Richard

Brian or Mike,
Can you help
Richard
Reply
Reply
post #9 of 26
3/20/07 at 6:21am
Thread Starter 
Brian Beezley, the SR100 (and the Philips model with amplification switched out) may not measure much different than a wire dipole, but they both DO receive more HD signals a few dozen miles out. Perhaps in the case of the silver ribbon it's because there's so much more contact area (it's wide but thin...think flexible blade!) than a simple wire. Just guessing.

I wouldn't worry too much about measured specs with the Phillips. In practice it's better than a folded dipole, but no better than the SR100...about identical. Still a great buy at thirty bucks. I've yet to find any indoor antenna that outperforms these.
Reply
Reply
post #10 of 26
3/20/07 at 8:26am
Quote:
Originally Posted by Mike Walker View Post

Brian Beezley, the SR100 (and the Philips model with amplification switched out) may not measure much different than a wire dipole, but they both DO receive more HD signals a few dozen miles out. Perhaps in the case of the silver ribbon it's because there's so much more contact area (it's wide but thin...think flexible blade!) than a simple wire. Just guessing.

I wouldn't worry too much about measured specs with the Phillips. In practice it's better than a folded dipole, but no better than the SR100...about identical. Still a great buy at thirty bucks. I've yet to find any indoor antenna that outperforms these.

MIKE,
Should I buy the amplified Phillip or the nonamplified Magnum Dynalab and if I buy the Phillip should the amp be on or off.
Richard
Reply
Reply
post #11 of 26
3/20/07 at 8:58am
Quote:
Originally Posted by Mike Walker View Post

I wouldn't worry too much about measured specs . . .


Specifications separate fact from opinion. While casual anecdotes can be suggestive, they are subject to error and contrivance. For example, without a controlled comparison it is easy to misjudge two antennas by ignoring field-strength variation with location, which often occurs indoors, or variation with time, which often occurs for distant signals. Measurements also can expose a hoax, where erroneous results are intentionally reported to cause embarrassment or prove a point.

Brian
Reply
Reply
post #12 of 26
3/20/07 at 9:44am
Thread Starter 
Brian the measured specs may not be that different for a folded dipole, but FACT: I could get ONLY WDAV (Davidson NC) in HD with a folded dipole...either the one that came with my Accurian, or the expensive one from C Crane. With the Silver Ribbon SIGNAL STRENGTH didn't look that different (on the crude meter on the Accurian), but there were MANY HD stations audible from Charlotte, Greensboro, Black Mountain/Asheville, as well as WDAV. Perhaps it was lower succeptibility to multipath, or again just the extra surface area. I DON'T KNOW! But I DO KNOW that the SR100 pulls in MANY stations where the folded dipole pulls in ONE! And this has been repeated in many positions, in three separate rooms of my home. I tried tweaking the dipole every-which-way to get the results some claim...vertical, horizontal, twisted into a loop (using a coathanger to help hold the shape, and later taped to the ceiling in a loop for circular polarization). NOT ONE OF THESE CONFIGURATIONS APPROACHED THE SR100!

So while traditional gain measurements may be similar, remember with HD gain is much less important than low noise. A Terk amplified antenna has a helluva lot more gain, and gets NO HD SIGNALS! Measurements are largely meaningless at this point not because differences can't be measured, but because gain isn't the be-all and end-all with HD that it is with analog (imho). I believe these differences CAN be measured (as can most every aspect of audio) when we learn to MEASURE THE RIGHT THING!
Reply
Reply
post #13 of 26
3/20/07 at 10:31am
Mike, if I got your results the first thing I'd do is to check the folded dipole for a broken wire, which is quite common. You can check it with an ohmmeter across the feedpoint. Next, measure its length. It should be roughly 58 inches long and consist of two parallel wires. The feedline should be 300-ohm twinlead that attaches to the tuner's 300-ohm antenna input. Some folded dipoles have an integral balun on the end and can be plugged directly into a 75-ohm coaxial input.

Forget the C. Crane antenna. It is not circularly polarized, despite the claim, nor is any dipole bent into a loop.

The ARRL Antenna Book offers a good background on antennas. It doesn't require a background in engineering to understand. Reading it will give you a good idea of what is possible and what isn't, and what's important and what's not. This can be invaluable when evaluating antennas.

Brian
Reply
Reply
post #14 of 26
3/20/07 at 2:26pm
Thread Starter 
Again Brian, I've used multiple folded dipoles, not just one (including the expensive C Crane unit, and the one that came with the radio. Same result...NO HD AT MY HOUSE).

With all due respect, don't lecture me about antennas to use at MY LOCATION. Folded dipoles DO NOT WORK as well as the SR100. Period. I found an old dipole, and tried it again today. Same result. No HD with the dipole (one from Radio Shack), booming HD with the SR100. You can't show me numbers to convince me that night is dark and day is light, WHEN I CAN SEE!

Here's an idea...try an SR100 and see if it doesn't work as I claim it does! Prove my results are false before criticizing them! A reasonable request? THESE ARE MY FINDINGS, and I didn't post them lightly. I experimented and repeated the tests under varying conditions before I posted my findings. I stand by them. PERIOD!
Reply
Reply
post #15 of 26
3/20/07 at 4:20pm
Mike, I'm not disputing your findings. I'm just trying to understand them.

The Philips antenna uses two 43" rods. In the most favorable orientation they provide about 0.7 dB gain over a dipole or folded dipole. This is when oriented to best receive a circularly polarized signal. 0.7 dB is a very small improvement, one that can't account for great differences in reception. The Philips also includes an amplifier. But unless the amplifier has an unusually low noise figure, it is unlikely to significantly improve the signal-to-noise ratio, as long as your tuner is working normally and has a reasonably low noise figure itself. Nearly all tuners do. Now, it may be that your tuner will not switch to HD unless the signal has a certain strength, regardless of the signal to noise ratio. That could explain why the Philips, with its higher output level, helps you receive more HD stations. Or it might be that your tuner has a defective front-end, with very low sensitivity. That could also explain it. Or it may not be defective, but simply very insensitive.

What tuner are you using? What sort of signal-strength indications do you get on the stations that you can't receive in HD on a folded dipole? If you switch between a folded dipole and the Philips, do analog signals get quieter?

Brian
Reply
Reply
post #16 of 26
3/20/07 at 6:53pm
TO MIKE WALKER AND BRIAN BEEZLEY

It's hoped that after you both clarify your positions, that one of you can help me since I want to buy an indoor FM Antenna. Should I buy the amplified Phillip or the nonamplified Magnum Dynalab and if I buy the Phillip should the amp be on or off.
Thank uou
Richard
Reply
Reply
post #17 of 26
3/21/07 at 3:41am
Thread Starter 
They both perform identically (in terms of the number of HD stations received) at my house (60 miles from the Greensboro HD stations, 80 miles from the Charlotte ones). Neither are better at analog reception than a wire dipole, but BUTH are better at HD!
Reply
Reply
post #18 of 26
3/21/07 at 3:47am
Thread Starter 
Brian I use the cheap Accurian table HD...using it as a tuner, with the audio run to an amplifier and speakers, also to a headphon amp (where I do most listening). The signal strength meter is rather crude in comparison to some expensive analog tuners (it's the same display, and probably lots of the same "guts" as the Sangean tuners). But I do get a couple more "segments" lit on HD with the SR100 or Philips vs the dipole most of the time. Interestingly, when the signal strength shows a rock-solid signal with the SR100, it often fluctuates...bouncing up and down with the dipole. Maybe it has something to do with the "ribbon" (metal strip...shaped like a blade) on the SR100 being locked into the perfect (?) position for HD reception, rather than flexible as in the dipole.

I agree with you that there's no reason I can explain (other than those I've suggested) why the SR100 should perform better. I only know that it does! If you were here, I could easily demonstrate it. I suspect you could duplicate my findings if you had access to an SR100.
Reply
Reply
post #19 of 26
3/21/07 at 6:31am
Mike, if all your antennas receive analog signals with about the same quieting but the active antennas let you receive more HD stations, it means that your tuner is lacking gain. I believe the Accurian uses the same LG Innotek HD module as my Sangean HDT-1. Later today I will put the HDT-1 on the bench and see if it also lacks gain on HD.

If this is the case, there is a simple way to improve your HD reception even more. The Philips antenna is a wideband design that covers TV as well as FM. It is not tuned. The internal amplifier makes up for the low signal level that results, but the amplifier noise is a greater percentage of the signal than it would be if the amp were fed a stronger signal. In other words, using an untuned antenna reduces the output S/N. This will hurt both analog and HD reception. If your tuner needs a stronger signal than an unamplified dipole can provide to switch to HD, you can just add an amplifier. This will provide greater S/N than is possible with the untuned Philips, as long as the amplifier noise is reasonable low.

I have some amplifiers (the kind used for cable TV that also cover the FM band). I will see if adding one to a folded dipole causes my HDT-1 to switch to HD on some stations when it won't without the amp.

Brian
Reply
Reply
post #20 of 26
3/21/07 at 6:45am
Quote:
Originally Posted by Mike Walker View Post

They both perform identically (in terms of the number of HD stations received) at my house (60 miles from the Greensboro HD stations, 80 miles from the Charlotte ones). Neither are better at analog reception than a wire dipole, but BUTH are better at HD!

Thanks Mike, I ordered the Magnum Dynalab for my third component system. I'm using a large rotary outdoor FM antenna for the other two systems and I did not want to further split the signal into three. I did not order the Phillip since I was concerned about the amplification.
Richard
Reply
Reply
post #21 of 26
3/21/07 at 7:35am
Mike, I tried an RF amplifier with my HDT-1 and it improved HD reception for only one station. With all other stations it had no effect or it degraded HD reception. I used an outdoor antenna, with and without an attenuator, pointing it away from desired stations to reduce the signal level. I did not try an indoor antenna because with the antenna nearby, it is difficult to control unwanted signal currents in the amplifier line cord and these can invalidate the results.

Nevertheless, I think you should try a folded dipole and RF amplifier with your Accurian. It should work better than amplified nonresonant rabbit ears. The amplifier I tried was made by Radio Shack and marked 10 dB gain, 50-450 MHz. It is about 2" x 4" in a shiny metal case. I measured the actual gain in the FM band as 13.5 dB. I find these things at garage sales for free or next to nothing.

Brian
Reply
Reply
post #22 of 26
3/21/07 at 7:53am
I just tried an indoor folded dipole, the one that came with the HDT-1 with an integral 300:75-ohm balun. The amplifier did not help on any station.

Brian
Reply
Reply
post #23 of 26
3/21/07 at 8:12am
I just compared resonant rabbit ears (http://users.tns.net/~bb/rabbit.htm) with the folded dipole on a few stations broadside to the dipole (its most favorable direction). The two antennas performed the same. This is to be expected since they have nearly the same gain and I have no multipath this morning, which the rabbit ears are capable of rejecting but the dipole is not.

All of these results suggest to me that your tuner lacks gain and the amplifier within the active antennas is making up for it. I'd try an outboard amplifier with a resonant antenna. It ought to work better than either of the wideband active antennas.

Another thing you might consider is seeing if Radio Shack will replace your Accurian with another one. If the radio has low gain, it could be due to the design or it could be due to a defective part.

Brian
Reply
Reply
post #24 of 26
3/22/07 at 6:42am
Thread Starter 
BRIAN I'm NOT USING AN AMPLIFIED ANTENNA! The SR100 IS PASSIVE! My radio receives HD signals from 80 miles, rock solid, with a PASSIVE INDOOR ANTENNA, here in very hilly, multipath-ridden terrain. Does that sound "insensitive" to you? Thanks for your concern, but I have none (concern) about my reception. Like all of us, I want to improve the reception I already have, but I've already gotten my money's worth!

What EXACTLY "suggests my radio has low gain"? Getting PHENOMENAL dx reception of weak HD signals with a passive indoor antenna surrounded by mountains? If that's insensitive, define SENSITIVE! Have you ever SEEN an SR100? IT IS A SIMPLE, PASSIVE antenna, that's electrically tunable by shortening and lengthening the elements (done by pulling a tab in the middle). It's a weird looking little device, but DOES have better reception than passive rabbit ears (which it would electrically seem to resemble) or a folded dipole. Dont' be so anxious for me to take the path YOU choose. It'll be a long wait (I don't mean to come off as harsh, but again, I'm GETTING 80+ mile HD reception with a passive, indoor antenna. That doesn't sound defective, or deficient in any way TO ME! And I've worked in all aspects of radio since the Nixon Administration, I'm very technically proficient, and do not appreciate unsolicited lectures...especially since ALL of your assumptions (that I use an amplified antenna, that my radio is insensitive, that a dipole would be better if only I would give it a try) ARE WRONG!

So to remove any lingering doubts, I'm not in need of any assistance, nor was advice being solicited. THANKS!
Reply
Reply
post #25 of 26
3/22/07 at 7:23am
Quote:
Originally Posted by Mike Walker View Post

BRIAN I'm NOT USING AN AMPLIFIED ANTENNA! The SR100 IS PASSIVE! My radio receives HD signals from 80 miles, rock solid, with a PASSIVE INDOOR ANTENNA, here in very hilly, multipath-ridden terrain. Does that sound "insensitive" to you? Thanks for your concern, but I have none (concern) about my reception. Like all of us, I want to improve the reception I already have, but I've already gotten my money's worth!

What EXACTLY "suggests my radio has low gain"? Getting PHENOMENAL dx reception of weak HD signals with a passive indoor antenna surrounded by mountains? If that's insensitive, define SENSITIVE! Have you ever SEEN an SR100? IT IS A SIMPLE, PASSIVE antenna, that's electrically tunable by shortening and lengthening the elements (done by pulling a tab in the middle). It's a weird looking little device, but DOES have better reception than passive rabbit ears (which it would electrically seem to resemble) or a folded dipole. Dont' be so anxious for me to take the path YOU choose. It'll be a long wait (I don't mean to come off as harsh, but again, I'm GETTING 80+ mile HD reception with a passive, indoor antenna. That doesn't sound defective, or deficient in any way TO ME! And I've worked in all aspects of radio since the Nixon Administration, I'm very technically proficient, and do not appreciate unsolicited lectures...especially since ALL of your assumptions (that I use an amplified antenna, that my radio is insensitive, that a dipole would be better if only I would give it a try) ARE WRONG!

So to remove any lingering doubts, I'm not in need of any assistance, nor was advice being solicited. THANKS!

I don't comprehend why you are getting upset with Brian-he's only trying to help. Couldn't you communicate in a more reserved manner. You may get upset with me but I'm immune to it since I handled medical malpractice claims and someone was constantly upset with me for 35 years.
Richard
Reply
Reply
post #26 of 26
3/22/07 at 10:45am
Thread Starter 
I apologize. Brian was telling me I shouldn't be using an amplified antenna. I'M NOT! He was telling me that I should return my radio, even though the reception is so incredible people have accused me of lying about the distance I live from HD stations. To me, it seemed that he kept harping about a problem I DIDN'T HAVE! I want better reception. Don't we all? I offer the above to explain how I felt. It wasn't an excuse for being impatient and sharp with him, and I sincerely apologize. In fact I apologize for this thread. I'm embarrassed that I made claims (about the performance of the Philips) that turned out to be false. I apologize to my first girlfriend, too, for not telling her how I felt when she broke up with me. Annette, you're a b##ch! There, that feels better!

Beer anyone? I'm buyin'!
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: HD Radio

AVS Top Picks

AVS › AVS Forum › Gaming & Content Streaming › HD Radio › Indoor Amplified Antenna That Works!