Definitely worth a try
Written: Sep 13 '03 (Updated Apr 15 '04)
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Product Rating:
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Pros: highly directional; small
Cons: highly directional; may need an additional amplifier if not close to HDTV transmitter(s)
The Bottom Line: Broadcast HDTV reception is still something of a trial-and-error process. The ZHDTV1 might be the end of your trials.
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| teamtempest's Full Review: Zenith ZHDTV1Z |
The ZHDTV1 HDTV_UHF Digital Indoor Antenna from Gemini (which licensed the Zenith brand name in 2001, BTW) is designed for reception of High Definition Television (HDTV) broadcast signals in urban areas. This antenna is also commonly known as the Silver Sensor, and sometimes as the Antiference Silver Sensor antenna. This last name is more common in England, which is where the antenna was originally designed.
The ZHDTV1 has something called a log-periodic design, which means nothing to me but is apparently quite sophisticated. More meaningful to me are several other features:
1) this is a UHF-only antenna
2) this is a highly directional antenna
3) this is an unamplified antenna
UHF Only
The ZHDTV1 is designed to receive only UHF television signals (channels 14 to 69) and not VHF television signals (channels 2 to 13). This probably accounts for its small size. The nature of VHF signals requires that antennas designed to receive them effectively be fairly large (a few feet long, such as provided by extensible "rabbit ears"). The nature of UHF signals is such that a much smaller antenna can receive them effectively.
Broadcast HDTV channels in any given area are actually placed on formerly unused television channels in that area. The vast majority are UHF channels. In my area (the Twin Cities), all the "new" HDTV channels are UHF channels, so the UHF-only characteristic of the ZHDTV1 isn't a problem for me. But there are a few HDTV stations operating on VHF channels, so you might want to check your local conditions (one website you can use to check is www.antennaweb.org, also mentioned below).
Highly Directional
The ZHDTV1 is designed to receive strongly signals from a transmitter it is pointed at (ie., in front of it) and to reject signals coming from other directions. This is helpful to eliminate multipath (the same signal being received directly from the transmitter and also as an echo after bouncing off some other object). Multipath shows up as "ghosts" on conventional analog broadcasts. On HDTV it can show up as video dropouts even if the signal is apparently strong.
I am again fortunate in that nine of the ten currently operating HDTV channels in my area are all broadcast from towers oriented between 89 and 92 degrees off magnetic north relative to my location. I got this information from www.antennaweb.org, which also told me all the broadcast channels in my area, whether they were analog or digital, and what kind of antenna I might need to receive them.
In English that means all I have to do is point the ZHDTV1 to the broadcast antenna farm located a couple of suburbs over to receive just about everything I might care to watch. If I want to watch that tenth HDTV channel, though, I'd have to re-orient the ZHDTV1 to point to 316 degrees off magnetic north (ie., point it at St Cloud, MN). That might not actually work though, because:
Unamplified Antenna
The ZHDTV1 is not amplified. Its gain is about 6 or 7dB in the forward direction (where it's pointed). That probably accounts for the "urban areas" part of its product description. The ZHDTV1 normally should be fairly close of the transmitter in order to function at its best. Within ten miles might be taken as a rough estimate, but in the real world the ZHDTV1 may function fine at much longer distances or not at all at closer ones depending on local conditions.
Here is where I ran into trouble with the ZHDTV1. I bought it because I was not happy with the broadcast reception performance of my original antenna and set-top HDTV box. I didn't (and so far still don't) know if the problem is the antenna or the box, but it's cheaper to play with antennas.
The bottom line is the unamplified ZHDTV1 did not provide as strong a signal on any channel as the Radio Shack amplified omnidirectional antenna I was already using. As measured by the set-top box, the signal was just a little weaker. It's not that I'm too far away from the antenna farm (less than ten miles). I suspect it has more to do with being shaded by a hill between myself and the farm.
But the signal from the Radio Shack antenna isn't all that great either. It reads about half the maximum scale the set-top box shows (the ZHDTV1 reads about a third or two-fifths) and on certain channels there is video dropout that I suspect might be multipath problems augmented by the omnidirectional nature of the antenna (which is not to say it's a bad antenna, just one that I'm using in the wrong way). So I'm still thinking about trying other antennas. Which brings me to:
My Second Thoughts
I returned the ZHDTV1 to Sears because I assumed it wasn't as good as what I already had. Much later it occurred to me that the Radio Shack antenna has absolutely no reception at all (zero, nada, blank) without its 20dB amplification circuits powered, so the ZHDTV1 clearly had it beat when on an equal footing. There are signal amplifiers available that can be added to unamplified antennas. Would the ZHDTV1 perform better with an additional external signal amplifier?
Well, the short answer is yes. Peter H Putman already thought of that, and you can read about his tests here at www.projectorexpert.com/Pages/antin.html. Nicely for me, he also used the same set-top box I do :)
So I'm fairly confident that adding an external signal amplifier to a ZHDTV1 would give me better performance than what I've got now. The only problem is that the combination costs more than another Radio Shack antenna that did fairly well in Mr. Putman's tests. So what I'm actually planning to do is get that one (or its successor) to try it out. If that doesn't work, then I'll try the combo method.
=== Update:
I did try that Radio Shack antenna. It didn't work at all well for me. But a simpler and cheaper Radio Shack antenna turned out to be the one for me. My review of the UHF Dual HDTV Indoor Antenna is here.
Recommended:
Yes
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Epinions.com ID:
teamtempest
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Member: Anton Treuenfels
Location: Minneapolis, MN, USA
Reviews written: 25
Trusted by: 1 member
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