Not All DTV Converter Boxes Are Equal

This is part of IEEE Spectrum's Special Report: The Day Analog TV Dies

I live about 80 kilometers from Mount Wilson (in Southern California). I use an outdoor double-bow-tie UHF antenna, 6 meters above grade, with a 300-to-75-ohm balun transformer to feed nearly 100 feet of coaxial cable terminating in a splitter for two TV converter boxes. Both get flawless reception on all channels.

However, not all converter boxes are equal. Some have the capability to adjust the volume of the sound coming through the television’s speakers; others do not. Some change channels in a few seconds; others required many seconds. Some have remotes that can control the TV, and others do not. Some feed through the RF signal so the boxes can be daisy-chained; others do not.

None of the converter boxes I know of allows its channel selection feature to be controlled by any video recorder. Thus, if you want to preprogram in the recording of two television shows on different television channels, you need to buy a new VCR or the digital equivalent. The only one I’ve found that can do that is the TiVo 80. I don’t object to the price of the TiVo 80-3 ($150 at Best Buy), but I do object to having to pay $15 per month to get it to work.

I own two adaptors, an Insignia NS-DXA1 and a Philco TB100HH9, and I was surprised by the differences I found. The Philco has the advantage that (when turned on and appropriately configured) it passes through the conventional VHF and UHF television signals. Thus, when the Philco box is between my antenna and my VCR, the full functionality of my programmable analog VCR is still available, although it will disappear in February 2009 when those stations are silenced. Meanwhile, I can watch the digital stations by feeding the video and audio outputs of the Philco box directly into my television. The Insignia does not have that pass-through feature, which effectively terminates many features of most VCRs unless you add an antenna signal splitter. I specifically bought the Philco for the feed-through functionality. What I did not expect were other differences in functionality. 

The Insignia unit takes about 5 seconds to switch from one channel to another, while the Philco takes about 10. When I’m channel surfing, the Philco seems to take forever to skip around the channels, even though my stopwatch says there is only a 5-second differential. The 5-second differential turns out to be more important than the stopwatch would imply.

The volume control on the Insignia remote control can be used to turn down the volume of the sound coming out of the speakers of the television set even when the signal from the converter box is being fed into the antenna input of the television set. This is a real convenience on old TV sets that do not have component video and audio inputs. The volume setting on the Philco remote control adjusts only the level coming out of the audio cables.

The Insignia remote has a button for turning the TV set on or off if the TV set has a compatible remote-control sensor. The Philco does not. The Insignia allows you to change the image format from letterbox to overscan, etc. with one push of the button. The Philco seems to have the same capability, but it takes several judicious clicks of the remote control.

There may be other differences as well. I couldn’t detect any differences in image and sound quality between the two I have, perhaps because I’m not using them as part of a sophisticated entertainment system or because I’m feeding them a strong signal.

To Probe Further

For more articles and special features, go to IEEE Spectrum's Special Report: The Day Analog TV Dies.

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