digital converter box -- surprising performance

[Dan.Strassberg]

Well, isn't Framingham closer to most of the transmitters than some
parts of Boston are? For sure that's true of "27" and "66," which
transmit from different locations in MetroWest, but isn't it also true
of "2," "4," "5," "7," "25," "38," "44," and "56?" It's not true of
"68," AFAIK; I think it transmits from the Pru. But even "62," which
is licensed to Lawrence, seems to be on the candelabra. However, "62"
is a special case; it's quite directional to the northeast and might
not make it into Framinaham all that well. BTW, I've enclosed the
channel numbers in quotes because in no case is the physical channel
currently the same as the nominal channel (or whatever the official
name is for the channel number you think you're watching--but aren't).

And where is "34" located? I know it's in Spanish because it came in
OK very briefly just once--in the early AM--but never before or since.
I usually get the "no signal" dialog. The timing--early on a hot,
humid morning--made me suspect that tropospheric ducting affects not
only low-band VHF and FM but also UHF.

I have an Insigna DTV converter box (same as a Zenith) and a Panasonic
26" LCD TV. Both are new within the last month. I live in Arlington
Heights, just north of Route 2 near Lexington. Should be a good
location; it's pretty high up--not too far from the top of Belmont
Hill, but there is no line of sight to any of the transmitters. Both
TVs have indoor antennas and both are located on the first floor of my
house. I purposely bought unamplified loop/rabbit ears antennas
because I thought an amplified antenna might be asking for trouble if
I didn't need the gain and a log-periodic might be so directional I
would have to adjust its location and position separately for each
station.

I went though LONG periods of playing to get satisfactory reception on
all channels without having to move or reorient the antennas, and tiny
changes in the antenna location or position can raise hell with the
recption. Windy days can still produce audio droputs and video
pixellation. Using the signal-quality indicators in both the converter
and the TV can be very frustrating because the display does NOT update
in real time; it's a couple of seconds behind. And there is a
fundamental flaw in the design of the stupid DTV signal! The first
thing to be affected by a weak signal is the audio. Video freezes and
pixellation do not appear--sometimes for many seconds--after the audio
has dropped out. The geniuses who designed the system must have been
unaware or didn't care that the most important part of a TV program is
the audio. If the audio is solid but the video is intermittent, it's
generally no big deal. You can usually follow the content if you can
hear the audio; the video is not essential. That's why people can
actually listen to Sixty Minutes on WBZ radio, for example. The audio
codecs need to be MUCH more robust even if improving them increases
the audio pipeline delay and necessitates adding memory to the
receiver's video chain to compenstate for the increased latency in the
audio chain. Making these changes now that large numbers of receivers
and converter boxes are in the hands of the public could be a
nightmare, though.

-----
Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "Maureen Carney" <m_carney@yahoo.com>
To: "Boston Radio Group" <boston-radio-interest@lists.BostonRadio.org>
Sent: Friday, June 13, 2008 3:03 PM
Subject: Re: digital converter box -- surprising performance


I bought the basic Magnavox model at Wal-Mart with my coupon and put
it in the bedroom in my apartment (Framingham on Route 9). I wasn't
expecting mutch since the TV isn't near the window, but with rabbit
ears it too pulled all the Boston stations and subs with no problem.


----- Original Message ----
From: George Allen <gallen2@nescaum.org>
To: boston-radio-interest@lists.BostonRadio.org
Sent: Friday, June 13, 2008 9:01:29 AM
Subject: digital converter box -- surprising performance

A bit off topic, but DTV coverage has been on past threads. I just
used my DTV box coupons by mail order [just before they expired] to
buy 2 different models for different features. First one is here, a
Magnavox TB100MGB, $80 before coupon and shipping. The web site
specs said it had analog pass-thru, which is why I bought it. But it
doesn't - it has both RF and RCA cable video out, but that ain't pass
thru as I understand it...

That said, the tuner is wicked. With just a junk pair of vhf wabbit
ears tossed onto the shelf, this thing got every Boston DTV channel
and then some the first time [no fussing with wabbits]. I'm in
Swampscott near the coast [ http://hazecam.net/boston.html ] and can
see the Needham towers, but this was on the opposite side of the
house, looking east. This box beat the crap out of my LCD DTV from
1.5 years ago - a cheap 32" Mag [Staples black-friday special] that I
have a powered inside antenna [$50] on, looking out the window at the
towers. That setup has a hard time getting 25.1, 38.1, and 56.1 even
with the Terc antenna [it can sort of get those with lots of
fussing]. But 68.x comes booming thru, as do 2-4-5-7.

So... Either ATSC tuners have come a long way in < 2 years, or I
bought a hot product [not a silicon tuner btw] by chance. Next DTV
box is a Channel Master CM-70 - it has s-video out but no
pass-thru. $75 before coupon without shipping. Too bad they dumb
these down to allow only 480i...
-- George