[opendtv] RCA's Mobile DTV Receiver Put to the Test
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 21 Apr 2011 18:18:29 -0500
I'm even more pleased to see that conventional ATSC reception is improving, in
these newer hybrid receivers. Glad to see this steady improvement is still
happening.
Now, if they would just replace that short monopole with a paper clip ...
Bert
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http://www.tvtechnology.com/article/119608
RCA's Mobile DTV Receiver Put to the Test
by Doug Lung, 04.21.2011.
Last week I mentioned that I'd ordered one of the new RCA Mobile DTV receivers
from RCAPortableTV.com. When I arrived in Los Angeles from the NAB Show, my
DMT335R was waiting for me. I had a chance to work with it over the weekend and
see how it compared with other ATSC and ATSC MH receivers.
ATSC reception was as good as, or better, than that of any ATSC portable
receiver I've tested, even though the antenna was shorter. As with all
receivers using a monopole antenna, it worked much better with a ground
plane--either in my hand or a sitting on a metal object.
I did a scan of Los Angeles channels, with most of the full power stations
being received, but none of the low-power operations. Even KLCS, one of the
lowest powered full-service stations on Mount Wilson, came in fine. I was very
happy to see that the receiver-with its small whip antenna--found that one, and
also could receive all four Los Angeles full-power DTV stations operating on
VHF frequencies--channels 7, 9, 11 and 13.
The RCA receiver has a signal meter that works in both ATSC and ATSC Mobile DTV
modes. It's handy for optimizing antenna position and length. I found that
reception was possible if the indicator was anywhere in the yellow or green
areas. As expected, orientation and positioning were more critical with
conventional ATSC reception than with Mobile DTV, but I don't see non-technical
viewers having a problem if they use the signal indicator display. It's
available by pressing the "OK" button in the center of a set of four navigation
buttons. The other controls are for volume and channel selection.
Unlike the handheld ATSC receivers without Mobile DTV capability that I've
tested, this one includes a full EPG, as well as closed captioning. Aspect
ratio can be set automatically or manually. Unfortunately the DMT335R has a 4:3
ratio display, so it goes to letterbox mode when viewing content in the ATSC
A/153 16:9 standard format, unless it's set to 4:3 for a center cut. Zoom
options in the menu make it possible to fill the screen regardless of content.
ATSC Mobile DTV channels have to be scanned and tuned separately. The modes are
selected using the "Menu" button. I didn't find any VHF Mobile DTV channels on
the air in Los Angeles, but had no problem locating the four UHF channels
carrying Mobile DTV programs. After switching between Mobile DTV channels, I
was surprised to see a "weak signal" message displayed when tuning to channels
found in the scan. These were the ones that came in perfectly using the
conventional ATSC tuner. There appears to be a bug in the receiver-I can't say
if it affects all units-causing the receiver to fail to recognize Mobile DTV
signals under many conditions. If any readers have these receivers, I'd be
interested in hearing your comments.
I found a simple solution. If the mobile signal doesn't appear, then turn the
receiver off, and then back on again. This will cause the Mobile DTV signal to
lock up soon after power on. It doesn't take long. This does not appear to be
signal level-related-stations showed "green" on the signal level menu after the
power cycle. Nor does it appear to be related to the type of Mobile DTV
transmission equipment the station is using. (The problem appeared on stations
using Harris exciters/multiplexers, as well as those using the Rohde and
Schwarz system).
Once the UHF DTV mobile signal was recovered by power cycling, it was rock
stable. In the middle of a building in Burbank, far from any outside windows,
the KNBC mobile signal never dropped out, even if the antenna was partially
retracted and the receiver moved through different orientations.
Tuning issues aside, the RCA Mobile DTV sensitivity appears to be on par with,
or perhaps a bit better, than the prototype Samsung Moment handset I've been
using. As RCA includes conventional ATSC reception as well as Mobile DTV, the
receiver will probably replace the Moment handset in my travel kit, even though
it's a bit wider and about twice as thick (and if I can find room for yet
another charger. The Moment was convenient as it uses the same charger as my
Samsung wireless LTE hotspot and my Motorola Bluetooth earset.) With the RCA's
strong performance on VHF ATSC, I suspect it will do better than the Moment on
VHF Mobile DTV.
On an unrelated receiver topic, I discovered that the Samsung LTE (700 MHz)
hotspot appeared to create interference to indoor conventional ATSC reception
on Channel 48 when using my favorite USB DTV tuner, the Pinnacle (now the PCTV
Model 801e "Pro stick"). The good news is that the prototype Hauppauge Aero-M
tuner (which also provides Mobile DTV reception) had no interference problems.
Another of my other favorites, the Artec T19AD also performed well. The
Hauppauge HVR950Q appeared to handle the 700 MHz interference better than the
PCTV, but I did observe some hits. The Hauppauge Aero-M looks like a good tuner
for conventional ATSC as well as Mobile DTV. I'll have more information this
after testing it in more locations. Unfortunately, neither the Artec T19AD nor
the Hauppauge Aero-M is supported in the current Linux kernel (2.6.38)
libraries.
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