The Official AVS 'Mobile DTV' (M-DTV) Topic! - Page 6

I've been put in touch with their support people regarding PCI tuners seemingly failing to function. I will let you know what they say.

- Trip

I'm using it on Windows 7 x64 home premium on a Sony VAIO with a mobile Core 2 Duo (Penryn). I think most of the issues here are that I am in a very noisy environment (electrically) and the glass in the windows probably contain metal to keep the heat out.

This evening I will try it on the bus, but I'm not holding out much hope. First of all I need a better antenna, preferably one that mounts on the top of the screen. Secondly this software's M/H decoder isn't much better at reception than regular ATSC.

The good news is that both of my tuner sticks work, the Hauppauge HVR 950q (QAM/ATSC/NTSC) and the Pinnacle PCTV 800e (ATSC/NTSC) which has a standard BDA driver. I wish that it would work on the HDHomeRun at home but that's no biggie anyway.

I was provided with an updated version of one of the control modules which now supports PCI receivers and the HDHR. While it does display the HDHR as an available device, I have yet to actually get any video out of it.

- Trip

Or more geared toward the layman, good article by Russell Brown on BE last year on the basics of ATSC-M/H ...

http://broadcastengineering.com/news...315/index.html

Boy .... My DTV tuner card must be a total oddball ....

AverMedia M780 combo card (White Box). Fails to work with the TS Reader and now this Mobile DTV application as well.

Error message says "no BDA devices detected."

Works fine with Windows MC on Vista but not much else I see.

I got the s/w to work with the Dell Lumanate USB ..but not with the V-Box USB 3560.

It has been updated. http://www.mobile-dtv-viewer.com/DownloadATSC.html

In addition to the frequency table issues, the update also:
• solved issue with BDA receivers not plugged via USB
• full screen mode (without windows borders) - return to normal display mode with ESC key
• display of mapped channel names
• improved channel scanning speed

- Trip

I found another M/H receiver that I have on the way to play with:

http://www.dealextreme.com/details.dx/sku.45315

One caution if you buy this tho: " Speed limit: 120km/h; in America: 60-70MPH/hour"

I have two USB Mobile DTV receivers, a Pixtree PTX-100 and a DTVinteractive Storm, sold in the US under the Colby brand as DTV111. Both included driver and player software and small magnetic base external antennas. The Pixtree antenna is a wire affair about 10 inches high with a small coil wound in the center, reminiscent of early cellphone auto antennas. The Colby antenna is about 7 inches high, tapered plastic, with a flexible tip. Both had about 7 feet of thin coax to the connector.These are the antennas utilized in Korea for vehicular reception of their DBM mobile transmissions.

The antenna connectors are similar, but due to the diameter of the connectors and the size of the ports, they aren't interchangeable.There was one exception though, I was able to connect the Pixtree antenna to the DTV111 and use it for both devices in comparing reception.

The Colby also came with a tiny 2 inch closed, 7 inch open telescoping antenna.

My Pixtree is an early model orange and black unit about 3 inches long and 1 inch wide, large for a USB drive. I was told that the final production units will be smaller, have greater sensitivity and also include a tiny telescoping antenna, but would not ship with the external one. The software was a Alpha build and did little but receive - one channel at a time. I had to rescan for each channel. Time shifting, recording, screen capture, all were non-functioning in my build. The production Pixtree was to go on sale in the us in August. I'm still waiting

The Colby is a production model about 3/4'" wide and just over 2" long. The software is ver. 1, but is fully functional. I did not test the time-shift or screen capture, but I'm confident they work.

I tested both units in both a Hannspree Netbook with 2gig of ram, 1.8Ghz cpu, running Windows XP-Pro, and a VILIV X70 tablet pc with 1 gig of ram, 1.3 Ghz cpu, running XP-Home.. The Viliv is the unit I wanted to use these tuners in.

My home, according to AntennaWeb, is about 24 mils from the DC transmission towers and these are the reception results.

Channel Station

4-1 WRC NBC 4
5-1 WTTG Fox 5
30-1 MHZ 1
30-2 MHZ 7
32-1 WHUT PBS Mobile
32-2 WHUT PBS Kids
66-1 Qubo

The Colby also received two channels of what it indicated as
ATSC Mobile Audio Service

32-3 WAMU 88.5 FM
32-4 WETA 90.9 FM

The audio was an unexpected pleasant surprise.

As expected, the Colby was a bit more sensitive, had quicker channel scan and lock times

Picture quality was good as long as the picture remained small. The Viliv has a 7 inch screen with 1024X600 resolution and when the video went full screen, the softness started to show..On the Hannspree with a 10 inch screen, also at 1024X600, it was definitely lowres. Forget about viewing on a big screen display.. Sound was in stereo

Now for the bad...

The reason I dwell ed so much on the antennas is because without them, there is no reception. The little telescoping antenna was useless- and that is exactly the kind of setup I wanted: something portable and unencumbered. As far as being mobile, I have no doubt that riding around in my truck, with that antenna stuck on the roof, I would get a signal.

In Korea, every device with a screen has the ability to receive DMB just about everywhere. Phones, gps, media players, they all can do it. I was there, I saw it in operation. I didn't expect our system, which really pales in comparison, with only one point of transmission, to match theirs, with thousands of repeaters, but come on, 24 miles and no signal? If this is the way its going to be, it will be a bust.



More Skeptical Then Ever

Thanks, I will have to try this on the laptop to see if it solves my "no network connection detected" problem while I'm on the road.

You explained to me that a network port (at least a loop-back) was needed, though I can't remember why exactly. I'm pretty sure it wasn't just a cheap trick of downloading these channels to us over the Internet.

Qualcomm has a bunch of repeaters for MediaFlo in the LA area and I still had lots of problems with that service when on the road. The "best" repeater was about 15 miles from my condo and it was ok while I was home. However, there are too many hills to make mobile DTV feasible, with just two local repeaters in South Orange County while on the road (it looks like there is a 3rd one now). I'm still baffled as to why MediaFlo wasn't on the most obvious choice in S OC (Santiago Peak). I gave up on MediaFlo/FloTV in January.

Keep in mind that signals inside a car can be about 20dB lower than just outside the car, so that works against reception even more.

The one main transmitter approach on mobile DTV (ATSC-M/H) is a dog that won't hunt.

It's why industry leaders such as Doug Lung are pushing DTS so heavily, but I think we are using the wrong system to try and shoe-horn in an SFN type network. ATSC wasn't made for it, but perhaps the best minds can make it work somehow! Then there's the issue of money. Who is going to pay for all these needed repeaters?

This version sees my HDHomeRun Tuner..It will find the tuner..tries to lock and indicates signal..but won't decode. Shows No DATA and gives No SIGNAL error. Upgraded HDHR F/w as well.

You need to add a firewall exception for the Control program.

- Trip

Not sure why, as HDHR software works fine on the same pc. Please elaborate...Nevah Mynd..I gots it. Looks like I'll be putting the HVR back in the closet now.

Long story short, the HDHomeRun driver runs with the access level of whatever program is using it. Most software firewalls won't block outbound connections, so telling the HDHomeRun to tune a specific channel works, but the video stream is an inbound connection from the HDHomeRun, which does get blocked. Adding the exception allows the program to receive the stream.

I overlooked it because there WAS an exception in the firewall..but it turned out to be for the PREVIOUS version..once I deleted that exception and added another one..it works fine.

Off topic..but have you thought of an antenna mounted HDHR with POE and advanced lightning protection?

It has come up as an idea before, but the difficulty in implementation means it's not something we're likely to pursue. Ethernet was never intended to be used outdoors, and twisted pair is a lot more difficult to ground correctly than coax is. Running significant power on top of that makes things even tougher.

Interesting..as we have a wireless LAN link atop a remote mountain site that uses Ethernet and POE. So far, no issues with it. Thanks for the info Jason.

I though KPXN-DT, Ion LA market was transmitting ATSC-M/H.

In any case, there are two Mexican stations transmitting h.264 channels in my area. I have a FusionHDTV5 lite pci card and a HVR-950 usb tuner. I was able to watch those channel with Fedora 13 linux, and Kaffeine player.

For Windows decontv's software worked with both as well. I note that if you install this software, when prompted make sure you install VLC even if you have a version installed.

Screen shots and TSReader posted
http://www.avsforum.com/avs-vb/showt...878152&page=20

Has anyone determined if Mobile TV is easier to receive than standard ATSC? Especially for weak or distant stations?

I'm with Ken.. initial tests say no..

Yeah I guess that makes sense. On HD Radio the low bitrate HD3s (typically weather and traffic reports) fade out before the high bitrate HD1 and HD2 channels.

I suppose it makes sense a low bitrate M/H signal would fade out first, ahead of the high bitrate ATSC.
.

I'm not disagreeng with you but it does seem a tad odd seeing that mobile is supposed to be more robust.

The robustness that was added to the M/H standard was primarily for reception while moving at highway speeds, not for long distance reception. Two features (these are not the only feature enhancements, but they are probably the most significant) added for better reception are:

1) A digital "pilot" signal (known bit sequences at fixed locations within the stream) that can be used to adjust for doppler effects. This feature is not really useful in aiding long distance reception.

2) A potential increase in error correction bytes (there is some choice in the number used, so the maximum amount of possible error correction may not be used by a particular broadcaster). This was primarily for the errors induced by the doppler effect, but it can also be useful for distance reception. However, it wouldn't help that much, because of the "cliff" effect that can already be observed with normal ATSC reception. Even more than doubling the number of error correction bytes probably won't add a significant distance to the reception area, and that would only be for stationary M/H receivers. So, if you are in a location where you are able to receive a certain station but your reception isn't "error free", then perhaps you will be able to receive that stations M/H programming without error (while stationary).

I have problems getting VHF12 when the sun is up. It resolves on the receiver but doesn't generate any usable picture (just a smear of colors).

It seems to me that both enhancements 1 and 2 would help with reception of 12. It would make it easier for the receiver to (1) lock on the image and (2) use the enhanced error correction to convert the smeared image into a watchable picture.
.

I may be wrong, but I don't see how enhancement 1 would help in locking the signal if your antenna is not moving in relation to the transmitter. The enhancement is used to correct the small timing errors that occur due to the movement.

Enhancement 2 would only be helpful if you are trying to receive the M/H programming of a particular broadcaster. The enhanced error correction is only applicable to that programming and does not cover the main ATSC programming. You do seem to be right at the edge of the "digital cliff", so yes, there is a good chance that the enhanced error correction would let you get a clear picture for the low resolution M/H video programming.