At what speed does mobile dtv reception become a problem?

jsmar

DTVUSA Jr. Member
#3
For ATSC-M/H reception, at what speeds does reception of signals become impossible? Over 100MPH? Just curious.
In looking up details for the Kenwood unit mentioned in another post, I noticed it mentioned reception up to 130 MPH. I don't know if that is an advanced capability that you get for your $500, or if all ATSC M/H receivers will be capable of reception at any speed you are likely to drive.

I wonder if the DVB-H standard is capable of higher speeds for those driving on the Autobahn!
 

Aaron62

Contributor
Staff member
#4
In looking up details for the Kenwood unit mentioned in another post, I noticed it mentioned reception up to 130 MPH. I don't know if that is an advanced capability that you get for your $500, or if all ATSC M/H receivers will be capable of reception at any speed you are likely to drive.

I wonder if the DVB-H standard is capable of higher speeds for those driving on the Autobahn!
;) Up to speeds 155 MPH would be nice, actually if I'm not mistaken, all German made cars have a governed speed of 155MPH. Then again, who the heck would want to watch TV at speeds 100+ MPH? :huh:
 

jsmar

DTVUSA Jr. Member
#5
;) Up to speeds 155 MPH would be nice, actually if I'm not mistaken, all German made cars have a governed speed of 155MPH. Then again, who the heck would want to watch TV at speeds 100+ MPH? :huh:
Perhaps the passengers who are trying to forget that they are in a car traveling at that speed? ;)
 

cjswann

DTVUSA Rookie
#7
Mobile DTV Reception -Parked or Crawling

Had a dvd/vhs system with an analog tuner that all came with the purchase of the car. I got used to watching the news on the way to work and watching the start of football games after leaving church on Sundays. Anyway, the conversion happened and I got a new radio/monitor system plus a DTV tuner. I though all was well with the world until I pulled out of the installer's parking lot, lost the signal, got it back at the light, lost it again when I starting moving, either that or the tiling thing going on.

What can I do??????
 

Piggie

Super Moderator
#9
For ATSC-M/H reception, at what speeds does reception of signals become impossible? Over 100MPH? Just curious.
I am not sure at what speed this would occur, but it could be calculated. The higher the channel number the slower this speed would occur due to shorter wavelengths.

But I am not talking about loosing the signal, but actually receiving it.

At some point you are passing through the peaks and nulls so fast with enough memory to interpolate signal loss in the device, it would have an easier time averaging out the data and drop out less!

From my experience using my ears and brain to interpolate audio data received on 146MHz, about 60 mph, one is driving so fast enough through the peaks and valleys of the signal the multipath flutter on FM audio all but goes away.

So it's possible that at 100 mph your reception on ATSC (not M/H) might be better than at 20 mph.

As far as ATSC-M/H goes, I don't think there is such a thing as driving too fast. The entire point of it was redundant data streams for error correction.
 

Piggie

Super Moderator
#11
Sounds like a case for Mythbusters. ;)
It would depend on the receiver. If the receiver has sufficient memory to take several frames as samples before rendering them to the screen

The shear speed of passing through the varying multipath interference patterns would create an analog type of interpolation.
 
#12
I found something here on how fast you can be travelling and still receive mobile dtv signals. It's not exact, but it does confirm that you can go faster than 100 miles per hour and still receive atsc-m/h signals,

Mobile reception - Clear, consistent reception tested at speeds greater than 100 miles per hour. The system processes the mobile program stream(s) with additional forward error correction and data redundancy to help ensure successful reception.
Open Mobile Video Coalition - About Mobile DTV - Mobile DTV 101
 

Piggie

Super Moderator
#13
Know what I hate about the internet at times? If you can post a link, it bears more weight than 30 plus years of experience.

Part of how the country is going downhill. Yes I am venting. Someone with zero experience with the correct newest degree will get hired over someone with some other degree but decades of experience.

Boils down to what happens all over the internet. Good links trump experience.

The faster you drive the better the reception will become.
 
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