Dumbed down consumer electronics: Adding DTV channels
in [Design]
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From: Michael A. Terrell on 10 Aug 2010 06:21 GregS wrote: > > In article ?8bo9bcFpu1U1(a)mid.individual.net?, news(a)analogconsultants.com wrote: > ?Paul Keinanen wrote: > ?? On Sun, 01 Aug 2010 14:14:29 -0700, Joerg ?invalid(a)invalid.invalid? > ?? wrote: > ?? > ??? Just curious: Why is it that "modern" TV/VCR/DVD devices only allow > ??? auto-scan for DTV channels but no "add some later"? As most of us know > ??? DTV is unreliable, meaning sometimes channel 6-1 pixelates out, > ??? sometimes 58-2 is gone. So upon setup it will only catch the ones that > ??? are currently receivable, which in our case is never more than 80% of > ??? digital channels. Changes all the time. > ?? > ?? You seem to suffer from frequency selective fading, which is typical > ?? in multipath conditions. This may eliminate the signal with sharp > ?? notches (usually less than 1 MHz) and these notches are constantly > ?? moving around the TV band when the propagation condition changes. > ?? Thus, a few channels are suffering from multipath nulls during each > ?? channel scan and hence, these are not stored. > ?? > ?? The 8VSB modulation used in ATSC is not known for robustness in > ?? multipath situations. The help the situation, an equalizer is used at > ?? the receiver that tries to compensate for the amplitude and phase > ?? errors created by the RF path. The equalizer needs a known training > ?? signal so that the equalizer parameters can be set up correctly. There > ?? have been claims that with 5th (or was it 6th or 7th :-) generation > ?? equalizers, the multipath performance is similar to COFDM DVB-T. > ?? > ? > ?I think they failed to achieve that level of performance. Yesterday > ?_all_ stations that carry evening news blue-screened. Meaning we could > ?not watch the news. I guess this is called progess. > > Lately, I frequently get one channel that stops. Sometimes if I go up a channel, then back, > it will work again. Another case of a 'Poorly Locked Loop'? ;-)
From: Jim Thompson on 10 Aug 2010 10:45 On Tue, 10 Aug 2010 05:41:50 -0400, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote: > >Jim Thompson wrote: >> >> That's pretty poor... Firefox claims _92_ "Radio Broadcast Companies" >> in Mesa alone... which I doubt... maybe 30 active AM and FM that I can >> think of. >> >> I have Sirius in the Q45, but I do web radio in my office...Roku >> Soundbridge. > > > Here are pictures of some of your local radio stations: > >http://www.fybush.com/site-010509.html >http://www.fybush.com/sites/2005/site-051125.html >http://www.fybush.com/sites/2009/site-090918.html Our house is one additional ridge south of the South Mountain towers, so I don't have to constantly see the !@#$% blinking lights ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Spice is like a sports car... Performance only as good as the person behind the wheel.
From: Jim Thompson on 10 Aug 2010 10:47 On Tue, 10 Aug 2010 05:30:26 -0400, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote: > >Paul Keinanen wrote: >> >> On Sun, 08 Aug 2010 09:28:58 -0700, Jim Thompson >> ?To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com? wrote: >> >> ?On Sun, 08 Aug 2010 17:48:42 +0300, Paul Keinanen ?keinanen(a)sci.fi? >> ?wrote: >> >> ??Are you really saying that some radio broadcasting companies in the US >> ??are still using medium wave AM as their main distribution channel ?? >> ? >> ?Some? There are probably 10's of thousands of AM stations in the USA. >> ?Your country is smaller than many/most of our states, so you don't >> ?appreciate the need for "medium wave" to cover large areas. >> >> Alaska, Texas and California have a larger land area than Finland, as >> expected. However, I did not expect Montana to be also slightly >> larger. >> >> FM started here in the early 1950's and only a few people relied on AM >> in the 1960's. In the 1990's medium wave AM was used to send news to >> Finnish speaking emigrants in Sweden and to the Finnish speaking >> minority in NE Russia. >> >> Since those days, only hobby based low power (0.1 kW) AM transmitters >> have been used during some selected weekends, mainly to support >> DX-listeners. >> >> To me, it is a surprise that medium wave AM is still actually used for >> commercial broadcasting. > > > Up to 50 KW AM transmitters are quite common. At one time WLW in >Cincinnati, Ohio ran 500 KW on 700 KHz. I vaguely recall multiple WLW's.... WLW-C, Cincinnati WLW-T, Toledo Weren't there others as well? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Spice is like a sports car... Performance only as good as the person behind the wheel.
From: Joerg on 10 Aug 2010 13:53 Jim Thompson wrote: > On Mon, 09 Aug 2010 18:07:50 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Mon, 09 Aug 2010 17:29:06 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Sun, 08 Aug 2010 13:54:51 -0700, Joerg <invalid(a)invalid.invalid> >>>>> wrote: >>> [snip] >>>>>> On long drives I listen to AM a lot. The reason is quite simple. The US >>>>>> is such a large country and there are long stretches of land with very >>>>>> sparse population. IOW not enough market for FM stations with their low >>>>>> range. You can always find this or that local station but if their >>>>>> programming is boring, well, then you must switch to the AM band. Also, >>>>>> the smaller FM station tend to drift into the noise after only a few >>>>>> country songs while AM stations usually stay around for hundreds of miles. >>>>> That's why I like satellite radio. The stretch of I8 from Gila Bend >>>>> to Yuma is devoid of FM and has only Mexican AM... although some of >>>>> their oom-pah-pah bands can be pretty entertaining... and their ads >>>>> are hilarious... all that shrieking, hooting and hollering ;-) >>>>> >>>> Ahora escuchen YUMAAAAAH! Ven al partido de futiboooooool EL DOMINGOOOOO! >>> OK. You have that down-pat. I'll see if I can get you an announcing >>> job with KPAZ ;-) >>> >> Isn't KPAZ a religious station? Can't recall any Espanol on there but >> it's been a while. > > KPAZ is _the_ major Hispanic station in Phoenix. > Ok, so now I did a web search: http://en.wikipedia.org/wiki/KPAZ-TV Only one of the sub-channels (21.4) is in Spanish. The rest is faith-based broadcasting: http://www.tbn.org/about-us Or is the Wikipedia entry wrong? -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 10 Aug 2010 13:55
Michael A. Terrell wrote: > Joel Koltner wrote: >> Hi Joerg, >> >> Joerg wrote: >> ? Yes, having landed a de-facto monopoly provides a plum position in the >> ? marketplace no matter how small that monopoly is. >> >> True... the problem with iBiquity is that the FCC let them have the entire >> market. At least with, e.g., Apple, while they get a cut of every (non-free) >> app that ends up on a (non-jailbroken) iPhone, there are plenty of other GSM >> phones out there. >> >> ? I vaguely remember one of the domestic car manufacturers offering it >> ? (Polk i-something) but I also remember seeing a $500 price tag there. >> >> The car manufacturers have incredibly inflated ideas about how much radios >> ought to cost -- even a simple AM/FM/CD player radio is often ?$200... > > > $40 for the radio & $160 for three union members to install it. No, only $20 for the radio. The other $20 is for the retirement fund and the "jobs bank" :-) -- SCRN, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |