The engineers warned the TV station managers, but they didn’t listen. I have mentioned it multiple times, but only 3 people read this blog.
Digital TV does not work well on channels 2-13 unless the viewer replaces their antenna, and even then its an “iffy” thing. Each analog TV station was given a “temporary” DTV frequency, and when June 12th came, each TV station had a choice to just stay on their UHF frequencies, or “return” back to their original analog frequencies.
Since many TV stations have large investments in their “Channel Brand” (aka Eyewitness 7 news), management opted to return to channel 7 – not knowing or not understanding that by doing so they would lose almost all of their “over the air” audience. This has been known since the early days of field testing of Digital TV.
Bad Choice.
Let’s see if the FCC holds firm, or creates an emergency process to allow stations to return to their “temporary” channels. In some markets, it’s not that easy as the “temporary” channels being vacated were the new channel chosen by a VHF station that made the correct choice to leave VHF. People on Cable TV won’t care one way or the other. This will be a windfall for Cable TV companies.
There are several possible ways out of this mess:
- Undo the DTV conversion again. This will be very very ugly. There are people waiting for the DTV to go dark to fire up new internet services like WiMax. TV stations have leases for their old transmitter locations that have expired.
- Create a procedure to let the station stay on their temporary frequency, and give back the original analog frequency. But those in the high numbers (60+?) have to stop using those channels, so they’ll still have to move to a lower UHF channel.
- Allow DTV stations to increase power. DTV operates at only a fraction of analog TV. Some of the reception problems may go away if the transmitter is allowed to use more power – but low VHF channels “skip” and allowing them to increase power creates more problems for nearby stations and interferes with Cable TV systems (your TV is probably on channel 2 or 3 when it is connected to the Cable TV box – a strong Channel 2 or Channel 3 DTV can interfere with the Cable TV connection)
As of the last time I checked, the FCC has not updated the database to terminate all of the old analog licenses. Several hundred of them are in place for 30 days doing “nightlight” service, which means playing a recorded messages telling you that your TV no longer works and what to do about it.
Look for another about face in Congress on Monday as the phones ring off the hooks. Sad that people are worried more about watching American Idol than losing all the freedoms and property.
One little technical detail – DTV uses “digital mapping”, which means the channel you see on the TV isn’t necessarily the channel the TV is actually listening to (as if it wasn’t confusing enough). So channel 2.1 my actually be on UHF channel 37. What matters to reception is if the actual channel is in VHF, especially low VHF (2-6). If you’re in the “fringe” area at all, you won’t get a usable signal, unless you get very expensive new antenna systems, in which case you’re probably better off signing up for cable TV (if you live in an area served by it)
My brother-in-law (an electrical engineer with two Master’s degrees in other techno stuff) did the converter box for my 83-year-old mom. Talked to her Friday. She had no tv signal. Had decided she would just read/listen to radio ’til my brother-in-law got over to her house to figure out the problem. She also couldn’t get the audio of the local ABC affiliate, Channel 6 (WPVI) on the radio. For years, that signal was available on the very low end of the FM dial and Philadelphians listened to Channel 6 (especially newscasts) in their cars/homes via the radio. That ended Friday as well. Also my little Sony portable “clutch” radios had a band to let me listen to all the local tv stations (channels 3,6,10, 12.) All gone now.
^^^^^^^^wow your story is exactly the same as Mr. Anonymous, what a coincidence!!
Haha… that’s amazing.
The actual problems with digital, is that the signal at the receiver must be of high strength or the decoding breaks down and stops until more signal satisfies the decoder. If in a short amount of time it doesn’t, the picture and sound are gone.
Channels 2 to 13 are the VHF channels, 2 to 6 low VHF and 7 to 13 high VHF. 14 and up is UHF.
With that in mind also note that LOW frequencies require LESS OUTPUT power to effect the same range as higher frequencies.
Just to make it easy to understand, and the figure is an example, 1 watt RF at 100 MHz travels 1 mile, 200 MHz double the frequency, and requires double the power to effect the same range, thus 2 watts RF to reach 1 mile (again note this is only an example, the figures only demonstrate and are not precise).
Furthermore, the real issue is the required signal strength to maintain a constant picture and sound. The digital picture and digital sound must be at full strength to run uninterrupted.
Analogue is the absolute most efficient signal possible, without the need by the receivers to have full strength signals they be at one third and still provide a decent quality audio and video display before any breakdown in quality. Digital looses with interruptions hitting even at 95% from things like rain, hail and adjacent signals and harmonic signals.
A different antenna, may or may not be required, either way, the better the antenna the better the signal, as example, GAIN is how antenna’s are rated, and an antenna with 20 elements has far more gain than one with only 10 elements.
UHF antennas have about 4 main DRIVEN elements, and many shorter DIRECTOR elements about 6 inches, mounted toward the front of the antenna, and a pair of angled REFLECTOR elements on the back end.
VHF antennas are much bigger elements, and usually are one pair per channel, with all sets angled forward, and some times straight out, the shorter elements to the front for the higher channels, and the longer elements to the rear for the lower channels and one element of each pair is grounded, and the other is driven or hot, the better ant’s stagger the hots, front to rear left, right, left, right etc. thus you see tie rods in a zig-zag pattern along the boom. Most of these antennas are by region, or by channel, and again the more elements the better. If you watch channel 5 your channel 5 element is collecting that hot signal and the other grounded elements act as directors and deflectors to aid in the received signal.
Lastly, a frequency also has a fixed size of its SIGNAL which is ANALOGOUS SIGN by nature. So 6 meter band is called that because a FULL WAVE LENGTH is 6 meters. Take a straight line across a page, draw an S laying down across the line, it starts at the center line and goes down, then swings back up to the center line, that is one HALF wavelength, it continues up above the same distance and swings back around down to the center line, and that is the full wave, positive and negative, and if you measure from the LOWEST point to the HIGHEST point that is your FULL WAVELENGTH, which is what the band figure is based upon. Generally speaking ALL TV antennas are quarter wave antennas, meaning the driven element is one fourth the length of the FULL WAVELENGTH of the frequency it is for.
To figure out what type of antenna you need, all you need to know is the frequency of what you intend to monitor. Wikipedia has a “LIST OF DIGITAL TV FREQUENCIES”, you can see the original analog and temporary UHF, and the number of sub channels they have, and other information on the stations.
From actual tests at 30 foot off the ground, only a few thin trees up close, basically flat land beyond, and a steep mountain behind, I receive good signal bounce off the mountain side less than a mile away, about triple what I get pointing directly at the stations. This type of bounce is like a convex mirror in a telescope, a much bigger capture field than my antenna itself deflecting the signal back at me much better than my antennas can do with the small 1/4 wave reflectors, BUT they capture in the very same fashion of a Satellite dish set up.
I use CATV RG6 or better cable, good connectors, sealed to keep out moisture, lightning arrestor element on top of everything, well grounded, with the towers base on a cement slab, with rebar in the ground and up into the base of the tower, along with a good 6 foot grounding rod, 12 gauge copper wire, and the coax shield grounded to it where the harness connects both TV antenna’s together, with the TV antenna’s spaced 3 foot apart for maximum signal and CO-PHASE impedance’s. In dry weather seasons, it may some times help by watering the base around the grounding rod your ground is very dry.
A good quality 30 Db antenna amplifier is a big plus. Just keep it close inline before the reciever, and if it’s a two pice unit, be sure to gethte CABLE TYPE, mening the part which mounts at the antenna has CABLE IN AND CABLE OUT, not the dumb 300 ohm looser in, and get a good 300 to 75 Ohm antenna mounted transformer, a 12 to 14 inch cable between the transformer and the pre-amp, even with COAX the cable stand offs do help when your talking DIGITAL TV signal. Be that the 300 ohm flat wire lead on the transformer does not touch anything, bend it around so its out away from things and mount the transformer so it won’t move around and your set.
Last of all, I have tried a several DIGITAL TV’s and CONVERTERS. TV’s suck, converters are hassle, but one stands out far above all others, and above all TV’s for many reasons, like response time, make it fast to to change channels and sound levels, and a fairly strong infra-red optic remote so their is no need for a hunting scope mounted on the remote to be sure your aiming into the receiver so it works, and being with a few feet so it has enough signal to change a channel, although not as good as a TV remote which is generally a hotter optic, (but poor receivers).
This is the Digital Stream DTX 9950, and in combination with a good DIGITAL TV it is great, except for the signal problems when the military flies over etc, it also has a power switch on the unit, and channel up and down buttons too, almost no other units have them, and all, even good ones are very sloooow responding.
The only reason I can see for mandatory digital TV is that some one got a BIG FAT $$$$$$$KICK BACK… Cable companies will profit big, so are they who made the pay off? Boycott Comcast and see what happens.
The FCC’s motivation was to correct the overly generous allocation of bandwidth given to TV back in the early days. If you’re as old as me, you remember the UHF tuner going up to 83. Each Analog NTSC TV station chews up 6 MHz of bandwidth. So by doing the whole AtoD conversion thing and compressing the TV band down, they will free up channels 52-69 for things like new wireless devices. Google was one of the companies that paid for the reallocation of spectrum. The Federal Government raised $19 Billion from the auction. On my personal wish list with the FCC is modification to the “Must Carry” rule – to either stop requiring cable TV to carry shopping channels, or to require some amount of locally originated programming to qualify for must carry.
P.S. Those little LOOP antennas TV NEWS STATIONS have said you need to buy are BS. they will work for close by analog signals, but a loop is basically best at locating the direct of the signal, since it is a very low Db gain. Smart antennas, I have seen work under special conditions only, and the coax must be good, and again line of sight, no obstructions between you and the transmitter. In most cases the best option is a good antenna pointed the right way, installed properly, and good coax….
S.P.S. I question the professionalism of so called Satellite TV Dish and Antenna Installers. They may know the parts to get something saet up, but the real down to earth technicalities of RF they don’t seem to understand much at all. I am retired, and of many years of radio work, testing, avionics, RF work, antenna design, and teaching others how to do it right so it actually works, I have learned the field well, and I have even learned others who were recently schooled need to learn a lot more and get some real hands on testing and experimenting under the belts before they go back to ripping off customers…
Enjoy your fished system, but above all, stay away from POWER WIRES, those yellow stickers mean what they say. I lost a couple friends who thought they could do without my help, and every week you hear about these so called pros getting a buzz, and it’s rare they live through it.
Electricity is UN-Forgiving…
There are right ways and wrong ways to raise a tower antenna mast, and swinging them up is generally WRONG.
If a mast is going to be on the ground and secured to the side of the building, you assemble it in a safe way and position where the tip of the antenna will be approximately where you want the base of the mast to be, and raise the antenna end upward into place so the base of the mast is dragged into place, also note that all GUY WIRES should be mounted with plenty extra length since most people will under estimate the needs
of their system. A 4 way tie down is best, but 3 will do for most, and the biggest mistake on these, is anchoring too loss, and anchoring to a weak item, like a screw hook in half rotted wood, you need a real good solid mount, a 50 mph gust can give a good jolt to an antenna system 20 foot above a roof. The more antenna and height the more wind it catches, and DO NOT RAISE ANTENNAS ON A WINDY DAY! You may go for a bad ride, or catch a power wire you thought would be no problem because its over in another direction
YOU HAVE BEEN WARNED!!!
The problem is the government. What a mess. They don’t solve problems, they just create them and then subsidize them.
The RF spectrum is not owned by anyone and should only be regulated by the FCC for the public in the USA. Surely not auctioned off driving up public and business cost just to pay the thieves on Capitol Hill.
All of this 480, 720, and 1080 and multiple formats would confuse anyone. What we see on our television channels today sucks. Seems to be no technical broadcast standards that public can rely upon at all.
On a scale of 0 to 10 I give the FCC a big fat 0.
From this blog and others that I have read, I think the best idea is to modify the stupid DTV law and allow analog TV again on the lower VHF channels. DTV is not working well at all on the channels and I have read that the needed antennas are much to big for mobile use there.
This would not cost nearly as much as a complete reversal of DTV and could possibly give people in Tornado Alley reliable broadcast weather on TV again. (DTV and satellite are both worthless in severe weather).