Dreams of a white Christmas come true
Tuesday, December 25, 2012
Thursday, December 20, 2012
Tuesday, December 11, 2012
Are over-the-air ATSC digital-to-analog converter boxes now failing with age? Maybe...maybe not!
At work, I oversee over a dozen granny boxes used to receive and convert local over-the-air digital TV channels for viewing on our in-house analog cable TV system. Reception of three channels was problematic, often locking up and freezing at will. The models we use are the most inexpensive available marketed under the brand names 'Micro Gem' and 'Access HD' sold for around $29.95. I tried swapping converters, testing converters for input sensitivity and analyzing the output of the wall-wart power supplies grasping for any clue. What was making decoding these specific channels so unreliable?
I discovered that these converters run fairly hot, especially when perched upon other pieces of gear in equipment racks. One tiny electrolytic capacitor, directly adjacent to the bright metal tuner module, sometimes dries out and limits the sensitivity of the converters. I have replaced a few of those under-rated caps, with good results, but this fix did not cure my endless lock-ups. A listing in The Worldwide TV-FM DX Association's bulletin, VHF-UHF Digest, showed a new WCBS translator on the air on RF Channel 22 from
My troublesome channels are all in the
What is the common thread? WNBC, WCBS and WWOR share a master antenna mounted high atop the
This is an interesting case. Thinking out loud, I know that ATSC DTV transmitters have sample loops that monitor various aspects of their broadcast signals. The transmitters themselves are most likely producing competent waveforms but, in this case, the antenna system is wildly altering the linearity of the signal equalization presented to the public. Digital TV transmitters pre-distort themselves to insure output signals are tight and square. Obviously, nothing compensates for severe antenna problems. It would take an enormous amount of EQ to correct these bumps! You would think that a glaring problem like this would cause warning flags due to excessive reflected power and lowered efficiency. Maybe not?
Although I have cured my WCBS reception by reverting to receiving another transmitter, I have no recourse for WNBC and WWOR. The closest alternative NBC broadcaster is WVIT Hartford which also uses Channel 33. WWOR is a MyTV affiliate. It features local content, most notably
Friday, December 7, 2012
An evil stepmother must be casting her spell over October 29th. Last year, a ferocious ice and snow storm brought us endless damage and peril as we sat in the dark for seven days without power. Exactly 365 days later, Hurricane Sandy demolished our area like never before. Its severe floods and wind damage crippled modern civilization. Some neighbors are still waiting for power to be restored. Homes and livelihoods were literally blown away. Will severe weather become 'the new normal?'
The night of the hurricane was troubled and dark. Power cut off at dusk, long before the storm fully raged. Little sleep was had as the powerful winds roared. I could hear my roof tearing apart highlighted by startling bangs and booms. Rain flew by horizontally and the trees wildly bended and swayed for hours. A memorable moment came at 8:30 pm. Looking out our back window, my wife asked: 'Where's the pine tree?' The 70 foot behemoth had broken apart leaving a 15 foot high stump and three huge pieces now lying across our hill.
The morning of October 30th brought up familiar memories. Again, we would experience a wet and muddy world filled with the smell of fresh tree sap from numerous felled maple and pine trees. Broken branches and limbs were scattered everywhere. Shingles littered lawns and debris torn from nearby houses surrounded us. Listen carefully and you'd still hear a large branch or limb fall, hopefully in the distance. Other sounds combined to create a multi-voiced harmony for the next ten dark days: the whirring of gasoline engines and the rip of power saws. This time recovery would be longer and harder than ever.
was the third event
in one calendar year that brought week-long power outages. In the aftermath,
many families made the best of a bad situation migrating to friends' and
relatives' homes that still had electrical service. Hotel rooms were cherished
and usually impossible to find. Others subsisted by huddling in warm cars and
mini-vans and using their workplaces as havens to maintain sanity. One item was
on everyone's most-wanted list: generators! Sandy
The smell of gasoline once again annoyed our noses. Hauling five-gallon jugs back and forth from the gas station became part of many daily routines.Pouring the gas, especially without a funnel, only heightened the aroma. Wear gloves or your hands will stink forever!
Our area did not suffer too badly from long gas lines.
was another story. Miles and miles of cars
idled along highway shoulders waiting for the gas considered nearly
unavailable. This madness seemed to be the result of media hype. Travel a few
exits down the parkway and you would find gas available for immediate purchase
without waiting. New
The storm left its signature everywhere. One neighbor had an enormous pine tree fall across her driveway violently tearing power, telephone and cable TV lines away from her house. She subsisted on gas generator power, via an octopus of extension cords through a window, for over three weeks. Cable TV was replaced by connecting up her old trusty roof-mounted TV antenna. She delighted watching good old over-the-air TV! With very little power draw, all she needed was a twice-daily fill-up of her generator gas tank and life was good.
Out of necessity, I became acquainted with the world of generators. Having managed the power of many, many TV remote trucks and a few amateur radio Field Days and a lifetime of household repairs, I was not a stranger to how to properly proceed when handling electrical hook-ups. I had one moment of complete horror. A good friend had purchased a generator at a local Home Depot. After trying to use it with just a few extension cords, he decided his basic design was inadequate. He recruited a local electrician who provided a quick fix to his problem. I was mortified to see what he had done!
I called the electrician on the phone and simply asked: ‘Is this really up to code?’ Even after he said ‘yes,’ I found it hard to believe. He added: ‘Just remember to keep your main breaker open. It’s your responsibility!’ What he had done was unbelievable. The electrician had wired in a standard male 3-prong plug to one breaker of my friend’s power panel. You could then use an everyday single A/C extension cord to connect the generator to the power panel and backfeed it bringing power to all the circuits in his house. Yikes!
As a public service announcement, I beg you to never do this! You may think you are achieving great results, but great danger can result. Using this jury-rigged arrangement, if you do leave your main breaker closed you could be feeding your generator’s electricity up to your streetside utility pole or farther. This could be life-threatening to workers trying to restore power to your neighborhood. Should your regular power be energized unexpectedly, it would directly hit your generator causing permanent damage, fires or explosions. In simplest terms, don’t do this!
To add to the peril, backfeeding power also stresses the extension cord that is probably not rated for a full 20 or 30 amps of power. Applying one phase 120 volt A/C to circuits looking for 240 volt power is another bad idea. Stressing household wiring runs inside walls can produce fires and other chaos. It isn’t difficult to install generator power correctly. Please do!
It’s inexpensive and easy to do the job right. All you need is a transfer switch. Now you will be able to switch back and forth from generator power with safety and grace. It allows you to manage your power distribution to each discreet circuit. I recommend using a 10 or 12 circuit switch adequate to feed all the essential power needs of your home.
A transfer switch is not a master A/B switch between your generator and utility power. It switches each household circuit on or off individually. This also aids installation. If it were designed as a true master switch, the power feed from your utility pole would need to be turned off during installation. Using the individual circuit method, all power management remains at a serviceable level. Many transfer switches include ammeters so you can monitor exactly how much your generator is providing at any given moment.
The transfer switch is energized via a special weather-proof 4-prong A/C outlet usually mounted outside your house. A single heavy-duty 4 conductor twist-lock power cord connects the generator to the transfer switch. The power cord is a short length of four large diameter conductors rated beyond what your generator can provide. Each individual circuit of the transfer switch is independently protected by its own circuit breaker. Now you can operate with safety and confidence!
If you decide to purchase a generator, auto-throttle is a feature that should not be overlooked. This circuit monitors the amount of current draw at any given moment and adjusts the generator’s idle speed to match. This one feature will minimize your gasoline usage and maximize the amount of time your generator will run before another fill-up. It also makes the generator run very, very quietly. What a pleasure to not having a mechanical roar going on outside your house 24 hours a day. Don’t forget wheels! Two wheels make moving generators so much easier to do!
Another invaluable feature is an intelligent voltage regulator. Sensitive electronic gear, like your computer or HF transceiver, won’t appreciate a delivery of 140 or 150 volts! Good generators also closely regulate the amount of alternation to exactly 60 cycles. Remember: Safety first! Ground your generator to a good earth ground. Operate the generator outside, not indoors or in an enclosed space!
Creating your own electrical oasis has all sorts of fringe benefits. Not only will you live in luxury when utility power goes off, you’ll be very popular with your friends (especially if they are in the dark!) Keep your generator well-maintained throughout the year and it will also serve as a perfect addition to your Field Day efforts. All power to you!