This post addresses several areas of HDTV reception: Finding True North, ATSC Reception Test Equipment, Satellite Dish Aiming, Paint, Washers and Antenna Pictures. See attached PDF files.Finding True North
The simple way is to use a good magnetic compass. A suitable compass can be found at your local Wal*Mart in the Sporting Goods section. You will need to account for your Magnetic Declination and that can be computed by NOAA Magnetic Declination
The sun can be used to find true north, go to NOAA Weather
site, enter your nearest city & state, then select Local Climatology, then select the nearest location to you under the Daily Climate Reports. There should be a section that will list the Sun Rise and Sun Set times. Format three cells in Quattro (or Excel) in 24 hour time mode. Enter Sun Rise as XX:XX:XX and Sun Set as YY:YY:YY. In the third cell enter this equation: (((Sun Set-Sun Rise)/2)+Sun Rise) This will calculate your local High Noon. At this time a vertical (plumb) pole or object will cast a shadow on a level surface (tangent) that points due North. Note: when the sun is close to The Tropic of Cancer the shadows will be short in the USA.
The North Star will also get you close. At night, position yourself so your antenna mast is inline between you and the North Star, now mark a spot at your feet. During daylight you can point your antenna boom to the spot previously marked as your starting reference.
Problematic DTV reception:
There will be situations were receiving DTV stations will be difficult. Without proper test equipment the most one can do is place and aim their antenna by trial & error. In most cases analysis with instruments should show if reception at a particular location will be feasible. At minium, the test unit has to have a spectrum analyzer with sufficient resolution and display to show echo nulls, desired channel flatness and other signal degradation. Unfortunately these instruments are fairly expensive and beyond the reach of many (most) serious hobbyists. Listed below are several devices that are designed to analyze DTV signals. A general purpose Tenma Spectrum Analyzer is included because it is relatively inexpensive for this class of equipment. Please note this unit does not cover all the L-Band frequencies and may not be suitable for common satellite use. The Sencore AT1506 seems to be the most advanced DTV analyzer, but I think it is being phased out of their product line.
DISCLAIMER: I have no experience or affiliation with any of the devices listed below except as noted.
At work we had a Tektronix RFM151 that I used for DTV signal evaluation. It appears to be available from Tempo as the Signal Scout RFM151. This was a fine unit but the operation was not very intuitive.Tempo Signal Scout RFM151
, Sencore AT1506
, Sencore SA 1454
, Sencore SLM 1456
, Leader LF 983
(Has been discontinued??) Tenma 72-6696
1GHz Spectrum Analyzer. Added: BK Precision Model 2630
Spectrum Analyzer and Sencore DTU-234 RF Probe
with optional software.
Peter Putmans comments on DTV reception, spectrum analyzers, and some antenna test. HEAVY METAL, PART I
, Spectrum Analyzers
. More Antenna Test
by Bob Chase using a spectrum analyzer.
The file Coaxial Balun-0001.PDF contains a drawing of resistive pads to convert the 50Ω input and tracking generator output of a spectrum analyzer to 75Ω in and out. A Tapered T Attenuator and a 75Ω, 43dB Symmetrical T Attenuator convert the output of a 0 dBm, 50Ω tracking generator to 0 dBmV, 75Ω. The attenuation of the Tapered T Attenuator was chosen so the value of R2 was 0Ω and therefore eliminated. Most outs will be adjustable in 10 dB steps so you could make the Symmetrical T Pad 13 dB and set the generator to -30 dBm. The resistors should be Dale/Vishay RN60 series or better, the 1Ω could be hard to find and one may have to use a thick film resistor. The input to the analyzer has a single 25Ω resistor added in series with the input. Just add 50.5 dB to the analyzers reading to convert to dBmV, i.e., -63.7 + 50.5 = -13.2 dBmV. The operation of a 1/2λ coaxial and a ferrite transformer balun (set to ideal) is included. The 1/2λ coaxial balun is in purple and the ferrite transformer balun is in green.Satellite Dish Aiming
Tic Mark Spacing-0001.PDF has degree markers for three common use pipe sizes. When printing this sheet make sure the Shrink to Fit option is not checked. A line that is 6 inches in length is at the top and is your reference, measure to make sure that it is the correct length. I print these on 24lb. paper, cutout the desired marker and attach to my dish pole. I cover them with clear weather proof tape (Frost King), see Antenna-0001.PDF for pictures.
Aim your LNB boom arm due South (those dishes with skew should be set to none or neutral skew), take a common paper clip and straighten one leg and temporally tape it to your dish incline bracket so that it is inline with a tic mark. Make a mark where the dish should be rotated to and rotate the dish so the pointer (paper clip) is at the reference mark you made (i.e., your location requires 213° W, 213-180 = 33° West rotation from due South [clockwise, looking down on the dish]). Set the elevation (and skew if multi satellite dish). If done correctly you should have a signal from the desired satellite(s). Tweak the azimuth and elevation for best signal, the skew should not be changed. For folks with small aperture dishes and using linear LNBs, set the skew of your LNB that corresponds to your location and desired satellite. Folks using an H-H motor mount should have their LNB skew set to 0°.Satellite Dish Paint and Washers
Rust-Oleum Smoke Gray 7786 [20066 77868] paint is a very close color match to the Winegard and KTI satellite dishes that I have. This paint is very slow drying. To touch-up minor scratches I tighten the cotton of a cotton swab, spray the swab and apply.
To minimized scratching the elevation marking on my satellite dish incline brackets used to adjust the dish elevation I procured 1/4 (≤ 76CM dish) and 5/16 (≥ 1M dish) inch nylon washers and placed between the bracket and flat washers.Pictures
Antenna-0001.PDF contains four pictures of my satellite dishes and antennas. I live in a condo and have very limited use of space. Upper Left: Winegard DS-3100 for Ku satellite (AMC-3 for PBS HD). KTI for Dish Network at 110° and 119°. Upper Right: Rear view of Winegard DS-3100. All the mounting items were fabricated by me from items available at the local building supply and online. 2-3/8, 16ga. fence post, 1-5/8 (actually 1.66") 17ga. fence post, 3/4 EMT, and treated lumber. The hardware items are: stainless steel, galvanized or Grade 8. Lower Left: Winegard PR-9032 UHF antenna, RCA dish for Dish Network at 61.5°. Lower Right: Closeup of the PR-9032.
09-19-05 Added to analyzer list
10-04-05 Added link to Bob Chase antenna test
Coaxial Balun-0001.pdf 21.3515625k . file
Tic Mark Spacing-0001.pdf 13.1396484375k . file
Antenna-0001.pdf 364.7939453125k . file