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Thread: Remote DTV DX Site

  1. #21
    Join Date
    Jul 2005
    Location
    Indianapolis, IN
    Posts
    356

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    So far in comparing the two horizontally stacked XG91s vs. the Finco P-7 parabolic, it seems that the P-7 is a little more directional, with a more narrow beam width. More info here on beam width. http://www.hdtvprimer.com/ANTENNAS/GlossaryA.html#beam Greg B. has found that a quad stack of XG91s is more directional than a stack of two.

    The more directional P-7 is good and bad for distant DX reception. It's good when attempting to get a decode from a weak DTV station when there is co-channel interference (CCI) and/or adjacent channel interference (ACI) as it is easier to find a null to cut down the signal level of the interfering station(s). As for using the autologger when unattended, the aim of the antenna becomes even more critical as being off the needed "sweet spot" by a few degrees could make or break the reception. Antenna placement (aim) becomes much more important. And after years of DXing ATV/DTV, many times it is a bigger factor in nulling the interfering station(s) than it is to have the antenna aimed directly at the station you are attempting to receive. Sometimes the "sweet spot" may be 5-20 degrees + or - the true azimuth reading.

    The P-7 was able to receive three new DTV logs on Sunday, May 8. All three were less than 200 miles, but were low-power LD or CD stations: WYTU-LD 17/63, Milwaukee, WI @ 171 miles (Channel 17 usually dominated by WAND, Decatur, IL or WYIN, Gary, IN); WDNI-CD 19/19, Indianapolis, IN @ 99 miles (Usually CCI from WGN, Chicago); WOHL-CD 35/35, Lima, OH @ 182 miles (Fred V., finally got this one!)

    More time and some better tropo conditions will provide comparisons between the two UHF antenna setups.
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  2. #22
    Join Date
    Jul 2005
    Location
    Indianapolis, IN
    Posts
    356

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    Mike G. has been engineering a new project at the Milford, IL remote DX site. A few months ago Mike's relative who owns the property was able to obtain a 100 ft. self-supporting tower from a nearby school. He then turned it over to us to install and use for DXing purposes. Mike had a special base made to hold this tower. At the previous location, the tower was installed on a hinged base, and Mike has continued with that plan. As of two weeks ago, the base was lowered into a V-shaped hole about 7 ft. each direction of the V and about 6 ft. in depth. Then a concrete truck arrived to pour 6.5 cubic yards of concrete. The bottom section of the tower is 42 ft. and the top section is 58 ft., but it is actually two sections so it can be divided in half. When the tower is ready to be pulled up, a crane from a company in Milford will lift it up. Mike and I are quite excited about this project and look forward to comparing tropo reception from the current 40 ft. tower (in the background of one pic) vs. reception from the 100 ft. tower. The two towers will be 50 ft. apart.

    Yesterday, Nov. 9, using the tractor, Mike lifted and moved the bottom tower section to the new base, lowered it into place so that two of the legs could be bolted to the footings, and then using the front bucket/lift of the tractor, lifted the tower into its upright position. Thanks to Mike's great engineering job, the tower legs fit perfectly into the footings! A huge step in the process of getting this tower installed.

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    Because we don't have any exact specifications of this tower, Mike isn't sure how much of a wind load the tower is capable of handling, so we are trying to keep the load at the top rather light to begin. While the base is quite massive, the top section tapers down to a fairly narrow section. We've decided to start with two UHF Yagis horizontally stacked and a single VHF-hi antenna. A Yaesu 800 model rotor will be used along with an old-style (dual inputs, UHF & VHF) CM 7777 preamp. Down the road, we might remove the top tower section, making it approximately 71 ft. in height, which in turn will make it quite durable and sturdy to hold larger antennas, like a CM 4251 (7 ft. parabolic).
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    Last edited by indysteve; 11-10-2017 at 10:03 AM. Reason: adjust pic

  3. #23
    Join Date
    Jul 2005
    Location
    Springfield, Missouri
    Posts
    957

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    And I can tell why the Milford location does so well catching tropo dx - flat as a pancake and no trees crowding the antennas. A dream dx location.
    Jim Thomas
    Springfield, MO

    Ozark Mountain DTV dxing Daredevil

    Dx Equipment - AntennaCraft MXU59 UHF antenna & homebrew version of AntennaCraft Y10-7-13 VHF antenna @ 25'. Both antennas fed through a Winegard HDP-269 12dB pre-amp; a Zenith DTT901 converter box & a Silicon Dust HDHomerun Dual ATSC tuner, using Rabbitears autologger support.

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