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Discussion Starter · #1 ·
I am setting up a OTA antenna on a chimney mast and would like to know what parts are needed. The antenna will end up about 30 ft off the ground, 10 ft above the roof line and 5 ft above the chimney. I would like to try to get everything from Radio Shack but I am willing to order online for a new antenna (VHF/UHF), diplexer and a amplifier if needed. If you can, please check the list below for completeness and accuracy. The items below are listed how they will be connect from the antenna to the Hughes STB.


1. Channel Master or Radio Shack antenna (Suggestions please - 30 mi almost due W of Chicago, Wheaton, IL) Mid-size directional was suggested from antennaweb.com.


2. 50 ft of RG-6 QS cable to grounding block


3. Grounding block connected with ground wire to pipe coming out of electrical box (2 inch diameter) Cable TV line and phone are already grounded to this same pipe.


4. RG- 6 enters house after grounding block and continues in #5.


5. 50ft of RG6 QS to diplexer to combine Sat and antenna feed or 5ft to antenna amp and 45 ft to diplexer.


6. After diplexer 10 ft RG-6 continues (RG6 now contains Sat and antenna signal together) to back of Hughes E86 STB to Sat/Ant input. Regular cable TV is being connected to Ant input due to CBS-HDTV through AT&T cable, a future possibility.


Notes


Sat Dish RG-6 run will be about 15-20 ft before it gets to the diplexer. Should I have the satellite installer run a second line just for a possible second set that may be added in the distant future?


Questions


Is this set-up logical and correct. Do I need an antenna amplifier with a total cable run of about 100ft run from antenna to diplexer?



Any suggestions or testimonials wrt hardware preferences would be appreciated.


Thank you in advance,

SW
 

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Some suggestions:


(1) Ground the antenna to a copper ground rod, NOT your house electrical ground. This will afford better protection in case of low-level electrical discharges and lightning strikes. There can be several hundred ohms of impedance from the electrical cabinet ground and true ground, and you really don't want to provide a path of lightning into your house.


Ground rods are available at Radio Shack or other electrical supply outlets and Home Depot stores.


(2) Use the Channel Master models 3021 4-bay screen or 3022 small suburban yagi. The 3022 works pretty well with a mod you can find at www.projectorexpert.com. It has slightly more gain than the 3021 on lower channels, but the 3021 has more gain above channel 60.


(3) I'd stay away from a diplexer and use a straight run from your OTA antenna to your set-top box, if you possibly can do it this way.


(4) Try the antennas without a preamp first to see how your reception works out. If it's intermittent, Channel Master's model 7775 UHF Titan 2 is a good choice and will make a big difference.


The www.projectorexpert.com site has several articles on DTV antennas and how they work and compare.


KC
 

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The National Electrical Code specifically accepts grounding to a service entrance, a secondary service panel, or a grounded "raceway" (the "pipe" you referred to) Furthermore if a separate grounding rod is used, the NEC specifically requires that it also be bonded to the house electrical grounding with #6 or heavier bonding wire (this is very THICK wire.). The bonding wire is to insure adequate conductivity since a ground rod, alone, will have varying degrees of conduction based on sub-surface soil moisture. The resistance involved with an unbonded ground rod can rise well above the "several hundred ohms" of resistance Kelvin Colorspace was concerned about. Your initial grounding plan is perfectly Ok. (By the way, impedence is an unrelated issue of alternating current circuits. Since it's also measured in ohms, it's often confused with resistance.) The recommendations for the Channel Master antennas are good, but RatShack makes a perfectly acceptable suburban yagi, too: the 15-2160; @ $19.99.
 

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Quote:
This will afford better protection in case of low-level electrical discharges and lightning strikes.
Just to clarify this myth! Grounding anything WILL NOT protect you from a lightning strike! There is nothing you could use (no matter how much money you spend) that will protect from a lightning strike. If lightning strikes all the equipment connected to the wire the lightning travels down on will be totally fried! Grounding is merely a way for you to bleed off static electricity (for whatever you are grounding) to prevent electrical spouts which attract lightning to strike!


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[This message has been edited by FrankS (edited 06-01-2001).]
 

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Discussion Starter · #5 ·
Guys,


Are the antenna's you described all UHF/VHF? All of the yagi's that I have seen are UHF only. I was considering the CM 4228 as a possible new antenna.


I need the VHF because CBS-DT will eventually be broadcasting on channel 3 and they have the most HD programming of any of the networks. I believe all of the other Digital OTA channels are UHF (14-69) in Chicagoland.


Thank again for you help.

SW
 

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No. The antennas listed in the prior posts are all UHF-only. If you'll need VHF, then you either get a combo unit, or get two separate (UHF and VHF) antennas and tie them together with a combiner. Channel Master's 3020 is considered a good combo unit, and should be availabel at Loew's for around $90.00. RatShack has a similar model, their 15-2156 that normally sells for about $100.00, but I noticed in the flyer that arrived in yesterday's mail that it's on sale for about $50.00 for this month (or most of it). I happen to have that antenna for my analog use, and I've been quite pleased with its performance. Your mileage may vary, of course, since every location has its own problems. This is a large antenna - 160" boom length. One thing about RatShack in their favor is their no hassle return policy as long as you're reasonable about the product and packaging condition.
 
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