What will it take

[Digitized]

For years I have been watching analog signals from the Augusta GA stations. Now that digital will soon be the only thing avail. I've started trying to come up with the best antenna solution. In my case the analog signals always give a picture although not always perfectly clear you could watch what you wanted to. With digital it's hit or miss, and my fox station is always iffy. Antennaweb shows only 1 digital station for my location, and interestingly it's the only station that I CAN NOT pick up at all.

I'm using standard tv's with converter boxes at this time. Would like to upgrade everything at some point (tv's and some means of recording for when Im at work) but I'm not going to invest much money in this if I'm not likely to get the stations I want. FOX, ABC, CBS, NBC, are "must haves"

(Two locations @ zip 31049) my house and my parents. I'm using a large unknown make older UHF/VHF antenna with a CM-7777 mounted on a telescoping guyed pole.
Parents have virtually the same setup with a CM-3671 antenna and a distribution amplifier for 4 TV's. Both locations have a rotator, and I have tried various height settings. Interestingly mine will pick up somewhat better with it set really low close to the metal roof. Signal reflection from the roof ??
Land around the area is basically flat with only pine trees nearby.

So now I'm looking to upgrade antennas and am confused about what to get, or if anything will give me the signals I want.
There seem to be unknowns since the frequency and power of the stations in Augusta will change next year. (will this help or hurt)
Todays antennas seem junky made to me. (poor quality plastic/steel hardware connections)
So I have thought about making my own antenna. (not something made from coathangers and 2X4's I'm talking about something special)
From everything I've read bigger is better in terms or gathering a long distance signal. Sooo if a 170" antenna is ok a 200"+ antenna should be better right??
Also I would think that getting away from the UHF/VHF combo antenna might help. Use separate larger antennas for each band.??
Any advice is much appreciated.

Thanks

[hdtvlabs]

Hey Digitized

Just checked your location. Pretty tough. You need a large directional antenna, a rotor, and a pre-amplifier. But it looks like you already have all that

Interestingly mine will pick up somewhat better with it set really low close to the metal roof. Signal reflection from the roof ??

If the antenna is close to the roof, the roof becomes a scattering plane, like the one you have in CM4228, CM4221, DB2 designs. See the pic below.



The metal plane behind the bow tie elements is required to block signals coming from behind. Having a scattering plane will improve front-to-back ratio for any antenna. If you have an inclined roof, and putting the antenna close to the roof improves the reception, that might be an indicator of having multi-path intererence issues. You mentioned that the terrain is flat, but at least according to tvfool.com you don't have a line-of-sight to your channels, with an exception of 1 or 2.

So now I'm looking to upgrade antennas and am confused about what to get, or if anything will give me the signals I want.

Well, you may try CM4228 + CM7777. High directionality, good front-to-back, and will probably work in the high VHF band that you will need after the Feb 2009 transition.

So I have thought about making my own antenna.

I am very pessimistic about the chances of beating CM4228, or in fact any deep-fringe antenna with a homemade one. You must know very well what you are doing. Building a junk coat hanger antenna that will perform better than rabbit ears is easy, but building a highly directional deep-fringe antenna is a whole different story. Homemade antennas need tuning. You have to know exactly how to tune the antenna SWR (and in your case you need reasonable SWR in a very large bandwidth, from high-VHF to high-UHF), and antenna resonance frequency. Even if you know how to do it, you must have the necessary tools to do that, and even a simple antenna analyzer that measures resonance and SWR, will cost you hundreds of bucks.

Sooo if a 170" antenna is ok a 200"+ antenna should be better right??

Longer boom - higher gain (also narrower beamwidth, might have a negative side). But again, it is very difficult to tune a homemade antenna to achieve really high gain. The higher the gain, the more difficult it is.

Use separate larger antennas for each band.??

Since you need only the high portion of the VHF band, you can build an antenna that will cover UHF and high-VHF for you. ChannelMaster have done just that with CM4228.

[Digitized]

Thanks for the info.

I've got a friend that could measure resonance + SWR. Only thing is I would still need to know the pricipals of antenna design in order to get in the ballpark. I've tried doing some research on antenna design but haven't found a whole lot. Guess I'll put that idea on the back burner for now. May have to try the 4228

One thing I've never understood about having LOS to the tower is that there are a lot of things in-between my antenna and the tower that are far away. The FOX tower is broadcasting it's digital from 363m (1191') which seems relatively low considering the distance to the tower. I'd have to do a little trig to figure how the curve of the earth compares to the straight line from tower to antenna. Even then that doesn't take hills, houses, and trees into account. In my case the signal is probably having to pass through or around thousands of trees, numerous structures, etc. No way of knowing what all is along the route 5, 10, or 15 miles from here.
I really don't see how you could get true LOS without going really high with the antenna.

One thing on tvfool that I thought was interesting is that WMUM comes in OK even though the antenna is pointed nearly 140 degrees the other way. It is the closest station though.

Thanks again,

Digi.