The Official AVS Antenna and Related Hardware Topic! - Page 50

The first thing I'd do is get a 7777. They're available at SolidSignal.com as well as from Starkelectronics and Warrenelectronics. The next thing is to be sure you're aiming precisely. Go to http://www.2150.com/broadcast/default.asp and put in your coordinates in decimal form for precise bearings/distances. A good place to get your lat/longitude is http://terraserver.microsoft.com/. That's not a bad antenna choice considering you need low band (vhf 2-6) for Chicago digitals, but the problem you may run into is it may or may not be adequate for UHF and you may have to end up using separate antennas. The 7777 will allow you to do this easily as it has an internal VHF/UHF diplexer. Try the RS antenna first with the 7777 and go from there. You can easily add a CM 4228 later for UHF and keep the RS antenna but use it for VHF only.

The 7777 has to be configured for using the combo vhf/uhf antenna. I believe it may come from the factory set to do so via the "combined" input but you'll need to open it up and check to be sure. I'd set the FM trap to "in" as well.

I think Radio Shack's numbers are usually highly inflated. Knowing the 15-2160 as I do, I'd be surprised if it has 9.5 db of gain on any frequency. More likely, it's a 7-8db of "real gain."

Joining two identical antennas together in a stack will get you no more than (and probably slightly less than) 3db of gain. It will get you a hefty increase of front-to-back ratio as well as a significant decrease in beamwidth. Those are good things, no doubt about it. But they're going to be larger than 1 4228 or DB8, because you're going to have to mount them a minimum of 30" apart.

If you're pointing the antennas in different directions to receive stations in two areas, it doesn't matter if they're the same, different, red, green, blue, or coated in a special polymer. They're going to mess each other's signals up unless you use a Jointenna or similar filtering mechanism. You can get cable lengths perfect, place them perfectly, and still have them mess each other up. I've said it a million times and I'll keep saying it until I'm blue in the face: You cannot combine two antennas designed to receive the same frequency, point them in different directions, connect them via a simple splitter/combiner and *expect* to get good results.

So I guess, in the immortal words of Clint Eastwood, "Do you feel lucky?"

i tried to post this question last night and today i can't find my post:
i recently aquired a winegard UHF antenna- model U-630. is anyone familiar with this model and how well it works? i can't find any info anywhere on it, the source i aquired it from says that it's a 120 mile range antenna. it's approximately 72" longe and looks like an extremely large yagi type antenna. i would like to know if it's even worth installing or not.


thanks in advance

If you have a digital camera, a shot would help us. A search on Winegard U-630 turned up zero hits on Google, a sure sign that the model number isn't correct.

If you can't take a picture, take a look at the Winegard website and see which antenna looks most like it. That will help us assess its abilities.

Most likely, you've got a UHF/VHF combo, and the 120 mile range is for the VHF side. No UHF antenna is capable of an advertised range greater than 60 miles.

Hello can some one tell me how to figure out this.

If at ground level how far is the Line of Sight. And if I was on a 2 story house, or if I added a pole at 20 feet above my house?

I am looking to pick up at 90 to 100 mile.
Thank You

Will a pre-amp survive in attic ambient temperatures?

Plug in your numbers here:
http://www.vwlowen.demon.co.uk/java/horizon.htm

For a broadcasting antenna at average height (approximately 400 meters) you need to go at least 200 meters to get line of sight.

90-100 miles for UHF is very difficult unless the broadcasting tower is very tall (such as the top of a mountain.) Things such as topography between you and the desired station, as well as weather conditions, are going to be far more important than antenna height. But doubling your antenna height AGL has a major boost to reception strength. Every time you do it, it's like going from a UHF loop at the lower location to the best UHF antenna out there at the upper, with no change in hardware.

I'm 75 or so miles from my desired stations, have a 54' tower, and I still don't get reliable reception all the time from those stations. I do have one station that is about 85 miles away and it oftentimes does come it. But I'd never count on it.

One important thing in fringe reception is the elevation or altitude of your location. I'm almost 1800 ft. above sea level and rock solid pick up UHF digital stations 125 miles away with attic antenna. I'm a strong believer in T&E (trial and error) for antenna techniques.

That's a great little calculator. Too bad it doesn't take into account intervening topography. I know of software you can buy that will do this but I've never seen anywhere free online you can do it. The software I've seen is called "TOPO USA terrain" I think and a local AVS'er sent me some cool profiles using it several mos. back for my location. Sorry for the zip file but it was the only way I could get it to upload. You have to save it to view it.

 

terrain profiles.zip 94.013671875k . file

This is for MAX HD from fay28301 again. I read your advice about using the DAT75's again and am going to give them another try. When I stacked them before, 3ft. apart, 40 ft. up, I used two pieces of RG-6QS the same length from each antenna to a RS gold combiner, then from there into my preamp. As I said before, the gain was comparable to one CM4228, why?, I don't know, however if you have any suggestions or can tell me what I did wrong about the previous installation PLEASE let me know. I will wait before installing them until I hear from you. By the way, The WB must have boosted power, as I can receive them wtw & ttt now.
fay28301

I just put up a new antenna (Wingard 8 bay double bow tie). I used the pre amp from my old antenna (blonder tongue vhf/uhf about 3 1/2 years old-don't know the specs--someone else installed my last antenna and I don't have any documentaion). One channel is problematic. Would, possibly, a UHF only pre amp (such as the CM 7775) make an improvement
(I know I will have to try it to know for sure). I probably need to replace the pre amp anyway. It's been baking in the Alabama sun for a good while.
I need to put a little more height on my antenna. When I bought my mast materials last Sunday the store only had three mast segments (a little over 5 ft each). I think I can add one more and still have a stable set up it is a ground mount attached to my soffitt--the house is one story). But anyway, since all my digital channels are UHF I thought I would try a UHF only pre amp.

It's hard to say why they didn't work better.Placement issue?Propagation issues over a short time period?When I had a vertical stack of them on the tower,spaced at 39",I had a lot of intermod and adjacent channel overload,due to the increased gain and decided to stack them horizontally.Less overload and better directivity.

The RS gold combiner wasn't a V/U combiner was it?That would NOT work.I always use the cheap 5-900Mhz two-way splitters and found they work as good as anything else.

i did find some info today from an ex-local dealer. it's definetly UHF only. this antenna has not been built for over 15 years now, it has 2 wing nuts on the top side of the antenna and has 2 vhf shorting stubbs, to connect a VHF antenna. on the bottom side it has the main lead going to the TV or pre-amp. when this antenna was new it was sold locally as a fringe long range antenna estimated to be a 120 mile UHF antenna.

my radio shack power amp and pre amp apparantly isn't all that hot ,so could i possibly do better with the channel master or winegard pre amp/ amp unit?

Sorry to rehash a question I asked a bit ago but I need further info on beamwidth of antennas, specifically the DB4 or DB8. My previous post stated that I have recently been able to receive my PBS station using an attic mounted Terk TV50. I'm fairly confident I can do better than the Terk by changing antennas. It is best during a storm but I can get an intermittent picture other days. I have not yet even seen ABC (low power). Here is my info from antennaweb.org (zip 95973 in Chico, CA)

KHSL-DT 43.1 CBS CHICO CA 30° 14.1 43
KNVN-DT 36.1 NBC CHICO CA 326° 32.1 36
KCVU-DT 30.1 FOX PARADISE CA 29° 14.6 20
KRCR-DT 34.1 ABC REDDING CA 308° 67.0 34
KIXE-DT 9.1 PBS REDDING CA 308° 67.0 18

CBS, NBC, and Fox are not difficult to receive. CBS and Fox are about 90 degrees from the Redding stations. If I switch to a DB4 or DB8, should I still be able to receive the closer stations with the antenna pointed at Redding? I currently can't put in a rotator. I have very favorable terrain here. CBS, NBS, and Fox are at 3500-4000 ft elevation. I am at about 400 ft. No mountains are in the way. ABC and PBS, although at 67 miles are at almost 6300 ft. Line of site over the horizon should not be an issue (I think). Oh, which would be better in my situation, the DB4 or DB8? If more information is needed, please ask.

Thanks again,
Chris

That's probably a pretty good preamp. I'm not sure you'd see much improvement with the CM 777x series, but you might. My 7777 gave me a small but significant improvement over a Blonder Tongue Vaulter III plus. If you decide on a new preamp, I'd get the 7777 just to have VHF capability as it's about the same cost. The performance on UHF will be the same. If your current preamp has a 300 ohm input, that may be a small advantage in not having to use a balun. The 777x series has 75 ohm inputs so you'll likely incur some minimal loss through the conversion which may offset any improvement the new preamp might give you.

What channel is giving you the problem? The Winegard 8-bay has a rep for not being very good in the upper UHF range. It's also possible the channel in question is still at low power or you have co-channel interference from an analog. Here's a computer simulated comparison of various antennas including the Winegard 8800:http://www.hdtvprimer.com/ANTENNAS/comparing.html

Assuming you're not using a rotor, the CM 4228 is pretty hard to beat for flat response up and down the UHF range. It can be hard on a rotor, though.

Did you see my post on 2/20/05 @ 2pm?
I posted the fol. link to an Excel spreadsheet that I prepared wherein the Gain, F/B Ratio and Beamwidth are plotted for over two dozen antennas, based on spec sheet data.
I also included a comparison to the NEC simulation data found on the hdtvprimer site for several different antennas.

http://hdtv.forsandiego.com/messages...9581#POST15793

The spec sheets for the DB4 and DB8 only indicate a single gain figure, which is probably the maximum reached at the best frequency, expressed in the more optimistic dBi (relative to isotropic, i.e. equal in all three dimensions), which is 2.15 dB higher than the more commonly used dBp (relative to a dipole) units.

To get a good idea of performance, compare the DB4/DB8 to other similar 4-Bay and 8-Bay models from C-M and W-G.

re. UHF Propagation Prediction....FREE DOWNLOAD:

Dave Lung's latest TV TECHNOLOGY column described SPLAT!, a free Linux based program which will do UHF Propagation Prediction with Diffraction Loss due to terrain, based on the Longley-Rice model.
Explanation and downloading links are in :
http://www.tvtechnology.com/features...02.02.05.shtml

[quote]Originally posted by holl_ands
Did you see my post on 2/20/05 @ 2pm?


Yes, I've looked through this and while it is good information, I'm looking for some real world recommendations. From the information I see the DB4 should be less directional than the DB8 with less gain but could I reliably receive stations spaced 90 degrees apart without a rotor? Is there another antenna which may be better?

Chris

Directional antennas nearly always have a NULL at 90 degrees.
So unless you are close enough to use an omni-directional antenna,
the best you can do is to operate way down on the sidelobes of
the antenna.....or go to multiple antennas.

Winegard YA-6260, 6 element low VHF antenna.

Anybody has experience with this?

I'm thinking of trying this in the attic to pick up channel 3 signal (WBBM-DT, Chicago) 30 miles from the tower.

It looks like WBBM will be moving to high VHF in a couple of years. A low VHF antenna is likely to have a short lifespan. On the plus side, you could replace it with a high VHF antenna at the appropriate time and have a smaller antenna for the duration assuming you already have a UHF antenna going. Otherwise, a full spectrum VHF or combo may make more economic sense.

I do have a combo antenna in the attic right now and can pull in all stations. It's a 15 year old RS. I don't know the model number but it's about 12' long and the V shaped (in the vertical plane) VHF portion. I could pick up WBBM-DT with the Samsung 151 (with occasional dropouts) but the signal is nominally below the threshold(?) for my Samsung 351 (that's another story). I'm thinking of building a PVR using the new MyHD 130 card and want to optimize the reception before I do it. I don't think I can improve the UHF reception much and was just thinking whether a VHF low or single channel antenna would help with WBBM. I found 5 element VHF low Antennacraft at Starkelectronics for about $21 dollars but they emailed me that they don't carry it anymore but they do have the 6 element Winegard. The other option is to try the V4 from Antennasdirect but they don't show any spec info. I understand WBBM is moving but spending <$50 to watch CSI and Saturday college football for 2 years with my front projector is worth it. Of course, the other option is to replace the 351 with a better tuner but that's more $.

This will work, but it's gonna be *big*. I'm currently picking up an analog 3 pretty decent at 130 miles with a modified CM 3016 (Lowe's). The VHF elements are designed to be swept forward, but I turned them back perpendicular to the boom and it makes this a pretty darn good low band antenna. In an attic, you could just adjust the elements and forget it with no worry for wind. I had to put small set screws in to hold the elements in place 'cause mine is outside. Also, since you don't damage the antenna (but be careful) you could simply return it if it doesn't work.
The bonus is that it still seems to work pretty well for high band vhf as well.

Edit: I didn't see that you are already using a large combo antenna. I doubt the CM 3016 modified is likely to give you much improvement, although for me it works better on low band than the VHF section of a Winegard 8200p. If you are having problems even with the large combo, you might need to consider going outside.

Well, their first choice is channel 11. If that fails, they're after channel 3.

Why would WTTW give up their lucrative hi-VHF digital channel for UHF channel 47? Did WBBM make a deal?

WBBM once requested use of a UHF channel that was not yet in service from another station but the price was too high. Maybe they got a better deal from WTTW. Maybe the head honcho at WTTW has a Silver Sensor on his TV top with a good WAF. Whatever the reason, some sort of deal is in the works.

Going outside would not be much of a challenge compared to the objection of my wife. I think I'll order the 6 element Winegard and try it out. If if does not work well, I could butcher it into a Ch. 3 specific 3 element antenna and try to convince my wife to put it below the eave in the back of the house.

Some have had success making a 93" dipole out of 300 Ohm antenna wire.

Thanks. I did tried a folded dipole and I picked up nothing inside the attic, although now I suspect I had bad balun so I'll try again and will try putting it outside also.

You been right on MAX HD! I now have the xg91 and the cm7777. Went and hooked it up, setting on pool fence next to house, pointing directly into large garage. It is pulling channels 60 miles away already. I cannot recieve anything from St Louis yet (77 mi), but have gotten 2 dozen channels, with 13 of those being digital. WoW. Still need to purchase a rotor, so I have'nt got it mounted on the tower. Hopefully, that will get me some signals from St Louis once it is correctly installed.

One question I still have is about the tilting of the yagi? I wonder since my general location is low lyeing, would there be any benefit in a slight angle upwards?

Some people have reported better results with tilting. I think this is more likely to be caused by moving the antenna into "hot spots" than anything else, but I haven't tested it personally.

If you use a rotor, you'll either need to invest in a remote tilter or you'll be pointed into the ground when you point in some directions.

If you've got hills that are more than 2-3 degrees above level, tilting might help. Otherwise, I'd go with a level install.