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The Official AVS Antenna and Related Hardware Topic! - Page 2

post #31 of 16104
There are several online sources. They're not expensive at all.
post #32 of 16104
I have a rather unique situation here. I live in San Francisco about 3/4 of a mile from Sutro Tower where 10 UHF digital stations are located, about 4 miles from the transmitters of two other UHF digitals, about 30 miles from two other UHFs, 45 miles from three other UHF stations and 55 from a VHF station.

I put up a CM4228 with a rotor, plus a Winegard 3113 for channel 12. I really don't need the outside antenna for the Sutro stations, but I'm able to find spots where they all come in okay. Trouble is, they all don't come in from the same direction, so I've had to label the rotor with the channel numbers. I find the 4228 to be VERY directive, and it doesn't allow much room for play one way or the other. A rotor is a must!

I get all 17 of those UHF stations with the 4228 except for one problem station. Channel 27 on Mt. San Bruno, just 4 miles away, won't come in at all! My antenna must be in a null for it. The other station up there on San Bruno comes in fine.

I get the VHF channel 12 station solid with the Winegard.

18 digital stations, yes, but it's a major headache for setting up a recording while watching something else. It's often impossible to get the two stations I want with the same antenna heading, and trying to record two programs back to back on different channels is a real challenge.

You folks that can set you antenna in one direction and get all the stations are really lucky!

If I run my HiPix card through the signal strength routine, I see four other digital stations that show very low signal levels in here, but they've never been strong enough to give me a picture. Two are in Sacramento, about 50 miles away over a mountain range, and two are in Santa Rosa, 63 miles away. I bet I'd get those too, if I added a preamp.

San Francisco
post #33 of 16104

Originally posted by Scooper
The only issue with that is FINDING a VHF only antenna now - I have one - bought a couple of years ago.


Check out the V4 VHF only antenna.
post #34 of 16104
That website is incorrectly showing channels 2-8 as "lowband" VHF. Channels 2-6 are lowband VHF. 7-13 are "highband" VHF.
post #35 of 16104
I am just starting to play around with OTA DTV and need some advice on tweaking my signal. Here are the facts:

- I live in Atlanta, GA and I am less than 7 miles away from all major station distribution points.

- All stations are in about a 30 degree spread from my point.

- I have a old antenna installed in my attic that was left by a previous owner. I ran new coax cable from the antenna to my outlet. It is about a 100ft of cable. Only running to one outlet, not split.

- I have the antenna pointed in the direction of the station cluster.

- With my receiver, the Samsung SIR-T151, I get all the stations I care about. In general when I check the signal strength it indicates that I am right in the middle.

- On occasion, loose the signal and or get pixelization. I have not done a real detailed test on this so it is hard to say what channels are worse.

My general question is what else can I do to boost my signal strength? Will a pre-amp help in this situation?
post #36 of 16104
A preamp is a good idea any time you exceed a 25' cable run. I noticed a drop of about 6% (on the receiver signal meter) when I went from a 6' cable to a 50' cable, so you could be losing much more of the signal.
post #37 of 16104

A preamp will probably cause you problems. They tend to work better when you are at a greater distance from the transmitter. I would think that an amplifier or a distribution amp would be better for signal loss due to your cable run. Did you make sure you have a good connection at the antenna?
post #38 of 16104
Thanks for the advice. I double checked my connections and tweaked the antenna direction a bit. I seem to be now getting a slightly stronger signal but the signal also seems more stable. I watched the entire NCAA Final last night with out a hitch. I saw no pixelization. It seems that my signal is not that bad after all.
post #39 of 16104
If I were to use an indoor amplifier, what tips would you offer on power, placement, etc... Why is an amplifier differerent from a preamp? At the moment I am only running my cable to one tv. I could see where I would want to split that and run it to other rooms in the house.
post #40 of 16104
W Auggie H,

I live about the same distance (5-6 miles) from my local tv towers here in Indy. Over the past two years I have experimented with various antennas and I have tried them in different locations, too. I didn't have much luck with them in the attic. I found it virtually impossible to find one location that would give strong signal results on all stations. I have had much better success with the antennas outside.

I do have a Channel Master preamp (7777) on my antenna setup but it is not for the local stations. It is to help with a few stations that are 40 to 65 miles away. I've found that my reception of the locals is usually much better WITHOUT the preamp. The preamp sometimes tends to overload the local signals. I've even seen some local DTV stations completely black out or show "0" (zero) signal on the STB from too much signal. The STB was simply overloaded.

At your distance from the towers I would tend to believe that your problem is probably with your antenna and/or the location of the antenna. You should have plenty of signal strength in your location to receive these local stations. The signal to your STB will only be as good as what the antenna is capable of producing. Also, your dropouts could be caused from multipath, with your strong signals bouncing around and off of other buildings, trees, etc. This condition seems to be even worse with weather changes, like windy conditions (trees moving around), rain, etc. Have you noticed any of these weather factors during your dropouts?

Just my two cents.

post #41 of 16104

Thanks for your 2 cents. I think you have provided a very good explanation of some of my questions. It is entirely possible that my dropouts were a result of some wind and or adverse weather. You see, in my neighborhood we have several large Oak trees that could very well be causing some of that multipath as you suggest. After moving some things around I seem to have a pretty sold signal and I think there is only one station that I don't get but I don't care about it. It would seem that if I want to take any more steps to improve my signal stability moving the antenna outside may be the best thing to do. Thanks again for your explanation.

post #42 of 16104
This link is a good read for us folk:

Pete Putman's Antenna article

In it, Mr. Putman provides a solution to multipath using two Yagi style antenna's. I didn't even think multipath could be a rural problem until Steve's post above (trees). My dropouts do correlate with wind.

I have a CM 4228 coming and look forward to posting in this sticky. Great idea, Ken!
My sitch:
-5.5 miles from towers at 40 and 51 degrees carrying all desired UHF stations.
-Despite relative short distance a Silver Sensor can't give decent strength on frequencies 56 and 30 (WB, CBS)
-A current question would be what's better: A 150-200ft run of rg6 and a clear line of site, or a 50ft run with the threat of multipath and a less than clear line of site? I have a berm behind my house and could mount the, somewhat omni-directional, CM 4228 high up on a tree.
post #43 of 16104

That article is very informative, but I didn't see anything about using 2 yagi's to reduce multipath. Can you point me in the right direction?
post #44 of 16104
Sorry, I thought it was in that article. If I find where I spotted it, I'll post a link, but basically the solution was to set up both Yagi's in parallel and stagger one behind the other just so that the first couple elements of the one overlapped the last couple elements of the other. AFAIK, there was no mention of how far apart the two antennas should be. I tried to draw it buy it wasn't working.
post #45 of 16104
Horizontal stacking in general is a way to deal with multipath. At http://www.atechfabrication.com you can see examples of this. This gentleman is receiving signals over a mountain which is frought with multipath problems. You can also search Google for "horizontal antenna stacking" and I think you'll find the other link on stagger stacking. If it were me, I'd try the basic horizontal stack first before getting really fancy. I'm currently using two Televes DAT 75's horizontally stacked at 57 inches (spacing recc. by Televes) with good results.

post #46 of 16104
Does anyone have a list of all available OTA HDTV recievers?
post #47 of 16104
cp cat where did you get your Televes antennas?

I am having great difficulty with my ota (55 miles+ from transmitters) and am open to trying anything. I have altrady tried 4 models from my local Circuit City and Radio shack and the Channelmaster favorites with no luck. I will try Antennas Direct, maybe I'll have better luck with them.
post #48 of 16104

Here's a link to Televes. http://www.stardubai.com/telantUHFPro.htm
post #49 of 16104
I ordered from Ruth Wigmore at CPC in the U.K.
Email is Internationalsales@cpc.co.uk.
Website is http://custom1.farnell.com/cpc/

They came in 3 days. Shipping is fairly expensive, though.


I'm getting WETP PBS-HD at 64 miles and only 4.8kw fairly consistently. Don't underestimate the importance of terrain factors, though. No guarantees but I can confidently say my reception is now better than with the CM 4228 at the same position and height.
post #50 of 16104
I spent the afternoon yesterday putting up a CM 3679 with a 9521A rotator and a 7777 preamp.

According to antennaweb, I'm about 15 miles from my local stations in DC
and about 45 miles from Baltimore and Annapolis (PBS). I've always
gotten Balt and Annapolis on analog with some snow but never digital. My
house is single story between two two-story homes with trees.

I had installed my last antenna about 12 years ago, a Radio Shack
'suburban' VHF/UHF antenna (similar to a CM 3016). I also installed a separate FM antenna on the same pole. The TV signal was split to feed two rooms. There was no amplifier and the antenna was fixed pointing essentially toward DC.

I had intended to reuse the same chimney mount and pole for the new
antenna and rotor. But when I got everything on the roof I found that
the old pole which was in sections had rusted together. Also, the
chimney mount bolts were heavily rusted as well as the old antenna
mounting bolts. So I removed the old antennas (broke rusted bolts), pole
and mounts and made a trip to Radio Shack. I returned with a new chimney mount kit and two 5' poles.

The new mount went up uneventfully. To prevent rust, I spray painted it
with some Krylon I had lying around. The 9521A rotor is well-built. It requires a 3-wire cable for connectivity. The wire does not have to be very large, but the longer the cable run the heavier the cable. Mine was 18-guage since my run was short. The instructions with the rotor state that the antenna should be no more than 3' about the rotor for stability and wind loads. Also, the rotor should be installed so that an arrow on the case points North. A 5' pole placed the rotor above the top of the chimney. I cut a 3' section from the remaining pole for the antenna.

The 3279 comes in two sections. It is jointed with two machine screws
and wingnuts. There are two metal 'rods' that join the VHF section to
the UHF section electrically and are also attached with wingnuts. Once
the two sections are joined, the antenna is over 10' long but is not
heavy. The unit also has a balun (300 to 75ohm transformer) and mounting bracket. I attached the mounting bracket to the pole, attached the 75-ohm antenna lead to the balun, attached a standoff and raised the
antenna and installed it in the rotor, making sure it was pointing due
North. I attached additional standoffs to the pole and ran the existing
antenna wire down the pole and down the wall of the house as before.

[I left the FM antenna for later on.]

At this point I wanted to see if the signal had improved without adding
the 7777 amp so I climbed down to finish the rotor install. I ran the
wire through the wall where the old cable entered the house. I connected
the 3 wires to the back of the 9521 controller and powered it up. Since
this was the first time it was powered, it went through SYNC function
which turns the rotor to '0' degrees. The control unit is not very big,
about like a paper-back novel. It has an infrared remote and is powered
by a brick transformer with a 4' cord. You enter a degree (000-360) for
direction and it starts turning immediately. The unit can also be
programmed by channel number to remember the direct it needs to point.
With this and the right kind of programmable remote you could have the
dish move whenever a channel change is sent to your tuner.

I commanded the rotor to point toward the towers and then checked the digital signal meter in my ATSC tuner (Samsung TS160). I was disappointed to see that the signal level had not improved that much (from about 66% to 75%). I checked other stations that I could not received before and also there was no joy.

So I pulled the 7777 out of the box. This unit comes in two parts, an outdoor amp and an indoor power supply. The outdoor amp attaches to the pole near the antenna. The indoor power supply provides DC voltage to the amp. The 7777 has switches inside for setting an FM trap as well as VHF and UHF amplification. The default is for FM trap Active and both VHF and UHF amplification active. I used the defaults. Since by now it was dark I installed the amp inside for now just to see the difference in signal.

With the amp, signals that had been %60-%70 went to %100. WMPT HDTV signal in Annapolis came in where it had not been before. Unfortunately, I was not able to get any of the Baltimore digital channels.

To complete the installation, I will move the amp up to the pole. I will also move the splitter to the second set. The original pole was ground but I need to move it to a better location. And I think I'll use an old sat dish pole mount for the FM antenna.
post #51 of 16104

You should be able to get Balt with your setup. I'll be interested to see the performance change when you get the preamp closer to the antenna.
post #52 of 16104
I have two locations I would like to feed from my main rooftop antenna, and I know how to use a splitter to do it, with the associated signal loss .

But, as it turns out, one of the locations is our home theater area where we do most of our viewing, and the second is in a less used loft. Therefore:

What if I run the antenna cable into my home theater's Zenith HDV420, then out the "RF out" loop on that receiver, through the in-house RG6 wiring, to the "RF in" of the loft receiver?

1.) Will I have avoided the splitter loss -- at the first location, maybe?


2.) if there is a loss from having "RF out" active on my main receiver, wouldn't I just be able to unhook the "RF out" from the Zenith HDV420 when going after a distant signal and get that full strength? . . . while cheating the secondary loft viewers, obviously?


post #53 of 16104
You are correct in your assumptions. However, you may find that if you're using a preamp that the extra gain will allow you to use a splitter without affecting the signal strength enough to cause a problem anyway. Just be sure the split is after the preamp and the preamp is outside on the antenna as close as possible to the source. If you're not using a preamp, you may need to consider one to split to two or more locations.


P.S. You also need to split after the preamp power supply unless you use a splitter that passes DC.
post #54 of 16104

I moved the 7777 up to the pole. I also removed the splitter. This made a huge difference. Where I was not able to get Baltimore stations before, I now have them at 75%-85%.

So now the antenna signal goes into the amp then to the power supply for the amp, then to a splitter. The two signals then go to the livingroom and bedroom TVs. The analog Toshiba in the bedroom never had such a clean picture. Must be spring because all the snow is gone!
post #55 of 16104

Congratulations! Enjoy DD5.1 on WMAR.
post #56 of 16104
Here is my current antenna. This stuff is alot of work but well worth it. I'm between 50-70 miles from locals. I initially had a CM4228 and CM Stealthtenna but with the upgrade have now picked up FOX as well as PBS-HD both at about 65 miles. My VHF CBS is much stronger and more solid as well. You have to save the zipped file and then open it to see the pictures. For some reason it won't open for me directly. I wanted to post the pictures in a more central area on the site but there doesn't seem to be an area for antenna setups in the photo gallery.

Televes DAT 75's x 2 57 inch spacing (UHF)
Antennacraft Y10-7-13(VHF HB)
CM7777 preamp
CM9251 rotor
RG 6 at antenna
Lindsay UHF combiner
RG 11 downlead
CM 30 ft. telescoping mast installed upside down



ant 3.zip 124.2568359375k . file
post #57 of 16104
You can never open zip's directly... you have to save/open, on AVS. Something to do with temp space?

Sound (and looks!) like a great rig, especially that RG-11, great for a long run!
post #58 of 16104
I am in a suburban area and local channels are short to mid-range in distance.

My Samsung 360 HDTV Receiver automatically selects the station via scan.

With a directional antenna, as I have, what may I be missing?

I have little use for the analog channels. Rotating the antenna is a pain...I'd rather surf.

Is multi-path much of a problem with local HDTV signals?

Has anyone experimented with an omni-directional antenna/amp such as those designed for RV use? If the local channels can lock on that without much of a multi-path problem, why not?

I have attempted to scan this thread for info - pardon please if I have missed significant comments.
post #59 of 16104
Anyone here have the new DB8 antenna? I was wondering how ell it was performing. Its 100 bucks at antenna direct. I was thinking of upgrading from my stealth to the db8. Anyone have any experience with it?
post #60 of 16104
Looks eerily similar to the CM 4228 to me which can be had for half the price. Either would be an upgrade from the Stealth (not very good on UHF).
I can personally vouge for the 4228, a very good value. It has very similar gain specs (for what that's worth) to those claimed by the DB8.

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