Canadian TV, Computing and Home Theatre Forums banner
1 - 14 of 14 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I live 80 miles away from the towers both North and West of me. I built an antenna to use in my attic. It works well without a pre-amp and better with a cheap one I got at walmart. I also bought a channel master preamp, for $75.00, no better than my cheap RCA so I sent it back. I built it with a refector made from metal screen. Much better with this reflector. About half of the channels in either direction are in and out. Of course always better at night. So 50% reliable. Any ideas how I can improve my antenna. I am going to try adding a line pre-amp, might work? But not bad considering the distance to the towers. I also read
that adding foil Brown Wood Floor Flooring Beam
to the reflector might improve performance. My channels are UHF 16-34 and VHF 7-13. Any ideas? Really liking the channels I get, just want them to come in better. The Rabbit ears website info suggests I need a medium outdoor antenna. So if I don't get any improvement I might look at that option, and fit it into my attic. Not going back to pay TV that's for sure. I had a basic subscription and counted over 100 channels I never used. What a waste.
 

·
Registered
Joined
·
141 Posts
I also did that, installed an attic antenna (grey-hoverman) with cheap in-line amplifier. Then I build an exterior version of the grey-hoverman and installed it outside on top of the chimney. That is about 10 ft higher. That is where you get a much better signal, being outside and higher.

That is also where an exterior pre-amp will help, because it can tolerate the elements, which is not the case for the cheap RCA amplifier. There is little gain in getting an antenna pre-amp for attic installation because you loose something like 20 dB because you are inside.

jf
 

·
Registered
Joined
·
142 Posts
More information will be required, before anyone can really give you any advice. Posting Rabbit Ears results and letting us know which channels your are interested will help. Better pictures, exact dimensions and orientation of your current antenna will help. It looks like your current reflector has fairly fine mesh, so I doubt if adding foil will gain much, if any. Is that a splitter on the back of the antenna? If so, just having a splitter in place will loose some signal. Have you tried just running one cable to one TV?

You stated that you have towers to your North and West. You may need to pick one or the other and set up to get channels from that one, or install two antennas, one for each direction. Installing two antennas can often create its own problems, and may require a switch, selecting one antenna or the other. Stronger antennas as always more directional, and will make it more difficult to pick up channels from both directions.

Installing an antenna outside, with a direct line of sight to the tower is always best. Installing in the attic may still work, if you have the proper setup. The loss, from being inside is more likely to be 2dB, not 20dB, but it may be more or less, depending on the construction of the attic. Most antennas work best in either the VHF(channels 7-13) or UHF(channels 14-36). You will have to decide if you need both of these, from either tower, before you can select the best antenna. From what I can see, from your picture, I'd guess that it will work best on the UHF frequencies. If you haven't already, I'd try aiming it directly at each tower, and see which channels you can get reliably.

Get us as much information as possible, and then we can give you more appropriate advise.
 

·
Premium Member
Joined
·
1,200 Posts
I live 80 miles away from the towers both North and West of me. I built an antenna to use in my attic......Any ideas how I can improve my antenna.
Hello, arswy0q; welcome to the forum.

I agree with ljhavener. We need more information about the signals at your location to give you any useful advice about improving your antenna.

In particular, a signal report from rabbitears.info would be most helpful. The following link is for making a report. (I use coordinates from Google maps for a location.) Your exact location will be hidden because the coordinates in the report will be truncated (shortened):
https://www.rabbitears.info/searchmap.php

If the signals are 80 miles away, set the distance for the report for at least 80 miles.

Please tel us what is going on here and what is connected to what:

Brown Wood Stairs Tints and shades Hardwood


What are the most important channels to you that you want to improve?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #5 ·
JF, in the end I may put one outside. But FYI the preamp I got is an outside preamp. I may change antenna and build the grey Hoberman. Thanks for the input.
More information will be required, before anyone can really give you any advice. Posting Rabbit Ears results and letting us know which channels your are interested will help. Better pictures, exact dimensions and orientation of your current antenna will help. It looks like your current reflector has fairly fine mesh, so I doubt if adding foil will gain much, if any. Is that a splitter on the back of the antenna? If so, just having a splitter in place will loose some signal. Have you tried just running one cable to one TV?

You stated that you have towers to your North and West. You may need to pick one or the other and set up to get channels from that one, or install two antennas, one for each direction. Installing two antennas can often create its own problems, and may require a switch, selecting one antenna or the other. Stronger antennas as always more directional, and will make it more difficult to pick up channels from both directions.

Installing an antenna outside, with a direct line of sight to the tower is always best. Installing in the attic may still work, if you have the proper setup. The loss, from being inside is more likely to be 2dB, not 20dB, but it may be more or less, depending on the construction of the attic. Most antennas work best in either the VHF(channels 7-13) or UHF(channels 14-36). You will have to decide if you need both of these, from either tower, before you can select the best antenna. From what I can see, from your picture, I'd guess that it will work best on the UHF frequencies. If you haven't already, I'd try aiming it directly at each tower, and see which channels you can get reliably.

Get us as much information as possible, and then we can give you more appropriate advise.
Is that a splitter on the back of the antenna? If so, just having a splitter in place will loose some signal. Have you tried just running one cable to one TV? Well first off, the splitter is there to connect two of these antennas, one facing magnetically at the towers in both directions. The antennas only feed to one tv. My antennas are 2ft tall and 3 feet wide, using Gray Hoverman concept. By using two antennas, I think they are interferring with each other. I live in Rolla Mo. and the towers are in Springfiel to the west and Jefferson city and Columbia to the north. Basically, there is CBS VHS channel 10, and UHF channel 28 in Sprigfield that I want to receive. Channel 10 would be the only VHS channel. The others are UHF. They are 82 miles away, as are the others I now receive. But channel 10 has a weeker output from the tower. If I could get those, I would forget about the channels to the north. But between the two antennas, I get 33 channels, but only 3/4 at any given time. Below are the rabbit ears results. I thought about using a folded dipole for the VHF channel 10, and attaching it to my antenna. Might work? Thanks for any guidance.



Result List
Shareable link: https://www.rabbitears.info/s/389642

InstructionsClick here.
Study Location37.95*, -91.77*
Study Date/Time2021-11-11 21:53:26ET
Receive Height30' (AGL); 1136' (AMSL)
Search Distance
 

Attachments

·
Registered
Joined
·
10 Posts
Discussion Starter · #6 ·
Hello, arswy0q; welcome to the forum.

I agree with ljhavener. We need more information about the signals at your location to give you any useful advice about improving your antenna.

In particular, a signal report from rabbitears.info would be most helpful. The following link is for making a report. (I use coordinates from Google maps for a location.) Your exact location will be hidden because the coordinates in the report will be truncated (shortened):
https://www.rabbitears.info/searchmap.php

If the signals are 80 miles away, set the distance for the report for at least 80 miles.

Please tel us what is going on here and what is connected to what:

View attachment 12339

What are the most important channels to you that you want to improve?
Is that a splitter on the back of the antenna? If so, just having a splitter in place will loose some signal. Have you tried just running one cable to one TV? Well first off, the splitter is there to connect two of these antennas, one facing magnetically at the towers in both directions. The antennas only feed to one tv. My antennas are 2ft tall and 3 feet wide, using Gray Hoverman concept. By using two antennas, I think they are interferring with each other. I live in Rolla Mo. and the towers are in Springfiel to the west and Jefferson city and Columbia to the north. Basically, there is CBS VHS channel 10, and UHF channel 28 in Sprigfield that I want to receive. Channel 10 would be the only VHS channel. The others are UHF. They are 82 miles away, as are the others I now receive. But channel 10 has a weeker output from the tower. If I could get those, I would forget about the channels to the north. But between the two antennas, I get 33 channels, but only 3/4 at any given time. Below are the rabbit ears results. I thought about using a folded dipole for the VHF channel 10, and attaching it to my antenna. Might work? Thanks for any guidance.



Result List
Shareable link: https://www.rabbitears.info/s/389642


InstructionsClick here.
Study Location37.95*, -91.77*
Study Date/Time2021-11-11 21:53:26ET
Receive Height30' (AGL); 1136' (AMSL)
Search Distance




Attachments




Save Share

Reply Quote
 

·
Registered
Joined
·
142 Posts
Hi, arswy0q
A couple of suggestions.

By using two antennas, I think they are interferring with each other.
Two identical antennas, pointed in the same direction will usually get some additional gain. If they are pointed in different directions, it usually causes multipath signals that degrade the results. The signal is still picked up by the antenna pointed in the other direction, but the signal is arriving at a slightly offset time. I'd try just one antenna at a time, pointed at each tower and see what the results are. Let us know what you can pick up, with each antenna, when you only hook up one at a time.

My antennas are 2ft tall and 3 feet wide, using Gray Hoverman concept
Without knowing exact dimensions, measured to the nearest 1/16 of an inch, its hard to know how well your antenna is working. Do you have the plans, that you used to build the antenna? The original Gray Hoverman antenna did not receive HiVHF signals that well. The later models with "hats" do pretty well with HiVHF(channel 7-13). This might be a good choice for the Springfield stations. Its a pretty large antenna, to put on a rotater, but if you could rotate it, it could be used on both directions.

Another different direction would be a commercial antenna. Based on HamiltonOTA2.0's recommendation, I picked up a couple of Monoprice 39303 antenna, on sale for $14.99, shipping included. They are normally $24.99, but are on sale, at the Monoprice web site. They seem to be very well built, for the price. See Modeled a Yagi from Primecables / Monoprice for a detailed discussion of the antenna, as well as a suggested improvement, that greatly improves the reception of HiVHF channels. The addition of a 32" long reflector, made from a 1/4" metal rod, fastened to the very back of the antenna, more than doubles the reception of HiVHF signals. I'm not sure that this antenna will last well outside, in the weather, but it should do great in a attic. They claim it is an indoor/outdoor antenna, but I think sun and ice, will limit it's outdoor life after a few years. The antenna is 35" long, 30" wide, and 17" tall, so I think it will fit OK in your attic. This antenna should pick up your desired channels, from one tower. The antenna is rated as a 70 Mile antenna, so you may need to add your amplifier, to get good results. It's not as fun as building your own antennas, but for the money, it is a quick and cheap route that should get you at least some of the channels, that you are looking for.
 

·
Registered
Joined
·
5,167 Posts
VHF 10 and UHF 28 while coming from roughly the same direction, are quite different.
vhf 10 is almost 500' higher than uhf 28, so it has a slightly better path on the way to your house.
uhf 28
In addition to all the other recommendations, I would try to keep an eye on propagation weather
conditions, and see how well it correlates with your reception for a while.

If I lived there, I most certainly would have a highly directional UHF antenna, up as high as possible on an antenna rotor normally.

But Looking through your rabbitears report, I see there are three RF 28 s used in Missouri, so that might open you up to more co channel IX on RF 28 during certain times. Why I suggest to keep an eye on propagation conditions vs your reception. If Interferers are allowed to propagate more due to enhanced propagation, I suspect it may cause you more grief.
Still, would be an interesting place to study, as it doesn't seem like the incentive auction was able to get very many stations to bite at moving down to the VHF Range down there.

Using the rotor, allows you to make changes from your couch, regardless of the antennas in use.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #9 ·
Ijhavener and MajorTom Thanks for your input. I will go back up in the attic next week. I will try pointing both antennas to the west tower by connecting them with the splitter. I will set them up next to each other, about 6 inches apart. If it improves, great, if not, I made a folded dipole antenna for VHF ch 10 and UHF 28, the two I am having trouble with. I will add that to the to of the antenna and take down the VHF elements I put up in the beginning. If no improvement, I will try pointing both antennas to the North tower, which is closer anyhow, by a few miles. If still no improvements, I will construct a Top Hat and give it a try. If still not satisfied, I will consider buying an antenna. I tried to stay away from manufactured antennas, because even though they boast 70-100 miles, they don't do that well. Now if anyone knows of such an antenna that will get my channels, please advise. Remember, we're talking 80 miles. As for RF 28, two of those are to my north, so could be problematic. After I get it strightened out and running the way I want, I will most likely get a rotor.
 

·
Registered
Joined
·
5,167 Posts
seperate VHF and UHF antennas (what I use up here), are best combined using a VHF/UHF Diplexor (UVSJ). Not a common splitter/combiner like in your photo(?). Some Preamps also allow you to easily hookup separate VHF/UHF antennas. The relatively cheap (affordable) RCA TV Preamp1R is one example. Another is one of the televees preamps from spain.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #11 ·
seperate VHF and UHF antennas (what I use up here), are best combined using a VHF/UHF Diplexor (UVSJ). Not a common splitter/combiner like in your photo(?). Some Preamps also allow you to easily hookup separate VHF/UHF antennas. The relatively cheap (affordable) RCA TV Preamp1R is one example. Another is one of the televees preamps from spain.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #12 ·
Majortom and ijhavener: So I took down my antennas, those similar to the Grey Hoverman, bought some #10 copper wire, and rebuilt the antenna using the Grey Hoverman instructions. Then I added 2 narods One on top and one on bottom, for the upper VHF. Then I took the reflector from my old antenna, placed it behind the antenna, 4.50 inches. 36x26 correctly this time. Last time I had the 36in ai the horizontal position. (Duh!) I pointed the antenna towards Columbia at mag. asthmith 330 degrees. Columbia being 70 miles and Jeff City being 54mi. I figured 330 degrees being the center asthmith of the two cities' towers. I also attached my RCA Preamp. Wow, I received both CH 17 and 18 along with 13 (VHF 12) out of Jeff City. Before changing antennas, I only received 13 part of the time and 17 and 18 very rarely.
So here's what's next, and I need advice. In my previous pics, I ran two antennas pointing two directions. I connected them with a splitter. I have since orderd a diplexer, or combiner. I will connect the two antennas to the combiner, and put the pre amp behing the combiner/duplexer. I know when splitting, the preamp belongs at the antenna, before the split. I am not sure how much signal I will lose. But would it be better using two preamps, one per antenna?
Rectangle Slope Font Gesture Parallel
Then the preamps would be before the combiner. Remember, I am shooting for towers between 70-80 miles away, so I need all the gain I can get. The investment of a second preamp would be worth it, but maybe not necessary. I will test before buying a second preamp, after I complete the second build. Using the splitter before the preamp previously, I think I lost some gain. Please advise...Thanks...
 

·
Registered
Joined
·
5,167 Posts
Sounds like your are having fun. What it's all about..
I would always combine antennas before any amplification.
Can you post a link to what you have bought for combining, so we can see what it is?

The televees preamp does allow for some more flexibility. In that it has multiple inputs, each with an input level adjustment, and agc. I just run mine wide open however. in my setup VHF Lo + VHF Hi yagis are combined via diplexer go to one input, while the db8e goes to the other input. The reason a common splitter isn't the best choice to combine VHF + UHF antennas, or UHF + UHF antennas is that there isn't much isolation between the combiner/splitter ports, so the antennas will interact, and cause multipath, which is even worse to begin with up in an attic. Antennnas are designed to be used in free space with no obstructions, so that signals aren't bouncing around.

We want to minimise multipath, not encourage it and maximise / encourage the direct Line of sight paths for best reception.

I do believe your existing RCA preamp will work fine with separate inputs, just that u'll be using one of the GH + Narod antennas as a VHF antenna, and the other as a UHF antenna. eg opposite band is basically wasted/overkill, but that may be OK. You can compare that configuration vs 2 GH + narod aimed in different directions using the diplexer that you bought in a single input configuration (just remember to flip the internal single/dual switch).
In either case, you'll have VHF from one direction, and uhf from another direction.
You should really be reading / understanding the hdprimer article about ganging antennas.
www.hdtvprimer.com/antennas/ganging.html

If the rebuilt antenna is generally working OK for you and ur trying to get some more Improvement. I would do a test, just move it outside, then up higher on the roof as the next steps. See what getting rid of all the attic attenuation and multipath buys you for yourself...

If no further improvement, fine leave in ur attic. But assuming there is, maybe it's time to
invest in some antenna mounting hardware, and not more electronics to allow a permanent installation.

 

·
Premium Member
Joined
·
1,200 Posts
1 - 14 of 14 Posts
Top