Northern Virginia 40-43 Miles to OTA ?

[keithhe]

Hi Folks,

Like most posting here, I need a little advice (antenna / amp??). My location in the Stafford Virginia area is a little fringe for the DC market stations to the north east I hope to receive. My report is here:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d1ddae3b5ba25fd

The good news is my house sits on top of a hill and I look down in every direction. The bad news, there are a lot of trees I have no hope to get above where the closest are ~ 80-100 feet from roof ridge I would plan to tripod mount antenna which would be about 40' AGL. I ran tests of altitude increase above this mark with no real changes until wild high numbers were entered. Really can't do a tower, so that is not in the cards.

Stations I hope to receive are the typical big 4 and anything else I may have come along for the ride. All are 40-43 miles and a few degrees off from one another. I need High-V and UHF only

So I have a tricky situation. I would like to hedge my bets and will plan to:

A) Use RG-11 with compression F connectors. (I already have plenty of very high quality RG-6 Quad Shield, and if not a difference would use that)
B) 50 - 60 feet cable run to a single TV (Tivo HD 2 channel)
C) Use best antenna or antennas possible to increase gain
D) Use a pre-amp to further increase my chances ??

So given my situation just several questions for the experts here.

1) What antennas would you recommend? Why and where to obtain?
2) What pre-amp would you recommend? Why and where to obtain?
3) Do I need any other amps?

I am highly technically savvy and the infrastructure is a cake walk for me, but have no idea what DB signal I need to have at TV to have a hope of picking up anything. Hope to not invest a lot of money only to have little or nothing to show for it, thus will go to the best out of the blocks. The trees near me are a worry and something I can't do anything about, although I would whack some to give me a little space between antenna and first trees.

I see I am primarily 1 and 2 Edge and know what that means, but via Google Earth looked to see and the "Edge(s)" are minimal height from mine, so hopefully won't be a show stopper.

Thanks folks and very much look forward to any and all advice

[teleview]

Install a Winegard HD7698P antenna above the roof aimed at about 50 degree magnetic compass direction.

The HD7698P antenna is High Gain and more directional in the forward direction to help reduce multi-path reflections of the surrounding trees.

Try reception without a preamplifier , and then try reception with a preamplifier , a Winegard HDP-269 preamplifier.

Here is a tall tripod antenna mount , http://www.ronard.com/Tripods%200703/4712.html.

Buy the ronard antenna mount at solidsignal by typing the word ronard in the solidsignal search box or buy from ronard.

Here are places to buy antennas and etc. .

http://www.solidsignal.com

http://www.amazon.com.

http://www.winegarddirect.com.

http://www.antennasdirect.com.

For 1 Tv connected use No splitter.

For 2 Tv's connected use a , HFS-2D , 2 way splitter.

For 3 Tv's connected use a , HFS-3D , 3 way splitter.

Buy the HFS splitters at http://www.solidsignal.com , or , http://www.hollandelectronics.com.

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Here is a way to get a antenna up higher.

http://www.ronard.com/tree_adjust.html.

Recommend do not install the HD7698P antenna in a tree , the antenna will not last long in a tree.

A Small Strong and Sturdy antenna is better.

Install a Antennas Direct - ClearStream 2 Complete UHF/VHF antenna.
http://www.antennasdirect.com/store/ClearStream-2V-UHF-VHF-Long-Range-Indoor-Outdoor-DTV-Antenna.html.

Also install a Channel Master CM7777 preamplifier.
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Tall straight pine trees work the best as a antenna tower.

Get the antenna Up High so that the antenna has a clearer shot at the transmitters to the north east.

Cut tree branches away in a manner that the tree branches can not whip around and beat up the antenna.

Do not underestimate the Desire trees have to beat up a antenna.

Cut the branches away in a manner that the branches Can Not whip around and beat up the antenna.

[keithhe]

Thanks for the quick reply Teleview !!

Might I ask a couple other questions?

How exactly do I interpret the two "db" numbers in the "radar report" ?? What am I looking for there, or more important what range means no way it will work? Just could not find a discussion about this on the site.

Although trees are not ideal, they will exist I suspect in every application at some range. At what distance do trees mean less in terms of interference? As my direction of needed alignment slopes away, I may decide to drop trees down the hill but when is distance enough?

Last, given my radar report, and I suspect many, many people asking all the time, do I have any chance? Good, bad, maybe or no way to know for sure?

Thanks again !!

[teleview]

1 or 2 or even 3 or 4 NM(dB) , is not important in the Green and Yellow reception zones of the tvfool radar report and channel list.

1 , 2 , 3 , 4 , NM(dB) becomes important in the Red and Gray reception zones when the signal strength is very weak and you want the signal real bad.

And -You say- you will do what ever it takes to get it.

((And some reception situations , the only Tv stations to receive are very weak signal strength ones.))

As an example , looking at your Pending Applications Included Digital radar plot and channel list.

Let's say that you have to have , WCVW Real UHF channel 44 PBS that has a minus -6.1 NM(dB) signal strength and is 67.9 miles distant and has 2 edge path obstructions.

The reception is not reliable with the HD7698P antenna and a amplifier.

And stronger amplifier does not make the signal reliable.

However changing the antenna height to 90 feet in the tvfool report will make the signal strength minus -2.0 NM(dB) , and at -2.0 the reception will most likely be reliable.

Will you go to 90 feet to get??

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At Very Low Signal Strengths.

The point of reference numbers for reception is ~ minus -8.0 ~ -10.0 NM(dB).

A few locations are getting reliable reception down to ~minus -12.0 ~ -15.0 NM(dB) , however it is the ->Exception<- not the rule.

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It is much better to start with reception in the Plus Numbers.

The Point of reference numbers at the Preferred Better Signal Strengths for Reliable Reception are ~ Plus +8.0 NM(dB) ~ +10.0 NM(dB).

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The trees and reception.

If you get the antenna up as high as you can reasonably get it.

By actually putting some real thought and effort in to it then your reception will most likely be reliable down the Pending Applications Included Digital Channel List to at least , WDCW UHF channel 50 The CW.

It is best to keep the front of the antenna in the direction of reception if you are installing the antenna above the roof , as far away from the trees in the direction of reception as possible and also have the antenna up high as possible.

The idea is to try and clear the tops of the trees or get as close as reasonable antenna height to clear the trees.

With out doing a any crazy monkey swinging and falling off the roof.

There are math formulas about angles and distance and etc.

The math formulas are not really helpful.

It is better to get up on the roof with some binoculars look into the distance and use your own evaluation and judgement.

As a ->Test<- , You can also , lay the antenna on top of a chimney of even put a chair on the top of the peak of the roof , 2 legs on one side of the peak and 2 legs on the other side of the peak of the roof , lay the antenna on the seat of the chair , aim the antenna at the Tv stations to the north east , connect one tv in the house and see what is received.

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I make the Point about the trees because many people place little to zero importance concerning the trees reducing reception , the person has the antenna 1 foot away from and aimed directly into a big fat dense tree , and then can not figure out why the reception is not good.

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After all is said and many points and evaluations are made.

-->The Only Way<--> to find out<-- is put a antenna up in the air and see what happens.

[keithhe]

Teleview,

Once again thanks for the very comprehensive answer. Answers were all very clear, but still having a hard time with the two columns that have "db" figures. Which means what? In particular to what you wrote above.

My only stations of concern are "yellow" and above and then only about 6 of them. The db numbers there mean little to me in either of the two columns. What is the difference beteen the columns?

I can get the antenna higher, but likely not to 90 feet. 40 is easy enough, and I could probably get to 70 or so AGL, but 90 starts to get difficult for me to deal with.

I will try the experiments you mention above as well, but kind of trying to figure out about where my "finish line" is and mostly what the two db columns mean to me.

My closest tree in direction I need (50 mag) is 80 feet away from antenna, and I can get that back further, but when is it enough? Would prefer to not clear a hole (path) through my entire lot that goes back about 1/4 mile in that direction. If what I think I interpret from what you wrote above, everything I want (yellow and above) is a positive number in one of the two columns, but the other column is negative. My trees back there are all about 90-100 AGL, but lot slopes down quite a bit back there, so I get some help with height, probably not enough to clear them completely though, short of clearing a path through the entire lot.

My only interest channels are all yellow lines and above

ABC
CBS
NBC
FOX
Channel 20
Channel 50

Don't at all care about any of the others.


https://www.dropbox.com/s/xe75380ne16cmka/TV%20Reception.JPG

Thanks once again, and very much appreciated !!!!

[teleview]

The numbers are side by side in the tvfool channel list and color reception zones of , Green , Yellow , Red , Gray , reception zones.

The color reception guide and numbers are Accurate for Every Day Practical and Useful Reception Guide.

The number in the column that is the reference point number for good reliable reception is Plus +10.0 NM (dB) , And stronger higher Plus numbers are better for reception.

You Add the antenna gain number to the number in the column and that 'pushes' the Plus number higher and that is good for reception.

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The 90 feet antenna height story is a Example , it is a reference story , it is a story that provides a point of reference.

I am Not Recommending Go Higher , the story is a ->reference point story<-.

The story suggests that might have to go higher to get some Tv stations/channels.

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The spirt of discovery and adventure is more important then understanding every thing first.

There is No Way to know for 100% sure if any reception will happen until a antenna is in the air and see what happens.

As I stated , the Tv stations/channels in the Green and Yellow reception zones will most likely be received down the channel list to and including WDCW The CW.

[keithhe]

Thanks Teleview.

I think that I understand the NM(db) column now as I found an old thread on that here that explained it.

What than is the next column "Pwr (dBm)" , and what does it represent?

I've ordered the antenna, mount and amp (in case I need it I will already have it). The rest I already have or is local purchase items, so should have this up by the weekend I hope and will advise how I did.

[GroundUrMast]

How exactly do I interpret the two "db" numbers in the "radar report" ?? What am I looking for there, or more important what range means no way it will work? Just could not find a discussion about this on the site. http://www.tvfool.com/index.php?option=com_content&task=view&id=57#how_to_read
http://forum.tvfool.com/showthread.php?t=109

The Signal (PWR & NM) columns offer the same information, referenced to different '0' points.

The PWR value is referenced to 1 milliwatt of power. 0 dBm = 1 milliwatt, -10 dBm = 0.1 milliwatts, -20 dBm = 0.01 milliwatts... -60 dBm = 0.000001 milliwatts. To use this information, you need to know how much signal power your tuner or preamplifier needs (or can handle). This should be a wide range, (very roughly, as low as -90 dBm and as high as -10 dBm).

The NM column is more user friendly in my opinion because even though it's derived from the same data as the PWR value, it's zero reference is based on the theoretical minimum signal-to-noise-ratio (SNR) needed to achieve reception using the ATSC (over the air digital standard signal format). An NM of 0 dB (notice the absence of the 'm', because the reference level is not 1 milliwatt) is the theoretical level at which a signal would be receivable... Higher levels are better, signal fade or noise would be less likely to interrupt reception.

In cases where you desire to receive signals that are lower than 0 dB NM in the air, you can use an antenna with gain to improve the net NM (noise margin). Amplifier gain doesn't work the same way though, noise is also amplified and to make matters worse, the amplifier adds yet more noise and distortion. So amplifier gain does not improve net NM... it makes it worse. An amplifier can only help overcome losses and/or noise generated on the output side of the amplifier.

[keithhe]

Thank you GroundUrMast

The second link is the one that perfectly helped me understand the NM(db). The other, despite your detailed explaination is still fuzzy, but may not matter to me. I modified your spreadsheet in order to trial in different altitudes across desired stations I wanted then added in my Loss/Gain factors to get the following:

NM(db)

WNVT-DT 64.6
WJLA-TV 21.2
WUSA 22.7
WHUT-TV 30.4
WNVC-DT 30.2
WDWA-LP 29.7
WTTG 29.5
WPXW-DT 29.0
WRC-DT 25.2
WDCA 26.6
WFDC-DT 26.7
WDCW 21.9
WETA-TV 19.8

The above are corrected for all loss gain factors, and green indicates channels I care about. Given the numbers, any reason to believe, all other things being equal, that I might anticipate receiving these OK?

[teleview]

All of your calculated NM(dB) numbers are above the Plus +10.0 NM(dB) reference point number.

The Plus +10.0 NM(dB) provides some elbow room for signal variances.

The stronger signal strengths provide more elbow room.

The FCC reference point number is 0 NM(dB) for LOS Line Of Sight transmission and reception.

And reliable reception does happen with negative -NM(dB) numbers.

[No static at all]

The only problem channel to areas south/west of DC is usually the WDCW 50. The lowest on the chart, WETA-PBS usually does well. You will most likely have reliable reception most if not all of the time from the DC stations given the numbers in the TV FOOL report. . .

[keithhe]

Thanks No Static

That makes me feel better as I was worried that given my situation I might end up puting all of this up and have "All Static at all" times :)

I have my most probable location on roof scouted now and will drop trees close in as needed to give some clear space between antenna and forest that surround my house. Closest now are about 80' away from mount location, but see several I might whack, if needed, in direct line.

Given my aim mag of 50 degrees, how far to either side is important to have clear? Can this just be directly in the path at 50 degrees or some margin on either side?

[No static at all]

I would test reception first before going crazy on the trees. You just won't know till you try.

[keithhe]

Thanks No Static. I plan to try everything prior to executing any plants.

[elmo]

A good thing is that your trees, if not confiers, are almost at full sail going into summer. That makes it prime time to figure out if they're blocking or not. Come fall, your signal will bump up accordingly while you're outside raking leaves. :D

[keithhe]

Hey guys, just wanted to stop in and say thanks to all that offered their advice. Success!!!! The Winegard is a beast at 14', and just got it up today. Really remarkable how well it is working given my distance (40-45 miles) and with all 1 and 2 Edge and the forest of trees in my aim direction all of which are much higher than my 40' AGL antenna.

I receive all I wanted, but surprisingly 20 is the weakest and 50 WETA works pretty well. WETA is weak and not consistant, but it was not on my list of must haves.

My coaxial run is quite short at about 35 feet or so.

Aside from downing trees which I'm still quite able and willing to do, anything else I can do to get higher signal strength (channel 20 and WETA 26 ?? Just curious.

I bought the HDP-269, just in case I needed it, but did not install. Would it help, given my short cable run, or just be a db loss with the connection.

Thanks again guys !!!!! Really do appreciate it.

[No static at all]

The HDP-269 may in fact help. Make sure the system is grounded properly as that particular pre-amp is sensitive to failure from static build-up. Of course, proper grounding is vital to better help the entire system avoid lightning strikes by draining off static build-up.

If adding the pre-amp doesn't help, try raising/lowering the antenna in 6 inch increments to find the best sweet spot for the problem channels.

Trimming or removing trees should be your last resort

[teleview]

Not a surprise for me.
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The amplifier will most likely provide reliable reception.

You can also do the following.

Most Digital Tv's have a Signal Strength Meter and some Digital Tv's have a Signal Quality Meter.

If the Tv has a Signal Quality meter , Signal Quality -> Is Important For Reliable Reception.

With some one watching the Tv for the best reception , raise and lower the antenna and adjust the aim direction of the antenna to find reliable reception.

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To keep water out of outside connections , use coax that has the Compression type connectors on the ends of the coax , not the old crimp type connectors.

To make double sure that water does not get into outside connections , wrap connections and coax with , http://www.coaxseal.com.

[keithhe]

Thanks No Static. Two questions.

On the Amp, it seems pretty lousy quality of plastic. The bottom is not sealed in any manner, so is the PC board in there potted in epoxy or something? Just figure that moisture would certainly corrode the things inside over time and it would fail. Should I seal the bottom with silicone or something??

On grounding the mast and coaxial........ My plan is to use #8 wire for this purpose.

Does the #8 AWG need to be solid or stranded? Copper or is aluminum OK too?

I bring coaxial in via pitch pocket directly through roof to minimize the cable run length so the grounding block is right at base of the tripod. Can the same ground wire (whatever it is) run through the hole in ground block and attach to the mast? Same wire for both purposes? This runs down roof to an 8' ground rod already installed for the satellite dish.

Thanks !!

[No static at all]

I wouldn't worry about sealing the pre-amp. Never heard of any corrosion issues inside the enclosure.

You will want to use solid wire for grounding. See page 20 of this (http://manuals.solidsignal.com/AntInstallGuide.pdf) Channel Master installation guide for detailed grounding instructions.

BTW, are seeing any signal from WMPT 42(PBS) Annapolis?

[keithhe]

Thanks No Static. I'll follow instructions on the manual you linked.

No sign of channel 42 here. It did "see" a few of the Baltimore stations, but not with enough signal to lock in anything. Same with channel 66 which has signal, but not enough.