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Old 3-Nov-2016, 8:43 PM   #1
jacksonh18
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Help in Northwest Montana

I bought a Clearstream 2V-J3 (or one that looks exactly like it) https://www.walmart.com/ip/Clearstream-2V-J3/24849758 and put it in my attic. I want NBC and CBS but no matter where I put the antenna (I have tried all over my roof too) I can't seem to pick up those stations. I see low-cost antennas on ebay and amazon that have rotators like this one (http://www.ebay.com/itm/HDTV-1080P-O...EAAOxyACJR404W) with good reviews claiming to get 150mi reception, but I'm skeptical and wonder what the best setup for my circumstance would be. I would also like to add another TV in a guest room too.
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Old 4-Nov-2016, 12:06 AM   #2
ADTech
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The 150 mile claims are pure BS.

The C2V is sold at various stores and websites with several variations of the SKU.

If you get the antenna out of the attic and up in the air, you'll have a (very) small shot at getting KCFW (NBC) with a suitable preamp. Since CBS comes from the same mountain but is a mere 270 watts on channel 51, you'd either have to move the mountain that is to your south or move away from behind it. There is no other source for CBS that's potentially receivable at your location.

Wish I had better news.
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Old 4-Nov-2016, 12:16 AM   #3
jacksonh18
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Old 4-Nov-2016, 1:58 AM   #4
rabbit73
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Yes, ADTech is correct; difficult, but not impossible.



I see these channels on you report; some easier than others:

KCFW NBC, real channel 9, Noise Margin 29.9 dB, 11.3 mi, 191 deg true/178 deg magnetic by compass
K24ID NBC, real channel 24, NM 12.1 dB, 14.8 mi, 119/106
K12LO CBS, real channel 12, NM 6.9 dB, 14.8 mi, 119/106
KAJJ CBS, real channel 39, NM -2.5 dB, 11.3 mi, 191/178
KTMF ABC/Fox, real channel 42, NM 17.1 dB, 1.4 mi, 276/263
K51HT CBS, too weak
K48EO CBS too weak

It is the real channel number that determines what antenna is needed.

VHF-Low, real channels 2-6
VHF-High, real channels 7-13
UHF, real channels 14-51

I went to rabbitears.info and entered my estimate of your address. If you click on the callsign there, you will see the networks. The callsigns will be listed in virtual channel number order, not strength as in a tvfool report.
http://www.rabbitears.info/search.php

Then I added Strength Search and antenna height. That gave me this in decreasing signal strength order. I deleted your street address.



Then I went to the tvfool interactive map browser to see the green signal lines.'
http://www.tvfool.com/index.php?opti...pper&Itemid=90



If you mount your antenna at the right spot, the tree behind the house to the south will not block the 191 or 119 path.
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File Type: jpg jacksonh18TVFmap.JPG (120.7 KB, 1311 views)
File Type: jpg jacksonh18TVFre.JPG (138.5 KB, 1446 views)
File Type: jpg jacksonh18TVFtree.JPG (75.4 KB, 1357 views)
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Last edited by rabbit73; 4-Nov-2016 at 3:26 AM.
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Old 4-Nov-2016, 2:14 AM   #5
jacksonh18
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Would you recommend sticking with the antenna I have and getting a "pre-amp" ?

Which one would you get?

Is there a difference between a pre-amp and regular amp or is it all the same? Also, I noticed that antennas direct made an amp called a juice, could using the pre-amp increase my chances at picking up that station I want, or is it more about pointing?
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Old 4-Nov-2016, 2:17 AM   #6
jacksonh18
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[QUOTE=rabbit73;56722]Yes, ADTech is correct; difficult, but not impossible.



I went to rabbitears.info and entered my estimate of your address. If you click on the callsign there, you will see the networks. The callsigns will be listed in virtual channel number order, not strength as in a tvfool report.


does that mean I point the antenna south at 191 degrees to get channnel 9?
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Old 4-Nov-2016, 2:21 AM   #7
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Please wait, I'm not finished with my previous post. It takes me a lot of time to do an analysis and produce the images that will help you.

I'm in the eastern time zone and it's late; if we don't finish tonight, I will come back tomorrow.
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Last edited by rabbit73; 4-Nov-2016 at 2:53 AM.
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Old 4-Nov-2016, 2:51 AM   #8
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Quote:
Would you recommend sticking with the antenna I have and getting a "pre-amp" ?
I think you should make some tests with your present antenna to see what it will do, and then upgrade based on the results of the tests.

First aim your C2V loops at K26DD just to see if your system is working. Then aim the UHF loops at 119 for K24ID NBC and the "V" dipole broadside (perpendicular to) at 191 for KCFW NBC. If the signals are too weak add an Antennas Direct Juice preamp and and perhaps an FM filter (if needed) because you have a strong FM transmitter that might interfere with the reception of real channel 9.
http://www.fmfool.com/modeling/tmp/2...9/Radar-FM.png

https://www.antennasdirect.com/store...on_filter.html

If the antenna is outside, the coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge which will tend to discourage a strike, but the system will not survive a direct strike.

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Last edited by rabbit73; 4-Nov-2016 at 3:15 AM.
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Old 4-Nov-2016, 3:01 AM   #9
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Quote:
does that mean I point the antenna south at 191 degrees to get channel 9?
Real channel 9 is a VHF-High channel. The "V" dipole kit that comes with the C2V should be aimed broadside to (perpendicular to) 191. The simple dipole for VHF-High doesn't have as much gain as the UHF loops but it is adequate for strong VHF signals. If the dipole doesn't have enough gain for channel 9 even with the preamp, it will be possible to add an inexpensive VHF antenna.



Quote:
Is there a difference between a pre-amp and regular amp or is it all the same?
A preamp is mounted close to the antenna, and its power supply/power inserter is inside. The coax carries the DC power up to the preamp, and the signals travel down the same coax to the TV. A distribution amp is used inside to compensate for long coax runs after splitting if the passive splitter makes the signals too weak for more than one TV. Just use one TV for initial testing and then split.

C2V > FM trap > preamp > coax > grounding block > power inserter > TV

Quote:
could using the pre-amp increase my chances at picking up that station I want
Yes, that is the purpose of a preamp.

You usually do not need a preamp AND a distribution amp; there is such a thing as too much amplification. Try just the preamp and a passive splitter first.
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File Type: png Dipole Pattern 3.png (81.6 KB, 1912 views)
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Last edited by rabbit73; 4-Nov-2016 at 7:45 PM.
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Old 4-Nov-2016, 4:05 PM   #10
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Quote:
Originally Posted by jacksonh18 View Post
Lol!

Not much of one...


With a mere 262 mW of power in your direction from almost 15 miles away, the channel 12 signal from K12LO is unlikely to make it to your location with a sufficient margin above the ambient noise for reception regardless of the data on your plot.

This is a case where the simulation engine is probably too optimistic.
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Old 5-Nov-2016, 12:24 AM   #11
rabbit73
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Oh, Wow; I missed that and went by the noise Margin number in the report and the dBm number from rabbitears.info.

For some odd reason the FCC Longley-Rice K12LO Coverage Map supports the tvfool report; is it also wrong?



http://www.rabbitears.info/contour.p...14.03869444444
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Last edited by rabbit73; 5-Nov-2016 at 1:05 AM.
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Old 5-Nov-2016, 4:16 AM   #12
jacksonh18
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I haven't tried putting the antenna where you put those marks yet, I have been getting about 24 channels without a preamp, including ABC fox (the 23 channels), PBS, Russian Television, and the rest mostly just religious channels. My neighbor is getting channel 9 next door from each of the spots I put a yellow dot with the same antenna.
Does that site your using tell you where the sweet spot is? I don't understand how to use that, is there a video tutorial somewhere? I am going to order one of those Juice Pre-amps, is that the best one to get since it was designed for my antenna or would you recommend something different?

Last edited by jacksonh18; 5-Nov-2016 at 5:40 AM. Reason: google drive sucks
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Old 5-Nov-2016, 6:21 AM   #13
jacksonh18
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Quote:
Originally Posted by rabbit73 View Post
Oh, Wow; I missed that and went by the noise Margin number in the report and the dBm number from rabbitears.info.

For some odd reason the FCC Longley-Rice K12LO Coverage Map supports the tvfool report; is it also wrong?



http://www.rabbitears.info/contour.p...14.03869444444

not sure what you mean. This is everything I can get by moving around my antenna.

250 degrees I get the following channels:

26.1 TBN
26.2 TCC
26.3 SBN
26.4 NRB TV
26.5 SOAC
26.6 SLSTV
26.7 WHT
26.8 DAYSTAR
34.1 ANT TV
34.2 RETRO
34.3 WALK
34.4 REVN
34.5 EBRU
34.6 GRIT
34.7 RT
34.8 YOUION
46.1 KUKLHD
46.2 KUKL
46.3 KUKLC
46.4 KUKLW
46.5 KUKLL

at 180 degrees I get:

23.1 KTMFABC
23.2 KTMFFOX
23.3 KTMFSWX
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Old 5-Nov-2016, 12:13 PM   #14
ADTech
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Quote:
For some odd reason the FCC Longley-Rice K12LO Coverage Map supports the tvfool report; is it also wrong?
They are mathematical simulations only.

The information missing from the simulation is the ambient background noise level on the channel of interest which, without a field measurement, can only be estimated. The simulations assume that the noise level is -106.2 dBm, the perfect case. Practical experience has shown that the ambient noise level in the high-VHF band may be anywhere from 5 to 20+ dB higher than the assumption. Subtract that from the calculated noise margin and and you'll see why I'm pessimistic about receiving channel 12.

Quote:
Does that site your using tell you where the sweet spot is?
No. The simulation is dividing the terrain into blocks (pixels, basically) that are anywhere from the size of a third of a football field to the size of several football fields, depending on the resolution chosen to use in the mathematical model.

Try aiming the antenna towards Bigfoot and give it a scan. When reporting results, it's only necessary to name the first channel on a station, listing the sub-channels only clutters up the report with info that doesn't add anything to the technical conversation.
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Old 5-Nov-2016, 6:18 PM   #15
rabbit73
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Quote:
Practical experience has shown that the ambient noise level in the high-VHF band may be anywhere from 5 to 20+ dB higher than the assumption.
Ah, yes; I forgot about that for a moment. The noise level at my location does reduce the SNR of my VHF-High signals.
Quote:
Try aiming the antenna towards Bigfoot and give it a scan.
Good idea. You should find something at 119 deg; if not now, then later with a preamp.
Quote:
When reporting results, it's only necessary to name the first channel on a station, listing the sub-channels only clutters up the report with info that doesn't add anything to the technical conversation.
Yes, then it would look like this:

250 degrees I get the following channels:

26.1 K26DD TBN (listed at 276 deg true)
34.1 KMJD ANT TV (276 true)
46.1 KUKL PBS (191 true)

at 180 degrees I get:

23.1 KTMF ABC/Fox (The KTMF-LD translator is listed as 276 deg true)

The main transmitter for KTMF in MISSOULA, MT is on real channel 23, virtual channel 23.1 (listed as 170 deg). The KTMF-LD translator in KALISPELL, MT is on real channel 42, virtual channel 42.1.
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Last edited by rabbit73; 5-Nov-2016 at 7:26 PM.
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Old 5-Nov-2016, 7:42 PM   #16
rabbit73
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Quote:
My neighbor is getting channel 9 next door from each of the spots I put a yellow dot with the same antenna.
Is he using a preamp?



Quote:
Reason: google drive sucks
They don't make it easy for you, but there is a link under Share. It would be better to upload your image from your computer as an attachment.
Quote:
Does that site your using tell you where the sweet spot is? I don't understand how to use that, is there a video tutorial somewhere?
No, it just lists the channels, gives the green signal lines, and gives coverage maps. I can walk you through it step by step with an example if you so desire. I use the tvfool interactive map browser:
http://www.tvfool.com/index.php?opti...pper&Itemid=90

To find the sweet spot I walk around with a test antenna in one hand and my signal level meter in the other hand. The sweet spot will vary with frequency; find the best spot for your weakest desired channel and hope that the stronger channels are still OK.






Quote:
I am going to order one of those Juice Pre-amps, is that the best one to get since it was designed for my antenna or would you recommend something different?
The Antennas Direct Juice preamp is very good. It has a low noise figure (that's desirable), medium gain for most applications, resists overload, and has an LTE filter to reject cell phone transmitters. It does not have an FM filter, but one can be added if necessary. There is the possibility that KZMN-FM might cause interference to VHF reception:
http://www.fmfool.com/modeling/tmp/2...9/Radar-FM.png

FM filter
https://www.antennasdirect.com/store...on_filter.html

An alternate preamp is the Channel Master 7778.

The RCA TVPRAMP1R is less expensive, but of lesser quality.

The Winegard LNA-200 Boost XT is of lesser quality.
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Last edited by rabbit73; 5-Nov-2016 at 10:55 PM.
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