TV Fool  

Go Back   TV Fool > Over The Air Services > Help With Reception

Notices

Reply
 
Thread Tools
Old 29-Dec-2010, 8:04 PM   #1
nukeman
Junior Member
 
Join Date: Dec 2010
Posts: 6
Question Help with north eastern Kansas install (Topeka)

Hi,

I want to receive HDTV broadcasts from the major networks. The closest transmitters appear to be around 60 miles from me in Topeka, KS. Is getting signal at that distance even possible?

The stations I'm interested in are KTWU (PBS), WIBW (CBS), KSNT (NBC), and KTKA (ABC). It looks like FOX in Topeka is KTMJ-CA and is owned by KSNT. KSNT broadcasts FOX content on their 27.2 channel (link).

I have a one story house with a relatively clear line of site. I would rather install an antenna in the attic, but from my brief research, it appears that would degrade reception quite a bit. There are so many options for equipment! What factors do I use to choose the best antenna?

I am new to OTA reception, but have been working with computer networks and home theater installations for years. I think I have the tools and ability to do the installation, but I'm having trouble getting started.

I ran the TV Signal Analyis here (http://www.tvfool.com/?option=com_wr...da32257c9f166a) but I'm not sure that to do next.

So now that I've ran the report, how do I actually choose an antenna? How do I know if I need additional equipment like an amplifier or rotor?

Thanks in advance for all the help.
nukeman is offline   Reply With Quote
Old 29-Dec-2010, 8:56 PM   #2
Tower Guy
Senior Member
 
Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,177
Quote:
Originally Posted by nukeman View Post
So now that I've ran the report, how do I actually choose an antenna? How do I know if I need additional equipment like an amplifier or rotor?
You select an antenna that has sufficient gain that when added to the NM number in your post and subtract the preamp noise figure you have sufficient margin to pick up the signal reliably.

For instance, channels 11 and 13 could be picked up with a VHF only antenna. The YA1713 has a gain of about 10 db and the noise figure of a 7777 preamp is about 3 db. Therefore the result NM would be 9+10-3=16 db. That should work fine. The Y10-7-13 could be substituted for the YA1713.

KTKA has a NM of -9 db. The gain of a UHF only 91XG is about 15 db, the preamp noise is 3 db. The result is 15-9-3=+3 db NM, which will drop reasonably often. KSNT's margin will be 1.5 db better. The trick will be to find the perfect spot on your roof to add a few db of margin. Once you do that for KTKA, check KSNT. I predict that it will take several hours of experimentation to optimize both channels simultaneously.

http://www.hdtvprimer.com/ANTENNAS/siting.html

The two-antenna solution is most likely to work for you. I would not plan on a rotor unless you wanted to watch the LPTV stations KETM-CA or K30AL-D

Last edited by Tower Guy; 29-Dec-2010 at 8:59 PM.
Tower Guy is offline   Reply With Quote
Old 29-Dec-2010, 9:28 PM   #3
nukeman
Junior Member
 
Join Date: Dec 2010
Posts: 6
Thanks for the reply.

Quote:
Therefore the result NM would be 9+10-3=16 db.
Where did the 9 come from in that equation? Is that an average between the 7.8NM of KTWU and the 10.6 of WIBW? You said 16 db should work fine but the 3 db in the other example wouldn't. What target db should I bee looking for?

Like I said in the first post, I'm very new to this. What made you recommend the YA1713 and the 7777 preamp. Besides the specs, are there certain brands of components that are better (more respected) than others? I see the Winegard name mentioned a lot.

Thanks for the link on placement. I plan to read more of that site. But basically, I'm going to need a VHF antenna, a UHF antenna, and a preamp, right? What is the purpose of the preamp?

Is there a good way to know if this will all work before I purchase the equipment? Are the equations good enough? Is the 60ish mile distance even doable? I have a friend that lives in a city. He's getting HDTV with just an indoor antenna. I assume this is going to be more of a challenge for me because of the distance, right?

Thanks again
nukeman is offline   Reply With Quote
Old 29-Dec-2010, 10:04 PM   #4
Tower Guy
Senior Member
 
Join Date: Dec 2009
Location: Delmar, NY
Posts: 1,177
Quote:
Originally Posted by nukeman View Post
Is there a good way to know if this will all work before I purchase the equipment? Are the equations good enough?
You're right, the 9 db is an average of the two VHF stations. Reliable reception of these two stations should be easy. The UHF stations are iffy.

The preamp is needed to overcome the line loss of the leadin wire from the antenna, remove mismatch losses from the equation, and to overcome the unpredictable and higher noise figure of your TV set.

The propagation equations are statisical approximations. In addition to the uncertainty of statistics, there are variables such as transmitter antenna patterns that cannot be accounted for precisely. I like to see a net NM of +10 db before I'm comfortable. Even then there will be days when the weather will interfere with the signal.

A tower will help if gets you over the tops of nearby trees or rooftops. Otherwise, the location of the tower could built be in a cold spot as easily as a hot spot for reception. Walking the roof should get you as much extra signal as a 50' tower.

If you want a "plan B" for UHF reception consider this, http://www.hdtvprimer.com/ANTENNAS/16bay.html but using two 91XG antennas.
Tower Guy is offline   Reply With Quote
Old 29-Dec-2010, 10:43 PM   #5
John Candle
Senior Member
 
Join Date: Jun 2010
Posts: 2,697
Tv Antennas and Reception

KTWU 36 , 30 , 11 are PBS . Analog KETM-CA 17 looks like a repeater for KTMJ FOX 43 . WIBW 13 is CBS , KSNT 27 is NBC , KTKA 49 is ABC .
John Candle is offline   Reply With Quote
Reply

Bookmarks

Go Back   TV Fool > Over The Air Services > Help With Reception


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off




All times are GMT. The time now is 12:00 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Copyright © TV Fool, LLC