AVS Forum banner
Status
Not open for further replies.
1 - 17 of 17 Posts

·
Registered
Joined
·
202 Posts
Discussion Starter · #1 ·
I'm awaiting my HDTV stb. I wanted to see if I could pull in the regular analog channels with an old antenna (one shaped like a v with one rabbit ear attached.) I could get most of the channels okay, not clear by any means, lots of snow. Should I get a double boe tie antenna and see if i can pull in them while I wait for my stb? I don't have the option of mounting an antenna outside or even in my attic. Any one try the analog test? what did you find once you got your stb? My set is downstairs and I get good reception in my kitchen on an old B&W relic (one level up.) Could it be the antenna?
 

·
Registered
Joined
·
457 Posts
First, determine whether your local Digital channels are transmitting over the VHF or UHF spectrum. Most likely, they will be using UHF. If indeed, your local Digital channels are using UHF, remember that ANY antennae that is designed for UHF will work just fine. There is no such thing as a "Designed for Digital TV" antennae.


The old "rabbit ears" are typically designed for VHF signals, but they may actually work for UHF too. I had moderate performance with an old set just leaning against the wall in a closet in the basement http://www.avsforum.com/ubb/smile.gif


If you want to get a head start, you can try tuning in to local channels that are already using the UHF spectrum for their analog signals. Channels like FOX, PAX - anything above channel 13.



------------------

DVI/HDCP makes your HDTV not ready
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #3 ·
I guess my market, Cleveland,is in the minority. I have two uhf (20 nbc,10 cbs) and two vhf (15 abc,31 fox)digital channels. Should I try the double rabbit ear antenna from rat shack? or is there another that would be better? Or should I be looking for a nearby closet to put a monster antenna into?
 

·
Registered
Joined
·
457 Posts
Actually, the channels 2-13 are VHF, and the ones above 13 are UHF. Since the double-bowtie is really just for UHF, I'm not sure how well it will work for VHF.


But there is good news. All of your local Digital stations appear to be transmitting from the SW, so you shouldn't have to worry about rotating you antenna for each channel.


You can certainly try some of the small indoor antennaes and see how your reception is for your current analog VHF channels (3,5,8) and UHF analog channels (19,25,55). Just make sure you use one that is designed for both VHF and UHF. If you can get a reasonable signal on these, chances are you'll be set for DTV.



------------------

DVI/HDCP makes your HDTV not ready
 

·
Registered
Joined
·
298 Posts
Wood,


If you're getting a snowy but stable UHF pic from rabbit ears, I think you're home already. Just make sure and get something newer than the RCA DTC-100 and you should be fine.


My Radio Snack double bowtie indoor UHF works fine for digital OTA, even though the analog UHF pics are snowy and Casper the Friendly Ghost. For $18, "even if it doesn't work, it's a bargain."
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #6 ·
Thanks all. Any ideas on which antenna to get? I guess I need something with both UHF and VHF. I don't know why I transposed the two earlier http://www.avsforum.com/ubb/confused.gif (I always think of that Weird Al/Michael Richards movie when I say UHF.) I also typed 20 instead 2! BTW, I ordered the Tosh DST-300 so it is a second gen stb.
 

·
Registered
Joined
·
90 Posts

·
Registered
Joined
·
457 Posts
Quote:
Originally posted by VicF:
Since all digital channels are in the UHF band you only need a UHF antenna.
Although this is true in most areas, Wooderson lives in one of the few areas where some of the local digitals are actually using the VHF spectrum.


Not trying to pick nits, just watchin' out for some of the newbies, who can easily gloss over some of these details http://www.avsforum.com/ubb/wink.gif





------------------

DVI/HDCP makes your HDTV not ready
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #9 ·
So should I just try the vhf and uhf bow-tie combo that I had at my parents house since childhood, or should I go buy an amplified Rat Shack FM/UHF/VHF antenna or a different one? I get snow filled analog pictures with it as of now.
 

·
Registered
Joined
·
1,570 Posts
Wooderson,


If you have an older outdoor antenna, it may be corroded. Corrosion will reduce the efficiency/effectiveness of an antenna. However, the most likely thing to wear out on an outdoor antenna is the cable from the antenna to the TV.


My mom has an outdoor antenna that has been on the roof since before she bought the house (15 years ago!). I climbed up on the roof and replaced the cracked, damaged 300 ohm twin lead. I used a wirebrush to clean the terminals on the antenna and then installed a 300 ohm to 75 ohm balun (balanced to unbalanced converter). I then ran some quad shielded RG-6 from the balan to the tv inside the house. Finally, I re-aimed the antenna (sometime in the last 20+ years strong winds had moved it out of alignment). Low and behold, she could actually get excellent reception from her existing tv antenna!


A new antenna would be your best option, but you'll need the cabling and balun anyway, right? Why not just try replacing the cabling, aiming the old antenna and seeing what kind of results you get. For $20-50 and a couple hours up on the roof, you might be surprised with the results you get.


Jim


P.S. If you live in a city with broadcast antennas in multiple directions, you may need to buy a rotor. Look at www.antennaweb.org to figure this out.


------------------

Let me get this straight, this show is hi-def and 5.1, but my local affiliate makes it crappy NTSC and mono?!
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #11 ·
I don't have the option of an outdoor antenna. I live in a townhouse-style condo. The old antennas that I was referring to were indoor antennas that were from random TVs. I wanted to get a step ahead of the STB's arrival, but I'm just going to try the those first. I get some decent pictures with even better sound with those antennas. It looks like I'll just have to play it by eye then. Any more info on HDTV specific antennas? I remember an indoor Terk when I first started looking into HDTVs.
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #13 ·
I've known about that info. I already submitted a waiver that I've yet to get back concerning putting a dish on my porch. My porch faces northeast, so I'm not sure if I can even bring in a signal from Directv. I may be able to get it with some help of true north.
 

·
Registered
Joined
·
3,875 Posts
Jim-

If I may tack on a couple of follow-up questions for a lot of us "stalking the wild HD signal" by OTA...is it your experience that tall oak trees significantly reduce signal strength/purity? Any experience with the Winegard CA series, e.g. 9085 or 9095 ? BTW, they are UHF only and I had heard that they were pretty effective for 30+ miles out.
 

·
Registered
Joined
·
729 Posts
Big oak trees can attenuate the signal. I am not familiar with those two wienguard numbers. Are they Yagies, panels or Log periodic? If they are panels multi-path could be the problem, is your area hilly? I saw that you were in Virginia. Does the analog from the same broadcast tower have bright ghosts? If so then multi-path is the culprit. If the analog does not have ghosts but is very snowy even with low or disappearing color then you need a pre-amp and/or get the antenna over the trees.


------------------

Jim Burns
www.dtvconsultants.com
 

·
Registered
Joined
·
987 Posts
tlcfargo:


Why should he get something newer than the DTC100? Is there something wrong with the DTC100 compared some of the newer models?


------------------

-Kieran.

(Member since ~01/98 but AVS killed my membership

after a few months of no posting.)
My HT page
 

·
Registered
Joined
·
729 Posts
There is such a thing as a HDTV antenna. Some of the broadcast frequencies are the same for analog and DTV (UHF) there are many differences in the modulation scheme. I have developed 5 DTV antennas specifically for use with 8,4 and 2 VSB modulation for UHF and one VHF model. While there are similarities to analog TV these antennas were designed to take advantage of the strengths and compensate for the weakness and shortcomings of DTV 8 VSB modulation. The designs were sold to Gemini and will be shipping shortly.


Here is an excerpt from a ATSC manual I wrote about antennas.


Aiming the Antenna


Before permanently mounting the antenna it is a good idea to perform a small sight survey to find the spot with the best signal. DONOT use a convention signal strength meter for this operation. Chances are this will give you false information and cause the antenna not to work reliably.


Most severe ghosting occurs in locations where there is plenty of signal strength.


There are two suggested methods for finding a good location for the antenna



1. Analog TV pointing Method Use a conventional analog tv to chose the best spot for the antenna. DTV is a little different than analog tv. In analog tv peak signal strength was the criteria for choosing the location for the antenna. With DTV peak signal strength is not the most important factor for good reception, it is the third quality we look for. In choosing a location for our DTV antenna we want to chose a couple of locations to try and look at the picture on our analog TV to determine where the best location is. What we are looking for is the location where we see the least amount of ghosts in the picture. We are not worried about snow in the analog picture, this is not a problem for DTV. We want a location where the analog TV has the least amount of ghosting, color in the picture and the audio can be clearly heard. Once again we are not worried about any other picture abnormalities because they will not interfere with the DTV picture.

2. Spectrum analyzer There are three characteristics to look for to ensure robust signal reception. The first is to ensure that you have a good clean square wave. (Picture A). Second, there should be no more than 3 dB of tilt across the signal waveform. Third is amplitude, +6 dB is needed with the current array of tuners on the market.





------------------

Jim Burns
www.dtvconsultants.com
 
1 - 17 of 17 Posts
Status
Not open for further replies.
Top