AVS Forum banner

Status
Not open for further replies.
1 - 20 of 27 Posts

·
Registered
Joined
·
61 Posts
Discussion Starter #1
I just got my new DTC100, but I'm not able to get a digital signal.


I've tried some random antenna that was in the attic when I bought the house, another antenna I bought: an RCA ANT3036X, and a Radio Shack 15-2162 UHF-only. With any, I'm able to get great signals on all the local VHF channels. There is an analog UHF channel located on the same transmission tower as some of the digital channels (which are also UHF). The analog channel (22, the local WB affiliate) comes in poorly with any of the antennas I've tried. I can't get the DTC100 to detect any digital stations when doing a full channel scan.


I live in Woodinville, WA (a suburb of Seattle) at Lat: 47.735428 Lon: -122.07252. I'm suspecting is that a hill a half mile or so west of me is blocking direct view of the transmitters. If this is true, what type of antenna should I be trying to compensate for this (I assume that I'll need to try to catch a reflection of the UHF somehow; I'm guessing the reason that I can get VHF is due to the knife edge effect).


Any ideas?


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

<yawn>

TiredGuy
 

·
Registered
Joined
·
3,665 Posts
Damn, the 2162 wont get a local UHF station? I used one here to watch a station in the next state, about 120 miles away before switching to a Channel Master Quantum combo antenna.


Have you replaced the feedline? If you have, then you will probably have to install a good low noise antenna mounted preamp to the 2162. A 300 ohm in 75 ohm out should work fine. If you dont run a preamp, you should be using the best RG6 you can (stay away from RG59).


I used to use RG-11 (75 ohm low loss cable about the size of RG8 the CBers used to use) at my previous location, since all the stations were over 70 miles away.


Being in a suburb though, either your hill is super high, the stations are quite low powered, or your transmission line is bad.



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

SVR-2000 2.0 130 hrs

HDR-112 2.0 14 hrs

REplay 3020 20 hrs
 

·
Registered
Joined
·
306 Posts
It doesn't surprise me that you get no signal if there is a hill near you. I tried every possible antenna combination to pick up CBS from a transmitter 6.5 miles away - NOTHING! Like you, I picked up tons of VHF and a few analog UHF channels, but never a signal from the DTV channel.


I bought and tried a lot of options - 2 Radio Shack antennas, a Channel Master 7' Parabolic on top of a 20 foot mast, amplifiers, short cable, long cable, tilting the anntena up, down and sideways - never a signal (did I say 6.5 miles away?)! (I wonder if this 8vsb is the way to go http://www.avsforum.com/ubb/wink.gif !!)


So I gave up, signed up for ExprssVu and reliably watch network HDTV whenever I want....
 

·
Registered
Joined
·
39 Posts
Sorry about the basic questions, but:

After installing each new antenna did you do a channel search? Just tuning to where the station is broadcasting will not bring it in. One should also make sure you are scanning the correct antenna input, either A or B. (not necessary if you do a full channel search instead of a quick channel search) I also second the use of good cable.

just basic things that you are most likely aware of.

Also be aware that many of the antennas you have tried are very directional, meaning that unless it is pointed right at the transmitter, no luck. It helps to have rotor if you do not already.


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

Paul


Up on a roof waiting to be struck by lightning.
 

·
Registered
Joined
·
61 Posts
Discussion Starter #5
Thanks everyone for the replies.


Davenlr: I've got a 100 foot length of RG6 laying around, I'll try using that. Also, do you have a recommendation on where to get a preamp like the one you suggested (can I get it at RS?)


Paul Snyder: I think I'm doing the right thing; I've got the antenna hooked up to antenna input 'A', and I've repeatedly asked the DTC100 to do a Full channel scan each time I've changed the antenna configuration. However, the manual that came with the box isn't very clear on all this, does it sound to you like I'm doing the correct thing?

As far as the directionality, there are a series of other UHF stations that are coming from a different transmitter (that doesn't carry any DTV on it) which is located further south of me and close to me and therefore doesn't seem to be blocked by the hill. All of my antennas pick up those stations regardless of the orientation of the antenna. However, I've been scanning the both the antennas back and forth trying to optimize the signal for the one UHF station located on the tower I'm trying to get.


MAX HD: I've been working with the antennas in a room on the top floor of my house, pointing them out out a window at the side of the house closest to the towers. I'll start messing around with them outside the house today.




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

<yawn>

TiredGuy
 

·
Registered
Joined
·
739 Posts
Tiredguy,

I am also in Woodinville at 47.74902 x 122.11587 (Canterwood) and just installed my HD-100 yesterday (temporarily as it would have gone back if I had a hint of your type problems) I had no antenna and I just tried to use it as OTA with a piece of wire. Nothing! I knew analog UHF was not too bad with small portable and whip antenna, so I assumed I should be ok with digital. Nothing.


When I auto scanned, no Digitals would show. I than moved the wire and re-scanned and it detected KIRO remapped to channel 7. OK, ran up to RS and got 15-263 bow tie (which I would return if I needed something more). Did another re-scan (this I think is key to getting anything) and knowing what general direction to point to, was able to detect remapped 4, 5, 7, 9 and 13. I am behind hill to transmitters. Amazing to see HDTV on my XBR400 for the first time. It turns out after moving antenna al over (evan out side on the deck, the best location was on top of the XBR! (I did re-scan after each move).

Current status I can get all channels above to "lock" in depending on antenna position (read direction) with 7 and 13 the least likely to drop out. 5 is good, but every couple of seconds will drop (sound like multipath) 9 seems to be On and off the air.


I think I will next try an amp. If no go, then maybe 15-2162 or CM equivalent outside. (dam hill!) I think I will keep the HD-100 as I will replace my exisitng B55 sat rcvr and use it in bedroom when I install new elliptical dish and switching to enable 199 and 509 on Directv. Right now I am concentrating on OTA (I know Directv ok here).


I have been "playing" with TV and antennas since 1948 and think I have developed a "feel" about things. I "feel" I will be alright eventually with all OTA channels. I suggest that a "key" thing you do as you continue your quest is always "re-scan".


The SONY HD-100 is great. I have no other STB experience so can't compare. The resolving of this OTA venture is taking a similar path as to when I first installed DIrectv. The SONY box "action" for OTA is very similar to that experience; i.e. on screen "acquiring satellite".


There are many threads about fan noise, but I know when I finally put the box in my cabinet to replace the B55, I will not hear it. I really don't notice it now as I crank up the sound.


We must be close to each other judging by the Lat/Long?

Bill



[This message has been edited by Babula (edited 03-24-2001).]
 

·
Registered
Joined
·
61 Posts
Discussion Starter #7
Bill, we're close, but it sounds like I'm a little further out than you. I'm a bit to your southeast, at the intersection of Mink Road and Bear Creek Road.


I just got back from the 'shack with a chimney mount; I'm going to see if I can get the UHF antenna to work for me....


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

<yawn>

TiredGuy
 

·
Registered
Joined
·
3,665 Posts
You can get a preamp at Radio Shack, or from several sources on the web. I use Radio Shack because I can take them back if they dont work for me.

If your problem is multipath, and not low signal, the preamp will make it worse though. Lets see what happens with the new RG6 and the antenna on the roof.


One thing I can see from reading these posts is, joe sixpack and his rabbit ears at gonna be down the tubes once they do shut off analog, unless the stations get together and share a single tower site in locations like mine, where there are 8 stations in 6 different directions.


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

SVR-2000 2.0 130 hrs

HDR-112 2.0 14 hrs

REplay 3020 20 hrs
 

·
Registered
Joined
·
739 Posts
Tiredguy,

I had 10dB amp in my cabletv line (???) and borrowed that. Put it on bow tie and no better. In fact, like Davenir said, it may make it a little worse. I think it did and really confirms multipath problems. Definitely need more directional antenna and perhaps rotor. My mood right now is one step at a time. When the pix are locked in, they are gorgeous! Good luck with your next step and will keep you informed here of my adventures.

Bill
 

·
Registered
Joined
·
61 Posts
Discussion Starter #10
Well, here's the update:


I got a set of straps to mount an antenna mast on the chimney. Using an RG6 cable and no preamp, the Radio Shack 15-2162 UHF-only looked about as bad on the chimney for all UHF channels as it looked in my 2nd floor room. It didn't seem to matter which direction I aimed it (I spun it all the way around, slowly).


The RCA ANT3036X looked bad also, no matter which way I spun it. However, after I gave up and was on the ground with it tearing it down, I noticed that if I had the VHF part of the antenna folded up, and the UHF part of it was along the side of my house, the UHF channels came in pretty well: minimal ghosting and slight snow (full color). I tried doing a channel scan then and I still got no digital channels. But when I put the antenna back on the roof in that configuration, the reception immediately went to hash. I'm thinking I've got some serious multipath problems.


after studying the topology around my house some more, I've realized that I'm in a wide, shallow valley between two ridges, the ridges run roughly perpendicular to the path that the signal would take from the transmitter to my house. So I'm thinking I've got severe multipath caused by being in this valley.


Any opinions what I should try next? (I also tried the radio shack preamp on the UHF antenna, as was suspected, it made things worse).



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

<yawn>

TiredGuy
 

·
Registered
Joined
·
739 Posts
TiredGuy,

Too bad about your lack of success! I don't know what to say. I always said RF is Black Magic. SOmetimes it does strange things.


MaxHD said:Maybe John Stephens will chime in on this thread and give you some ideas. He has the knack for identifying "things in the way" of signals. Check other antenna threads.


Did you buy the antenna at Woodinville RS? :)

I went there today and it was so busy I got short schriffed. Young lady there has too much to do and could not find the 2162 from yesterday. Threw a vhf/uhf thing at me, so I left! WIll order CM on line.

Bill
 

·
Registered
Joined
·
61 Posts
Discussion Starter #12
Bill,


If you'd like to try the 2162 that I've got, I'll be glad to let you see if it helps you; I'm going to return it since it doesn't seem to help me.


Let me know....


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

<yawn>

TiredGuy
 

·
Registered
Joined
·
1,738 Posts
Quote:
Originally posted by Paul Snyder:
Just tuning to where the station is broadcasting will not bring it in.
I have found this not to be true on my DCT-100. I have just entered the physical channel number as new stations have come online in NYC and it finds them perfectly. The Sony and the Toshiba I have tried do require a scan, the RCA did not.




[This message has been edited by Bogney Baux (edited 03-24-2001).]
 

·
Registered
Joined
·
1,084 Posts
Quote:
Originally posted by Babula:
I always said RF is Black Magic.
You got that right! Add in digital, and a hill, and it becomes a black hole. I hate to say it, but this technology is not quite ready for prime time, and if these new generation receivers - supposedly improved over the DTC100's ability to lock digital broadcasts - are any indicator, the outlook is bleak for general OTA DTV/HDTV reception. (whimper...)

 

·
Registered
Joined
·
957 Posts
Watch it Ray, or the guys with the five letter acroynm will take the thread over.




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

RJW
 

·
Registered
Joined
·
887 Posts
Tired Guy,


Did you try these antennas outside or in the attic? Your post was not clear on this aspect.Definitely try them outside on the roof if possible.


Maybe John Stephens will chime in on this thread and give you some ideas.


Good Luck!


[This message has been edited by MAX HD (edited 03-24-2001).]
 

·
Registered
Joined
·
887 Posts
TiredGuy,


Sorry about your bad luck! Sounds like you need some professional help. If it comes down to getting an antenna up higher to "see" over that ridge I would use a Silver Sensor as it has basically no wind load and could be mounted atop a very tall mast or light duty tower.It also is one of the best for fighting multipath.

I tried it out on my crank-up tower from 34-64ft. and it performed as well as some of my larger "Big gun" UHF antennas on DT channels.


Good Luck!
 

·
Registered
Joined
·
61 Posts
Discussion Starter #18
OK, ordered a Silver Sensor. Hopefully it arrives this week.


This is so frustrating because my problem is not one of no signal or weak signal, but of too many signals (multipath). Reading some of the articles on the web about this, it looks like lots of people are having multipath problems (even people very near transmitters in NYC).


Next house I buy is on top of a mountain with no trees and unobstructed views to the dbs satellites and the television transmitters http://www.avsforum.com/ubb/smile.gif


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

<yawn>

TiredGuy
 

·
Registered
Joined
·
3,665 Posts
Although it is a relatively expensive experiment, and Ive never actually tried one here, I have heard that a parabolic has quite a sharp beamwidth. Channel Master makes one I believe. You might also want to contact one of the engineers at the stations you are trying to receive, and they might be able to offer some local help as well.


Another thing you might try, rotate the antenna from horizontal to vertical. It will drop roughly 20db off your signal (unless the station also transmits dual polarity), and may make the ghosts easier to get rid of.


Failing that, you might try building a helically wound antenna




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

SVR-2000 2.0 130 hrs

HDR-112 2.0 14 hrs

REplay 3020 20 hrs
 

·
Registered
Joined
·
3,080 Posts
Woodinville friends:


Sounds like you have tried lots. I live in Renton and struggled to get digital 4 (38), 5 (48), 7 (39), 9 (41) and 13 (18). I ended up with a Radio Shack UHF only directional outdoor antenna (the $20 unit), but the trick was raising and accurately aiming the antenna.


Channel 13 comes from Gold Mountain near Bremerton. Channels 4, 5 and 7 come from Queen Anne Hill and Channel 9 comes from Capitol Hill. From where I live, 13 was the real challenge because it is way out of line compared to the others.


I found a web site that helped me understand where the transmitters are in relation to my home. They also asked some simple questions about hills and other potential blockers/reflectors, and finally suggested omni- vs. uni-directional antenna types and the approximate amount of gain needed for each channel.


Go to ...

http://www.antennaweb.org


... and click on "Choose an Antenna" to use this wonderful web site. You will end up with a map that you can print that gives vectors pointing to all of the TV transmitters in our area from your house! We took our map up on the roof while we were aiming of our antenna.


At this point, we have used RG6 (satellite) coax (could be overkill?) to connect the RS UHF antenna directly to my DTC-100. I found a compromise angle for pointng the UHF antenna that split the difference between the Seattle transmitters and Gold Mountain. I watched the signal strengths vary (on the DTC-100) for channel 13 (west-most) and channel 9 (east-most) to get the angle right. I did not add any amplification. My antenna is about 6 feet above the top of my chimney. There is a gradually rising hill between me and all of those transmitters. Testing the antenna at lower elevation was unsuccessful and discouraging, but moving it up made a major difference, including the ability to use the compromise angle. Indoor antennas, amplified and non-amplified, gave me NO usable digital signal EVER.


The web site suggested that I could use an amplified, omni-directional antenna. Later I will try one so I can finally terminate my unreliable cable service once and for all. We still need to get channels 11, 16, 22 and a few others that we watch. The web site map shows where they are located. I may leave the RS UHF only antenna as ANT A (and select only the digital channels on the DTC-100) and add the other antenna as ANT B for all other analog VHF and UHF, as well as distribution throughout the house. That way ANT A is all digital and ANT B is all analog.


I'm no expert, but I've heard or read statements that claim that if you can get sufficient signal strength, you can pull the digital signals in successfully, regardless of multipath problems.


On my original VHF antenna (8 feet above the chimney) I could never get rid of prominent ghosts from the 4, 5, 7 Queen Anne hill stations. The digital versions come in fantastic from the very same transmitter towers. To me, this proves the point for the value and quality of digital transmission.


Channels 4, 7 and 13 broadcast their entire schedule of programs digitally, either HDTV or DTV depending on their available source (no HD on channel 13). Channel 5 (48) does local and network news and Jay Leno only in HD. The rest of the time they broadcast a demo loop of HDTV. (Sure wish they would broadcast all shows digitally like the others.) Channel 9 has some HD programs, and several HD demos that repeat.


We also receive channels 4, 5, 7, 13 and National PBS digitally via satellite from DirecTV. The off the air (OTA) digital signals from the UHF antenna provide much higher quality in all cases. I'm told that the satellite versions are compromised by limited bandwidth and heavy, variable bit rate compression. We have these local channels via satellite for two reasons: 1) so we can record programs digitally on our DirecTiVo DSS Personal Video Recorder (works only on satellite) and, 2) so we can take a portable satellite dish on our boat to watch local stations anywhere in Puget Sound and north into Canada. (We mostly like to watch the local news when we're out for an extended period.)


BTW, channel 9 (41) does go on and off the air at times, especially in the wee hours. Or, perhaps I've aimed my antenna just a little to far in the Bremerton direction. Sometimes, 41.1 is gone but 41.3 is still there.


GOOD LUCK from Renton!

 
1 - 20 of 27 Posts
Status
Not open for further replies.
Top