[blood_donor]

Hi,


I live in a complex of 2 story brick condos (once apartments) which are clustered in U shaped blocks of 2 units. In other words, I have brick a brick building adjacent to me and also parallel to me about 25 yards away. There are a few approx 2 story trees scattered around, but nothing much higher than the rooftops.


I live about 7 mi from Southfield, MI where the Detroit market TV transmitters are located.


My first attempt at HDTV OTA was with the old rabbit-ears and loop antenna. Many channels were detected by my receiver (Toshiba DST 3000) but no channel would come in solid for more than a minute before dropping out.


My second attempt was with the "Silver Sensor" passive indoor UHF antenna. This did quite well on some channels, but couldn't see other channels at all unless I rotated the antenna, losing the first set. The odd thing about this antenna is that, according to Antennaweb, I was pointing in the wrong direction for some stations when they came in, which makes me wonder if I wasn't watching reflected signals off of the nearby buildings?


Can someone suggest what I should try for #3?


I was thinking maybe a RadioShack U74R in my attic, however, I wonder if this will be futile? The heading directly towards the local transmitters would face a cinderblock firewall. My roof is made of plywood sheathing covered by ashphalt type tiles, I believe. Is this a good choice, or is it a waste of money?


Unfortunately, I don't think that getting an antenna mast installed on the roof of my comonly owned building is an easy proposition--I would be better of paying for a couple of years of basic cable than going through the trouble, I suspect. But I'd hate to pay for TV!


DTV Antenna

Type Call Sign Channel Network City State Live

Date Compass

Orientation Miles

From Frequency

Assignment

* yellow - uhf WJBK-DT 2.1 FOX DETROIT MI 193° 6.4 58

* yellow - uhf WMYD-DT 20.1 MNT DETROIT MI 176° 7.4 21

* yellow - uhf WKBD-DT 50.1 CW DETROIT MI 237° 7.5 14

* yellow - uhf WTVS-DT 56.1 PBS DETROIT MI 176° 7.4 43

* yellow - uhf WXYZ-DT 7.1 ABC DETROIT MI 211° 6.2 41

* yellow - uhf WWJ-DT 62.1 CBS DETROIT MI 176° 7.4 44

* yellow - uhf WDIV-DT 4.1 NBC DETROIT MI 190° 4.8 45

* yellow - uhf WADL-DT 39.1 IND MOUNT CLEMENS MI 96° 15.9 39

UPDATE: Jan 29 2007


Here is what I did, and the result. I put a ChannelMaster 4221 4 bay UHF reflector in my attic, connected to 75' of RG59 cable. The result: all of the stations come in pretty well except for Fox 2 (58). Exasperated, I called Fox 2 and spoke to one of their engineers. After describing my setup to him, he said that my problem was my cheap cable. "Get yourself some RG6, or better yet, RG11 if you can", he said. Apparently, at the high frequencies that Fox2 is broadcast on, using RG59 results in too much signal loss.


So my next step is to (argh!) pull the cable out and put in RG6. Which means crawling into my attic again.


The good news is this: the 4221, pointed roughly towards where all the transmitters are, does just fine for allmost all of my stations, even over a 75' run of cheap ($20 at Walmart) Phillips coax cable.

UPDATED Jan 29 2007


Just finished fishing the new RG6 cable (Home Depot, 100', white) through the holes of the old cable. Neat trick I figured out: use a coax coupler, and use the old cable to pull the new one through.


Early results: Fox2 is now coming in consistently at 80% strength! Woohoo!


Lessons learned:


1) Use good cable, RG6 or better

2) Use a good antenna

3) Get the antenna up as high as practical

 

[Riverplace]

CC carries Philips MANT950. I am very happy with mine. It is a little more expensive to compare with a rabiit-ear type but I get rock solid performance from mine. Plus the design is not too bad to use indoors.

 

[blood_donor]



Quote:
Originally Posted by Riverplace /forum/post/0


CC carries Philips MANT950. I am very happy with mine. It is a little more expensive to compare with a rabiit-ear type but I get rock solid performance from mine. Plus the design is not too bad to use indoors.

Wow, $100! It looks like it is a gigantic amplified dipole...


For $100, I can put nice UHF outdoor antenna like a DB2 or a U75R in my attic, with an amplifier and cable included.


Does anyone else have experience with the MANT950?

 

[afiggatt]

You have stations spread around in azimuth and may have multi-path issues as well. But aiming the Silver Sensor in other directions is not proof of multi-path as it may be picking the station off in a side lobe of the antenna pattern.


Appears that you were getting decent performance with the Silver Sensor, but your spread in azimuth for the stations is too large for that particular antenna. Your attic does not sound promising, although a cinder block firewall is not a total showstopper. It will reduce your signal strength, but you are close enough to the stations that an antenna in the attic may work. One possibility is a AntennasDirect DB-2 mounted down in the condo area; has more gain and wider pickup in azimuth than the Silver Sensor, but may be worse for multi-path.


You mentioned getting the Radio Shack U-74R. Did you mean the U-75R yagi? If so, the wrong antenna for your situation. The U-75R is a very directional medium to long range UHF only antenna. Very touchy for the right aim.


The Channel Master 4221 4 bay is an option, but it would have to go in the attic. The flat panel bowties have the advantage of wide pickup in azimuth. I get 17 stations spread all around me in azimuth with a CM 4221 in my attic.

 

[blood_donor]



Quote:
Originally Posted by afiggatt /forum/post/0


You have stations spread around in azimuth and may have multi-path issues as well. But aiming the Silver Sensor in other directions is not proof of multi-path as it may be picking the station off in a side lobe of the antenna pattern.


Appears that you were getting decent performance with the Silver Sensor, but your spread in azimuth for the stations is too large for that particular antenna. Your attic does not sound promising, although a cinder block firewall is not a total showstopper. It will reduce your signal strength, but you are close enough to the stations that an antenna in the attic may work. One possibility is a AntennasDirect DB-2 mounted down in the condo area; has more gain and wider pickup in azimuth than the Silver Sensor, but may be worse for multi-path.


You mentioned getting the Radio Shack U-74R. Did you mean the U-75R yagi? If so, the wrong antenna for your situation. The U-75R is a very directional medium to long range UHF only antenna. Very touchy for the right aim.


The Channel Master 4221 4 bay is an option, but it would have to go in the attic. The flat panel bowties have the advantage of wide pickup in azimuth. I get 17 stations spread all around me in azimuth with a CM 4221 in my attic.

Excellent information, thanks! Yes, the problem with the Silver Sensor was that I had to turn it to a different heading for almost every group of channels I wanted to watch. It was also very sensitive to things like the neighbors opening a door, or someone walking across the room. Very frustrating.


So it sounds like my best bet for a not-to-directional antenna is a bowtie+reflector design, such as the DB2, DB4, or 4221?

 

[DrBri99]

I have a CM 4228 set up in Afton, Virginia to (hopefully) receive Richmond, Virginia Digital TV stations. The Richmond transmitters are from 75 to 81 miles from my house, and 1 degree apart on the compass.


Charlottesville's TV towers are 15 degrees away from Richmond and I have no problem receiving them. Charlottesville stations offer all four major networks, but only one is HD.


My goal is to get the four networks from Richmond, 6.1, 8.1, 12.1, and 35.1.

From antenna web, these are the results:


(* yellow - uhf WVIR-DT 29.1 NBC CHARLOTTESVILLE VA 109° 19.8 32 )

* red - uhf WRIC-DT 8.1 ABC PETERSBURG VA 126° 76.6 22

* red - uhf WCVE-DT 23.1 PBS RICHMOND VA 126° 76.6 42

(* red - uhf WCVW-DT 57.1 PBS RICHMOND VA 126° 76.6 44)

(* red - uhf WHTJ-DT 41.1 PBS CHARLOTTESVILLE VA 109° 19.7 46)

* red - uhf WTVR-DT 6.1 CBS RICHMOND VA 126° 76.6 25

* red - uhf WWBT-DT 12.1 NBC RICHMOND VA 125° 81.6 54

* blue - uhf WUPV-DT 47.1 CW ASHLAND VA 111° 88.8 47

* blue - uhf WRLH-DT 35.1 FOX RICHMOND VA 126° 76.6 26


The ones in parentheses are the ones I receive, basically the Charlottesville stations, and one station from Richmond, 57.1 WCVW.


According to the FCC database, WCVW-DT is broadcasting at 100 kW compared to 800 kW for WRLH-35.1, 1000 for WWBT-12.1. The tower for 35.1 is of similar height and location, and the 12.1 tower is 85 Meters lower and in a different location.


I've done some fine tuning of the antenna, just to get one station (from Richmond)24/7, it would come and go before this.


I do get 12.1 sometimes, usually early in the morning when the weather is clear.


I have tried the CM 7777, and the channel master single line distribution amplifier. I have a long run over 50 feet, but I have also run a 15' run to a small monitor to check and I had the same results.


The Charlottesville/Harrisonburg AVS forum has been very helpful, and the only thing I haven't tried from their suggestions is to try a different place on the roof for the antenna.


The only other place I can think of to mount it is the chimney which would only move it over slightly based on the angle of the house and where I'm aiming.


Does anyone have anything else to offer that could help?

 

[Davinleeds]

Different location or height can make all the difference. Hope you can experiment this time of year with location. I raised mine 4 ft and it reduced cbs but I gained abc. I found a rotor is essential even if you use it once in awhile.

 

[thenewcc]

I'm in Chicago and just got the Philips MANT950.

Being half underground in a garden unit, I currently have it sitting on the inside window sill (about ground level) facing east (arms of the unit are pointing north/south). I can pick up all local digital channels, but I think I'd get better signal strength if I could aim the antenna south east and/or get it mounted outdoor or on the roof of my building.

Signal strength varies from 45% to 85% indoors.

Overall, not bad, but could be better for the weaker signals, like PBS, CBS and WGN.


If I get permission to mount it on the roof, I'll let you guys know how it improves.

Quote:
Originally Posted by blood_donor /forum/post/0


Wow, $100! It looks like it is a gigantic amplified dipole...


For $100, I can put nice UHF outdoor antenna like a DB2 or a U75R in my attic, with an amplifier and cable included.


Does anyone else have experience with the MANT950?

 

[DrBri99]



Quote:
Originally Posted by Davinleeds /forum/post/0


Different location or height can make all the difference. Hope you can experiment this time of year with location. I raised mine 4 ft and it reduced cbs but I gained abc. I found a rotor is essential even if you use it once in awhile.

I've read a little on hdtvprimer.com about dealing with multi-path, and it sounds like I should be able to find a place with rotating the antenna that will put the multi-path signals in a null position on the antennas "beam".


Did you find your stations came and went before moving the antenna?


Are they constant now?

 

[DrBri99]

I purchased a Samsung DTB-H260F about 5 days ago.


The tuner alone has overcome my multipath problems (most of the time), I still get some drops of signal during the day.


I've posted a full review on the Hardware Forum for the Tuner.

http://www.avsforum.com/avs-vb/showthread.php?t=728392

 

[hlg1951]

You are close enough that you should not need much. You can try making a DB2 bowtie UHF antenna like described at this site, http://www.lumenlab.com/forums/index.php?showtopic=9613 .


Or you can purchase one from Antennas Direct or a local supplier. One brand calls it a DB2. Channel Master makes a 4-bay (4221) and 8-bay(4228). I made a 4 bowtie and put it in the attic. It is picking up signals from the towers 36 miles away. I need to add an amplifier at the antenna to increase the signal and/or shorten the 25ft. cable.