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post #1 of 32 Old 10-11-2005, 07:59 AM - Thread Starter
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I Bought The Db-8 And Split It Into 2 Seperate Antenna's- If I Point Them In 2 Different Direction And Use There Combiner Do I Need To Have Equal Lengths Of Wire From Each Antenna To The Combiner? And How Far Apart Do They Need To Be So They Don't Cause Multi Pathing?
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post #2 of 32 Old 10-11-2005, 12:42 PM - Thread Starter
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30 People So Far 2 Visit This Thread With No ADVICE
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post #3 of 32 Old 10-11-2005, 12:49 PM
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Quote:
Originally Posted by MHD1080
30 People So Far 2 Visit This Thread With No Advise
Probably 'cos no-one knows the answer after they read your question??? And it was up only 4 hours and 43 minutes.

I have combined 2 UHF antennas successfully, but do not know what a "DB-8" is. I have a CM 4228 and a $25 UHF antenna from Radio Shack which are very close on a 10ft pole. They point in different directions. I combine them via a 1GHz splitter used backwards with a 6dB attenuator on the CM feed to reduce the signal it gets off its backside preventing it from interfering with the Radio Shack antenna.

As with all these things, try something and see what works - more of an art than a science. It took me a lot of trial and error. Same goes with your cable lengths - the ideal is to have them the same which you should be able to if you are using the same mast, but different lengths could work also.

peter
p.s hope you feel better now 31 people have read your post and you did get a reply ;-)
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post #4 of 32 Old 10-11-2005, 12:53 PM
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Quote:
Originally Posted by MHD1080
30 People So Far 2 Visit This Thread With No ADVICE
Jeez - you don't have to keep updating your MESSAGE! (as in turning "Advise" in to all CAPS "ADVISE"!)
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post #5 of 32 Old 10-11-2005, 12:59 PM - Thread Starter
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Sorry Been Working For A Year On This ,db8 Is The Same As Cm4228 But Can Be Taken Apart To Make 2 Uhf Anteenas Similar To The Cm4221
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post #6 of 32 Old 10-11-2005, 01:02 PM - Thread Starter
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One Of The Antenna Has To Be Angled To Get My 2,11,13,16,22,53, And The Other Need To Be 120 Degrees The Other Way To Get Channel 4,so If They Were On The Same Mast It Would Point Down And Get No Signal
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post #7 of 32 Old 10-11-2005, 01:53 PM
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Quote:
Originally Posted by MHD1080
One Of The Antenna Has To Be Angled To Get My 2,11,13,16,22,53, And The Other Need To Be 120 Degrees The Other Way To Get Channel 4,so If They Were On The Same Mast It Would Point Down And Get No Signal
With a 10ft mast you should able to put up 2 regular sized antennas, no? I have that set up. But I guess it depends on the size of youe chimney if you use a chimney mount.. What about 2 10ft mounts on the same chimney?

Try stuff and see what works for you..

peter
p.s. did you read this?
http://www.tvantenna.com/support/tut...combining.html
I was lucky and didn't need a JOIN-TENNA
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post #8 of 32 Old 10-11-2005, 10:35 PM
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Quote:
Originally Posted by MHD1080
One Of The Antenna Has To Be Angled [...]
Don't your pinkies get tired from hitting the shift key so often? :D :D
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post #9 of 32 Old 10-11-2005, 11:27 PM
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Jeez, the same question is posted in the antennas thread http://www.avsforum.com/avs-vb/showt...&&#post6337985

Did you guys stop to think about all the VHF channel numbers? I'm guessing he is using analog channel numbers and doesn't know the true digital channels or he's trying to get VHF analog channels with UHF antennas. I've asked for antennaweb results but have gotten no reply.

Edit: I figured out from the numbers that he's in Pittsburgh and using analog numbers. The channel 4 he's talking about is carried on 51 and, as far as I can tell, all his locals are UHF. A channel 51 jointenna will kill his channel 50 station though. Sure enough, he's posting the same stuff in the Pittsburgh thread. He seem to be convinced that all he needs is to find out how far apart to install the antennas and he's not listening to anything else.

Pat

While I may link to and mention products as examples, I don't recommend specific products.
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post #10 of 32 Old 10-12-2005, 07:15 AM - Thread Starter
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I Don't Want Vhf Channels !! Just Want Uhf Hd Channels, Which Are 51,50,25,48,38,26,42,43.
Put Up One Of The Db4 Last Night Works Great Picked Up 50,25,48,38,26,42,43
Now Looking To Putt The Second One Up To Pick Up Channel 51 Which Is Hd Channel 4, That Is Why I Asked About Joining Antennas
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post #11 of 32 Old 10-12-2005, 07:40 AM
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MHD1080, No need to slpit the DB8 into two antenna's. When assembling connect one bay backwards, worked great for me, until I realized no VHF reception, sent it back an began using my 4228 again.

Scan not a friend with a microscopic glass. you know his faults, let his foibles pass.
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post #12 of 32 Old 10-12-2005, 08:05 AM
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Now that it's clear the channels are all UHF, only shorter wavelengths are involved. Keeping the antennas 5ft apart is a general recommendation but all UHF means closer is usually okay. Too close and the combo acts like one bad antenna instead of two good ones. Plumeria's link has more info about wavelength and separation.

You could try an ordinary splitter combiner to connect the antennas but usually reflected signals from buildings, hills, airplanes, etc. get picked up by the wrong antenna and interfere with the signals picked up by the right antenna.

A Channelmaster jointenna tuned to Channel 51 will pass 51 on one side and block 49, 50, 51, 52 and 53 on the other. http://www.channelmaster.com/Pages/TVS/Passives.htm has information. If you don't care about channel 50 and an ordinary splitter/combiner causes problems, it's a perfect solution. So if you don't care about channel 50, order a jointenna number 0585-3 tuned to channel 51. If you do care about channel 50 and a splitter/combiner isn't the answer, a rotator with one antenna or an A/B switch with two antennas may be required. About the only other option would be to move the channel 51 antenna around and hope to find a spot where it doesn't interfere too badly with the signals on the other antenna.

Pat

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post #13 of 32 Old 10-12-2005, 08:34 AM - Thread Starter
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Thanx Very Much Tried It, It Works Well With A Splitter And 5 Ft Apart, You Were A Great Help!!!
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post #14 of 32 Old 10-12-2005, 10:45 AM
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That's great. Easy, inexpensive solutions that work are my favorites. If only they were all like that.

Pat

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post #15 of 32 Old 10-13-2005, 06:15 AM - Thread Starter
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How Much Is The Jointenna? Where Can I Buy It? Splitter Failed, Knocks Out My Channel 25
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post #16 of 32 Old 10-13-2005, 06:19 AM - Thread Starter
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Channel 51 Knocks Out 25
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post #17 of 32 Old 10-13-2005, 06:55 AM
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It's not channel 51 that knocks out 25 but 25 on the second antenna coming in out of phase with 25 on the first antenna. That's why splitters rarely work. A jointenna will prevent 25 on the second antenna from getting into the combined line. Starkelectronic.com may still order them. Warrenelectronics.com is another big name. It's a special order item because Channelmaster has to tune the device to channel 51 specifically. Remember you'll probably lose channel 50 that way because a jointenna cannot be tuned to such a narrow range that it won't affect nearby channels. I thought I remembered the price being around $20 but I may be way off.

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post #18 of 32 Old 10-13-2005, 07:33 AM - Thread Starter
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Channel 50 Is A Christian Station,does't Matter To Me ,i Don't Watch It,so It Would Hook Up To My Second Antenna Then ? Would It Affect My Channels 42,43 Then?
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post #19 of 32 Old 10-13-2005, 07:53 AM
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The jointenna would simply replace the splitter. It only affects the channel it's tuned for and, to a lesser extent, two channels above and below. See my post #12 in this thread again and check the link.

A simplified statement would be that the jointenna blocks 51 on one side while allowing all other channels through. On the other side, it allows allows only channel 51 through. In actuality, the cutoff isn't that sharp so up to two channels above and below 51 are affected to some extent.

Pat

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post #20 of 32 Old 10-13-2005, 08:27 AM - Thread Starter
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No Way To Make It So That My Second Antenna Just Picks Up 51 And Blocks Out 25,48,38,26,42,43?
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post #21 of 32 Old 10-13-2005, 08:49 AM
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That is exactly what a jointenna tuned to channel 51 does. Repeating my post #19 "On the other side, it allows allows only channel 51 through."

Pat

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post #22 of 32 Old 10-13-2005, 08:57 AM - Thread Starter
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Sorry Didn't Understand The First Time ,thought It Only Blocked 1 Channel Out, It Only Lets One Channel In Is What You Meant
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post #23 of 32 Old 10-13-2005, 09:12 AM - Thread Starter
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You Are So Much Help ,thanx Man
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post #24 of 32 Old 10-13-2005, 09:12 AM - Thread Starter
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Just Need Order It An I'll Be Set
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post #25 of 32 Old 10-13-2005, 09:14 AM
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It's like a splitter but it lets only one channel through on one side and all channels except that channel on the other side. For the third time,

A simplified statement would be that the jointenna tuned to channel 51 blocks 51 on one side while allowing all other channels through. On the other side, it allows allows only channel 51 through. In actuality, the cutoff isn't that sharp so up to two channels above and below 51 are affected to some extent.


Look, I'm getting frustrated repeating and you need to slow down and absorb the information. I'm going take a day off to calm down and you can take time to develop a better understanding of the information. If you need more help, I'll look at this thread again tomorrow. If you ask a question tomorrow that I've already answered, I'll refer you to the answer and then I'll take another day off. Please slow down and try to understand what has already been posted.

Pat

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post #26 of 32 Old 10-13-2005, 09:24 AM
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Ah-h-h-h... the patience of a saint. :)
Well said greywolf!
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post #27 of 32 Old 10-13-2005, 09:43 AM
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Quote:
Originally Posted by Ratman
Ah-h-h-h... the patience of a saint. :)
Well said greywolf!
Hear, hear.... Your approach is commendable. Too often these things end in flame wars, so thanks from all of us out there (the silent readers) for your infinite patience ;-)

regards

Peter
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post #28 of 32 Old 10-13-2005, 07:48 PM
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seems much neater and easier to get a good highly dirctional UHF antenna with a roter and, maybe, a pre-amp. With this set up, a persoanl can get all uhf stations in a 40 mile radius if the antenna has a clean line of sight. It is best to keep any antenna set up as simple and clean as possible.
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post #29 of 32 Old 10-21-2005, 10:35 PM
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Quote:
Originally Posted by richard korsgren
It seems much neater and easier to get a good highly dirctional UHF antenna with a roter and, maybe, a pre-amp.
But a lot of people want to be able to set their DVRs to be able to record shows from stations in different directions without them first re-aiming their antenna.
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post #30 of 32 Old 10-22-2005, 08:14 AM
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Quote:
Originally Posted by jtbell
Don't your pinkies get tired from hitting the shift key so often? :D :D
LMAOROTF :D

MDH 1080, stop putting a capital letter before every word!
Thank you................

.
.
Abundant OTA television is what makes this country different from all others. Lets keep it this way. If you like Wi-Fi so much, OTA fits right in. After all, it is wireless.
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