Alternative to Jointenna? - AVS Forum
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post #1 of 12 Old 11-27-2007, 06:41 AM - Thread Starter
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Does anyone know if there are any other alternatives to the concept used by "Jointenna"? They seem to offer single channel insertion for most of the VHF channels but for UHF the blocks of channels are very wide. I have one channel from New Mexico on 23 and every thing else is from El Paso which even after 2009 will include a channel 18 and 30. The Jointenna would notch out 14 through 29 which is too course of a channel selection.

At this time I use a RF switch which works fine, however with Tivo it prevents me from recording from the two antennas unattended.

Any input would be appreciated.
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post #2 of 12 Old 11-27-2007, 05:34 PM
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I concur with Rick0725 regarding the application of the channel 23 Jointenna. It is manually tunable from channels 14-29, but at any given tuned value, it will only wipe out a few channels above and below the tuned channel.

Regarding using a Channel 56 Jointenna to couple 54 and 56, YMMV. I have gotten away with spacing that tight myself, but you need to have a lot of things going your way for it to work.
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post #3 of 12 Old 11-27-2007, 11:05 PM
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The CM 7777 preamp can act as a combiner for separate UHF and VHF antennas.
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post #4 of 12 Old 11-28-2007, 06:43 AM
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Quote:
Originally Posted by Mister B View Post

Does anyone know if there are any other alternatives to the concept used by "Jointenna"?

http://www.tinlee.com/MATV_headend.php?active=3#CMN7

Single Channel Injectors, join a single channel antenna with a broadband antenna or separate one channel from a broadband antenna. This three port device consists of:

1. Single channel input (bandpass) which provides 20dB rejection at: ±8 MHz (VHF), ±18 MHz (UHF). Insertion loss: 2 dB typical
2. Broadband input (bandstop) which reduces signal overlap between the single channel input and the broadband input. Rejection: 15dB. 3dB points: ±8 MHz (VHF), ±18 MHz (UHF)
3. Thru-port (common). Passband: 40 to 860 MHz, thru-loss: 1dB
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post #5 of 12 Old 11-28-2007, 02:32 PM - Thread Starter
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Thanks for all of the advice. I did some more research including the Tinlee site and decided to give the Jointenna a try. Initially I was confused by Warrren's web site as it looked like the device notched out channels 14 through 29, however that is just the base model and one still must specify which channel is to be notched out of that range.

Consensus seems to be that attenuation can be expected no more than 5 channels each way from the added channel (23 in my case). I should be safe as the channels 18 and 30 are very strong. I was also concerned as to how much loss I could expect in the added channel as I just put up a Winegard HD-9032 to pull in that New Mexico PBS station at about 80%. It hopefully will not be more than about 2db, and I know that I loose a little signal from the remote RF switch.

I hope to have it by Christmas and will post the results.
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post #6 of 12 Old 11-28-2007, 02:39 PM
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I haven't priced the Tin Lee coupler but would guess it costs over $100. They charge me a hundred and something each for four custom tuned bandpass filters I had them make up, and their joiner may be a more sophisticated device that that.
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post #7 of 12 Old 11-28-2007, 04:51 PM
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Quote:
Originally Posted by AntAltMike View Post

I haven't priced the Tin Lee coupler but would guess it costs over $100. They charge me a hundred and something each for four custom tuned bandpass filters I had them make up, and their joiner may be a more sophisticated device that that.

I have found the same thing with Tinlee's prices. Yet, they are relatively inexpensive if you need a better filter than a Jointenna.
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post #8 of 12 Old 12-04-2007, 06:07 AM - Thread Starter
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My Jointenna arrived in the mail yesterday much before I expected it. Within a few minutes I had it hooked up for testing. As expected I lost about 2% in signal quality on the inserted channel which I can afford. It had been explained that the attenuation of unwanted signals is in the form of a bell shaped curve and that is also true. I am adding a channel 23 from Las Cruces, NM but the inserted antenna can still get analog and digital stations on UHF 18 through 32 from a side lobe picking up the stronger El Paso stations. However, after connecting the "all channel" antenna there were no problems with ghosting on the analog channels or reduction of signal quality on the digitals.

In my situation this was a very good alternative to a RF switch or a rotor. Of course it is only good if you need to add only one channel from only one alternative direction and I would not recommend it if signal strength is very weak and you need every bit possible.
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post #9 of 12 Old 02-16-2009, 09:13 PM
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A coax splitter may work just as well; search google for hdtvprimer merging feedlines.
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post #10 of 12 Old 02-18-2009, 08:27 AM
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I use a $2 combiner/splitter with equal length leads. In my situation, there are no concurrent channels. If you are using a highly directional antenna with good back side rejection you may find that the combiner is all you need.

Sailn...
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post #11 of 12 Old 02-18-2009, 11:11 AM
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Equal length leads are of no benefit unless you are pointing both antennas in the same direction and are trying to keep their signals in phase with one another.
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post #12 of 12 Old 04-10-2009, 06:57 AM
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Quote:
Originally Posted by internetuser View Post

A coax splitter may work just as well; search google for hdtvprimer merging feedlines.

As Ken Nist says in HDTVPrimer about Merging feedlines, using a broadband combiner (such as a splitter) can cause various problems including 3.5 to 4 dB of signal loss. You can also have phase distortion issues if both antennas are able to pick up the same signal.
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