AVS Forum banner

New Orleans: Combining Antennas ?

969 views 14 replies 6 participants last post by  turtleworld 
#1 ·
I currently have this antenna on a 25' mast.
http://www.mcmelectronics.com/product/STELLAR-LABS-30-2430-/30-2430

I have it pointed towards New Orleans (approx 65 miles) and it catches 30 channels.

I was thinking of adding another to face Baton Rouge (approx 65 miles)
They would be at 90 deg to each other.
I have a pre-amp in attic near location where cable enters roof.

Do I bring antenna cables separately into attic, then split to pre-amp ?
or
Do I combine the cables near antenna with one cable to pre-amp ?

Any advice appreciated.
 
#2 ·
It doesn't matter which way you do it, either will perform nearly the same. Make both cables the same length and give it a try. Keeping the cables as short as you can before amplification is suggested so as to keep system noise figure as low as possible.

Don't be surprised if it doesn't work out the way you want it to. Be happy if it does.
 
#5 · (Edited)
When you combine Two Antennas pointed in different directions, interaction between Antennas is Minimized since the Antenna Pattern is usually a NULL towards the sides. However, in rare cases, it is POSSIBLE that Multipath will be picked up by one Antenna, degrading the Other if the signal is bouncing off Terrain, Building or Bridge located between the two directions.

The Noise on one Antenna (whether Thermal or Man-Made) will ADD to the Noise already present on the Other Antenna, degrading the Sensitivity by a MINIMUM of 3 dB and much more for Man-Made Noise sources. So it's always BEST to use separate Coax downleads to an A/B Switch. But you can TRY using an RF Combiner (3.5+ dB Loss), where you stand half a chance if you have strong enough signals to overcome the various degradation factors.

BTW: Strong local signal(s) coming from one direction might need to be Attenuated [DC PASS Attenuators are available] to reduce Adjacent (and Next-Adjacent, etc) Interference into the weaker signals coming from the Other direction....or at least chose Preamps with different amounts of Gain to reduce the spread in signal strengths. Single Channel Filter(s) are also available...or a JoinTenna, if you can find one.
 
#7 ·
lacogada,

I have 3 of those antennas marketed under the Solid Signal brand as model HDB8-X.

Why don’t you try adjusting the four bay panels pointing one towards New Orleans and the other towards Baton Rouge? You’ll have a couple of dB less overall gain in each direction but it should give you a feel for how much destructive interaction you’ll experience with that orientation when using two 8-bays. You already have the required type of combiner combining the two panels.

You can also use the lead from each panel to test each direction separately. Just connect the short cable from each antennas balun through an F-81 barrel coupler to your existing down lead. Or, if your existing down lead will reach connect it to one panel’s balun to test and then move it over to the other panel’s balun and test in that direction. This will give you a feel for the difference in performance achieved by running separate cables and using a coaxial A-B switch near your TV.
 
#8 ·
lacogada,

Why don’t you try adjusting the four bay panels pointing one towards New Orleans and the other towards Baton Rouge?
I have tried that. Caught different channels, but overall, I lost channels.
That's why I thought maybe 2 antenna's, with all four bays facing each direction would be OK.

I have an unusual setup.
Antenna located on back of my storage/shop/barn. Cable goes into attic and into old radio shack pre-amp.
It then passes through the soffit into pvc that goes underground to the house.
Back through house soffit into attic and connects to channel master pre-amp that feeds 3 TV's. ( 80' to 90' run )

That's why the rotor or a/b switch is out ... I cannot get the wire run, wish I would have thought of it before.

I ran 2 cables at the time.
Thunderstorms roll around and I disconnect cable from antenna to 1st pre-amp.
Pain in the butt ... but I have to protect my cable lines.

Thanks for the info Pete.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top