The RV Forum Community

RVing message boards => PCs, Communications, Electronics => Topic started by: Kevin Means on September 09, 2017, 08:03:40 PM

Title: Two Antennas On One Mast
Post by: Kevin Means on September 09, 2017, 08:03:40 PM
This one's for the radio gurus here.

I've been considering buying a Weboost cell phone booster, and a wifi booster (brand yet to be determined). Both devices have external antennas, and I'd like to mount them on a single mast - perhaps with some type of "T" bar at the top of the mast for separation.

Since both antennas send and receive RF energy (presumably on different frequencies) I was wondering if one would interfere with the other. Are their frequencies far enough apart that separating them by two feet (or so) would prevent any/most RF interference problems, or is that wishful thinking?

Kev
Title: Re: Two Antennas On One Mast
Post by: Stephen S. on September 10, 2017, 12:44:28 AM
Well... for one thing, if they are directional antenna, you would have to use one or the other. Most of the time the closest cell tower will not be in the same direction as the closest WiFi router.

For omni-direction antenna, you could mount one above the other on a non metallic mast, putting them in each others "shadows".
Title: Re: Two Antennas On One Mast
Post by: Arch Hoagland on September 10, 2017, 01:01:55 AM
I use two antennas on the same mast.

I attached the Jefa Tech Wifi Omnidirectional antenna to the batwing TV antenna so I can crank it up when necessary.   

I think the only way you are going to be able to determine if it will work is to hook it up and try it.  My money says it will work fine and I come from a history of repairing high power radio transmitters and military walkie talkies.
Title: Re: Two Antennas On One Mast
Post by: Kevin Means on September 10, 2017, 01:17:38 AM
Thanks Arch (I was hoping someone would say that. ;)) I forgot to mention that they're both omni antennas, so thanks for mentioning it.

Kev
Title: Re: Two Antennas On One Mast
Post by: John From Detroit on September 10, 2017, 06:46:04 AM
There is indeed a POSIBILITY of interference, but considering the power of the units it is fairly low.
It can be further reduced by using direcitonal antennas.  And by VERTICAL seperation.

FOr example.. Where I am just now I have a clear view of the park's non-Working WI_FI antenna (Sadly I can connect to the router like gangbusters but nothing past it even pinging by IP will not get past the router) from "Eye level" standing on the ground so I dont' need height.. THe WI-Fi. Well I dont' need height there either considering the tower location but I'd put that antenna tt the TOP of the mast.

ALso odds they will point the dsame direction are 1 in 360
Title: Re: Two Antennas On One Mast
Post by: Gary RV_Wizard on September 10, 2017, 08:37:34 AM
The Weboost amps are available with either omni or directional external antennas, but the more powerful Weboost models are always directional. Don't confuse the inside antenna (nearly always omni) with the external one (directional or omni).

Wifi is in a much different radio frequency range than cellular, gigahertz vs megahertz, so interference is unlikely.

You can rotate the antenna on the mast rather than the entire antenna, so multiple antennas can be tuned on one mast. If a U shaped extension is mounted on a single base mast, the two arms of the U could be individually rotated as well. Of course, that means using a ladder or taking it down for each adjustment.
Title: Re: Two Antennas On One Mast
Post by: HappyWanderer on September 10, 2017, 09:29:11 AM
Two feet is multiple wavelengths at those frequencies, so there shouldn't be any interaction between the two antennas. Worst case scenario is one shadows the other in a very weak signal environment.
Title: Re: Two Antennas On One Mast
Post by: Kevin Means on September 10, 2017, 12:36:27 PM
That's all very helpful. Thanks!

Kev