Minimum spacing for antennas on mast

[Mr Tony]

Now that I got my distant VHF issue resolved thought about putting both antennas on the roof

What is the minimum spacing apart on the mast do they need to be?

It would be the Winegard VHF Hi antenna and either a Radio SHack U-100 (or 120 I forget) antenna or the HBU33 I got recently.

I thought I read like 3 feet apart but is that right?

 

[FaT Air]

Rule I've always used is the width of the antennas, whichever is the widest. at its widest point.
Another rule, if combining the antennas, use equal length coax between antennas and combiner.
If not equal length coax, or on different masts, your going to have multipath problems.
Can't remember where I learned, heard or read them though, it's been a Looooong time.
But they've always worked for me.

 

[highspeedmike]

i was reading last night you can put them on same mast need 4-6 ft vertical

 

[No Static At All]

What is the minimum spacing apart on the mast do they need to be?

The general rule of thumb is 3.5 to 4 feet for VHF-Hi/UHF. I have gone as close as 1 foot with no noticable degredation on either band.

The sweet spot of the UHF antenna (heightwise) is usually the most important factor for spacing if room is tight. Many times I end up lowering the UHF antenna 6 to 12 inches from the initial height to achieve the best reception of "all" UHF stations. (Even strong UHF stations can be sensitive to just a few inches)

 

[Mr Tony]

good information guys. So it looks like I was right with the 3-4 feet but it also looks like trial and error which is ok too

 

[Mr Tony]

well I had issues so I moved the combo antenna off the roof and back to the deck

VHF seemed to clash because the antennas were in opposite directions so I was losing 5-8 points on the VHF channels

on the converter box
9 showed a 85-88
11 showed 91-92
12 showed 74-76 during the day and 88 at night (the distant station)

moved the combo unit away and now I get
9 93-95
11 95-96
12 81-83 right now

 

[ynnedibanez]

VHF seemed to clash because the antennas were in opposite directions so I was losing 5-8 points on the VHF channels

try reversing the wires on 1 of your antennas to correct the phase

 

[Mr Tony]

what do you mean?

The antennas are not conjoined anywhere in the setup right now

top antenna for the distant VHF station comes from the antenna directly into a converter box (since they rarely have anything in HDTV a converter box right now is fine)

bottom antenna goes down a separate cable to a 4 way splitter to 2 converter boxes, DTVPal DVR and the HDTV

 

[ynnedibanez]

oh, ok, my bad, i thought you had them combined to get signals from different areas.
i set up 2 antennas on different sides of the house so i could get the knoxville and tri-cities channels out of tennessee and a few of the channels out of north carolina.
when i first set them up my sig on either antenna was great, but when combined, it dropped drastically there was a 140 to 150 degree difference in how they pointed, so i figured that it might be a phase problem so i reversed the wires on one of the antennas and it worked great.

 

[Mr Tony]

nah I kept the VHF only separate from the others

I have my main antenna for Minneapolis and the VHF only for Mankato. Its weird as the VHF only gets good results on most channels (VHF & UHF) and its facing 180 degrees opposite way of MInneapolis