multiple antennas on a mast

[tomhrrs69]

Currently, i have the radio-shack 20-176 antenna mounted to a pvc pipe on my roof for my scanners. I just purchased a new J-pole antenna 2 Meter Amateur Radio Antennas | KB9VBR J-Pole Antennas for my 2m rig.
I was thinking about extending my pvc pipe and mount the antenna to that. Will having the 2 antennas on the same pole cause any intererence?

 

[Rt169Radio]

If their close enough the 2 meter antenna when transmiting might overload the scanner that is attached to the scanner antenna or even destroy it if the 2 meter antenna is putting out enough power.

How is that PVC pipe working out as a antenna mast?

 

[reedeb]

It MAY not effect it. I did learn that if you have a tower and have multiple antenna's it will diffuse a static build up and keep lightning from striking it [NOT a gaurantee tho]

 

[tomhrrs69]

my 2m rig is a HT ,so it will only be putting out 5w at the most. The pvc works good, though i cheated a bit, i had a J-mount on my roof (from an old satellite antenna) so I placed a 3 ft piece of pvc into the j-mount pole and mounted the antenna to the pvc. It's pretty solid. I might need to look at mounting the 2m j-pole antenna someplace else then.

 

[LtDoc]

Any two (or more) antennas can affect each other. That 'affect' may or may not be detrimental, it depends on several things. Proximity in both distance and frequency, their physical positioning with each other, and to some extent, the color of socks you're wearing. About the only way to tell for sure is to try it.
Considering the power levels a typical radio deals with, 1 watt can be 'too much', back to that proximity, etc, thingy. It's fairly common, so it's worth at least trying to see.
- 'Doc

 

[W2NJS]

The general "key" to mounting antennas on the same mast is vertical separation. Get them as far apart as possible vertically and see if when one or the other radio transmits it desenses the other radio's receiver. In your case it would be only one radio transmitting but you get the idea.

 

[tomhrrs69]

thanks for all the suggestions, unfortunately, the new antenna has not arrived yet, so looks like i have to wait until after the holidays to get up on the roof and install the antenna. Hopefully before all the snow hits.
If i can't get up on the roof, might just set up a temp location on my deck railing or fence post so I can at least use it.

 

[wv8mat]

I have my 10m vertical and my 2m/440 vertical on the same mast, real close together and no problems. Just make sure to use good coax and you would most likey be ok.

 

[tomhrrs69]

good news, the antenna arrived this morning, couldn't get on the roof to permantly mount it, so i hooked it to a pole that i had in the ground, and tested it with my ht. I was able to pick up and talk clearly on a repeater about 50 miles away. Hopefully tomorrow i will have time to run the feed into the house and up to my desk. I have to say so far, I'm really impressed with this antenna.

 

[vannossc]

I put a 2 meter antenna, a scanner antenna and my weather station on a Radio Shack mast with some good PVC as outriggers to hold the latter two. Weathered Hurrican Irene (50+ mph) winds up here in NY. All worked fine. I transmit 5W on the 2m and no bleed over on the scanner at all. NOr any interference on the weather station.

 

[vannossc]

Picture here

 

[Rt169Radio]

Picture here

Thats nice!

 

[SCPD]

Schedule 80

Been reading this thread for a bit. Couple of comments:

1. Always try to use Schedule 80 PVC. Thicker wall.
2. If putting a vertical beam up, always use PVC if it's not an end mount. One common mistake is that folks will put a center mounted vertical beam on a metal mast. This adds one additional "way out of resonance" element, and will cut the gain in half.
3. I find that antennas always work best when they are put up in the nastiest, coldest, most crummy weather possible.

I just like to mention item 2 from time to time. It don't really pertain to the thread.