Antenna Distance

[717seemore99]

I have a Dimond discone on the roof for my scanner. I want to put a cb base up as well. Maybe the a99. My question is, can I put it right beside the discone and expect it to perform without any problem?

 

[KingCobra_CDX882]

I suppose you can
However you CB antenna will not like it and can cause both SWR issues
As well as issues with your scanner picking up huge splash from your cb

I would say is best to keep the 2 antennas 18 or further feet apart
If you simply do not have the room...well it is what it is

 

[W5LZ]

Can you do it? Sure, but there will always be some interaction between any two antennas that are near each other. I would imagine there would be at least some detraction from the CB antennas radiation pattern, sort of like placing a large metal obect in the same place. May not affect much, but it could.
The scanner would be what I would be worried about. That CB antenna does produce energy that's going to end up inside that scanner. May not do anything harmful, but it certainly can. If both are on the same frequency, or maybe just the same band or a harmonic, the scanner isn't gonna like it much. Best bet is to put them as far apart as possible, then be careful about operating both at the same time.
It really depends on what 'close' means, a couple'a few inches, or a couple'a few yards. In this sort of case, yards are better than inches. Miles would be better than either of those two, but that's sort of ridiculous...
- 'Doc

 

[park]

I was always told to keep verticals at least a 1/4 wavelength from each other. That's what I've always done and have had no problems. 27 mhz is about 4 1/2 feet (In the 400 mhz UHF band that's about 4 inches!).


A side note here. I did damage the receive board once on a FT-101 that was on 75 meters while transmitting on 160 meters on another rig with separate antennas.