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				Underground mobile antenna issues
				Posted: Thu Aug 19, 2004 10:39 am
				by grinthock
				I love my 5/8 antenna, on 2M it gets out real well, but when I go under my building, the top 5 inches hit's the pipes.  
I know there are knock back antenna's what other solutions have people here used for underground parking?
			 
			
					
				
				Posted: Thu Aug 19, 2004 11:41 am
				by va3wxm
				I use a Larsen nmo2/70b dual-band antenna (approximately 36" tall) for low-overhead situations.  There are also 1/2 wave antennas around that are, well, a third shorter than your 5/8. 

  The gain difference between the two is negligible.
 
			
					
				
				Posted: Thu Aug 19, 2004 6:04 pm
				by kf4sqb
				Unless you are going really fast, I don't think you will hurt the antenna. Or maybe the noise bothers you , like it does my wife.....
			 
			
					
				
				Posted: Thu Aug 19, 2004 7:25 pm
				by grinthock
				Well there are two options as I see it....
The whip I have now is black painted copper core (standard Larsen) but the paint is pretty much gone now, from hitting the pipes.
Noise doesn't much bother me.  But I figure if I goto a stainless whip it won't be "Damaged" like the copper one is.  Plus it's going to be alot less subseptible to bending
			 
			
					
				
				Posted: Thu Aug 19, 2004 8:10 pm
				by 70351
				I also had the same problem when I used to have to park in an underground facility. I was using a black Larsen NMO-150 on the trunk and it scraped the pipes and ceiling in places, rubbing off the black paint exposing the copper core. I put a Larsen NMO-270 in it's place, which was shorter, and didn't have that problem any more. I found the gain on 2-meters to be the same as the longer two meter-only antenna.
Randy
			 
			
					
				5/8 antenna ??
				Posted: Tue Aug 24, 2004 1:52 pm
				by raymond345
				We have found in the past the 5/8 wave ground 
plane antenna worked better for morning skip than
the 1/2 wave antenna.
We get a lot of inversion on 5/8 than what is 
heard on the 1/2 wave.