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Message |
    
Big_m
Member
Username: Big_m
Post Number: 98
Registered: 9-2007
| | Posted on Thursday, March 18, 2010 - 12:55 am: | 
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While talking to a few friends the subject of 2 meter antennas came up. And I was told that a 1/2 wave Diamond SG-7500A 40in tall would out perform a 7/8 wave Diamond SG-7900A 62in tall on the roof of a Mini Van. I say it's not so. And If so why? Thanks for any help. |
Allagator
Advanced Member
Username: Allagator
Post Number: 810
Registered: 9-2002
| | Posted on Tuesday, November 01, 2011 - 6:48 pm: |
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big m ive got a good friend that has a ham shop and he had 2 of them antennas the 7/8 was better ! but also picked up more noise !
hope it helps !
CEF 115 / CEF HAM 290 /KC9OKX
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Press_man
Intermediate Member
Username: Press_man
Post Number: 265
Registered: 5-2008
| | Posted on Wednesday, November 02, 2011 - 8:11 pm: |
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Not the same antennas but I had a 1/4 wave mag mount on my Toy P'UP and tried to bring up a 2m machine in Melbourne Florida once from Wabbasso FL. (20miles) with 1w on 146.850 and couldn't. I switched to a MFJ 5/8 bottom load mag mount and brought the repeater up with 1/4w and 1w was full quiet. This was in 1992 and I still like the MFJ. I know there are better antennas out there but the MFJ works good for me.
73
Pressman/KC4ZWM
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Tech237
Moderator
Username: Tech237
Post Number: 1486
Registered: 4-2004
| | Posted on Monday, November 07, 2011 - 9:24 am: |
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Press-Man, in yor case the biggest difference would ahve been teh angle of radiation. A !/4 wave radiates at around 45 degrees above the horizon, while the 5/8th is around 35 degrees. yes the 5/8 does have some gain ove the 1/4 wave, but not that much.
Big_M, I have always p[refered the 1/2 wave where I could run one dropping to a 1/4 wave where I needed the extra clearance (if I knoew I would be using underground parking). I have never used a 7/8 wave but would expec that there would be little difference in gain over the 1/2 wave and maybe just a little lower angle of radiation.
I'll wait now and let 833 tell me I'm wrong..
Tech237
N7AUS
God only made some many perfect head, on the rest he put hair.
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Press_man
Intermediate Member
Username: Press_man
Post Number: 273
Registered: 5-2008
| | Posted on Tuesday, November 08, 2011 - 8:01 am: |
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Hey Simon;
Funny you'd mention underground parking. The 1/4 wave did offer the advantage of not hitting the condo parking structures. On property at the HOA where I worked I ran the 1/4 and off property I ran the 5/8. I was constantly parking under a building to gain access to the swimming pools.
The owners knew I was a ham and would flock around any time the Shuttle went up to listen to it on my HT.
73
Pressman/KC4ZWM
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Tech237
Moderator
Username: Tech237
Post Number: 1489
Registered: 4-2004
| | Posted on Thursday, November 10, 2011 - 9:00 am: |
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Lets just say I leanrt by experience. Forgot about a roof mounted Hustler 10m antenna and took out 36 fluro tubes, 1 Hustler antenna and a rather large bedn in the roof.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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