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Message |
    
Keithinatlanta
Advanced Member
Username: Keithinatlanta
Post Number: 904
Registered: 3-2003
| | Posted on Monday, January 10, 2011 - 2:47 pm: | 
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Hi guys. What would be advantage for CB radio with AM/SSB, a beam with 6 elements versus 4 elements? Further transmitting and receiving? Thanks.
Keith in Atlanta
CEF 150 |
N8fgb
Intermediate Member
Username: N8fgb
Post Number: 101
Registered: 5-2002
| | Posted on Tuesday, January 11, 2011 - 9:26 pm: |
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yes |
Tech833
Moderator
Username: Tech833
Post Number: 1902
Registered: 8-2002
| | Posted on Thursday, January 13, 2011 - 9:53 am: |
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About 1.5 dB gain difference and a narrower beamwidth, slightly improved F/B ratio.
The rule of thumb with yagi type beams is, every time you double the number of elements (by adding directors), you add 3 dB gain.
Your radio 'Mythbuster' since 1998
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Henry_hpsd
Junior Member
Username: Henry_hpsd
Post Number: 10
Registered: 2-2007
| | Posted on Wednesday, June 29, 2011 - 2:51 pm: |
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A bit late perhaps, but were here to learn form eachother. And although i highly appriciate your posts, i have to disagree on this one.
We cant be sure about gain or beamwidth
As more gain is related to a narrower beamwidth. e.g. Gain has to come from somewhere..so if we "push" the beamwidth on the sides it will go "deeper" hence..more gain.
But back to where i mentioned: we cant say such a thing..
A 4elements on a 6,7 meters boom will show approximently 10dBI
a 6elements on a 7,3 meters boom will show
approximently 10,1 dBI
For both antennas i would have prefered other element numbers on the boomlength given, but were sticking to 4/6 elements
On the other hand,
If i had a 4elements on a 3,5 meters boom it will show approximently 7,5 dBI
If i had a 6elements on a 13 meter boom it will show 12 dBI.
So the difference beeing actually nothing upto almost 5dB's.
So, its not the number of elements wich add gain but the boomlength.
A maco 8 elements will show 11,4dBI in gain
www.dx-antennas.com/MACO8.htm
A 5elements on a 8 meter boomlength normal yagi can show 11 dBi as well.
The "rule" you probarbly had in mind is the one of DL6WU in wich he proved that by doubling the BOOMLENGTH there is a additional 2,7dB.
The best thing for the thread starter would be to provide the information of the two antennas in question. As there are more things wich are of intrest. Like how stable is the antenna in aspect to QRN etc.
Kind regards,
Henry HPSD 19SD348
www.dx-antennas.com |
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