Changing Electrical Tilt On DB420-B

[tcp2525]

A question for all you gurus out here. I'm dealing with the antenna in the title that is up about 100' that performs perfectly in the northerly direction, but sucks going south. The hill I have to go over really isn't overly high, but high enough to attenuate an antenna with electrical down tilt. My question is do you guys have any ideas or a source of literature that can point me in the right direction? Thanks.

[Lscott]

29 minutes ago, tcp2525 said:

A question for all you gurus out here. I'm dealing with the antenna in the title that is up about 100' that performs perfectly in the northerly direction, but sucks going south. The hill I have to go over really isn't overly high, but high enough to attenuate an antenna with electrical down tilt. My question is do you guys have any ideas or a source of literature that can point me in the right direction? Thanks.

The antenna you mention in the title shows a "beam" tilt of zero degrees in the attached datasheet. I think you'll have to find another solution.

DB420-B.pdf

[tcp2525]

16 minutes ago, Lscott said:

The antenna you mention in the title shows a "beam" tilt of zero degrees in the attached datasheet. I think you'll have to find another solution.

DB420-B.pdf 585.61 kB · 0 downloads

I have the same data sheet. What's the difference between "beam", which I assume is mechanical and electrical, which I am assuming is done with phasing. Did I misread the title on the data sheet?

Just to add, a zero degree tilt would be optimal in this situation. 

 

[Lscott]

2 hours ago, tcp2525 said:

I have the same data sheet. What's the difference between "beam", which I assume is mechanical and electrical, which I am assuming is done with phasing. Did I misread the title on the data sheet?

Just to add, a zero degree tilt would be optimal in this situation. 

 

I think it means about the same thing.

Yup, the tilt is done by altering the phasing of the elements a bit. I think it could be done by changing the length of the cable between the elements, or the element spacing, which likely will affect the match to some degree. Myself I wouldn't try messing with it. You need really good equipment to measure the field pattern and or simulation software to see the effects.

[tcp2525]

13 minutes ago, Lscott said:

I think it means about the same thing.

Yup, the tilt is done by altering the phasing of the elements a bit. I think it could be done by changing the length of the cable between the elements, or the element spacing, which likely will affect the match to some degree. Myself I wouldn't try messing with it. You need really good equipment to measure the field pattern and or simulation software to see the effects.

I think you answered my question. I definitely don't want to cut into the harness. This thing definitely has a certain degree of down tilt, which is killing performance to the south. My next question would be, do you have any recommendation for a good commercial antenna that doesn't have down tilt?

[Lscott]

You can look at the attached data sheets. The down tilt is spec’ed at zero I believe.

DB408-B Product specifications.pdf DB404-B Product Specifications.pdf

[tcp2525]

2 hours ago, Lscott said:

You can look at the attached data sheets. The down tilt is spec’ed at zero I believe.

DB408-B Product specifications.pdf 337.38 kB · 1 download DB404-B Product Specifications.pdf 350.34 kB · 0 downloads

Got it. I don't know how I missed that in the first place. Damn tunnel vision got me.