Antenna Question

[WSAH786]

Greetings oh wise ones,

First basic information: I have recently installed a repeater to my attic due to HOA restrictions and am trying to make it the best I can, given the limitations and budget. The equipment being used at the moment is a BridgeCom BCR-40U. Originally, I was running it at a full 40-watt output but after some testing, I turned it back to 25 watts with no evident fall off that I can tell, in range (5-6 miles), or quality so why run it at maximum. There is a 50-foot run of LMR-400 up three stories to an Ed Fong GMRS antenna in the attic which resides 38 ft up. I live in area with gentle hills that has subtle changes of elevation of roughly 20 feet with only a couple of spots dropping 50-75 feet for the cutout that the interstate runs through. 

I've been reading through many threads here on the subject and quite frankly my head's starting to hurt. I've been trying to understand the difference between low and high gain omni antennas having doughnut or pancake patterns. Then there's DBi vs Dbd (don't get me started trying to understand that when comparing). As mentioned, I'm currently using a Ed Fong which I've seen advertised at different gain numbers. Not sure if it is considered high or low.  My understanding that since UHF is line of sight, that low gain (doughnut pattern) is better for higher mounting application while a high gain (pancake pattern) might miss users close to the antenna. But since there are many homes and trees in my area and my antenna is in the confines of an attic at only 38 feet, might I gain coverage with a high gain and not lose local users close to me? Or would it even make enough difference for the investment. My expectations were met with the current setup, but I might splurge for a better antenna. I mean the distance to horizon at 38 feet of height is about 7.5-8 miles. There still are trees and buildings. Sounds like I'm talking myself out of it. Just want to make sure it's not due to ignorance. 

[OffRoaderX]

Assuming nothing is wrong with your current antenna, it is doubtful you will hear/notice much difference with a different antenna - and the kicker is that no-matter what anybody here says, no matter how many formulas they post, and now matter how many licenses they brag about having, the ONLY way to know for sure if it would make a difference is to buy the new antenna and try it.

Stop over-thinking it and just use the damn thing.

[OffRoaderX]

31 minutes ago, WRXP381 said:

I’d move out of the hoa and ditch the ed fungus

Just when I think I've seen the most UN-helpful post ever, you come along and up the ante.

[WRYZ926]

I have to agree that the only way to know is to try a different antenna. You can try a different antenna if you want to or stick with what you have if it is meeting your needs. You are already using a good repeater and good coax.

The Comet CA712EFC is an excellent antenna. The CA-712EFC has 9dBi of gain which will be more of a pancake radiation pattern. That being said. I run my CA-712EFC with the base at 20 foot above ground and have no issues with RX or TX with people close to me. A couple of friends are also running the CA-712EFC. One is at 40 foot and the other at 60 foot. Neither one has issues with radios that are close to their antennas.

To keep things simple when it comes to dBi versus dBm, just subtract 2.15 from the dBi value. So for an antenna with 9 dBi of gain that equals 6.85 dBm of gain.

 

[WSAH786]

5 hours ago, OffRoaderX said:

the ONLY way to know for sure if it would make a difference is to buy the new antenna and try it.

Stop over-thinking it and just use the damn thing.

I appreciate the honest words. My repeater really does meet my expectations and maybe in the future I will try something else. I was just trying to wrap my head around the tech talk on antennas. 

And that other guy (WRXP381) was kind of like an unhinged liberal insulting my situation and choices. 

 

[WSAH786]

Thanks, WRYZ926 for your concise answers and with what both, you and Randy's responses are along what I was thinking, but it's nice to hear it from seasoned veterans of the GMRS community. Also, thanks for your suggestions on antenna types. It gives me food for thought going forward. I may try one in the future just to see where things go. I'll enjoy allowing my repeater to service the local airport industrial airpark which it has good coverage as well as the I95 and I295 corridor if even for only a few miles here in Virgina. It's what I had expected.

Thanks guys.

[OffRoaderX]

9 minutes ago, WSAH786 said:

(WRXP381) was kind of like an unhinged liberal insulting my situation and choices. 

no, he's just a social-retard and is incapable of expressing himself in a socially-acceptable way with other people.

[WRQC527]

20 minutes ago, WSAH786 said:

And that other guy (WRXP381) was kind of like an unhinged liberal insulting my situation and choices. 

He is the poster child, a classic use case, as it were, for the Ignore User feature of this site. I suggest placing him on your list.

[WSAH786]

Ok, I really appreciate all the information above and have looked into the Comet CA712EFC. Unfortunately, the length of this antenna has exceeded the height of my attic as I only have roughly 9 1/2 feet of head space and it appears the Comet needs about 10 1/2 feet of height. I have noticed that the Tram 1486 seems to be popular as well and is with in my constraints. Is there any input someone would like to share about this antenna's performance or lack of? 

 

Thanks in advance, Mark

[WRXP381]

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