Antenna

[Drewster]

Hello! I'm in the process of my first roof (chimney) mount antenna.  As far as brand I'm leaning towards comet per positive feedback I've noticed. 

I am in a somewhat heavily wooded area, dB gain is where I'm still learning. I'll be able to mount up around 40-50 feet or so in total but no chance of outreaching  all the trees. I was thinking a 6 dB would be my best route?

Still learning and open to any feedback. Thank you in advance!  

[Socalgmrs]

30 minutes ago, Drewster said:

Hello! I'm in the process of my first roof (chimney) mount antenna.  As far as brand I'm leaning towards comet per positive feedback I've noticed. 

I am in a somewhat heavily wooded area, dB gain is where I'm still learning. I'll be able to mount up around 40-50 feet or so in total but no chance of outreaching  all the trees. I was thinking a 6 dB would be my best route?

Still learning and open to any feedback. Thank you in advance!  

Comet 712efc is the best for the money antenna we have found in our club.    200miles from a 20w radio is what I get from my 712 and it’s only 30’ off the ground. Don’t forget the Lmr400 

[BoxCar]

The coax used is as important as the antenna. The signal going through coax is always reduced by a constant amount. The amount of loss depends on the coax itself and is expressed as a loss measured in dB per 100 meters. Choosing low-loss coax such as the Times Microwave LMR 400 or LMR 600 improves the amount of power reaching the antenna. When you subtract the coax loss from the antenna gain (if any) you can then calculate the amount of radiated power. Your transmitter is limited, by regulation, to a maximum of 50W of power but there is no regulation on the amount of power radiated from your antenna.

[Drewster]

I am running LMR 400 @ 40 FT and 45 watts. just wasn't sure if the higher db would send upward enough to help my dense tree problem. 

[Socalgmrs]

8 minutes ago, Drewster said:

I am running LMR 400 @ 40 FT and 45 watts. just wasn't sure if the higher db would send upward enough to help my dense tree problem. 

Line of sight is the only thing that will help tree problems. And more power through the teees many or many not help.  If you send all you rf up it will never come back down 

[Borage257]

If you are in a mostly flat area higher gain antennas are pretty good. If you are in a hilly or mountainous area, lower gain antennas may be better.

[WRUW493]

Right on the higher vs lower in the above post.

Further, at heights of "merely" 40-50ft in a wooded area, you will do better with a lower gain that is higher elevation than a higher gain lower elevation. Getting above the trees is paramount if you can do so. Feedline losses are important too as previously mentioned. Another thought, IMHO, never, never, never, did I say never, use 9913 coax unless you are certain how to seal it from the weather. Any amount of water inside that stupid coax will kill the performance in a heart beat.

Hope this helps.

[Drewster]

I appreciate all of your feedback on this! its good fuel for my brain right now. 

 

should have new antenna and setup this week sometime. I'm going to stretch up as far as I can. 

 

Again , thank you all!