Unity Ground plane for GMRS repeater

[linboogy]

Hello
I currently have a GMRS repeater. I have a Laird 7 DB gain antenna mounted at 50 feet. The coverage is very spoty. I have been advised that I need a lower or "unity" DB gain antenna because we are at such a hill terrain area. I am wondering if anyone is familiar DB201
Its a Unity gain ground plane antenna.
So basically I am wanting to confirm it is ok for duplex operation as my current antenna is DC ground?
Thanks!

 

[NDRADIONUT]

Your current antenna is better than the db201....

 

[linboogy]

Your current antenna is better than the db201....

Are you referring to unity or ground plane that makes this a poor choice?

 

[NDRADIONUT]

A ground plane sends more of the signal up in the sky than the design of the laird...

 

[mmckenna]

Hello
I currently have a GMRS repeater. I have a Laird 7 DB gain antenna mounted at 50 feet. The coverage is very spoty. I have been advised that I need a lower or "unity" DB gain antenna because we are at such a hill terrain area. I am wondering if anyone is familiar DB201
Its a Unity gain ground plane antenna.
So basically I am wanting to confirm it is ok for duplex operation as my current antenna is DC ground?
Thanks!

7dB isn't a lot of gain for a base antenna. I'd doubt you'd see an improvement from a 0dB ground plane antenna like that.
If I was in your shoes I'd be looking at other possible causes. Mistuned diplexer, damaged antenna, damaged coaxial cable, wet cable, etc.

I've been in Cincinatti a few times and I'm sort of familiar with the terrain. I know it's pretty hilly. Depending on exactly where your antenna is mounted may be a big issue. Unless it's on top of one of the hills, you are not going to see much coverage.

Before spending money on a new antenna, I'd suggest getting someone with the right tools to check out your antenna system. Having that done will give you an idea where the issue is.

 

[Project25_MASTR]

Also a Los coverage plot should give you a decent idea of what you can expect to see out of the repeater to help confirm other issues within the system.


Sent from my iPhone using Tapatalk

 

[prcguy]

You should not have a problem unless you get higher than maybe 1,000 above average terrain with a 10dBd gain antenna according to some of the big antenna companies and even then its usually not a problem. I've had many 10dBd gain sticks on 5,000ft mountains and you can only notice degradation up close to the base of the mountain.

Check the specs on your antenna to see if its rated in dBd, dBi or some made up number. Going to the ground plane will put you backwards at any level.
prcguy

 

[SCPD]

Feedline

I'd start with the suggestions that McKenna gave.
If the coax is more than 10-15 years old, start with running new. Even if it looks OK.
A good ham swaps his coax out every 10 years. So should any radio system.

 

[linboogy]

It's the antenna. Thank you all for the replies. I am also have been considering a db404 or 408