I built a repeater out of (2) Retevis RA87 40W Mobile Radios

[WSHF963]

I built a repeater out of (2) Retevis RA87 40W Mobile Radios, Duplexer, and GMRS Fiberglass Base Antenna on my house. I should be able to hit it with my HT or my 50W Mobile in the truck. 
 

For some reason it’s only picking up in less than 0.50 miles of the house. Ground elevation is 4870 Feet mount on roof maybe 17-20 feet above ground. What could my issue be? 

[OffRoaderX]

Desense...
There is more to a repeater than just duck-taping two radios together.

[Socalgmrs]

32 minutes ago, WSHF963 said:

I built a repeater out of (2) Retevis RA87 40W Mobile Radios, Duplexer, and GMRS Fiberglass Base Antenna on my house. I should be able to hit it with my HT or my 50W Mobile in the truck. 
 

For some reason it’s only picking up in less than 0.50 miles of the house. Ground elevation is 4870 Feet mount on roof maybe 17-20 feet above ground. What could my issue be? 

I just can’t…… tuning, type of coax, antenna, programming…. Retivis radios….. so much could be wrong here.  

[Jaay]

I agree with OFX, Desense is a BIG problem when using a Single antenna and/or the the duplexer not being tuned.