Best Answer Corey , 14 March 2019 - 07:20 PM
Hello, I am in a bit of a pickle today. I am getting what I believe to be sub-par simplex performance with my new GMRS mobile radios. Though, I may just be at the limit of the service. I am hoping someone may have a recommendation or some information for me.
I have 2 trucks that I put Midland MXT400's in. I am using the Midland 6 DB gain antenna. Both antenna's are hard mounted to the windshield cowl, about 8 inches forward of the windshield and vertical. The antenna base on one truck is 60 inches off the ground and the other antenna base is 54 inches off the ground.
I have a UHF SWR/Watt meter. Both vehicles are reading about 1.1:1-1.2:1 and there is zero reflective energy on either setup.
With both radios, I can successfully talk to repeaters 20+ miles away and they sound great. On simplex, in as straight of a line as I can get on any road around here, I can only talk about 2.5 miles with 5 watts scale (3.7 measured). When I bump the power to the 40 watts scale (35 measured), I don't pick up any more than 25 to 30 yards of more range.
I tried buying a couple of magnetic mount antenna bases and put both antenna's in the center of each vehicles roof and gain zero performance. I also saw about the same forward and ref energy reading as well as SWR.
I am a HAM and on 440 (70cm), on a 5 watt hand held, I am getting about 7 miles on a 5 DB gain antenna. With my 2m/440 setup in my car, I get about 17 miles on 440 simplex with 35 watts. I am having a hard time believing that the small jump from 440's to 460's is crippling my simplex performance. Especially since I am able to use repeaters 20+ miles away.
Any suggestions? Is this what I should expect out of this part of the UHF band or am I overlooking something? I feel like I am probably making a simple mistake and I am just missing it.
Thanks in advance for any help.
The MXT400 is narrow band and overall is not a great performer. I get 10 solid miles simplex on the highway using a Motorola XPR 5550 and a 1/4 wave thru mounted in the roof of a 2015 GMC pickup. The MTX400 and others in the lineup have been discussed in the equipment review section of this site.
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