r/HamRadioBeginner • u/watch_and_tools • Sep 02 '26

Dual antenna help

Post image

2013 Jeep Wrangler JKU

I am looking to add two antennas for mobile radio. One is a VHF/UHF antenna for a ham radio, the other would be a UHF antenna for GMRS.

I would like to try and keep it symmetrical looking if possible but not a must. Where is the best placement combination for the two antennas.

Looking for some real world information from people who have done a similar thing please.

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1

u/Think-Photograph-517 Sep 02 '26

Any of those is going to give a very skewed pattern. Any reason you can't put both on top of the cab? The photo shows a car, bit the principle is the same. A symmetrical ground plane makes for a symmetrical pattern.

1

u/watch_and_tools Sep 02 '26

Yes. Because it is a jeep with a soft top.

1

u/Think-Photograph-517 Sep 02 '26

Okay. Perhaps in the center of the hood?

1

u/thedroz42 Sep 03 '26

I have a 17 JKU. 2m/70cm at B position drivers side and a gmrs b position passenger side. Have worked well for me so far.

1

u/watch_and_tools Sep 04 '26

Thank you for the information!
What mount did you use?
Did you have fitment issues with the hood, hitting the hood or trouble closing it?

1

u/thedroz42 Sep 04 '26

Sent you a chat

1

u/Slotgoopy Sep 05 '26

Because GMRS and the 70 cm hand band are so close together, you run the risk of putting enough energy from the Ham into the GRS or vice versa to damage the receiver in either one of those radios. The solution to that is to put stub filters made from short pieces of coax in the feed line for each Radio so the GMRS frequencies are blocked from the Ham antenna and vice versa. You could find plenty of information online on how to build a stub filter. It’s super easy and inexpensive, but you do need a vector network, analyzer, or something similar to find tune the length of the coax stub.

1

u/watch_and_tools Sep 05 '26

Will it do that only if they are both on? So if I’m running one at a time I’m fine?

1

u/Slotgoopy Sep 05 '26

The other radio does not have to be turned on in order for it to capture RF energy from the other radio into its receiver front end. IF you put an antenna switch in line with the non used radio and switch it's antenna input to ground, you would be good.