I just finished loading the GMRS channels into the radio and decided to do a bench test for swr. The cable that I used for the bench test was a Larsen NMOKHFCXMPL with a Laird trab4503 antenna. That's the pic with the 1.91 swr reading bench test inside. Go to the jeep and hook up the radio attached to a RFMAX, RNMOV-195-SUM-C-17I cable and used the pctel muf4505ngp antenna check the readings and get 6.86. Switch to a trab4500n antenna no ground plane needed and get 4.71. Take the radio out go back to the bench and repeat with original Larsen cable and 4503 that needs a ground plane again and get the same 1.91 reading.
Remove the rfmax cable from the jeep and replace with a Larsen cable same as the bench test above and repeat the process this time the swr with the 4505ngp is 1.01 and with the trab4500n different antenna from bench test I get 2.95. If I switch the trab4500n no ground plane for the trab4503 I get 1.45. The mount used is on the passenger side of the jeep 2nd bolt Topsy Jk mount.
I am confused with this so the question is how does a non ground plane antenna work worse and the ground plane antenna work the best? I was under the impression that the fender mounts did not have enough for a ground plane. Also the cable being that far off with swr I'm glade I did not try to cut the antenna. Has anyone else had this happen to them?
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aapaws
I just finished loading the GMRS channels into the radio and decided to do a bench test for swr. The cable that I used for the bench test was a Larsen NMOKHFCXMPL with a Laird trab4503 antenna. That's the pic with the 1.91 swr reading bench test inside. Go to the jeep and hook up the radio attached to a RFMAX, RNMOV-195-SUM-C-17I cable and used the pctel muf4505ngp antenna check the readings and get 6.86. Switch to a trab4500n antenna no ground plane needed and get 4.71. Take the radio out go back to the bench and repeat with original Larsen cable and 4503 that needs a ground plane again and get the same 1.91 reading.
Remove the rfmax cable from the jeep and replace with a Larsen cable same as the bench test above and repeat the process this time the swr with the 4505ngp is 1.01 and with the trab4500n different antenna from bench test I get 2.95. If I switch the trab4500n no ground plane for the trab4503 I get 1.45. The mount used is on the passenger side of the jeep 2nd bolt Topsy Jk mount.
I am confused with this so the question is how does a non ground plane antenna work worse and the ground plane antenna work the best? I was under the impression that the fender mounts did not have enough for a ground plane. Also the cable being that far off with swr I'm glade I did not try to cut the antenna. Has anyone else had this happen to them?
Thanks
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