antenna SWR

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DAL-COM
Posts: 213
Joined: Sat Jan 25, 2003 10:03 pm

antenna SWR

Post by DAL-COM »

While working on the previously mentioned VHF MTR2000, I checked forward and reflected power in the antenna feedline. It was 72W forward and 8W reflected which I calculated to mean an SWR of 2:1. This seems excessive to me, what do you Batlabbers think?
I did not have time to climb the tower to look at the antenna or feedline unfortunately.
"depending on your point of view, either the changing magnetic flux makes the electric field, or the changing electric flux makes the magnetic field- but you can't have one without the other"
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Will
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Post by Will »

That is more like 1.5 to 1 SWR and not too bad. What kind and age are the antenna, feedline, and any jumpers or adaptors???? Oh, some antennas are affected by the way they are mounted. That can cause eronious and or high SWR readings.
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RKG
Posts: 2629
Joined: Mon Dec 10, 2001 4:00 pm

Post by RKG »

According to the program I use (from Celwave):

72W up and 8W down equals 11.11% reflected.

11.11% reflected equals VSWR of 1.999:1 or a return loss of 9.54 dB.

Yes, in my judgment that is excessive. Moreover, it may signal a degrading condition that will get worse with time.
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Will
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Post by Will »

Opps, I guess that my batteries must have been low, yep..more like 1.99 to 1..
Looks like a job for the AEA or Anritsu.
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