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Author Topic: FT-817 puzzling SWR  (Read 1384 times)
VE3VVF
Member

Posts: 48




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« on: April 09, 2017, 05:12:58 AM »

Hi there,
I have 2 inverted V dipoles fed with COAX each with 2 sets of wires giving me 4 bands between them.  On the 4 bands I used a Keysight Fieldfox to measure SWR and the actual tuned frequency of the antennas as follows:
7.04 mHz - 1.5:1
10.100 mHz - 1.3:1
14.06 mHz - 1.9:1
18.08 mHz - 2:1

This is the best I can get with trimming the wires. With TX set to 5W:

When connected to my FT-817 the 40M band is fine...no SWR bars.
When connected to my FT-817 the 30M band I get 2 bars of SWR.
When connected to my FT-817 the 20M band I get  2 SWR bars.
When connected to my FT-817 the 17M band I get 2 SWR bars.

I would have thought that no SWR bars at 1.5:1 would mean no SWR bars at 1.3:1.  Some days the bars are more but it is a windy location and sometimes the antennas are being jostled about. Should I be worried about these SWR bars or take solace in the fact that I know the SWR readings are generally acceptable from the Fieldfox?  Should I pop a tuner in line...I'd rather not introduce additional loss especially when I am at 1W.

Thoughts?
Thanks,
Scott ve3vvf
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W9IQ
Member

Posts: 1707




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« Reply #1 on: April 09, 2017, 06:02:24 AM »

The SWR meter in the 817 is so coarse and non-linear that it is not worth worrying about if you have accurately determined the SWR through other means.

- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
VE3VVF
Member

Posts: 48




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« Reply #2 on: April 09, 2017, 07:17:56 AM »

Thanks Glen
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