Re: SWR cable or ant problem?

Ryan - KJ7GIE
 

Updates:
*All testing being done at 5W with a HT now as my ic-7100 is packed away until I get my shack back.

The replacement element arrived and that did drop SWR to 1.9/2.0 on 2m and 1.5/1.7 across 70cm. Not great yet. Testing continued.

Last night I had the antenna at the park and had some additional eyes on it* as well as using a different meter but same coax and radio for testing. This was also the first time I had tested it on the ground as recommended by Arrow. Results:
- Some frequencies were blowing past 3 SWR
- Antenna worked better with some height instead of sitting directly on the ground (thanks Howard for being brave enough to hold this thing above your head!)
- Howard identified that I had installed the base plate upside down. This caused the "lip" on the mast mounting side of the plate to sit above the radiating element instead of below. If you look at the install instructions on Arrow's website for the GP140/440 you'll find a visual of this plate. At this point, and without tools, we abandoned further testing.

This morning I corrected the base plate issue and rebuilt the antenna. I tested both outside in my wet grass on the ground and upstairs in a bedroom with the antenna sitting on a bed. The second story bed install gave me better results by ~.2 or so SWR:
144.1 1.5
145.5 1.4
147.5 1.4
426.0 1.5
432.5 1.0
439.0 1.1
446.5 2.2

This antenna is not rated for better than 1.5 SWR across the bands. So, in this configuration I'm now technically "within spec" except for the high side of 440. That really kind of sucks because that's right where the repeater is and so I'm losing half my 5W towards our repeater. I have another e-mail into Arrow and the story will continue.

*I just wanted to mention the value in having multiple eyes looking at the same problem. As humans we can get into a troubleshooting rut. It happens more often than we realize. That's when we miss the obvious... like you installed the thing upside down. If you're having an issue ask others to look at it. Somethings will be obvious to fresh eyes but you'll never see it after becoming "too invested" in trying to solve it on your own. Really glad I brought this thing to the park last night. Really glad Robin organized these get togethers. Really glad Howard was willing to keep at it and asked to see the instructions. And the others that have given advise along the way. Progress.. <high five> See everyone next week.

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