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Chimney mounted vertical antenna grounding

Mar 6th, 09:05

KinSea

Joined: Apr 24th 2021, 07:45
Total Topics: 0
Total Posts: 0
Antenna: Cushcraft r5

I tuned the antenna without the ground wire attached, getting all SWR readings within tolerances for each ban. I want to use the Yaesu FTDX10 built in automatic tuner.

My problem is that in order to ground the antenna I have to use a rather long ground #8 copper ground - about 25’. This, of course increases the SWR well beyond the required 3:1 max. I installed a grounded lightning protection device at the point where the coax enters the house and shack located on the second floor. This is grounded to the service house ground rod. I’ve done a bit of research, but can’t find any work arounds to solve the issue.

Can anyone give me pointers on how to solve the issue?

Thanks
Mar 7th, 05:39

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
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https://forums.qrz.com/index.php?threads/cushcraft-r5-vertical-ground-mounted.330858/page-2
This page discusses the mounting of Cushcraft half wave verticals.
Mar 7th, 09:51

KinSea

Joined: Apr 24th 2021, 07:45
Total Topics: 0
Total Posts: 0
Thank you so much for the help. The link gives me a bit more insight. So, my understanding after reading thru the comments is that I can get by just grounding the mast to the service connection - don't have to carry the ground to the antenna itself above the matching box. The shielding ground is grounded through the lightning arrestor since it has an earth ground. The radials attached to the insulator and matching network act pretty much as the antenna ground.

Sorry to be so dense - still trying to learn about a somewhat complicated subject.
Mar 7th, 10:50

KinSea

Joined: Apr 24th 2021, 07:45
Total Topics: 0
Total Posts: 0
Oh, and I notice the shielding is grounded through the bottom bracket of the box attached to the mast below the insulator.
Mar 7th, 12:11

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Yes, half wave verticals are different in that you can't ground directly to either the antenna element or elevated radials. They need to float above ground.
Mar 14th, 21:35

K0WUQ

Joined: Dec 3rd 2012, 11:13
Total Topics: 0
Total Posts: 0
KinSea,

Here's something I remember that I have no idea whether it will be helpful or not, but I thought at the time (1960s) that it was a neat and logical design detail.

I purchased a 40M vertical, Hy-Gain brand, I think. At the bottom end it had a big plastic mounting that brought the aluminum antenna and the mast together in such a way that a small lightning gap was formed between them. I don't remember how that was adjustable, but it seemed logical because it gave lightning a short, straight path to ground (assuming the mast was fully grounded, of course). One property of lightning is that it will try to take the straightest low-impedance path - one reason you should never have short, elbow-like bends in your grounding wire.

Probably an 'old hat' idea, but maybe something you haven't seen before if you're new to working with verticals.

Larry K0WUQ

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