[600MRG] more antenna musings

[patrick hamel]

JIM,
My best working 600 meter antenna had an inverted-L or bedspring antenna. The top loading fit where I could get it. 
I made the lucky mistake of asking a fellow-ham to bring me some wire from a hamfest. He came back with partial 6000 foot spools of # 20 wire.
I made up twisted pairs and ran 11 of them between spreaders on about 120 foot spaced 50 foot trees.
The inverted - L is considered loading when it starts going horizontal, so EIRP do your calculations on the vertical section only.
Further reading caused me to get 10 wires laid out for the vertical radiator, but cold weather and a lack of round spacers led me to twist them into a 3/4 inch diameter radiator instead of the six-inch cage I had planned. It worked for 10 years, and will go back up when I finish shovelling out stuff at the next few hamfests. However, to keep from wasting power heating the tree sap, keep the vertical portion away from the trees.
73,
Pat W5THT & WD2XSH/6

----- Original Message -----
From: "J Mcvey" <ac2eu at yahoo.com>
To: "600MRG" <600mrg at w7ekb.com>
Sent: Friday, October 27, 2017 9:13:50 AM
Subject: [600MRG] more antenna musings

I took a look at the LF antenna book onn 500KC.com.The only design that I would consider is the "flat top vertical" due to it's relative simplicity and size.If I read it correctly, the graph seems to say that a 60 degree length ( 1/6 lamda) can yield a radiation resistance of 10 ohms. The only problem with that is ; 60 degrees is a whopping 344 feet!
I don't have a tower, but I do have 75-100 ft trees and may be able to accommodate a 250-300 ft "run".
Has anyone tried a "inverted L" design? It works surprisingly well on 160M when used with a good ground.
Jim AC2EU



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