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KB9YOJ

Joined: Wed, Dec 20th 2000, 00:00 Roles: N/A Moderates: N/A

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Topic Created Posts Views Last Activity
RF Ground question Oct 6th 2015, 17:21 5 1,362 on 7/10/15
RS/RST in contests May 15th 2015, 19:56 4 4,138 on 5/7/15

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Topic Author Posted On
RF Ground question KB9YOJ on 7/10/15
Good point. I guess I based my question on the fact that I will be using an unbalanced feedline to a phased vertical array. I'll try it with the choke at the feedpoint and see how she fares without the counterpoise.
RF Ground question KB9YOJ on 6/10/15
Thank you Zack for the references. I skimmed the article http://rudys.typepad.com/ant/files/antenna_halfsquare_array.pdf and reviewed the section about current fed half squares. The 'phasing element" will be around 25' to 30' off the ground with the vertical elements hanging down from the corners. This arrangement should exhibit lower ground losses making it easier to use a current choke on the coaxial feedline. Plus, my station is only 100W anyway. And, I can always lay copper on the ground to increase the antenna efficiency(floating counterpoise) and lower the "Earth losses" if needed.

Not looking to make a ground plane as the Half-square doesn't need a radial field. I am inquiring about an RF counterpoise in the shack. Is this even needed for my proposed antenna system (transceiver, ATU, and antenna)?

Matt
KB9YOJ

160 Loop SIZE358 on 6/10/15
I'd say stick with the 4:1 for now. You may need to shorten the loop a bit but 3.5 to 1 is not too bad with a resonant loop for 160. Another option is to switch to a 1:1 balun and feed it with balanced feed-line and use an external tuner. You'll make up some efficiency lost to the coax and you also will be able to tune it on all bands. MFJ makes some very affordable external tuners. Just something to think about for the future.
160 Loop SIZE358 on 6/10/15
Are you feeding the loop with coax or balanced feedline?
RF Ground question KB9YOJ on 6/10/15
Hello-

I am going to be building a Half-square antenna for 20 meters and feeding it in a corner with RG-8x and a bead-balun(choke). The antenna will be hung between my chimney on the house and a tree, suspended by pulleys and counter-weights. My question is regarding an RF ground system.

My shack will be located on the second floor of my house and all system equipment will be DC grounded to a single point for safety. Regarding the RF ground, should I place a screen underneath my carpet, or should I run a quarter-wave radial for (20 meters) along the baseboard? How large does the screen have to be? Should the radial/screen terminate on the station ground buss or extend from my antenna tuner?

Matt
KB9YOJ

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