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Re: [TowerTalk] Beverage on Ground: 50 ohm or 75 ohm system?

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Beverage on Ground: 50 ohm or 75 ohm system?
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 24 Jan 2018 09:57:40 -0800
List-post: <mailto:towertalk@contesting.com>
On 1/24/2018 4:47 AM, Richard Thorne wrote:
I don't have room for traditional beverages.  Ground mounted receive loops like the K9AY array will not be a good solution as I have a large deer population that would end up tearing it down.  We had an 8 point buck with xmas lights hanging off his antlers so I don't think loops would survive

Over the years, we have had a lot of deer running around (although fewer now with growth of the mountain lion and coyote populations). My Beverages have been up for 11 years, with no apparent damage from deer. The only issues are limbs (and even a tree) falling on them, which typically pulls the wires out of the termination or feed boxes.

As I go through the design I'm trying to determine if I should use a 75 ohm system (the most common due to cheap rg-6 coax I suppose) or a 50 ohm system.

The difference doesn't matter for RX systems for the low bands. The only effect would be a fraction of a dB greater loss, and the loss would attenuate both signal and noise picked up on the antenna. We use RX antennas to separate desired signals from other noise picked up on the antenna, NOT from circuit noise in the receiver.

Most commercially built RX antenna products use F-connectors because both the connectors and the coax designed for CATV systems are inexpensive, and a particular variety of CATV coax designed for direct burial is commonly used because it's "flooded" with a sticky substance that self seals any breaks in the jacket, and because "varmints" tend not to like the taste of it.

73, Jim K9YC

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