A 1/4 wave vertical over perfect ground will have an impedance of 36 ohms. That
would be a roughly 1.3:1 SWR with 50 ohm feedline. Without radials, you will
have a complex impedance of real and imaginary resistance. As you add radials,
the imaginary component lessens in value, the real component gets closer to the
"perfect" impedance and the "Q" (for lack of a better term) of the antenna will
increase, decreasing its 2:1 SWR bandwidth as the imaginary component decreases
in value.
Do you have an analyzer? Are you sure the antennas peak resonance isn't
outside the band? What is the impedance (real, complex) at the antenna
feedpoint?
Al
AB2ZY
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of Test
Sent: Sunday, February 5, 2023 6:35 PM
To: towertalk@contesting.com
Cc: K7OGW@drirsh.com
Subject: [TowerTalk] More Radials = Higher SWR???
I recently erected my first Vertical (Hy-Gain AV-18HT) antenna and the more I
try improving it, the more confused I become.
I added the Hy-Gain MK-160A kit that converts the Vertical to an "L" antenna on
160M. For the first time in 50 years of Ham Radio, I was able to work EU
stations on 160M. WOW!!!!
I decided to start "Improving" and added my first 4 radials. There's a
rumor: "You gain and extra 6db of signal if you install antennas in the middle
of winter in a blizzard." NOT TRUE!!!! The SWR went up a little higher, but
still workable so I added 4 more. Now the SWR is over 2:1 on all of 160M and
is not usable for transmitting. I disconnected the last 4 radials from the
ground plate but left them in place and now the SWR is back to 1.6.
Grounding Issues? Maybe?
The ground here is very poor with MANY rocks and solid basalt 18 inch down.
8ft ground rods are not practical. Instead I have installed three 20ft
galvanized 1 1/2 inch pipe buried as deep as possible in 3 directions from the
base of the Vertical. Also I have 500 ft #2 solid tinned ground wire bonding
all antennas, towers, Vertical, Power entrance point and all devices in shack.
I'm located on an 800 ft cliff above Lake Coeur d' Alene in North Idaho and we
get lots of lightning strikes but that's another story...
All radials are evenly spaced and 65ft long.
I'm not sure if I can included attachments of the comparison SWR Graphs so I'll
also describe the comparisons:
The colors refer to the attachment if present. The shift in resonates is
explainable: The antenna wire was slightly lengthened.
Below are the minimum SWR on 160M taken at the base of the Vertical.. All
other bands were just slightly affected .
No Radials= 1.2 SWR (Fuchsia)
4 Radials = 1.6 SWR (Red)
8 radials = 2.2 SWR Green)
Any comments would be greatly appreciated!
73 es gud DX
Dennis - K7OGW
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of
towertalk-request@contesting.com
Sent: Sunday, February 5, 2023 9:00 AM
To: towertalk@contesting.com
Subject: TowerTalk Digest, Vol 242, Issue 4
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Today's Topics:
1. Re: Tower mounted capture device (bill steffey ny9h)
----------------------------------------------------------------------
Message: 1
Date: Sat, 4 Feb 2023 20:40:55 -0500
From: bill steffey ny9h <ny9h@comcast.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Tower mounted capture device
Message-ID: <6a703ed4-f398-e76b-9f14-2f91731e2b11@comcast.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
the Tempest installed here will eventually trip the "lower the tower"
circuit for both lightning and windspeed.
Mine is mounted at the second topmost section... ?? 40-50 feet up . ? ?
An old anemometer is mounted at the top and works with a Heliotrack
programmable wind alarm switch. ?? The Tempest lightning sensor is very widely
adjustable.
Tempest will talk to any smart device.... which will throw your switches.
bill
On 1/31/2023 3:28 PM, Jim Miller wrote:
> Google weather flow tempest.
>
> Wireless. Solar powered. No moving parts.
>
> Jim ab3cv
>
> On Tue, Jan 31, 2023 at 3:04 PM Richard Karlquist
> <richard@karlquist.com>
> wrote:
>
>> The only sensor you need up on the tower is an anemometer. since wind
>> speed varies with HAAT. Get a wired (not wireless) one to avoid
>> having batteries at the unit. Leave the WX station on the ground for
>> the
other
>> readings, including ground wind speed. You would want that in addition
>> to wind speed at the top of the tower.
>>
>> Hazers are very fussy things that you should avoid if at all possible.
>>
>> --
>>
>> Rick Karlquist
>> N6RK
>>
>> On 2023-01-31 08:21, Rick Harrington N0VT wrote:
>>
>>> I would like to have the sensing unit of my home weather station
>>> near
>> the top of my tower (80'). But instead of a fixed installation, I'd
>> like to be able to raise/lower it via rope & pulley for battery
>> changes, cleaning etc. There would have to be a way at the top of
>> the tower to dock it into the same north/south orientation each time.
>> (I'm thinking of some sort of small hazer-like contraption.)
>>> Has anyone ever done this, or seen info on doing it?
>>>
>>> 73,
>>>
>>> Rick N0VT
>> _______________________________________________
>>
>>
>>
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