[Lowfer] No luck with - JH

Sat Dec 1 20:16:50 EST 2012

Heck  John

I thought I was in a bad place under a hardwood canopy. From everything I read , I thought it was a lost cause. I seem to be doing OK , so my advise would be put up an antenna  and give it a try. I sure am having fun.

Pat

John Andrews <w1tag at charter.net> wrote:

>Pat,
>
>Just one additional thought - I wouldn't use 5 foot radials either! But 
>the issue for most of us is that our land doesn't scale with the 
>wavelengths we use. I could only dream about radials a couple hundred 
>feet long. Of course, that's part of the reason that I've stuck with 
>loops in all these nasty trees.
>
>John, W1TAG
>
>On 12/1/2012 4:31 PM, pbunn at patbunn.com wrote:
>> John,
>>
>> I agree that some of the test data is not scalable, but I do not agree
>> that radials should be limited to the height of the antenna (especially
>> if it is 5 feet high) nor do I agree that two radials is half as good as
>> many. If that were the case, I'd double my power and forget about it.
>>
>> I was trying to get the point across to John is that one 8' ground rod
>> and 4 -  5' rods will not be very effective. He needs some radials and
>> if he adds some he will improve his ERP. I certainly was not telling him
>> he needed 2000 foot length radials - "as long as you can make them" for
>> most people is a couple hundred feet.
>>
>>
>>
>> Pat Bunn
>> N4LTA
>>
>>
>>
>> -----Original Message----- From: John Andrews
>> Sent: Saturday, December 01, 2012 9:26 PM
>> To: Discussion of the Lowfer (US, European, &amp;UK) and MedFer bands
>> Subject: Re: [Lowfer] No luck with - JH
>>
>> Pat,
>>
>> Those articles were excellent. But I don't recall if they were aimed at
>> 5 foot verticals on 160 meters or 2.5 foot versions on 80 meters. That's
>> the kind of scaling that Garry was talking about. A 50 foot antenna at
>> actual LF (185 kHz) is going to be very inefficient with any practical
>> ground system for amateur/experimental use. His point was that you can
>> only go out just so far on typical house lots or small fields, and the
>> concept of diminishing returns seems to come into play.
>>
>> And since most of us have to put up with nearby houses, trees and
>> shrubs, ground wires are only going to help to a certain extent. I
>> really don't think that some of this can be modeled well at HF. For
>> example, "ground" is mostly resistive at 185 kHz, but has significant
>> dielectric properties at 3 MHz. Some of the older literature really
>> isn't all that useful - Laporte wrote mostly of large
>> commercial/government installations, and George Brown did most of his
>> work just below 80 meters.
>>
>> John, W1TAG
>>
>> On 12/1/2012 3:31 PM, pbunn at patbunn.com wrote:
>>> I would recommend reading the excellent QEX articles on radials  that
>>> were published over the last few years. They did extensive testing with
>>> short, long and skewed radials as well as elevated radials.
>>>
>>> Pat
>>> N4LTA
>>>
>>> -----Original Message----- From: Garry Hess
>>> Sent: Saturday, December 01, 2012 8:12 PM
>>> To: lowfer list
>>> Subject: Re: [Lowfer] No luck with - JH
>>>
>>>> Ground rods are not a substitute for radials. At lf,  they need to be
>>>> as long as you can make them
>>> and as many as you can afford.
>>>
>>> I beg to disagree. Page 3 of The Lowdown, July 1980 article by Ed
>>> Phillips (available for download at
>>> http://www.maxmcarter.com/lwantennas/index.html) cites the following
>>> conclusions of E.A.Laporte's 1952 study of ground systems:
>>>
>>> (1) "... radials of length equal to the antenna height are almost as
>>> good as those of infinite length, and that a length of half the antenna
>>> height (outside diameter of radial system equal to antenna height) is
>>> about 2/3 as effective as very great length."
>>>
>>> and
>>>
>>> (2) "... 2 radials are about half as good as a very large number, and 16
>>> radials are within a few percent of being as good as 112.
>>>
>>> Thus, one need not fear that thousands of feet of radials are necessary
>>> to produce a lowfer that can be heard out of the back yard. I'm quite
>>> happy with the performance of my lowfer vertical antenna of 35' height,
>>> 15' tophat, and 8 x 35' radials (4 of which are terminated by 4' ground
>>> rods; a pair of 8' ground rods are located at the antenna base).
>>>
>>>
>>>
>>>
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