Topband: Ground loss query (re inverted L, antenna radiation resistance, & Jerry Sevick)

[ZR]

A very effective on ground radial system is the 2x4" mesh fencing that is 
welded, then hot dip galvanized and then dipped in plastic. Cover as much of 
the backyard as possible, cover with 1/2 to 1" of loam and wait for the 
grass to grow thru it. Mow high until it is completely hidden.
Certainly it is not as good as a full system or elevated radials but it wont 
boil as many worms as a handful of random length wires.

Carl
KM1H



----- Original Message ----- 
From: "Guy Olinger K2AV" <olinger at bellsouth.net>
To: <herbs at vitelcom.net>
Cc: <topband at contesting.com>
Sent: Wednesday, October 19, 2011 10:27 PM
Subject: Re: Topband: Ground loss query (re inverted L, antenna radiation 
resistance, & Jerry Sevick)


> This IS true for some hams, because their counterpoise situation is quite
> lossy. It would definitely not be true over a commercial dense radial 
> system
> that was in good repair.  It's very easy to measure by starting with a 
> dense
> radial system and removing radials between subsequent measurements.  I've
> done some of that myself.
>
> It becomes critical for a ham if their circumstances will not allow an
> efficient radial system.  Then the name of the game becomes doing anything
> that will reduce ground losses, which would include somehow avoiding a 
> high
> current feed when the ground/counterpoise connection is unavoidably lossy.
>
> The issue in the commercial controversy referred to, for me at least, 
> would
> be accurately quantifying the "quality" of a radial system to come up with 
> a
> sufficiently questionable field.  How do you do that?
>
> 73, Guy.
>
> On Wed, Oct 19, 2011 at 7:50 PM, Herb Schoenbohm <herbs at vitelcom.net> 
> wrote:
>
>> On 10/19/2011 2:28 PM, shristov wrote:
>> >
>> >
>> > Folding has nothing to do with either radiation resistance or ground
>> losses.
>> > It is impedance-transforming device only.
>> >
>> > You've just performed 1:4 impedance transformation, nothing else.
>> >
>> > 73,
>> >
>> > Sinisa  YT1NT, VE3EA
>> Sinisa,  A well known broadcast consulting antenna group Mullany and
>> Associates made a detailed NAB presentation in the 60's on why a folded
>> unipole and a cage feed made significant improvements for stations with
>> questionable ground systems. They presented  FSM reading with and
>> without to prove their point.  From that point on it became sort of an
>> urban legend.  Other studies have discounted the claim completely. The
>> acid test by du Treil, Lundin, & Rankin out of Sarasota, FL, was
>> ungrounding and directly feeding a tower and hooking the cage to the
>> feed point and getting exactly the same FSM reading at 1 mile with when
>> the cage was fed unipole style! Their findings were presented at the
>> 1996 NAB Broadcast Engineering Conference.  The original Mulany papers
>> in the early 60's suggested that by raising the feed point impedance
>> less current was flowing in the ground system thus improving the overall
>> efficiency.  Many hams still believe that is still true.  Thanks for
>> the  clarification.  But the legend continues to have legs.
>>
>>
>> Herb Schoenbohm, KV4FZ
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
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